Efficacy of phytase supplementation in improving mineral digestibility in Labeo rohita fingerlings fed on canola meal-based diets

A feeding trial of ten weeks was conducted to evaluate the effect of microbial phytase supplementation on mineral digestibility in Labeo rohita fingerlings fed on canola meal-based diets. The experiment consisted of a reference diet and a basal diet. The reference diet was prepared according to the requirements of L. rohita and was used as a standard diet. The basal diet was made by replacing 30% reference diet with canola meal which was used as the test ingredient in this experiment. Seven test diets were prepared by spraying graded levels (0, 250, 500, 750, 1000, 1250 and 1500 FTU kg-1) of phytase on canola meal-based basal diet to assess the optimal dose required to achieve best performance in terms of mineral digestibility coefficients. Chromic oxide was incorporated as an indigestible marker in the diets. Phytase supplementation significantly increased mineral digestibility in L. rohita fingerlings at 750 FTU kg-1 followed by that at 1000 FTU kg-1 as compared to the reference diet. The results of our study suggested that phytase supplementation in canola meal-based diet at the rate of 750 FTU kg-1 is optimum to release sufficient chelated minerals in L. rohita.