Growth Rate, Proximate Composition and Fatty Acid Profile of Juvenile kutum Rutilus frisii kutum Under Light/Dark Cycles

This study investigated the growth rate, proximate composition, and fatty acid profile in juvenile of kutum Rutilus frisii kutum in different dark-light cycles. Fish were stocked randomly in eighteen 2000-L fiberglass tanks and received six photoperiod regimes: natural photoperiod, 24L (light):0D (day), 16L:8D, 12L:12D, 8L:16D and 0L:24D. Application of continuous dark (0L:24D) and an intermediate photoperiod (12L:12D) resulted in the highest specific growth rate (SGR) as well as lowest feed conversion ratio (FCR) (P 0.05) in kutum. The quantity of crude protein and ash of kutum subjected in continuous dark (0L:24D), exhibited higher rate than other photoperiod regimes. The proportion of DHA (docosahexaenoic acid) +EPA (eicosapentaenoic acid) content ranged from 3.20% in natural photoperiod to 3.52% in continuous dark, n-3/n-6 and PUFA/SFA fatty acids ratio slightly ranged from 0.15-0.18, and 0.99-1.08 in all photoperiod regimes, respectively.