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GM Animal Feed Safety Papers (abstracts)Compiled by Wayne Parrot
Abstract: A genetically modified Bt176 corn hybrid, which contains an insecticidal protein against the European corn borer, and its conventional, nonmodified counterpart were evaluated in 4 separate trials to verify substantial equivalence in feeding value and animal performance. Thirty-six individually kept laying hens and 3 replicates of 94 broiler chickens each, assigned to 12 cages, were fed 2 different hen and broiler diets containing either 60% conventional or 60% Bt176 corn. The nutrient compositions of the 2 corn hybrids and the 2 corn diets revealed no major differences. Furthermore, metabolism and performance data revealed no significant differences between the birds that received the conventional, nonmodified corn, and those that received the modified corn diets. The detection of the genetic modification, by PCR, in feed obtained from insect-resistant Bt corn, in tissues and products from animals fed Bt corn is described. In all evaluated chicken tissues of muscle, liver, and spleen, the corn-chloroplast ivr gene fragment was amplified. It can be deduced from these findings and from other studies that the transfer of DNA fragments into the body is a normal process that takes place constantly. Nevertheless, no recombinant plant DNA fragments such as recombinant bla or cry1A(b) fragments could be found. Bt-gene specific constructs from the Bt corn were not detected in any of the poultry samples, neither in organs, meat, nor eggs.
Abstract: The stability of transgenic DNA encoding the synthetic cp4 epsps protein in a diet containing Roundup Ready (RR)® canola meal was determined in duodenal fluid (DF) batch cultures from sheep. A real-time TaqMan® PCR assay was designed to quantify the degradation of cp4 epsps DNA during incubation in DF at pH 5 or 7. The copy number of cp4 epsps DNA in the diet declined more rapidly (P < 0.05) in DF at pH 5 as compared to pH 7. The decrease was attributed mainly to microbial activity at pH 7 and perhaps to plant endogenous enzymes at pH 5. The 62-bp fragment of cp4 epsps DNA detected by real-time PCR reached a maximum of approximately 1600 copies in the aqueous phase of DF at pH 7, whereas less than 20 copies were detected during incubations in DF at pH 5. A 1363-bp sequence of cp4 epsps DNA was never detected in the aqueous fraction of DF. Additionally, genomic DNA isolated from RR® canola seed was used to test the persistence of fragments of free DNA in DF at pH 3.2, 5, and 7, as well as in ruminal fluid and feces. Primers spanning the cp4 epsps DNA coding region amplified sequences ranging in size from 300 to 1363 bp. Free transgenic DNA was least stable in DF at pH 7 where fragments less than 527 bp were detected for up to 2 min and fragments as large as 1363 bp were detected for 0.5 min. This study shows that digestion of plant material and release of transgenic DNA can occur in the ovine small intestine. However, free DNA is rapidly degraded at neutral pH in DF, thus reducing the likelihood that intact transgenic DNA would be available for absorption through the Peyer's Patches in the distal ileum.
Abstract: A study was conducted to determine the extent of genetically modified (GM) protein from Roundup Ready Soybeans in tissues and eggs of laying hens. Because a breakdown of the modified portion of protein was expected due to the digestive process of the hen, an immunoassay test was run. By using a double antibody sandwich format specific for the CP4 EPSPS protein, a qualitative test was performed to determine the presence of modified proteins in various samples. Raw soybeans, soybean meal, complete diet, whole egg, egg albumen, liver, and feces from laying hens were collected from two independent commercial egg producers. Roundup Ready soybeans, soybean meal, and complete diets ere determined to contain the GM proteins. Whole egg, egg albumen, liver, and feces were all negative for GM protein. In conclusion, the digestive process of the laying hen effectively broke down the GM protein from the soybean meal portion of the diet, hence no modified protein was found in the liver, egg; or feces in this brief field trial.
Abstract: Investigates the substantial equivalence of a transgenic Bacillus thuringiensis (Bt) corn and nontransgenic hybrid Cesar and a nutrition psychology for poultry, pigs and ruminants. Details of experiments conducted on corn, laying hens, broilers, pigs and ruminants; Overview on the cultivation of transgenic plants; Information on the concept of substantial equivalence.
Abstract: A genetically modified Bt176 corn hybrid (Rh208Bt)-providing control of European corn borer damage-and the conventional isogenic hybrid (Rh208)-harvested as whole plant silage-were evaluated in three separate feeding trials to verify that the in vivo feeding value was substantially equivalent among modified and conventional hybrids. In the first trial, after a week of preexperiment, two sets of six Texel sheep, housed in digestibility crates, were fed silage sources of Rh208 and Rh208Bt; hybrids, and silage of three additional control varieties of low, intermediate, and high feeding value (Rh289, Adonis, and Adonis bm3) for 1 wk. Feed offered to sheep was adjusted to maintenance requirements based on metabolic body weight. Agronomic and biochemical traits were similar among the Rh208 and Rh208Bt; hybrids. Organic matter digestibility (67.1 and 67.6%), crude fiber digestibility (52.9 and 54.2%), and neutral detergent fiber digestibility (50.2 and 49.0%) were not significantly different among Rh208 and Rh208Bt hybrids. In the second trial, two sets of 24 Holstein cows were fed silage from Rh208 and Rh208Bt corn hybrids for 13 wk, 9 wk after calving, and including 2 wk of preexperiment. Fat-corrected milk yield (31.3 and 31.4 kg/d), protein content (31.7 and 31.6 g/kg) and fat content (36.7 and 37.0 g/kg) in milk of dairy cows were unaffected by hybrid source. Body weight gains of cattle were not different. However, intake was significantly higher in cows fed Rh208Bt silage. In the third trial, five midlactation multiparous Holstein cows were successively fed the silage from Rh208 and Rh208Bt corn hybrids 2 or 3 wk. Data were considered only for the last week of each period. There were no significant effects on protein fractions, fatty acid composition, or coagulation properties of milk between Rh208 and Rh208Bt fed cattle. Cattle and sheep can perform equally well with a conventional or a genetically modified Bt176 corn silage
Abstract: To analyse substantial equivalence of genetically modified sugar-beets and maize, in which the glufosinate-tolerant (Pat) gene is inserted, crude nutrients, the amino acid and the fatty acid profiles as well as the composition of the NDF-fraction of maize grains were determined and compared with those of the corresponding non-transgenic cultivars. Due to the genetic manipulation differences in crude nutrient contents including sugar and starch were not detected, The amino acid profile of maize grains was analysed to be the same, Fatty acid profile and composition of cell wall constituents did not show any influences as well. Digestibility of Pat-sugar-beets and maize grains for pigs did not demonstrate meaningful differences as compared to the corresponding non-transgenic cultivars. Digestibility of sugar-beet roots and sugar-beet top silage for ruminants proved to be also in the scope of natural variance. As the digestibility of the macro nutrients remained unaffected, the Pat-gene introduction into both crops did not show an influence on the energetic feeding value. For pigs the ME-content of Pat-sugar-beets was determined to be 14.1 MJ/kg DM versus 13.7 MJ of the non-transgenic cultivars. ME-content of Pat-maize grains was 16.0 MJ/kg DM versus 15.8 MJ for controls. For ruminants the feeding value of Pat-sugar-beets was found to be 8.5 MJ NEL/kg DM or 13.2 MJ ME/kg DM, regardless of whether the Pat-gene was inserted or not. The corresponding energy values of sugar-beet top silage ranged between 5.2 and 5.5 MJ NEL/kg DM or 8.6 and 9.1 MJ ME/kg DM, with differences considered in the biological range
Abstract: The health safety of Bt (Bacillus thuringiensis) corn (Zea mays L.) was studied using mouse testes as a sensitive biomonitor of potential toxic effects. Pregnant mice were fed a Bt corn or a nontransgenic (conventional) diet during gestation and lactation. After they were weaned, young male mice were maintained on the respective diets. At 8, 16, 26, 32, 63, and 87 days after birth, three male mice and an adult reference mouse were killed, the testes were surgically removed, and the percentage of germ cell populations was measured by flow cytometry. Multigenerational studies were conducted in the same manner. There were no apparent differences in percentages of testicular cell populations (haploid, diploid, and tetraploid) between the mice fed the Bt corn diet and those fed the conventional diet. Because of the high rate of cell proliferation and extensive differentiation that makes testicular germ cells highly susceptible to some toxic agents, it was concluded that the Bt corn diet had no measurable or observable effect on fetal, postnatal, pubertal, or adult testicular development. If data from this study were extrapolated to humans, Bt corn is not harmful to human reproductive development.
