Microbial phytase supplementation in rohu, Labeo rohita, diets enhances growth performance and nutrient digestibility

A feeding trial was conducted for 60 d to study the effect of dietary microbial phytase on growth performance and nutrient digestibility of rohu, Labeo rohita, fingerlings. One hundred and twenty fingerlings (average initial weight: 9.17 g/fish) were equally distributed into five experimental tanks, each with four replicates. Five isonitrogenous (35%) and isocaloric (16.79 kJ/g) diets were prepared from plant-based ingredients, supplemented with microbial phytase at the level of 0, 250, 500, 750, and 1000 U/kg diets and fed to T-0, T-1, T-2, T-3, and T-4 groups, respectively. Weight gain %, food conversion ratio, protein efficiency ratio, and apparent net protein utilization were significantly (P < 0.05) improved in groups fed phytase-supplemented diets compared to control, the highest being observed in T-3 group. Maximum apparent digestibility of phosphorus and crude protein was recorded in T-3 group. Bone ash, phosphorus (P), and calcium (Ca) contents were also significantly (P < 0.05) increased in phytase-fed groups. However, maximum was recorded in T-3 group. Results from the present study indicated that addition of 750 U microbial phytase/kg diets effectively improved nutrient utilization, bone mineralization, and hence growth of L. rohita fingerlings.