This article describes the nutrient and elemental composition, including residues of herbicides and pesticides, of 31 soybean batches from Iowa, USA. The soy samples were grouped into three different categories: (i) genetically modified, glyphosate-tolerant soy (GM-soy); (ii) unmodified soy cultivated using a conventional "chemical" cultivation regime; and (iii) unmodified soy cultivated using an organic cultivation regime. Organic soybeans showed the healthiest nutritional profile with more sugars, such as glucose, fructose, sucrose and maltose, significantly more total protein, zinc and less fibre than both conventional and GM-soy. Organic soybeans also contained less total saturated fat and total omega-6 fatty acids than both conventional and GM-soy. GM-soy contained high residues of glyphosate and AMPA (mean 3.3 and 5.7 mg/kg, respectively). Conventional and organic soybean batches contained none of these agrochemicals. Using 35 different nutritional and elemental variables to characterise each soy sample, we were able to discriminate GM, conventional and organic soybeans without exception, demonstrating "substantial non-equivalence" in compositional characteristics for 'ready-to-market' soybeans.
This study was conducted to investigate the long-term effects of feeding plant products from both traditional breeding and from biotechnology on intestinal somatic indices, histology and cell proliferation in first-feeding Atlantic salmon, Salmo salar L. (initial weight 0.21 +/- 0.02 g). A standard fishmeal diet (standard fishmeal) was formulated to contain fishmeal as the sole protein source and suprex maize as the main starch source. Six experimental diets were then developed: two in which some of the fishmeal was replaced with commercially available, genetically modified Roundup Ready full-fat soybean meal (GM-soy) or commercially available, non-GM full-fat soybean meal (nGM-soy) at a level of 12.5% of the total diet, and four diets in which the suprex maize was replaced with two lines of GM-maize (Dekalb 1; D1 and Pioneer 1; P1), both products of event MON810, and their half-sibling non-GM counterparts (Dekalb 2; D2 and Pioneer 2; P2), at a level of 12.1% of total diet. Each diet was fed to fish in triplicate tanks and the experiment lasted for 8 months, during which the fish reached a final weight of 101-116 g. There was no significant effect of diet on the intestinal indices, nor were histological changes observed in the pyloric caeca or mid intestine. In the distal intestine, one of nine sampled fish fed nGM-soy showed moderate changes, two of nine sampled fish fed GM-soy showed changes, one with moderate and one with severe changes, and two of nine fish fed nGM-maize D2 had moderate changes. Using a monoclonal antibody against proliferating cell nuclear antigen (PCNA), cell proliferative responses to the experimental diets were assessed. In fish fed both soy diets, a significantly higher (P < 0.05) cell proliferation response was observed in the distal intestine concomitant with an increased localization of PCNA positive cells along the whole distal intestinal folds. The PCNA response among the nGM-soy group was significantly higher compared with all the other diet groups. In contrast, for fish exposed to dietary maize (type D) compared with fish fed the standard fishmeal, the soy-diets (GM-soy and nGM-soy) and maize (type P), a significantly lower (P < 0.05) cell proliferation response was observed in the distal intestine. Results indicated that the GM plant products investigated in this study, at about 12% inclusion level, were as safe as commercially available non-GM products, at least in terms of their effect on indices and histological parameters of the Atlantic salmon intestinal tract.
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 ä ), 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 Ôcompositional equivalentÕ 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 antinutrients 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. KEY WORDS
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