Abstract: A 38-d feeding study evaluated whether standard broiler diets prepared with transgenic Event 176-derived "Bt" corn (maize) grain had any adverse effects on male or female broiler chickens as compared to diets prepared with nontransgenic (isogenic) control corn grain. No statistically significant differences in survival or BW were observed bet ia een birds reared on mash or pelleted diets prepared with transgenic corn and similar diets prepared using control corn. Broilers raised on diets prepared from the transgenic corn exhibited significantly better feed conversion ratios and improved yield of the Pectoralis minor breast muscle. Although it is not clear whether this enhanced performance was attributable to the transgenic corn per se, or due to possible slight differences in overall composition of the formulated diets, it was clear that the transgenic corn had no deleterious effects in this study
Abstract: A feeding study evaluated whether standard broiler diets prepared with grain derived from Syngenta Seeds NK Brand Bacillus thuringiensis (Bt) Corn hybrids had any adverse effects on male or female broiler chickens. Four kinds of corn grain were used in this study: (1) grain from the Bt-expressing field corn hybrid N7070Bt, (2) grain from the N7070Bt hybrid that had been sprayed with Liberty brand herbicide (glufosinate) according to manufacturer's instructions (N7070Bt + Liberty), (3) grain from standard N7070 (non-Bt isoline of N7070Bt) grain, and (4) a lot of North Carolina grown grain from the 2000 growing season (NC2000). The amino acid balance for the four lots of corn was similar relative to their crude protein content; however, the NC2000 corn had higher protein content. Diets with the higher protein NC2000 season corn were amended with a combination of sand, ground cardboard (Solka Floc), and poultry fat so that the metabolizable energy and crude protein content of the diluted diets would be similar to that of the isoline and transgenic diets. Growth of broilers was excellent with males being significantly heavier than females (2,497 g vs. 2,103 g) at 42 d of age. BW of live birds at 42 d was within 26 g for the three treatment groups fed corn that was from the same genetic background, i.e., the two Bt transgenic groups (N7070Bt, N7070Bt + Liberty), and the non-Bt N7070 isoline corn group, while BW for the NC2000 group was significantly lower by 93 g. There was no overall corn source effect on feed conversion ratio (FCR) among the isoline and transgenic corn sources to 42 d of age, but FCR was poorer for broilers consuming the commercial NC2000 corn. There was no overall effect of corn source on survivability to 42 d. Carcass analysis at 48 d demonstrated no differences in percentage carcass yield due to corn source among males and females. The transgenic N7070Bt and N7070Bt + Liberty hybrid diets supported excellent broiler chicken growth with mortality and FCR that were similar to that supported by the N7070 isoline control and better than rates from the commercial NC2000 corn without significant differences among treatment groups in carcass yield. It was clear that the transgenic corn had no deleterious or unintended effects on production traits of broiler chickens in this study
Abstract: A 49-d feeding study evaluated whether standard broiler diets prepared with Syngenta Seeds VIP3A transgenic derived corn grain had any unanticipated adverse effects on male or female broiler chickens as compared with diets prepared with nontransgenic (isoline) control corn grain. Two commercial lots of grain grown in North Carolina during the 1999 (NC 1999) and 2000 (NC 2000) seasons were included for reference purposes. Broiler growth was excellent with males reaching 3,466 g and females reaching 2,882 g at 49 d of age. Final BW of the VlP3A, isoline, and NC 1999 corn groups were within 21.1 g, whereas the NC 2000 group was 42.4 g lower than the lowest of this group. There was no overall corn source effect on adjusted feed conversion ratio (FCR) or mortality to 49 d of age. Carcass analysis demonstrated no differences in percentage yield due to corn source among males and females other than percentage wings in females. Comprehensive clinical chemical analyses of blood taken from representative birds at 49 d of age showed no differences due to corn sources. The transgenic VIP3A hybrid diets numerically supported the most rapid broiler chicken growth, the second lowest mortality rate and best FCR, without practical differences in carcass yield. The few differences found in this study were not unique to a given corn source but instead appeared to be distributed equally across the diet groups evaluated in the study. Although it was not clear whether small differences in performance were attributable to the transgenic corn per se or were due to possible slight differences in overall composition of the formulated diets, it was clear that the transgenic corn had no deleterious effects on broiler performance and carcass yield in this study.
Abstract: Silage from a genetically modified potato expressing the 1-SST (sucurose:sucrose 1-fructosyltransferase) and the l-FFT (fructan:fructan 1-fructosyltransferase) was used in a feeding experiment with pigs. After a feeding period of 42 days samples from various organs and digesta were collected and investigated with four different real time PCR systems, in order to identify the fate of the foreign DNA. No plant specific DNA or DNA specific for the genome alteration in the transgenic potato were detected in any organ. In contrast, chloroplast specific DNA was detected in the digesta of duodenum, jejunum, colon and rectum. The single-copy metallo-carboxypeptidase inhibitor gene sequence was detected only in samples from the stomach content of pigs fed the isogenic potato and in those from duodenum and jejunum of animals fed the transgenic one. No evidence for the integration of the foreign DNA into the host genome was observed.
Abstract: Studies on genetically modified (GM) feedstuffs, for poultry (and other livestock species) have not added any substance to public concerns in Europe about their safety for human or bird health. The compositions of maize lines engineered for insect resistance (Bt-maize) or herbicide tolerance (glyphosate) and herbicide-tolerant soybean have all proved to be essentially indistinguishable from their conventional counterparts. Consequently, and not surprisingly, comparative feeding studies with broilers and layers in which conventional maize (50 to 78%) or soybeans (27%) were replaced in feeds by transgenic varieties, also have failed to show differences of any significance in production parameters. These data indicate that feeding studies with target livestock species contribute very little to the safety assessment of crops engineered for input traits that have little or no detectable effect on chemical composition. However, comparative growth studies made with broiler chicks, particularly sensitive to any change in nutrient supply or the presence of toxic elements in their feed, can be used to screen for any unintended adverse consequence of the recombinant event not detected by compositional analysis. This does, however, depend on whether the GM plant can be matched to a parental line or another suitable control and its suitability for inclusion in broiler diets. The discovery that DNA fragments from the digestive tract can be found in the tissues of animals evoked interest in the fate of ingested transgenes. Plant DNA derived from feed has been detected in the muscle, liver, spleen and kidneys of broilers and layers, although not in eggs. However, no fragments of transgenic DNA or its expressed protein have been found to date in poultry meat or eggs or in any other animal tissues examined
Abstract: Sixteen multiparous Holstein cows averaging 74 d in milk were used in a replicated 4 x 4 Latin square to compare the effects on animal performance of feeding whole plant silage and grain from a glyphosate-tolerant corn hybrid (event NK603), a nontransgenic control hybrid, and two commercial nontransgenic hybrids (DK647 and RX740). The grain and silage from the four corn hybrids were produced using the same procedures and under similar agronomic conditions at the University of Illinois. On a dry matter (DM) basis, diets contained 30% corn silage and 27.34% corn grain produced either from event NK603, a nontransgenic control, or commercial hybrids. Apart from the DM content of silages, the chemical composition of both grain and silage produced from the four corn hybrids were substantially equivalent. Feeding diets that contained event NK603 and DK647 hybrids tended to decrease DM intake (DMI) compared with the control nontransgenic and RX740. The intakes of crude protein (CP), acid and neutral detergent fiber, and nonfiber carbohydrates were not different for cows fed event NK603 and control diets. The RX740 diet resulted in the highest intakes of fiber and CP, whereas the DK647 diet resulted in the lowest intake of CP. These differences in nutrient intake arose from small variations in both the DMI and the chemical composition of feed ingredients and experimental diets. Production of milk and 3.5% fat-corrected milk; milk fat, CP, and true protein percentage and yield; milk urea N; milk total solids percentage and yield; and somatic cell count were not affected by treatments. These data indicate that the stable insertion of the gene that confers tolerance to glyphosate (event NK603) in the corn line used in this experiment does not affect its chemical composition and nutritional value for lactating dairy cows when compared with conventional corn.
Abstract: Presents a study that determined the composition and nutritional value of conventional and transgenic maize with an introduced gene of glyphosate resistance that was fed to rats. Background on genetically modified crops; Details on the chemical analysis performed; Implications of the results.
Abstract: Die Verfütterung gentechnisch veränderter Pflanzen oder von Teilen dieser Pflanzen und die anschließende Nutzung der tierischen Produkte werfen mannigfaltige Fragen auf. Die Diskussion hierüber wird bislang ähnlich dem Lebensmittelbereich weitgehend auf emotionaler Ebene geführt.
