Effects of supplementation of phytase in diets with various monocalcium phosphate levels on growth, phosphorus utilization, body composition and digestive enzyme activity of Jian carp(Cyprinus carpio var. Jian)

Abstract:

The present study was conducted to evaluate the effects of supplementation of coated acid phytase in diets with various monocalcium phosphate levels on the growth performances, phosphorus (P) utilization, body composition and digestive enzyme activity of Jian carp(Cyprinus carpio var. Jian) with initial body weight of (12.8±0.2) g. Five diets were prepared as diets supplemented with 2.5%, 2.0%, or 1.6% Ca(H₂PO₄)₂, and diets with 2 000 U/kg phytase supplementation in 2.0% or 1.6% Ca(H₂PO₄)₂ diet. After 90 days feeding, the fish fed 2.5% Ca(H₂PO₄)₂ diet had the highest weight gain (WG), the lowest feed conversion ratio (FCR) and body lipid content, and the fish fed 1.6% Ca(H₂PO₄)₂ diet had the lowest growth and the highest body lipid content. The supplementation of phytase in 2.0% Ca(H₂PO₄)₂ diet did not significantly affect the growth, P deposition and body composition, but improved P apparent digestibility and intestinal lipase activity. The supplementation of phytase in 1.6% Ca(H₂PO₄)₂ diet significantly improved the growth, contents of body protein and ash,P deposition, and P apparent digestibility, and decreased FCR and body lipid content, but had no effects on intestinal digestive enzyme activity. Results above showed that the supplementation of phytase in 1.6% Ca(H₂PO₄)₂ diet could improve the growth and P utilization, and decrease the body lipid content of Jian carp.