Comparison of growth performance, biochemical and fatty acid compositions between all-female diploid and triploid rainbow trout Oncorhynchus mykiss (Walbaum, 1792)

This study compares the performance (in terms of survival and growth), biochemical and fatty acid compositions among all female diploid (AFD) and triploid (AFT) rainbow trout (Oncorhynchus mykiss). AFD and AFT fish with mean initial weights of 1,040.1 +/- 1.3 and 1,039.7 +/- 1.6 g, respectively, were reared and fed from March to August with a commercially extruded trout feed in a commercial freshwater fishfarm located in the Black Sea region (Samsun, Turkey). Survival was reduced throughout the experimental period in the AFT group with increasing water temperatures. At the end of the experiment, survival rates were 98.57 +/- 1.43% and 82.38 +/- 7.39% for the AFD and AFT groups, respectively. The AFD group showed significantly better growth performances in terms of weight gain, feed conversion rate (FCR), relative growth rate (RGR) and specific growth rate (SGR) than the AFT group (p < .05). Significantly less protein and greater fat content were also observed in the AFT group (p < .05). There was no significant difference between groups for fatty acid composition in meat, except for stearic acid (SA, C18:0) and docosahexaenoic acid (DHA, 22:6 n-3). While the greatest SA concentration was in the AFT group, the greatest DHA concentration was observed in the AFD group (p < .05). The results indicate that female triploid rainbow trout are more susceptible to suboptimal environmental conditions (especially to higher water temperatures) than female diploids. Although poor triploid performance was observed in this study, relative productivity might be enhanced by rearing triploids in optimal environmental conditions.