Abstract: Lactating dairy cows were used to determine effects of feeding glyphosate-tolerant or insect-protected corn hybrids on feed intake, milk production, milk composition, and ruminal digestibility. Corn resistant to European corn borer (Ostrinia nubilalis) infestation (Bt-MON810), or its nontransgenic control (Bt-CON), were planted in alternating fields, during two successive years. One-half of each strip was harvested for whole plant corn silage and the remainder was allowed to mature and harvested as grain. Effects of feeding diets containing either Bt-MON810 or Bt-CON grain and silage were determined in two experiments (1 and 2) conducted during successive years. In experiment 3, glyphosate-tolerant Roundup Ready corn (RR-GA21) or its nontransgenic control (RR-CON) corn were grown in alternating fields during one cropping season. Diets contained 42 to 60% corn silage and 20 to 34% corn grain from Bt-MON810, RR-GA21, or the appropriate nontransgenic counterpart; treatments were applied using a switchback design. Cows were fed ad libitum and milked twice daily. There were no differences for nutrient composition between silage sources or between grain sources within an experiment. Data for experiments 1 and 2 indicated similar dry matter intake (DMI), 4% fat-corrected milk (FCM) production, and milk composition between Bt-MON810 and Bt-CON diets. There were no differences for DMI, 4% FCM production, and milk composition between RR-GA21 and RR-CON diets. There was no difference in ruminal degradability, determined separately for corn silage and corn grain, for RR-GA21 or Bt-MON810-hybrids compared with their respective controls. These data demonstrate equivalence of nutritional value and production efficiency for corn containing Bt-MON810 compared with its control and for RR-GA21 corn compared with its control
Abstract: The aim of this study was to trace selected nucleic acid and protein components of isogene versus Bt transgene maize within the bovine gastrointestinal tract (GIT). After feeding 22 cattle for 4 weeks with Bt176 maize, different plant genes and the recombinant protein CryIAb were quantified during digestion. Furthermore, a first initial characterization of rumen bacteria was approached, using 16rDNA gene sequencing comparing isogene- against transgene-fed animals. Ingesta samples of different GIT sections (rumen, abomasum, jejunum, colon) were analysed for chloroplast, maize invertase, zein and Bt toxin (CryIAb) gene fragments using quantitative real-time PCR. First, the initial gene dose of these maize genes was detected in maize silage. During digestion, a significant reduction of high-to-medium abundant plant gene fragments was shown depending on the dwell-time and the initial gene copy number. Immunoreactive CryIAb protein was quantified by ELISA in intestinal samples indicating a significant loss of that protein. Remarkable amounts of Bt toxin were found in all contents of the GIT and the protein was still present in faeces. For the first time, the influence of CryIAb transgene maize on rumen bacterial microflora was investigated compared to isogene material through analysis of 497 individual bacterial 16S rDNA sequences. In principle, specific bacterial leader-species could be identified in all bovine rumen extracts, but no significant influence of Bt176 maize feed was found on the composition of the microbial population. This investigation provides supplementing data to further evaluate the fate of novel recombinant material originating from transgene feed or food within the mammalian GIT
Abstract: Diets containing genetically modified (GM) potatoes expressing the lectin Galanthus nivalis agglutinin (GNA) had variable effects on different parts of the rat gastrointestinal tract. Some effects, such as the proliferation of the gastric mucosa, were mainly due to the expression of the GNA transgene. However, other parts of the construct or the genetic transformation (or both) could also have contributed to the overall biological effects of the GNA-GM potatoes, particularly on the small intestine and caecum.
Abstract: The range and stability of expression of the transgenic CryIA(b) protein was examined in Ciba Seeds Bt maize plants derived from Event 176. Specifically, CryIA(b) levels were determined for: (1) various plant tissues and developmental stages in three maize lines from 1993 field tests; (2) pollen and leaves from plants representing four backcross generations of two genotypes; (3) leaves of 6 precommercial hybrids; and (4) silage from one Bt maize hybrid. Significant levels were found only in pollen and leaves. Genetic background did not greatly impact the level seen in either tissue. CryIA(b) expression in maize plants derived from transformation Event 176 was stable over at least four successive generations. On a per acre basis, the highest amount of CryIA(b) protein (estimated to be 2-4 g CryIA(b) protein/acre) was found to occur at anthesis, consistent with the stage at which maximum plant vegetative biomass is reached. CryIA(b) was not detected in silage prepared from CryIA(b)-expressing plants. The maize-expressed CryIA(6) protein was found to have the expected size and to be immunoreactive with antibodies prepared against crystals from Bacillus thuringiensis subsp. kurstaki
Abstract: This study assessed the nutritional and biological value of a noncommercial, transgenic line of the Australian sweet lupin, Lupinus angustifolius, (cv. Warrah), produced to increase the methionine content of the seed. An initial experiment demonstrated that differences in the methionine content of the transgenic and nontransgenic control lupins had no apparent influence on the growth of juvenile red seabream fed practical diets. Re-evaluation of the nutritional characteristics of the lupin meals with subsequent digestibility studies allowed the determination of the digestible value of the protein and energy content of each of the varieties. The digestible protein content of either variety was similar, however significant differences in the digestible energy value of each variety existed (56.3% cf. 64.0%). This re-evaluation of the nutritional value of the genetically manipulated (GM) and non-GM lupin varieties enabled the reformulation of diets on a digestible protein and energy basis. A second growth trial was undertaken using sub-satietal pair-feeding regimes, with the experiment also involving protein-restrictive diets to allow expression of the differences in the methionine content of the transgenic and nontransgenic lupin meals. A significant benefit of the enhanced methionine level in the transgenic lupin was observed. It is argued that in the high-protein fish diets used, the importance of amino acid composition is relatively limited. Economic modelling of the potential value of the increased methionine in the transgenic lupin suggests that this will have limited benefit for aquaculture industries, and that greater value would be attributable to higher protein and energy levels in ingredients
Abstract: Two studies were conducted to evaluate the effect of a glyphosate-tolerant (event nk603) and a corn rootworm protected (event MON863) corn hybrid on feed intake and milk production compared with the nontransgenic hybrid and two reference hybrids. In Experiment 1, 16 multiparous Holstein cows were assigned to one of four treatments in replicated 4 x 4 Latin squares with 28-d periods. Diets contained 40% (dry matter [DM] basis) of either 1) glyphosate-tolerant corn silage (GT), 2) nontransgenic control corn silage, or 3) two nontransgenic reference hybrids which are commercially available. Each diet also contained 23% corn grain from the same hybrid that supplied the silage. At ensiling, rapid drying conditions prevailed and the GT hybrid was the last to be harvested which resulted in greater DM content at similar physiological maturity. The 4% fat-corrected milk (FCM) yield and DMI were reduced for cows fed the GT corn diet due to the higher DM content of the GT silage (37.1 vs. 33.2 kg/d and 4.05 vs. 3.61% of BW, respectively). There was no effect of the GT diet on milk composition or efficiency of 4% FCM production that averaged 1.43 kg/kg of DM intake for all diets. In Experiment 2, 16 multiparous Holstein cows were assigned to one of four treatments in replicated 4 x 4 Latin squares with 21-d periods. Diets contained 26.7% (DM basis) corn grain from either 1) corn rootworm protected (event MON863) corn hybrid, 2) nontransgenic control corn hybrid, or 3) the same two nongenetically enhanced reference hybrids used in Experiment 1. The 4% FCM yield (34.8 kg/d) and DM intake (4.06% of BW) were unaffected by diet. Efficiency of FCM production (average 1.32 kg/kg of DMI) was not affected by diet. In summary, these two studies indicated that insertion of a gene for glyphosate tolerance or corn rootworm protection into a corn hybrid did not affect its nutritional value (as measured by efficiency of milk production) for lactating dairy cows compared with conventional corn hybrids.
Abstract: Roundup Ready (RR) genetically modified (GM) corn and soybean comprise a large portion of the annual planted acreage of GM crops. Plant growth and subsequent plant decomposition introduce the recombinant DNA (rDNA) into the soil environment, where its fate has not been completely researched. Little is known of the temporal and spatial distribution of plant-derived rDNA in the soil environment and in situ transport of plant DNA by leachate water has not been studied before. The objectives of this study were to determine whether sufficient quantities of plant rDNA were released by roots during growth and early decomposition to be detected in water collected after percolating through a soil profile and to determine the influence of temperature on DNA persistence in the leachate water. Individual plants of RR corn and RR soybean were grown in modified cylinders in a growth room, and the cylinders were flushed with rain water weekly. Immediately after collection, the leachate was subjected to DNA purification followed by rDNA quantification using real-time Polymerase Chain Reaction (PCR) analysis. To test the effects of temperature on plant DNA persistence in leachate water, water samples were spiked with known quantities of RR soybean or RR corn genomic DNA and DNA persistence was examined at 5, 15, and 25 C. Differences in the amounts and temporal distributions of root-derived rDNA were observed between corn and soybean plants. The results suggest that rainfall events may distribute plant DNA throughout the soil and into leachate water. Half-lives of plant DNA in leachate water ranged from 1.2 to 26.7 h, and persistence was greater at colder temperatures (5 and 15 C).
Abstract: Bollgard II cotton event 15985 producing the Cry1Ac and Cry2Ab2 proteins has been developed by genetic modification to broaden the spectrum of insects to which the plant is tolerant and to provide an insect resistance management tool to impede the onset of resistance. The purpose of this study was to evaluate the composition and nutrition of Bollgard II cotton, relative to the use for food and animal feed, compared to that of conventional cotton varieties. Compositional analyses were conducted to measure proximate, fiber, amino acid, fatty acid, gossypol, and mineral contents of cottonseed from a total of 14 U.S. field sites over two years. Compositional analysis results showed that the cottonseed and cottonseed oil from Bollgard II cotton were comparable in their composition to those of the conventional control cotton line and other commercial varieties. The composition data are supported by nutritional safety studies conducted with dairy cows, catfish, and quail. Results from these studies showed that Bollgard II performed similarly to the conventional control cotton varieties. These data demonstrate that Bollgard II cotton is compositionally and nutritionally equivalent to conventional cotton varieties. These data support the conclusion that Bollgard II cotton is as safe and nutritious as conventional cotton for food and feed use.
