Partial replacement of monocalcium phosphate with neutral phytase in diets for grass carp, Ctenopharyngodon idellus
Article first published online: 8 SEP 2012
© 2012 Blackwell Verlag GmbH
Journal of Applied Ichthyology
Volume 29, Issue 3, pages 520–525, June 2013
How to Cite
Liu, L. W., Luo, Y. L., Hou, H. L., Pan, J. and Zhang, W. (2013), Partial replacement of monocalcium phosphate with neutral phytase in diets for grass carp, Ctenopharyngodon idellus. Journal of Applied Ichthyology, 29: 520–525. doi: 10.1111/jai.12021
- Issue published online: 6 MAY 2013
- Article first published online: 8 SEP 2012
- Manuscript Accepted: 15 MAY 2012
- Manuscript Received: 15 DEC 2011
- Wuhan SunHY Biology Co., Ltd.
- National Program on Key Basic Research Project. Grant Number: 2009CB118706
A 9-week experiment was designed to study the effects of partial replacement of monocalcium phosphate (MCP) with neutral phytase on growth, body compositions, serum biochemical statuses and intestinal digestive enzyme activities of grass carp, Ctenopharyngodon idellus. The control diet (designated as P2.0) was prepared with 2.0% MCP but without phytase. The three other diets (designated as PP1.5, PP1.0 and PP0.5, respectively) were supplemented with 1.5, 1.0 and 0.5% MCP, respectively, along with 500 FTU of neutral phytase kg−1 diet in each. After a 9-week feeding trial, fish (initial body weight: 43.44 ± 2.37 g) fed with PP1.5 and PP1.0 had no significant change in weight gain (WG), specific growth rate (SGR), protein efficiency rate (PER) or feed conversion ratio (FCR) compared with the control (P > 0.05) whereas fish fed with PP0.5 showed significantly lower growth performance in the above parameters. The crude lipid content in whole body or muscle of the fish fed with PP1.5 was significantly lower than the control while significantly higher in fish fed with PP0.5 (P < 0.05), whereas no obvious change was observed in the fish fed with PP1.0. For serum indices, higher serum alkaline phosphatase (Alkp), phosphorus (P) and calcium (Ca) contents were observed in fish fed with phytase-supplemented diets in comparison with the control. In addition, dietary phytase supplementation increased amylase activity and decreased lipase activity in both foregut and hindgut. The present study suggests that dietary MCP can be reduced when neutral phytase is added to the grass carp diet, and that the maximum MCP reduction level can be up to 1% when neutral phytase is supplemented at 500 FTU kg−1 diet.