Efficacy of phytase enzyme and citric acid on growth performance, nutrients and mineral digestibility of Cirrhinus mrigala fingerlings fed guar meal-based diet

The study was carried out to estimate the effects of phytase, and citric acid (CA) supplemented guar meal based diet on growth performance, nutrients and mineral digestibility in Cirrhinus mrigala fingerlings. The experiment consisted of nine test diets. Diets were formulated by spraying graded levels of phytase (0, 500 and 1000 FTU kg-1) and 0% (0g), 2.5% (75g) and 5% (150g) citric acid supplementation to a guar meal-based diet. Chromic oxide was added as an indigestible marker. Fingerlings were fed at the rate of 5% of live wet weight. The maximum growth performance, minerals, and nutrients digestibility value were observed in fingerlings fed diet supplemented with 1000 FTU kg-1 level of phytase and 2.5% CA. These values were significantly different from fish fed the control and other test diets. It was concluded that the phytase and CA supplementation to a guar meal based diet at 2.5% CA and 1000 FTU kg-1 level is optimum to release sufficient amount of chelated minerals and nutrients for C. mrigala fingerlings. Our findings also suggested that phytase and CA supplementation can help in the development of sustainable aquaculture by reducing the feed costs and nutrient discharge through feces into the aquatic ecosystem.