Abstract: The present paper represents a part of a major scientific effort aiming to reveal possible effects, nutritional or health related, of genetically modified (GM) feed ingredients for Atlantic salmon. For 3 months groups of post-smolt Atlantic salmon were treated with diets holding 130 g kg(1) of the protein as soybean, one which contained 800 g kg(-1) GM type RR (Roundup Ready((TM))), and compared with a standard counterpart (commercial hybrid, not isogenic line) analysed to be non-GM (nGM), and again compared with a standard fishmeal diet without soybean protein. All diets were composed to be within the category 'compositional equivalent' and held exactly the same proximate compositions, starch and sugar levels, above requirements for methionine and lysine, equal fatty acid profiles, vitamin, mineral and pigment contents. There was, however, a slight difference in levels of anti-nutrients between the three diets. The various dietary treatments resulted in more than tripling of fish weight in all groups. In addition no significant differences in feed utilization, whole body, liver and muscle proximate compositions, and no significant differences in muscle fatty acid profiles were measured. The diet without soybean of either type resulted in greater retention of lipid, but equal retention of protein (protein productive value). The relative sizes of liver, kidney, head-kidney and brain were the same in all dietary groups, while the relative size of the spleen showed significant differences between fish fed the genetically modified soy diet compared with fish fed the nGM soybeans. Fish fed the soy diets of either type also showed a somewhat reduced mean erythrocyte cell volume. All other haematological values were equal between diet groups. The detoxification system, measured as glutathione peroxidase (GPx) and lysozyme activities, showed equal values for all groups when measured in plasma and liver or head-kidney. The distal part of the intestine showed reduced sizes as an effect of soybean additions, without any differences between the GM and nGM type. Our results showed high growth, no mortality, haematological values within normal ranges, and efficient and equal responses in the detoxification system. This was a first indication that up to 130 g kg(-1) RR-soybean protein can safely be used in diets for Atlantic salmon. However, there is still a need to elucidate higher inclusion levels of GM feed ingredients, and why spleen index was reduced, and if this was a long- or short-term effect.
Abstract: Two studies were conducted at two locations to evaluate growth performance and carcass characteristics of growing-finishing pigs fed diets containing either glyphosate-tolerant Roundup Ready (event nk603) corn, a nontransgenic genetically similar control corn (RX670), or two conventional sources of nontransgenic corn (RX740 and DK647). A randomized complete block design (three and four blocks in Studies 1 and 2, respectively) with a 2 x 4 factorial arrangement of treatments (two genders and four corn lines) was used. Study 1 used 72 barrows and 72 gilts (housed in single-gender groups of six; six pens per dietary treatment) with initial and final BW of approximately 22 and 116 kg, respectively. Study 2 used 80 barrows and 80 gilts (housed in single-gender groups of five; eight pens per dietary treatment) with initial and final BW of approximately 30 and 120 kg, respectively. Pigs were housed in a modified open-front building in Study 1 and in an environmentally controlled finishing building in Study 2. The test corns were included at a fixed proportion of the diet in both studies. Animals had ad libitum access to feed and water. Pigs were slaughtered using standard procedures and carcass measurements were taken. In Study 1, overall ADG, ADFI (as-fed basis), and gain:feed (G:F) were not affected (P > 0.05) by corn line. In Study 2, there was no effect of corn line on overall ADFI (as-fed basis) or GY ratio. In addition, overall ADG of barrows fed the four corn lines did not differ (P > 0.05); however, overall ADG of gilts fed corn DK647 was greater (P < 0.05) than that of pigs fed the other corn lines. There was no effect (P > 0.05) of corn line on carcass yield or fatness measurements in either study. Differences between barrows and gilts for growth and carcass traits were generally similar for both studies and in line with previous research. Overall, these results indicate that Roundup Ready corn (NK603) gives equivalent animal performance to conventional corn for growing pigs.
Abstract: Sixteen multiparous Holstein cows averaging 74 d in milk were used in a replicated 4 x 4 Latin square to compare the effects on animal performance of feeding whole plant silage and grain from a glyphosate-tolerant corn hybrid (event NK603), a nontransgenic control hybrid, and two commercial nontransgenic hybrids (DK647 and RX740). The grain and silage from the four corn hybrids were produced using the same procedures and under similar agronomic conditions at the University of Illinois. On a dry matter (DM) basis, diets contained 30% corn silage and 27.34% corn grain produced either from event NK603, a nontransgenic control, or commercial hybrids. Apart from the DM content of silages, the chemical composition of both grain and silage produced from the four corn hybrids were substantially equivalent. Feeding diets that contained event NK603 and DK647 hybrids tended to decrease DM intake (DMI) compared with the control nontransgenic and RX740. The intakes of crude protein (CP), acid and neutral detergent fiber, and nonfiber carbohydrates were not different for cows fed event NK603 and control diets. The RX740 diet resulted in the highest intakes of fiber and CP, whereas the DK647 diet resulted in the lowest intake of CP. These differences in nutrient intake arose from small variations in both the DMI and the chemical composition of feed ingredients and experimental diets. Production of milk and 3.5% fat-corrected milk; milk fat, CP, and true protein percentage and yield; milk urea N; milk total solids percentage and yield; and somatic cell count were not affected by treatments. These data indicate that the stable insertion of the gene that confers tolerance to glyphosate (event NK603) in the corn line used in this experiment does not affect its chemical composition and nutritional value for lactating dairy cows when compared with conventional corn.
Abstract: Questions regarding the digestive fate of DNA and protein from transgenic, feed have been raised in regard to human consumption and commercial trade of animal products (e.g., meat, milk, and eggs) from farm animals fed transgenic crops. Using highly sensitive, well-characterized analytical methods, pork loin samples were analyzed for the presence. of fragments of transgenic and endogenous. plant DNA and transgenic protein from, animals fed meal prepared from conventional or glyphosate-tolerant Roundup Ready (RR) soybeans. Pigs were fed diets containing 24, 19, and 14%, RR or conventional soybean meal during grower, early-finisher, and late-finisher phases of growth, respectively, and longissimus muscle samples were collected (12 per treatment) after slaughter. Total DNA was extracted from the samples and analyzed by PCR, followed by Southern blot hybridization for the presence of a 272-bp fragment of the cp4 epsps coding region (encoding the synthetic enzyme 5-enolpyruvylshikimate-3-phosphate synthase derived from Agrobacterium sp. strain CP4) and a 198-bp fragment of the endogenous soybean gene le1 (encoding soy lectin). Using 1 mug of input DNA per reaction, none of the extracted samples was positive for cp4 epsps or le1 at the limit of detection (LOD) for these PCR/Southern blot assays. The LOD for these assays was shown to be approximately one diploid genome equivalent of RR soybean DNA, even in the presence of 10 mug of pork genomic DNA. A 185-bp fragment of the porcine preprolactin (prl) gene, used as a positive control, was. amplified from all samples showing that the DNA preparations were amenable to PCR amplification. Using a competitive immunoassay with an LOD of approximately 94 ng of CP4 EPSPS protein/g of pork muscle, neither the CP4 EPSPS protein nor the immunoreactive peptide fragments were detected in loin muscle homogenates from pigs fed RR soybean meal. Taken together, these results show that neither small fragments of transgenic DNA nor immunoreactive fragments of transgenic protein are detectable in loin muscle samples from pigs fed a diet containing RR soybean meal.
Abstract: The fate of transgenic DNA in products derived from farm animals fed genetically modified feed was assessed. Sensitive methods were developed to analyze milk for the presence of transgenic and plant DNA from cows fed a diet containing conventional or transgenic cottonseed or maize. Genomic DNA was extracted from milk and analyzed by PCR followed by Southern blot for fragments of the cry1Ac transgene and an endogenous cotton gene, acp1, from cows fed a diet containing whole cottonseed. Additionally, milk, liver, kidney, and spleen were assessed for fragments of the cry1Ab transgene and an endogenous maize gene, sh2, from animals fed a diet containing maize grain. No sample was positive for transgenic or plant DNA fragments at the limits of detection for the assays following detailed data evaluation criteria. Results for sh2 analyses of milk were, however, indeterminate. A fragment of a bovine gene, prl, was amplified from each DNA extract to show that all preparations were amenable to PCR. These results indicate that DNA, whether derived from conventional or transgenic feed, is not present at detectable levels in bovine milk or organs.
Abstract: There have been inconsistent reports that maize (Zea mays L.) hybrids with the Bacillus thuringiensis (Bt) cry1 Ab transgene contain more lignin than non-Bt hybrids of similar genetic background. Our objective was to evaluate the impact of the cry1 Ab transgene on lignin concentration (using three different assays), yield, and forage quality traits of maize. Replicated trials were conducted at four locations in Minnesota with 12 commercial hybrids (three MON810 and three Bt11 cry1 Ab transgene event hybrids, and respective near-isogenic controls). Whole plants and the fourth elongated, above-ground internodes were harvested at silage maturity. Samples were analyzed for crude protein, starch, neutral detergent fiber (NDF), acid detergent fiber, 24- and 96-h in vitro ruminal NDF digestibility, and lignin (acid detergent, Klason, and acetyl bromide). European corn borers (Ostrinia nubilalis Hubner) were not controlled and damage was limited to the non-Bt hybrids, averaging 1.5 internodes plant(-1) with tunnels. Environment and environment x hybrid interactions affected all measures of maize performance and quality, but comparisons of non-Bt/Bt hybrid pairs, for both whole plants and internodes, found no consistent differences in yield, nutrient content, in vitro ruminal NDF digestibility, or lignin concentration. Differences in lignin concentration were infrequent, small in magnitude, and inconsistent between a few non-Bt/Bt hybrid pairs at individual locations. Two non-Bt/Bt hybrid pairs did not differ in lignin concentration at any location. Contrary to some earlier reports, presence of the cry1 Ab transgene did not alter lignin concentration or other forage quality traits of maize stover in commercial maize hybrids.
