Flesh nutritional content of growth hormone transgenic and non-transgenic coho salmon compared to various species of farmed and wild salmon

This study assessed the flesh proximate and lipid composition of two year classes and sizes of non-transgenic (NT) and transgenic (T) coho salmon (Oncorhynchus kisutch) that were grown to market size in the same rearing environment and on similar commercial feeds. The data also assessed land-based commercially raised farmed coho salmon, as well as two other species of ocean-raised farmed salmonids, and four species of wild Pacific salmon. The largest differences in nutritional content were seen between wild and farmed salmon. Farmed salmon contained higher muscle lipid levels and had higher levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) relative to wild counterparts. Moreover, the farmed fish also contained higher levels of n-6 poly-unsaturated fatty acids (PUFAs) and a lower omega-3 to omega-6 ratios (n-3/n-6). There were small differences in nutritional content between NT and T coho salmon, but most of these differences were due to the lower body weight and consequently lower lipid content in the small T coho salmon group. The larger NT coho salmon were very similar in nutritional content to their T counterparts. Overall, fish diet composition and rearing location (commercial feeds in culture vs. natural prey in the wild) had a much larger influence on the flesh nutritional content than did effects of the transgene, and all salmon, regardless of source, were found to be rich sources of EPA and DHA.