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For aquaculture assessments, the length-weight relationship and condition factor are considered as standard methods for determining fish growth, its health and the potential yield. A year-long study was conducted to calculate length-weight relationships (LWRs) and condition factor (K) for seven fish species, Schizothorax niger (Alghad or snowtrout), S. curvifrons (Sattar snowtrout), Cyprinus carpio (Common carp), Carassius carassius (Crucian carp), Pethia conchonius (Rosy barb), Crossocheilus diplochilus (Kashmir latia) and Gambusia holbrooki (Mosquito fish) in Manasbal Lake. The results revealed that four captured fish species (S. niger, S. curvifrons, C. diplochilus and G. holbrooki) exhibited negative allometric growth, while other fish species (C. carpio, C. carassius, P. conchonius) exhibited positive allometric growth. LWR was significant at P < 0.01 in all seven fish species, with a coefficient of determination (R2) ranging between 0.73 to 0.96. The K was higher in C. carpio than C. carassius, P. conchonius, G. holbrooki, C. diplochilus, S. niger and S. curvifrons. The current study providing the LWRs and condition factor of seven fish species from Manasbal Lake, Kashmir will be helpful for the management of fish species as well as for assessing the ecological condition of the Lake.

Vitamin A requirement in fingerling common carp, Cyprinus carpio var. communis (1.64 ± 0.02 g; ABW ± SD), was evaluated by conducting a 10 week growth experiment. Casein-gelatin-based test diets representing six graded levels of vitamin A (0, 0.03, 0.07, 0.11, 0.15, and 0.19 g/kg, dry diet) were designed and fed to the triplicate group of fish at 08:00 and 16:00 hrs at the rate of 4% body weight per day. Growth parameters like live weight gain (LWG %), feed conversion ratio (FCR), protein efficiency ratio (PER), specific growth rate (SGR), and body protein deposition (BPD) improved significantly ( P < 0.05 ) with each elevated dietary vitamin A level and found maximum growth rate along with the best- FCR at 0.11 g/kg diet. Dietary vitamin A levels also significantly ( P < 0.05 ) affected haematological parameters of the fish. Highest haemoglobin (Hb), erythrocyte count (RBC), haematocrit content (Hct %), and lowest leucocyte count (WBC) were observed at 0.11 g/kg vitamin A fed diet compared to all the diets. Highest protein and lowest fat content were observed in the group of fingerlings fed with 0.11 g/kg vitamin A containing diet. Blood and serum profile also showed some significant ( P < 0.05 ) differences with elevating concentration of dietary vitamin A levels. Serum parameters like aspartate aminotransferase (AST), alanine aminotransferase (ALT), and cholesterol values decreased significantly ( P < 0.05 ) at 0.11 g/kg vitamin A fed diet compared to control diet. However, except albumin the other electrolytes improved significantly ( P < 0.05 ) and maximal values of these parameters were also evident at 0.11 g/kg of vitamin A fed diet. Better value of TBARS was found in the group that fed 0.11 g/kg vitamin A diet. Hepatosomatic index and condition factor improved significantly ( P < 0.05 ) with fish fed at optimal dose 0.11 g/kg of vitamin A diet. Based on quadratic regression analysis of LWG%, FCR, BPD, Hb, and calcium values of C. carpio var. communis against the varying levels of dietary vitamin A, an optimum growth, best FCR, higher BPD, Hb, and Ca values lie in the range of 0.10 to 0.12 g/kg diet, respectively. The data generated during this study would be important in developing vitamin A balanced feed for successful intensive culture of C. carpio var. communis.

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