Abstract: The composition of the fruits of non-transgenic or transgenic (GM) cucumbers with genes coding the synthesis of a sweet protein, thaumatin, were compared and effects of feeding the fruits in balanced diets to rats were determined. The transgenic cucumbers contained more protein (20.3 vs 17.9% DM) and less fibre (9.4 vs 11.4% DM) and also had lower Na, K, Ca and Mg contents and higher levels of Fe and Cu in ash than normal cucumbers. Feeding male rats of initial body weight 150 g for 5 weeks on isoprotein diets containing 0 or 15% lyophilized transgenic or non-transgenic cucumbers did not affect weight gain, apparent health status, or relative organ weights of animals. Protein digestibility was slightly but significantly lower (89.2 vs 90.0%), that of crude fibre was higher (28.2 vs 15.0%) in diets containing transgenic than non-transgenic cucumbers, while digestibility of fat and N-free extractives did not differ
Abstract: In a 4-week experiment, growing rats were fed diets containing 30% transgenic potatoes with overexpression of PI4-3-3 protein, non-transgenic dehydrated potato tubers of the same variety (Desiree), or a control diet. The activity of dehydroepiandrosterone (DHEA) as well as increases in the concentrations of NO3- ions, Fe and Zn in the liver of rats fed diets containing transgenic potatoes were observed. The reaction might be related to oxidative stress linked to the altered chemical composition of potato tubers resulting from transgenesis, changed concentrations of some minerals or biologically active substances.
Abstract: Immunoblotting assays using commercial antibodies were established to investigate the unexpected persistence of the immunoactive Cry1Ab protein in the bovine gastrointestinal tract (GIT) previously suggested by enzyme-linked immunosorbent assay (ELISA). Samples of two different feeding experiments in cattle were analyzed with both ELISA and immunoblotting methods. Whereas results obtained by ELISA suggested that the concentration of the Cry1Ab protein increased during the GIT passage, the immunoblotting assays revealed a significant degradation of the protein in the bovine GIT. Samples showing a positive signal in the ELISA consisted of fragmented Cry1Ab protein of approximately 17 and 34 kDa size. Two independent sets of gastrointestinal samples revealed the apparent discrepancy between the results obtained by ELISA and immunoblotting, suggesting that the antibody used in the ELISA reacts with fragmented yet immunoactive epitopes of the Cry1Ab protein. It was concluded that Cry1Ab protein is degraded during digestion in cattle. To avoid misinterpretation, samples tested positive for Cry1Ab protein by ELISA should be reassessed by another technique.
Abstract: No direct evidence that genetically modified (GM) food may represent a possible danger for health has been reported so far; however, the scientific literature in this field is quite poor. Therefore, we investigated the possible effects of a diet containing GM soybean on mouse exocrine pancreas by means of ultrastructural, morphometrical and immunocytochemical analyses. Our observations demonstrate that, although no structural modification occurs in pancreatic acinar cells of mice fed on GM soybean, quantitative changes of some cellular constituents take place in comparison to control animals. In particular, a diet containing significant amount of GM food seems to influence the zymogen synthesis and processing.
Abstract: No direct evidence that genetically modified (GM) food may represent a possible danger for health has been reported so far; however, the scientific literature in this field is still quite poor. Therefore, we carried out an ultrastructural morphometrical and immunocytochemical study on hepatocytes from mice fed on GM soybean, in order to investigate eventual modifications of nuclear components of these cells involved in multiple metabolic pathways related to food processing. Our observations demonstrate significant modifications of some nuclear features in GM-fed mice. In particular, GM fed-mice show irregularly shaped nuclei, which generally represents an index of high metabolic rate, and a higher number of nuclear pores, suggestive of intense molecular trafficking. Moreover, the roundish nucleoli of control animals change in more irregular nucleoli with numerous small fibrillar centres and abundant dense fibrillar component in GM-fed mice, modifications typical of increased metabolic rate. Accordingly, nucleoplasmic (snRNPs and SC-35) and nucleolar (fibrillarin) splicing factors are more abundant in hepatocyte nuclei of GM-fed than in control mice. In conclusion, our data suggest that GM soybean intake can influence hepatocyte nuclear features in young and adult mice; however, the mechanisms responsible for such alterations remain unknown.
Abstract: We carried out ultrastructural morphometrical and immunocytochemical analyses on pancreatic acinar cell nuclei from mice fed on genetically modified (GM) soybean, in order to investigate possible structural and molecular modifications of nucleoplasmic and nucleolar constituents. We found a significant lowering of nucleoplasmic and nucleolar splicing factors as well as a perichromatin granule accumulation in GM-fed mice, suggestive of reduced post-transcriptional hnRNA processing and/or nuclear export. This is in accordance to already described zymogen synthesis and processing modifications in the same animals.
Abstract: An optimized DNA extraction protocol for animal tissues coupled with sensitive PCR methods was used to determine whether trace levels of feed-derived DNA fragments, plant and/or transgenic, are detectable in animal tissue samples including dairy milk and samples of muscle (meat) from chickens, swine, and beef steers. Assays were developed to detect DNA fragments of both the high copy number chloroplast-encoded maize rubisco gene (rbcL) and single copy nuclear-encoded transgenic elements (p35S and a MON 810-specific gene fragment). The specificities of the two rbcL PCR assays and two transgenic DNA PCR assays were established by testing against a range of conventional plant species and genetically modified maize crops. The sensitivities of the two rbcL PCR assays (resulting in 173 and 500 bp amplicons) were similar, detecting as little as 0.08 and 0.02 genomic equivalents, respectively. The sensitivities of the p35S and MON 810 PCR assays were approximately 5 and 10 genomic equivalents for 123 bp and 149 bp amplicons, respectively, which were considerably less than the sensitivity of the rbcL assays in terms of plant cell equivalents, but approximately similar when the higher numbers of copies of the chloroplast genome per cell are taken into account. The 173 bp rbcL assay detected the target plant chloroplast DNA fragment in 5%, 15%, and 53% of the muscle samples from beef steers, broiler chickens, and swine, respectively, and in 86% of the milk samples from dairy cows. Reanalysis of new aliquots of 31 of the pork samples that were positive in the 173 bp rbcL PCR showed that 58% of these samples were reproducibly positive in this same PCR assay. The 500 bp rbcL assay detected DNA fragments in 43% of the swine muscle samples and 79% of the milk samples. By comparison, no statistically significant detections of transgenic DNA fragments by the p35S PCR assay occurred with any of these animal tissue samples.
Abstract: Ten Holstein /Friesian cows with an average liveweight of 630 kg and producing 25.3 kg milk/day received a total mixed ration (TMR) in which the forage component formed 55% of total DM and contained non-genetically modified (GM) grass and maize silage in a 1:3 DM ratio. In study weeks 1-3 the TMR DM also contained non-GM supplernents of 18.5% cracked wheat and 26.1% rapeseed meal. In weeks 4-12 soyabean meal, genetically modified (CP4EPSPS) to be herbicide tolerant, replaced rapeseed meal at 26.1% of the total diet in weeks 4-5 and 13.9% of the total diet in weeks 6-12. Weekly milk samples were taken from all cows. Samples were spiked with DNA extracted from the soyabean meal to establish the limit of detection (LOD) of transgenic DNA using a polymerase chain reaction (PCR) analyses designed to detect transgenic DNA fragments smaller than 200 bp. Subsequent PCR analyses carried out in duplicate on TMR and milk samples collected at weeks 3, 4 and 122 of the study used three DNA primer sets to establish the presence or absence of transgenic DNA, The LOD of transgenic DNS in milk was 7.5 mug/l. Feed and milk samples analysed at week 3 were negative. The TMR feed samples at weeks 4 and 12 were positive for CP4EPSPS soyabean meal DNA, but all milk samples were negative. The results showed that transgenic DNA could not be detected in milk from cows receiving upto 26.1% of their diet DM as herbicide (glyphosate)-tolerant soyabean meal.
Abstract: The objective was to determine the presence or absence of transgenic and endogenous plant DNA in ruminal fluid, duodenal digesta, milk, blood, and feces, and if found, to determine fragment size. Six multiparous lactating Holstein cows fitted with ruminal and duodenal cannulas received a total mixed ration. There were two treatments (T). In T1, the concentrate contained genetically modified (GM) soybean meal (cp4epsps gene) and GM corn grain (cry1a[b] gene), whereas T2 contained the near isogenic non-GM counterparts. Polymerase chain reaction analysis was used to determine the presence or absence of DNA sequences. Primers were selected to amplify small fragments from single-copy genes (soy lectin and corn high-mobility protein and cp4epsps and cry1a[b] genes from the GM crops) and multicopy genes (bovine mitochondrial cytochrome b and rubisco). Single-copy genes were only detected in the solid phase of rumen and duodenal digesta. In contrast, fragments of the rubisco gene were detected in the majority of samples analyzed in both the liquid and solid phases of ruminal and duodenal digesta, milk, and feces, but rarely in blood. The size of the rubisco gene fragments detected decreased from 1176 bp in ruminal and duodenal digesta to 351 bp in fecal samples.
