The effect of different growing conditions to proximate composition and fatty acid profiles of rainbow trouts (Oncorhynchus mykiss)

The experiment was carried out using escaped rainbow trout (weights between 268 and 310g) caught in Seyhan Dam Lake, Adana, Turkey and three groups of rainbow trout (weights between 226 and 277g) cultured in concrete freshwater ponds, in freshwater cages in Seyhan Dam Lake and in marine cages in Black Sea by private companies. Proximate composition and the fatty acid profiles of the fishes were determined. Analysis of the proximate composition of the present study revealed that the escaped rainbow trout flesh to have the highest water (74.23%) and the lowest lipid (4.47%) content while lowest level of moisture and highest levels of lipid was observed in farmed fish in ponds (68.69% and 7.78%). According to the results of fatty acid analysis, the highest saturated fatty acid (31.3%) and the lowest polyunsaturated fatty acids (PUFA) (26.51%) levels were in the escaped group obtained from wild, while PUFA levels were higher in the cultured groups. On the other hand, the levels of n3/n6 ratio were higher in escaped and marine cages groups (2.71 and 2.58) than in ponds and Dam Lake cages groups (1.75 and 1.33). According these results, rainbow trout from all groups studied are a desirable food item for human consumption.