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Optimization of de‐oiled rice bran inclusion level in the diet of Labeo rohita: Effect on growth performance, nutrient utilization, insulin‐like growth factors I and II gene expression

Kumar, Sarvendra, Sahu, Narottam Prasad, Ranjan, Amit, Gupta, Subodh, Sardar, Parimal, Kumar, Munish, Gupta, Gyandeep
Aquaculture nutrition 2019 v.25 no.2 pp. 477-485
Labeo rohita, RNA, diet, feed conversion, fingerlings, gene expression, growth performance, insulin-like growth factor I, lipids, muscles, protein efficiency ratio, regression analysis, rice bran, specific growth rate, weight gain
A 60‐day feeding trial was conducted to optimize the inclusion level of de‐oiled rice bran (DORB) in the diet of Labeo rohita fingerlings. Six iso‐nitrogenous (260g/kg), iso‐lipidic (70g/kg) and iso‐energetic (15 MJ/Kg) diets were prepared with different inclusion level of DORB viz., T33, T38, T43, T48, T53 and T58. One hundred and eighty fingerlings (9.8 ± 0.5 g) were randomly distributed in seven experimental groups in triplicates following a completely randomized design. The weight gain %, specific growth rate, protein efficiency ratio and feed efficiency ratio were found similar in 33%, 38% and 43% DORB fed groups. The expression of both insulin‐like growth factors I and II (IGF‐I and II) was significantly (p < 0.05) higher in T33, T38 and T43 groups. Based on second order polynomial regression analysis (y = −0.0059x² + 0.4573x − 4.8404, R² = 0.95), the expression of IGF‐I was found to be maximum at 39.5% inclusion level of DORB. Significantly (p < 0.05) lower muscle RNA content, RNA‐DNA ratio and higher feed conversion ratio were found in T58 group. Hence, from these results, it can be concluded that the optimum inclusion of DORB in the diet (260g/kg CP and 70g/kg lipid) of L. rohita should be 39.5% to support maximum nutrient utilization and growth performance.