The fate of transgenic sequences present in genetically modified plant products in fish feed, investigating the survival of GM soybean DNA fragments during feeding trials in Atlantic salmon, Salmo salar L

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.