Transgenic Soybean Feeding Studies

A genetically modified soybean (Optimum GAT) was produced by insertion of two genes that provided tolerance in the soybean plant to glyphosate, sulfonylurea and imidazolinone herbicides. The objective of this study was to compare the nutritional equivalence of these transgenic soybeans to nontransgenic soybeans in a 42-d feeding trial in broiler chickens. Diets were prepared using processed fractions (meal, hulls, and oil) from untreated soybean plants or from soybean plants treated with a mixture of herbicides. For comparison, additional diets were produced with soybean fractions obtained from a nontransgenic near-isoline and nontransgenic commercial Pioneer varieties. Diets were fed to Ross x Cobb broilers (n = 120/group, 50% male and 50% female) in 3 phases. Starter diets contained 30% soybean meal, grower diets 26% soybean meal, and finisher diets 21.5% soybean meal. Soybean hulls and oil were added at 1.0 and 0.5%, respectively, across all diets in each phase. No statistically significant differences were observed in mortality, growth performance variables, or carcass and organ yields between broilers consuming diets produced with transgenic soybean fractions and those consuming diets produced with near-isoline control soybean fractions. Additionally, all performance and carcass variables from control and transgenic soybean treatment groups fell within the tolerance intervals constructed using data from reference soybean groups. Based on the results from this study, it was concluded that transgenic soybean was nutritionally equivalent to nontransgenic control soybean with a comparable genetic background.

McNaughton, J., and co-workers. 2007. Comparison of broiler performance when fed diets containing event DP-356Ø43-5 (Optimum GAT), nontransgenic near-isoline control, or commercial reference soybean meal, hulls, and oil. Poultry Sci: (86): 2569-2581.