Abstract: Data from 60 multiparous Holstein cows were used in a 12-wk continuous design feeding trial. Cows were allocated to 1 of 4 experimental treatments (T1 to T4). In T1 and T2, the total mixed ration (TMR) contained either corn silage from the genetically modified (GM) variety Chardon Liberty Link, which is tolerant to the herbicide glufosinate ammonium, or its near isogenic nonGM counterpart, whereas the TMR used in T3 and T4 contained corn silage from the commercially available nonGM varieties Fabius and Antares, respectively. The objectives of the study were to determine if the inserted gene produced a marked effect on chemical composition, nutritive value, feed intake, and milk production, and to determine if transgenic DNA and the protein expressed by the inserted gene could be detected in bovine milk. The nutritive value, fermentation characteristics, mineral content, and amino acid composition of all 4 silages were similar. There were no significant treatment effects on milk yield, milk composition, and yield of milk constituents, and the dry matter (DM) intake of the GM variety was not significantly different from the 2 commercial varieties. However, although the DM intake noted for the nonGM near-isogenic variety was similar to the commercial varieties, it was significantly lower when compared with the GM variety. Polymerase chain reaction analyses of milk samples collected at wk 1, 6, and 12 of the study showed that none of the 90 milk samples tested positive, above a detection limit of 2.5 ng of total genomic DNA/mL of milk, for either tDNA (event T25) or the single-copy endogenous Zea mays gene, alcohol dehydrogenase. Using ELISA assays, the protein expressed by the T25 gene was not detected in milk.
Abstract: A grower finisher performance trial with forty-eight pigs was designed to compare the growth performance of pigs fed diets containing either genetically modified (GM) Bt-maize (NX6262) or its parental maize (Prelude) line. During the experiment, the pigs were fed with a grower and a finisher diet both containing 70% maize investigated in a previously study which showed that they contained similar ME values and digestibility of crude nutrients. The pigs with an initial live weight of 23.9 +/- 3.0 kg were allotted to single boxes. During a 91 days growing period the pigs of both groups recorded equal performance in daily weight gain (DeltaW) 815 +/- 93 vs. 804 +/- 64g/d depending on equal amounts of feed intake 1.95 +/- 0.15 vs. 1.94 +/- 0.15 kg/d (parental vs. transgenic). The results confirm equal performance among growing-finishing pigs fed parental or genetically modified maize containing diets. For slaughtering the pigs were divided into 4 groups with a different duration of the finishing period. After slaughtering the carcass characteristic were registered.
Abstract: The objective of the present study was to determine the composition and the nutritional value of parental and transgenic maize seeds fed to pigs. The parental maize line was genetically modified to incorporate a gene from Bacillus thuringiensis (Bt) expressing a toxin against the European corn borer (Ostrinia nubilalis). Both (parental and transgenic) maize lines were analyzed for crude nutrients, starch, sugar, non-starch polysaccharides (NSP), amino acids, fatty acids, as well as for selected minerals. Furthermore, four complete diets were mixed and were analyzed for the same nutrients and some selected ingredients. The diets contained 70% maize to attain a high effect level. To evaluate the feeding value of one variety of genetically modified maize (transgenic) compared to the feeding value of the unmodified maize (parental) line, a balance study with twelve pigs was designed. Three collecting periods were used for each maize line each with six animals. The collected faeces were analyzed for crude nutrients. All measured parameters were virtually the same (e.g. crude protein 11.59% vs. 11.06% in DM), especially the digestibility of crude protein (85.8 +/- 2.3% vs. 86.1 +/- 1.8%), the amount of nitrogen-free-extract (92.8 +/- 0.6% vs. 93.2 +/- 0.6%) and the metabolizable energy (15.7 +/- 0.2% vs, 15.8 +/- 0.2% MJ/kg DM) for both maize lines. Compared to the parental line, the chemical composition and digestibility of crude nutrients and energy content were not significantly affected by the genetic modification of maize. Therefore, from the view of a nutritional assessment, the genetically modified maize can be regarded as substantially equivalent to the parental maize line.
Abstract: The passage and fate of ingested DNA in 48 pigs fed with diets containing (n = 12) parental or (n = 36) transgenic (Bt) maize were examined. Pigs were fattened from an initial live weight of 24 kg to approximately 108 kg. Animals fed transgenic maize were slaughtered in groups (n = 6) 4, 8, 12, 24, 48 and 72 h after feeding the last maize-containing diet. Those slaughtered at up to 12 h received no further feed, while those held for longer prior to slaughter received a diet in which maize was replaced by barley and wheat. Control animals were slaughtered at 4 and 8 h. DNA extracted from tissues and gut contents was examined by PCR for the presence of plant DNA and for any transgenic material. Recombinant DNA was detectable in the intestinal contents up to 48 h after the last feeding of a diet containing the transgenic maize. PCR amplification of plant gene spacers produced fragments of different sizes, dependent on feed source. The feed source of rectum samples depended on individual passage rate in the groups and their restriction analysis showed grain species-specific patterns. Recombinant or maize-specific DNA was not detectable in tissue samples of pigs. In contrast, plant DNA fragments were detectable in the investigated pig tissues.
Abstract: The composition of glyphosate-tolerant (Roundup Ready) corn event NK603 was compared with that of conventional corn grown in the United States in 1998 and in the European Union in 1999 to assess compositional equivalence. Grain and forage samples were collected from both replicated and nonreplicated field trials, and compositional analyses were performed to measure proximates, fiber, amino acids, fatty acids, vitamin E, nine minerals, phytic acid, trypsin inhibitor, and secondary metabolites in grain as well as proximates and fiber in forage. Statistical analysis of the data,was conducted to assess statistical significance at the p < 0.05 level. The values for all of the biochemical components assessed for corn event NK603 were similar to those of the nontransgenic control or were within the published range observed for nontransgenic commercial corn hybrids. In addition, the compositional profile of Roundup Ready corn event NK603 was compared with that of traditional corn hybrids grown in Europe by calculating a 99% tolerance interval to describe compositional variability in the population of traditional corn varieties in the marketplace. These comparisons, together with the history of the safe use of corn as a common component of animal feed and human food, support the conclusion that Roundup Ready corn event NK603 is compositionally equivalent to, and as safe and nutritious as, conventional corn hybrids grown commercially today.
Abstract: Two different corn cultivars were compared with their genetically modified counterparts containing the gene coding for the Cry1A(b) protein of Bacillus thuringiensis (Bt). There were no analytical differences between the conventional and transgenic genotype kernels, whereas stovers from Bt(+) plants had higher sugar (148.3 g kg(-1) versus 115.9 g kg(-1); P < 0.01) and lower NDF (592.7 g kg(-1) versus 631.5 g kg(-1); P < 0.05) contents than Bt(-) maize. A comparison of the amino acid profiles showed higher phenylalanine content in kernels from the Bt(+) plants (49.1 g kg(-1) vs 47.8 g kg(-1); P < 0.05) which was, however, not reflected in the protein content. The initial dry matter rumen degradability of the isogenic kernels was higher than that of Bt(+) varieties (569.5 g kg(-1) vs 543.7 g kg(-1); P < 0.05), whereas the lower fibre content increased the dry matter (548.6 g kg(-1) vs 526.6 g kg(-1); P < 0.01) and protein (695.6 g kg(-1) vs 647.9 g kg(-1); P < 0.01) degradability after 24 h of incubation in stovers from Bt(+) plants. The NDF degradability was higher in Bt(-) corn varieties because of the higher proportion of hemicellulose in the total fibre.
Abstract: The aim of the study was to evaluate the effect on broiler performance of transgenic Bacillus thuringiensis (Bt) corn containing the Cry1A(b) protein compared with the corresponding near isogenic corn and to analyze the degradation of the CryIA(b) gene in the digestive tract. Ross male broilers (432) were fed for 42 consecutive days with diets containing Bt or isogenic corn. Diet, Bt corn, and the isogenic form of the Bt corn were analyzed for composition and aflatoxin B-1, fumonisin B-1, and deoxynivalenol contents. Broiler body weight and feed intake were recorded at regular intervals (d 0, 21, and 42). The presence of the CryIA(b) gene and plant-specific genes Zein and Sh-2 in gut contents of crop, gizzard, jejunum, cecum, and samples of blood was determined in 10 animals per treatment at the end of the trial using a PCR technique. Chemical composition was not different between Bt and its isogenic form, whereas the fumonisin B, content for Bt was lower than for isogenic corn (2,039 vs. 1,1034 ppb; P < 0.05). The results of the growth study showed no difference for average daily weight gain (129.4 vs. 126.0 g/d), feed intake (63.4 vs. 61.8 g/d), and feed conversion ratio (1.95 vs. 2.02) among the groups. No significant relationship was observed between mycotoxins content and growth performances. Feed-derived DNA is progressively degraded along the digestive tract. Detection frequency of short fragments of maize-specific high copy number Zein gene was high but significantly decreased in distal sectors. An 1,800-bp fragment of the Cry1A(b) gene, corresponding to the minimal functional unit, was detected only in crop and gizzard of birds fed Bt corn. Sh-2 showed the same detection frequency of CryIA(b) and was also found in birds fed isogenic corn. Blood samples were positive with low frequency only for the Zein gene fragment. No significant difference in DNA detection was observed between birds fed Bt and isogenic corn, indicating that DNA derived from transgenic feed undergoes the same fate as isogenic feed
Abstract: Preliminary research conducted by Iowa State University and funded by the Leopold Center for Sustainable Agriculture shows no difference in the performance of cattle that grazed Bt corn crop residues and those which grazed non-Bt corn crop residues. "The bottom line is that in one year there was no effect of Bt corn on the quality of stalks for winter grazing," said Jim Russell, forage grazing specialist at the Iowa Beef Center at ISU. Russell said there was little difference in the amount of hay required to maintain comparable body condition in cows grazing the crop residues from different hybrids. The research was conducted in direct response to cattle producers' questions about Bt corn stalks as a forage.
