Distal intestinal gene expression in Atlantic salmon (Salmo salar L.) fed genetically modified maize

In the current experiment, RNA was isolated from the distal intestine (DI) of Atlantic salmon‐fed fishmeal‐based diets containing either genetically modified (GM) maize (Bt maize, Mon810®, Monsanto Company, St. Louis, Missouri, USA) or its conventional near‐isogenic parental line (non‐GM) for 82 days, both at 300 g kg−1 inclusion. From a suppression subtractive hybridization (SSH) cDNA library, 192 clones with similarity to both known and novel Atlantic salmon sequences were identified. Real‐time PCR was used to study the differential expression of 10 clones between the dietary groups. Expression of a clone showing high protein similarity to proton‐dependent high‐affinity oligopeptide transporter was significantly upregulated in fish‐fed GM maize compared with fish‐fed non‐GM maize. No significant differences in expression were observed for the nine other clones showing similarity to the following proteins: heat shock protein 90B, procathepsin B, interferon gamma‐inducible protein 30, ferritin heavy subunit, serum lectin isoform/C‐type mannose‐binding lectin, fatty acid‐binding protein/gastrotropin, ATP synthase [H+ transporting, mitochondrial F0 complex, subunit c (ATPSYNT)], sonic hedgehog and translationally controlled tumour protein. In conclusion, only minor differences in DI transcriptional gene expression was observed between fish fed the GM and non‐GM maize diets.