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

Abstract

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) higher weight gain %, specific growth rate, RNA content and RNA-DNA ratio in comparison to control. However, 20% and 30% HSLM fed groups were found to be non-significant (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 < 0.05) higher amylase activity with the control. Addition of exogenous enzyme in rohu diets were significantly increased the muscle AST (LM10EE, LM20EE) and ALT (LM20EE, LM30EE) activities in compared to non-supplemented counterparts. The present study concludes that 30% HSLM can be incorporated in the diet of rohu with complete replacement of DORB. However, the exogenous carbohydrase supplementation in the HSLM-based rohu diet could not result extra benefit in fish in terms of growth.