Abstract: One non bt-corn hybrid (Pioneer 3489) and three bt-corn hybrids (Pioneer 34RO7, Novartis NX6236, and Novartis N64-Z4) were planted in replicated 7.1-acre fields. After grain harvest, fields were stocked with 3 mature cows in midgestation to be strip-grazed as four paddocks over 126 days. Six similar cows were allotted to replicated drylots. All cows were fed hay as necessary to maintain a condition score of 5 on a 9-point scale. Cows were condition-scored biweekly and weighed monthly. Forage yield and weathering losses were determined by sampling one 4-m2 location per grazed or ungrazed paddock in each field with a minimum total of 2 locations of grazed or ungrazed forage per field. To measure forage selection during grazing, samples of grazed forage were collected from the rumen of one fistulated steer that grazed for 2 hours after ruminal evacuation. Non-bt-corn hybrids had greater (P<.05) infestation of corn borers in the upper stalk, lower stalk and ear shank than bt-corn hybrids. However, there were no differences in grain yields or dropped grain between hybrids. Crop residue dry matter, organic matter and in vitro digestible dry matter yields at the initiation of grazing did not differ between corn hybrids. Dry matter, organic matter and in vitro digestible dry matter losses tended (P<.10) to be greater from the NX6236 and N64-Z4 hybrids than from the 3489 and 34RO7 hybrids and were greater (P<.05) from grazed than non-grazed areas of the fields. At the initiation of grazing, dry matter concentrations of the crop residues from the NX6236 and N64-Z4 hybrids tended to be lower than those from the 3489 and 34RO7 hybrids. Crop residues from the NX6236 and N64-74 hybrids had lower concentrations of acid detergent fiber (P<.05) and acid detergent lignin (P=.07) and higher concentrations of in vitro digestible organic matter than the 3489 and 34RO7 hybrids. Over the grazing season, corn hybrid did not affect mean rates of change in forage composition. The concentration of in vitro digestible organic matter in forage selected by steers after two weeks of grazing did not differ. However, steers grazing corn crop residues consumed forage with higher (P<.05) concentrations of neutral detergent fiber, acid detergent fiber, and acid detergent insoluble nitrogen than steers fed hay. The acid detergent fiber concentration of forage selected by steers grazing the 3489 and N64-Z4 hybrids was lower (P<.05) than concentrations from the 34RO7 and NX6236 hybrids. In order to maintain similar body condition score changes, cows grazing crop residues from the 3489, 34RO7, NX6236, and N64-Z4 hybrids required 650, 628 625, and 541 kg hay DM/cow compared with a hay requirement of 1447 kg hay DM/cow for cows maintained in a drylot.
Abstract: Two maize silages (whole plants) were produced out of the isogen strain 'Pactol' and the transgen strain 'Pactol CB' from the crop year 1997. These silages were investigated in a digestibility trial with rams and in a feeding trial with dairy cows (tied up, individually fed). In two 5-week periods, the maize silages were fed alternately to 2x12 cow groups (cross over). There were only small differences in content and digestibility of the crude nutrients within sampling and analyzing error. In the feeding trial, the cows got contstantly 18 kg maize silage/day, grass silage ad libitum and concentrate was apportioned by milk yield. The consumption of dry matter varied during the trial, but no significant differences could be found between the groups of the two strains. In view of the relatively great individual variation, the groups differed only small in the milk yield criteria (milk amount, percentage of fat and protein, FPCM). The milk contents (lactose, urea, number of somatic cells), measured in the single milk amounts, showed as well as the protein fractions, freezing point, vitamins and minerals in mixed milk no systematic effects of the two maize strains. In none of the investigated criteria could be found a noticeable difference. So can be concluded that the two maize silages are similar in their effect of feeding to dairy cows.
Abstract: Vegetable protein sources like soybeans, canola and maize gluten are good alternatives to fish meal. However, a large proportion of such products available on the international market may possess genetically modified (GM) components. This report concerns a study to investigate the fate and survival of ingested GM soy DNA fragments (120 and 195 bp) and a 180-bp fragment of the lectin gene of soybean (Glycine max) during feeding trials with Atlantic salmon post-smolt. Specifically, the study focused on the fate of selected GM soy DNA fragments from feed to fish to investigate their survival through the fish gastrointestinal (GI) tract and whether the DNA could be traced in a variety of fish tissues. Fish were fed three experimental diets for 6 weeks, which were formulated from defined components and represented either GM or non-GM materials (17.2% of the fish meal was replaced with either GM or non-GM soy). A control diet composed of fish meal as the only protein source was used for comparison purposes. The transgenic sequences (120 and 195 bp) and the lectin gene (180 bp) could be detected in the GM soy feed. In the fish GI tract, however, only the smaller DNA fragment (120 bp) could be amplified from the content of the stomach, pyloric region, mid intestine and distal intestine. No transgenic or conventional soy DNA fragments could be detected in liver, muscle or brain tissues resected from sacrificed fish. The sensitivity limit of the method was evaluated to be 20 copies. These data indicate that GM soy transgenic sequences may survive passage through the GI tract but that they cannot be traced in fish tissues.
Abstract: Two 42-d experiments compared the nutritional value of YieldGard Rootworm corn (MON863; experiment 1) and YieldGard Plus corn (MON810 x MON863; experiment 2) to their respective nontransgenic controls and 6 commercial reference corn hybrids when fed to growing broilers. For each experiment, a randomized complete block design was used with 8 dietary treatments in each of 5 replicated blocks of pens. In experiment 1, no differences among diets were observed (P > 0.05) for final live weights and feed conversion. Broilers fed diets containing MON863 corn had adjusted feed conversion similar to the nontransgenic control and the population of control and commercial diets. On a weight basis, there were no differences among diets for chill, fat pad, and thigh, drum, and wing weights. Differences (P < 0.05) between MON863 and commercial corn diets were noted for breast meat, chill and thigh, drum, and wing weights on a percentage of weight basis. No differences were observed (P > 0.05) in the percentage of moisture, protein, and fat in breast meat or thigh meat across treatment diets. In experiment 2, there were no significant differences among diets for all broiler performance and carcass parameters evaluated. Broilers overall performed consistently and had similar carcass yields and meat compositions when fed diets containing MON863 corn or MON810 x MON863 corn as compared with their respective nontransgenic control and commercial diets, supporting a conclusion of similar feeding values among diets.
Abstract: This 42-day experiment was undertaken to compare the nutritional value of insect-protected corn event MON810 (YieldGard) and YieldGard x herbicidetolerant corn event GA21 (Roundup Ready) to their nontransgenic controls as well as four different commercial reference corns, when fed to growing Cobb x Cobb broilers. A randomized complete block design was used, an each treatment was replicated with five pens of males and five pens of females with 10 broilers per pen. Broilers were fed approximately 55% wt/wt corn during the first 20 d and approximately 60% wt/wt corn thereafter. The corn component of diets fed to broilers was supplied entirely with grain from the eight hybrids included in the experiment. Final live weights averaged 2.09 kg/bird fed YieldGard corn and 2.15 kg/bird fed YieldGard x Roundup Ready corn and were not different (P > 0.05) from final weights for birds fed control or commercial corn. Feed conversion was not affected (P > 0.05) by YieldGard (1.72) or YieldGard x Roundup Ready (1.77) corn feeding when compared with the feeding of other corn diets. Chill weights, fat pad, thigh weights, and wing weights were not affected by diets (P > 0.05). Differences (P < 0.05) were noted for breast and drum weights across treatments. Broilers overall performed consistently and had similar carcass yield and meat composition when fed diets containing YieldGard (event MON810) or YieldGard (event MON810) x Roundup Ready (event GA21) as compared with their nontransgenic controls and commercial diets.
