Efficacy of Phytase Supplementation on Growth Performance and Mineral Digestibility of Labeo rohita Fingerlings Fed on Cottonseed Meal Based Diet

Phytate, present in plant feed ingredients, act as anti-nutritional factor by chelating indispensable minerals and other nutrients making them unavailable to the fish. These undigested nutrients are excreted out causing pollution in the water bodies. The present study was conducted to evaluate the efficacy of phytase supplementation on growth performance and minerals digestibility of Labeo rohita fingerlings. Reference diet was made by replacing 30% of reference diet with cottonseed meal as test ingredient. Seven cottonseed meal based test diets were prepared by spraying graded levels of phytase (0, 250, 500, 750, 1000, 1250 and 1500 FTU kg(-1)) to the basal diet. Chromic oxide was included as inert marker in the diets to assess the minerals digestibility. The results of present study showed improved growth and feed performance of fingerlings in response to phytase supplementation. Maximum performance was obtained by the fish fed on test diet-IV having 750 FTU kg(-1) phytase level. Similarly, minerals digestibility performance was also positively affected by phytase supplementation. Again, maximum response of minerals absorption was recorded at the phytase level of 750 FTU kg(-1) diet. It was concluded that the phytase supplementation to cottonseed meal based diet at 750 FTU kg(-1) level is optimum to release adequate chelated minerals for maximum growth performance of L. rohita fingerlings. These results suggest that phytase supplementation to cottonseed meal based diet can help in the development of sustainable aquaculture by reducing the feed cost and minerals discharge through feces in the aquatic ecosystem.