Effect of phytase supplementation on growth performance and mineral digestibility in Labeo rohita (Hamilton, 1822) fingerlings fed on sunflower meal based diet

Present study was conducted to evaluate the efficacy of phytase supplementation on growth performance and mineral digestibility of Labeo rohita fingerlings fed sunflower meal based diet. Control diet I without inclusion of sunflower meal and phytase, and control diet II with inclusion of sunflower meal but without supplementation of phytase were prepared. Six experimental diets were prepared by spraying graded levels (250, 500, 750, 1000, 1250 and 1500 FTU kg(-1)) of phytase in the control diet II. All the diets were isonitrogenous (30.63%) and isoenergetic (4.28 kcal g(-1)). Chromic oxide was used as inert marker and mixed in the diets at 1% level. Total duration of the experiment was ten weeks (70 days). Initially, the fingerlings were fed at the rate of 2% of live wet weight on their prescribed diet twice daily and subsequently adjusted on daily feed intake. The experiment was run under completely randomised design (CRD). The results of our study showed increased growth performance of fingerlings in response to phytase supplementation. Maximum growth was observed in fingerlings fed on test diet supplemented with phytase at 750 FTU kg(-1). Maximum digestibility of minerals such as Ca, P, Mg, Na, K, Fe, Cu and Mn was also noticed in fish fed diet supplemented with phytase at 750 FTU kg(-1) level. It was concluded that the phytase supplementation in sunflower meal based diet at 750 FTU kg(-1) level is optimal to release adequate levels of chelated minerals for maximum growth performance of L. rohita fingerlings. These results also suggest that phytase supplementation in sunflower meal based diets may decrease the need for supplementing minerals, which will reduce the cost of fish feed and mineral discharge through faeces into the aquatic environment resulting in ecofriendly aquaculture.