Abstract: Two 42-d experiments compared the nutritional value of the glyphosate-tolerant corn event NK603 (Roundup Ready corn) (experiment 1) and the combined traits, insect-protected corn event MON 810 (YieldGard corn) x glyphosate-tolerant corn event NK603 (experiment 2) to their respective non-transgenic controls and to commercial reference corn, when fed to growing broilers. For each experiment, a randomized complete block design was used with eight dietary treatments in each of five replicated blocks of pens (eight pens for males and eight pens for females per block). Final live weights and feed conversion were not different (P > 0.05) across all treatments in both experiments. In experiment 1, broilers fed diets containing Roundup Ready corn had similar feed conversion adjusted for mortalities to those fed the non-transgenic control and one of the commercial corn diets. Chill weights and thigh, drum, and wing weights were not affected by diets. Differences (P < 0.05) were noted for breast meat and fat pad weights across treatments. In experiment 2, the adjusted feed conversion and carcass parameters were not affected by diets. Differences (P < 0.05) were noted only for protein content of breast meat. Differences observed in both experiments were consistent with natural variability. Broilers in general performed consistently and had similar carcass yields and meat compositions when fed diets containing Roundup Ready corn or YieldGard x Roundup Ready corn as compared with their respective non-transgenic control and commercial diets supporting similar feeding values among diets. Erratum
Erratum
Abstract: Insect resistant Bt 176 maize has been developed by genetic modification to resist European borer infection. In the present investigation, the experiment was conducted to determine the effect of feeding a new hybrid of Bt 176 maize (NX 6262-Bt 176) on general health condition and performance of broiler chickens. Maize grains and diets were subjected to proximate analysis. Amino and fatty acids investigation were applied for both maize grains before used. To evaluate the degradation of NX 6262 - Bt 176 maize DNA and its metabolic fate in broiler blood, muscles and organs. One-day-old male broilers were fed ad libitum on either an experimental diet containing NX 6262- Bt 176 or a control diet containing the non-modified maize grains for 35 days. Feed consumption and body weight were recorded weekly during the experimental period. All chickens were subjected to nutritional evaluation period at day 20 of age for 5 successive days, to calculate the percentage of apparent digestible nutrients in both diets. At day 35 samples were collected at several intervals after feed withdrawal. Prior to slaughter blood samples were collected from all birds by heart puncture to prevent DNA cross contamination. Samples from pectoral and thigh muscles, liver, spleen, kidney, heart muscle, bursa and thymus glands were collected. Digesta from different sections of the gastrointestinal tract (GIT) were collected as well. Packed cell volume (PCV) and some serum parameters were investigated. There were no significant differences between control and experimental group concerning chemical composition of feeds, apparent digestible nutrients, and all performance parameters measured (P > 0.05). Furthermore, there were no differences in the PCV and the analysed serum parameters between the control and experimental group. The results of maize DNA digestibility showed that the new variety takes the normal physiological passage along broiler GIT similar to the conventional line. In addition, Bt 176 maize DNA appears to be partially degraded in different parts of GIT comparable to the DNA of the control maize line. Results of the metabolic fate of maize DNA in broiler blood, muscles and organs indicated that only short DNA fragments (199 bp) derived from the plant chloroplast gene could be detected in the blood, skeletal muscles, liver, spleen and kidney, which disappeared after prolongation the fasting time. In heart muscle, bursa of Fabricius and thymus, no plant chloroplast DNA was found. Bt gene specific constructs from Bt 176 maize were not detected in any investigated blood or tissue samples.
Abstract: Forage from genetically modified (GM) maize in two consecutive years (1999 and 2000) was ensiled in bins of 120 l volume in two combinations: with formic acid (85%) and without. In the samples of ensilage material GM maize, basic parameters have been determined such as pH and dry matter. The determination of biological activity of the components of translational apparatus in model translation systems showed the complete inactivation of biological activities. In addition, degradation of nucleic acids in examined silages was discovered.
Abstract: Most crops developed through biotechnology that are on the market today provide farmers with increased convenience and product quality while requiring fewer chemical inputs. According to the USDA Economic Research Service (http://www.ers.usda.gov/data/biotechcrops), herbicide- and insect-resistant biotech varieties accounted for about 85 percent of U.S. soybean acreage and 45 percent of corn acreage in 2003. Livestock eat the meal from approximately 70 percent of the soybeans and consume 80 percent of the corn grain and silage grown in the United States (Etherton et al. 2003), making the livestock industry a major user of biotech crops. Plant breeders are concentrating on enhancing grains or protein sources to produce feedstuffs that will improve feed utilization, performance, product quality, and health of livestock while reducing production costs and environmental impacts. It is likely that biotech crops of the future will play an important role in this arena. This publication discusses potential applications and safety issues associated with such products.
Abstract: 1. A diet with addition to normal barley of malt from transgenic barley expressing a protein engineered, thermotolerant Bacillus (1,3- 1,4)-beta-glucanase during germination has previously been demonstrated to provide a broiler chicken weight gain comparable to maize diets. It also reduced dramatically the number of birds with adhering sticky droppings, but did not entirely eliminate sticky droppings. One of the objectives of the broiler chicken trials reported here was to determine if higher concentrations of transgenic malt could alleviate the sticky droppings. 2. Another aim was to investigate the feasibility of using mature transgenic grain containing the thermotolerant (1,3- 1,4)-beta-glucanase as feed addition and to compare diets containing transgenic grain to a diet with the recommended amount of a commercial beta-glucanase-based product. 3. Inclusion of 75 or 151 g/kg transgenic malt containing 4.7 or 98 mg/kg thermotolerant (1,3- 1,4)-beta-glucanase with 545 or 469 g/kg non-transgenic barley instead of maize yielded a weight gain in Cornish Cross broiler chickens indistinguishable from presently used maize diets. The gene encoding the enzyme is expressed in the aleurone with a barley alpha-amylase gene promoter and the enzyme is synthesised with a signal peptide for secretion into the endosperm of the malting grain. 4. Equal weight gain was achieved, when the feed included 39 g/kg transgenic barley grain [containing 66 mg/kg thermotolerant (1,3- 1,4)-beta-glucanase] and 581 g/kg non-transgenic barley instead of maize. In this case, the gene encoding the enzyme has been expressed with the D-hordein gene (Hor3-1) promoter during grain maturation. The enzyme is synthesised as a precursor with a signal peptide for transport through the endoplasmic reticulum and targeted into the storage vacuoles. Deposition of the enzyme in the prolamin storage protein bodies of the endosperm protects it from degradation during the programmed cell death of the endosperm in the final stages of grain maturation and provides extraordinary heat stability. The large amount of highly active (1,3- 1,4)-beta-glucanase in the mature grain allowed the reduction of the transgenic grain ingredient to 0.2 g/kg diet, thus making the ingredient comparable to that of the trace minerals added to standard diets. 5. A direct comparison using transgenic grain supplement at the level of 1 g/kg of feed with the standard recommended addition of the commercial enzyme preparation Avizyme 1100(R) at 1 g/kg yielded equal weight gain, feed consumption and feed efficiency in birds fed a barley-based diet. 6. The production of sticky droppings characteristic of broilers fed on barley diets was avoided with all 9 experimental diets and reduced to the level observed with a standard maize diet by supplementation with transgenic barley. 7. The excellent growth and normal survival of the 400 broilers tested on barley diets supplemented with transgenic grain or malt showed the grain and malt not to be toxic. 8. The barley feed with added transgenic grain or malt containing thermotolerant (1,3- 1,4)-beta-glucanase provides an environmentally friendly alternative to enzyme additives, as it uses photosynthetic energy for production of the enzyme in the grain and thus avoids use of non-renewable energy for fermentation. The deposition of the enzyme in the protein bodies of the grain in the field makes coating procedures for stabilisation of enzyme activity superfluous. 9. Barley feed with the small amount of transgenic grain as additive to normal barley provides an alternative for broiler feed in areas where grain maize cannot be grown for climatic reasons or because of unsuitable soil and thus has to be imported
Abstract: In experiments on rats, nutritional properties of a
diet with high content (40%) of potato tubers obtained from conventional
or genetically-modified potato were determined. The potato cultivar Irga
was transformed with viral genome sequences in order to improve its resistance
to a necrotic strain of potato virus Y (PVYN). Four lines of genetically-modified
potato were compared with non-transgenic somaclone from cv. Irga and three
conventional cultivars Irga, Maryna and Ania. Potato tubers were autoclaved,
dried and introduced to the diets which contained similar amount of protein
(levelled through small addition of casein), fat, minerals and vitamins.
Abstract: The potential effect of genetic modification on nutritional properties of potatoes was determined in a rat experiment. The potato cultivar Irga was transformed with viral genome sequences in order to improve its resistance to a necrotic strain of potato virus Y (PVYN). Four clones of genetically-modified potato were compared with the conventional variety Irga and non-transgenic somaclone from cv. Irga. Autoclaved and dried potato tubers were introduced in a high amount (40%) to rat diets. The genetic status of the potato had no effect on the mass of the caecum and caecal digesta. The parameters tested were pH, dry matter content and bacterial enzyme activity, comprising a- and ß-glucosidase, a- and ß-galactosidase, and ß-glucuronidase. The results indicate that improvement of potato resistance to PVYN by genetic transformation had no negative effect on the ecosystem of the caecum of the rats, activity of serum enzymes (aspartate and alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase and creatine kinase) and non-specific defence mechanisms (lysozyme and ceruloplasmine level, number of bacteria taken up per cell and the percentage of the phagocytic cells in the serum).
Abstract: This study was conducted to compare the safety of soybean
meal prepared from genetically modified (GM) glyphosate-tolerant (Roundup
Ready; RR) soybeans and conventional soybeans. Eighty Sprague-Dawley rats
(40 males and 40 females) were randomly allotted to one of four groups
according to sex and body weight for a 13-week feeding experiment. The
rats were fed corn-based diets containing 60% conventional soybean meal,
a mixture of 30% conventional and 30% RR soybean meal, 60% or 90% RR soybean
meal. All diets were adjusted to an identical nutrient level except the
90% RR diet. The two soybean meals were similar in chemical analysis and
amino acid composition. During the 13-week growth trial, body weight (P<0.05)
and feed intake (P<0.05) decreased only in rats fed with 90% RR soybean
meal at the first week. No treatment-related deaths occurred during the
experiment. Gross necropsy findings, haematological or urinalysis values
and clinical serum parameters showed no meaningful differences between
rats fed the control and RR soybean meals. A 145 bp of cp4 epsps gene
specific for the GM constructs from RR soybean meal or a 407 bp of lec
gene from endogenous soybean DNA could not be detected in investigated
masseter muscle samples. No adverse effects of glyphosate-tolerant soybean
meal on rats were seen even at levels as high as 90% of the diet. |
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