Effects of Dietary Xanthophyll Supplementation on Growth Performance, Body Color, Carotenoids, and Blood Chemistry Indices of Chinese Soft‐Shelled Turtle Pelodiscus sinensis

A 12‐week experiment was conducted to investigate the effects of diets containing 0 (CD), 40 (X1), 80 (X2), and 120 mg/kg (X3) xanthophyll on the growth, body color, and blood chemistry of the Chinese soft‐shelled turtle Pelodiscus sinensis. Four hundred and eighty turtles with initial weight of 37.90 ± 0.26 g were randomly stocked equally in 12 cement ponds (4.0 × 5.0 × 0.8 m) to form four groups in triplicate. The turtles were fed one of the four diets (crude protein 48%, crude lipid 6%) twice daily, with the feed amount set at 3% of their total body weight. The results indicated that the supplement of 80 mg/kg xanthophyll in the diet had the most significant effect on growth, feed conversion ratio, and amino acid content in muscle tissue. The yellowness of the carapace and the plastron skin increased with higher xanthophyll levels. Moreover, the final yellowness in the plastron skin was higher than the initial yellowness. The carotenoid content in the liver and carapace was significantly enhanced with increasing xanthophyll levels and showed a significant linear correlation with the dietary xanthophyll supplement levels. The liver carotenoid content in the X2 and X3 groups and carapace skin carotenoid content in the X3 group were markedly higher than were those in turtles that were fed the control diet (P < 0.05). Compared with the control diet, adding xanthophyll significantly increased acid phosphatase activity in serum while obviously lowering the alanine aminotransferase activity. The triglyceride and total cholesterol content decreased with increases in xanthophyll. There were no significant differences in the serum superoxide dismutase and glutathione peroxidase activity in animals that received the xanthophyll‐supplemented and control diets. The current study results suggest that the growth performance and skin coloration of Chinese soft‐shelled turtle can be improved by including 80–120 mg/kg xanthophyll in the diet.