日粮硒添加水平对泰和乌骨鸡生产性能及组织黑色素含量的影响

 【目的】研究日粮添加硒对泰和乌骨鸡生产性能及组织黑色素含量的影响，探讨硒影响黑色素合成的作用机制。【方法】选用1日龄泰和乌骨鸡450只，随机分成6个处理组，每组设5个重复，每个重复15只鸡。6组试验鸡分别饲喂基础日粮添加0、0.10、0.30、0.50、0.70和0.90 mg·kg-1硒的日粮，饲养至4周龄。在4周末计算平均日增重和料重比，测定血清和组织谷胱甘肽过氧化物酶（GSH-Px）、酪氨酸酶（TYR）活性和黑色素含量。【结果】基础日粮中添加硒可显著改善泰和乌骨鸡生产性能（P＜0.05），当日粮硒添加水平为0.30 mg·kg-1时，泰和乌骨鸡生产性能最佳。添加0.10—0.70 mg·kg-1硒，可显著提高血清、肝脏、肾脏、胸肌和皮肤GSH-Px、TYR活性，并显著提高这些组织的黑色素沉积（P＜0.05）。平均日增重、料重比、血清和组织GSH-Px、TYR活性、黑色素含量与日粮硒添加水平呈显著的二次曲线变化（P＜0.05）。组织黑色素含量与组织GSH-Px、TYR活性以及组织TYR活性与组织GSH-Px活性存在显著的正相关关系（P＜0.05）。泰和乌骨鸡取得最大组织黑色素含量时硒的适宜添加水平高于取得最大日增重时的添加水平。【结论】日粮添加硒可改善泰和乌骨鸡生产性能和提高组织黑色素合成，且乌骨鸡维持组织最佳黑色素沉积时硒的适宜需要量高于维持最大生长需要量。日粮硒促进组织黑色素合成的作用与其提高机体抗氧化能力密切相关。

Effects of Dietary Selenium Supplementation on Growth Performance and Melanin Content in Tissues of Taihe Silky Fowls

【Objective】The objective of this study was to investigate the effects of dietary selenium (Se) supplementation on the growth performance and melanin content in tissues of Taihe Silky Fowls and to preliminarily explore the mechanism underlying the effects of selenium on melanin biosynthesis.【Method】A total of 450 one-day old Taihe Silky Fowls were randomly allotted into 6 groups with 5 replicates of 15 birds each. Each group was fed the basal diet supplemented with 0.00, 0.10, 0.30, 0.50, 0.70 or 0.90 mg·kg-1 Se to 4 weeks of age, respectively. At the end of 4 weeks of age, average daily gain (ADG) and feed to gain ratio (F/G) were calculated, and glutathione peroxidase (GSH-Px) activity, tyrosinase (TYR) activity, melanin content in tissues were determined.【Result】Se supplementation in the basal diet significantly improved the growth performance of Taihe Silky Fowls (P＜0.05), and the maximum performance was obtained when Se supplementation level was 0.30 mg·kg-1. GSH-Px and TYR activities in serum, liver, kidney, pectoral muscle and skin were significantly improved and the melanin contents in these tissues were also increased (P＜0.05) when the diets were supplemented with 0.10-0.70 mg·kg-1 Se. Remarkable quadratic curve relationship between Se supplemental levels and ADG, F/G, GSH-Px, TYR activities and melanin content in tissues was observed (P＜0.05). Melanin content in tissues was positively correlated with GSH-Px and TYR activity (P＜0.05), respectively. The optimal Se supplementation level for obtaining maximum melanin content in tissues was higher than for obtaining maximum ADG.【Conclusion】Dietary supplementation with Se could improve growth performance and stimulate melanin biosynthesis of Taihe Silky Fowls, and the optimum Se requirement for melanin deposition in tissues was higher than for maximal growth. The stimulating effect of selenium on melanin synthesis may be related to the increased antioxidant capacity of body exerted by Se.