Dietary Valine Requirement of Fingerling Catla catla

A 12-week feeding trial was conducted to determine the dietary valine requirement of fingerling Catla catla (3.50 ± 0.15 cm, 0.63 ± 0.04 g). Seven casein gelatin-based diets (33% crude protein; 3.34 kcal/g digestible energy) containing graded levels of valine (0.51%, 0.69%, 0.91%, 1.12%, 1.31%, 1.49%, 1.71% dry diet) were fed to triplicate groups of fish to apparent satiation at 08:00, 12:30, and 17:30 h. Absolute weight gain (AWG), feed conversion ratio (FCR), specific growth rate (SGR%), protein efficiency ratio (PER), protein productive value (PPV), valine retention efficiency (VRE), valine gain (VG), energy retention efficiency (ERE), and carcass protein improved significantly (P < 0.05) with the increasing concentrations of dietary valine from 0.51% to 1.12%. Quadratic regression analysis of AWG, PPV, DPD, VG, ERE, and carcass protein at 95% maximum (Y_95%max) response against varying levels of dietary valine yielded the requirement at 1.04%, 1.03%, 1.05%, 1.04%, 1.01%, and 0.98% of dry diet, respectively. It is recommended that inclusion of valine at 1.02% of dry diet, corresponding to 3.09% of dietary protein, is optimum in formulating valine-balanced feeds for fingerling C. catla.