Optimum utilization of Hygrophila spinosa leaf meal in the diet of Labeo rohita (Hamilton, 1822) fingerlings

•Complete replacement of de-oiled rice bran (DORB) is possible in the diet of rohu with Hygrophila spinosa leaf meal (HSLM).•The dietary combination of 10% HSLM and 20% DORB is better than only DORB based diet.•Dietary supplementation of cocktail exogenous xylanase and cellulase enzyme is not necessary for the inclusion of 30% HSLM in the diet of rohu. A 60-day feeding trial was conducted to study the optimum dietary inclusion of Hygrophila spinosa leaf meal (HSLM) as a replacer of de-oiled rice bran (DORB) in the diet of Labeo rohita (rohu) fingerlings. Eight iso-nitrogenous (31% crude protein) and iso-caloric (330 Kcal DE/100 g) experimental diets were prepared with inclusion of graded level of HSLM with or without supplementation of 0.1% exogenous xylanase and cellulase enzyme (EE) viz.- C, control (0% HSLM), LM10 (10% HSLM), LM20 (20% HSLM), LM30 (30% HSLM), CEE (control + EE), LM10EE (LM10 + EE), LM20EE (LM20 + EE) and LM30EE (LM30 + EE). Two hundred and eighty eight (288) fingerlings were randomly distributed in eight experimental groups in triplicates. Feeding of fish were done to satiation by using respective experimental diet throughout the experimental period. Fish fed with 10% HSLM containing diet were exhibited significantly (p 0.05) with the control group. Further supplementation of the exogenous enzyme in the leaf meal-based diets (LM10EE, LM20EE and LM30EE) could not improve the growth performance of fish significantly in compared to their non-supplemented counterparts (LM10, LM20 and LM30). Experimental groups except LM30 showed significantly (p