Effects of dietary phosphorus and starch levels on growth performance, body composition and nutrient utilization of grass carp (Ctenopharyngodon idellaVal.).

摘要

Six iso-nitrogenous (410 g kg--1) diets with three levels of total phosphorus (P4, P10 and P18 g kg--1) and two levels of starch (S200 and S350 g kg--1) were fed to triplicate groups of 30 fish to evaluate whether the high level of dietary phosphorus could improve the utilization of starch. Over 8-week-growth trial, best weight gain (WG) and specific growth rate (SGR) (P < 0.05) were observed in fish fed the P10/S200 and P18/S200 diets. WG and SGR significantly decreased as starch levels increased whereas for P4, while lipid contents of liver and whole body, hepatosomatic index and intraperitoneal fat ratio (IPF) significantly increased. These results suggested that high dietary starch will depress the growth performance and cause lipid accumulation. Within both starch levels, fish fed diet with P4 tended to produce lower (P < 0.05) WG and SGR, and had higher (P < 0.05) values of IPF. The whole body lipid, ash, calcium, phosphorus and iron contents were significantly affected by dietary phosphorus levels. Supplied phosphorus could improve the growth and decrease the whole body lipid, but there is no more effect after the phosphorus requirement was met at 10 g kg--1