The dietary protein requirement of a new Japanese strain of juvenile Chinese soft shell turtle, Pelodiscus sinensis

A feeding trial was conducted to determine the optimum dietary protein requirement of a new Japanese strain of juvenile Chinese soft-shell turtle, Pelodiscus sinensis. Five iso-energetic diets were formulated to contain graded protein levels of 340, 370, 400, 430 or 460 g kg(-1) diet and fed to triplicate groups of turtles (mean initial weight, 3.70 +/- 0.05 g) for eight weeks. The turtles were reared in 350-L indoor plastic containers (15 turtles/container) provided with aerated freshwater. For each graded increase of dietary protein up to 430 g kg(-1) diet, growth performance of the soft-shell turtles increased significantly. No further growth increase was observed beyond this dietary protein level. The highest feed efficiency and protein productive value were observed in P. sinensis fed the 430 g protein kg(-1) diet. In general, the apparent digestibility coefficients (ADC) of dry matter, crude protein and gross energy increased significantly with increasing dietary protein levels. No significant differences were observed in the ADC of crude lipid among all experimental groups. Turtle whole-body protein content increased significantly from 15.2% to 16.8% with a corresponding decrease in moisture content (75.5% to 74.2%) when fed increasing dietary protein levels. The lowest concentrations of serum protein and cholesterol were observed in turtles fed 340 or 460 g protein kg(-1) diet. Aspartate transaminase activity in turtles fed 340 g protein kg(-1) diet was significantly higher compared to those fed 400 or 430 g protein kg(-1) diet. Broken-line regression analysis indicated that juvenile P. sinensis (Japanese strain) requires 422.0 g protein kg(-1) diet for optimum growth. (C) 2013 Elsevier B. V. All rights reserved.