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    Comparison of growth performance, biochemical and fatty acid compositions between all-female diploid and triploid rainbow trout Oncorhynchus mykiss (Walbaum, 1792)
    (Wiley, 2018) Karayucel, I.; Akyuz, A. Parlak; Dernekbasi, S.
    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.
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    Effects of Canola and Safflower Oil Supplementation in Diets, on Growth Performance and Fatty Acid Composition of Russian Sturgeon (Acipenser gueldenstaedtii Brandt, 1833)
    (Israeli Journal Of Aquaculture-Bamidgeh, 2016) Tiril, S. Ustaoglu; Dernekbasi, S.; Karayucel, I.; Kerim, M.; Akyuz, A. Parlak
    The aim of this study was to determine the impact on growth performance and muscle fatty acid composition, of replacement of 50% fish oil (FO) with canola oil (CO) and safflower oil (SFO) in the diets of Russian sturgeon (Acipenser gueldenstaedtii). Two isoproteic (48%) and isolipidic (12%) diets were formulated combining two oil sources (50% fish oil + 50% canola oil or 50% fish oil + 50% safflower oil). The diets were fed to apparent satiation to triplicate groups for 15 weeks, twice a day. No significant differences were observed between the experimental groups fed CO and SFO diets in terms of weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio. The experimental groups fed CO and SFO diets did not show significant differences in terms of protein, lipid, ash, and moisture content in their muscle. There were no significant differences in muscle between total n-3 fatty acids but total n-6 fatty acids were significantly higher in SFO group (24.90%) than in CO group (21.30%). Total n-6 fatty acids were also higher than (20.43%) at the start. In conclusion, 50% replacement of FO by CO or SFO in Russian sturgeon diets had no negative effect on growth performance, feed efficiency and fatty acid composition in the muscle of this species.