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.