维生素A、D对肉鸡钙磷代谢相关激素水平的影响

试验旨在研究维生素A、D对肉鸡钙磷代谢相关激素水平的影响。采用4×4完全随机试验设计,将8日龄健康艾维茵雄性肉鸡384只称重后随机分为16个处理组。每个处理组设3个重复,每个重复8只鸡,试验期5周。其中,维生素A设4个添加水平,分别为1 500、3 000、15 000和45 000 IU/kg日粮。维生素D设4个添加水平,分别为500、1 250、2 500和5 000 IU/kg日粮。结果表明,45 000 IU/kg维生素A组的肉鸡血清BGP含量相对于1 500 IU/kg维生素A组有显著的降低趋势(P=0.08);随着日粮维生素A水平的增加(1 500～45 000 IU/kg),血清CaBP浓度呈趋于显著的一次线性降低趋势(P=0.092),血清维生素D3与CT含量也呈现降低趋势(P=0.12,P=0.18),其中,以15 000、45 000 IU/kg维生素A组较低,尤以45 000 IU/kg维生素A组最低;血清PTH含量呈显著的一次线性增加(P=0.029)。随着日粮维生素D水平的增加,血清维生素D3含量呈趋于显著的一次线性增加趋势(P=0.093),血清BGP浓度也呈一次线性增加趋势(P=0.14);其中,以2 500和5 000 IU/kg时较高,5 000 IU/kg时最高。由此可知,日粮维生素A过量引起肉鸡骨骼钙磷代谢发生障碍与血清CaBP浓度的降低及PTH浓度的增加有关,也与过量维生素A对维生素D的拮抗作用有关。

Effect of vitamin A and D on the hormone levels related calcium and phosphorous metabolism in broilers

The experiment was conducted to elucidate the effects of vitamin A and D on the hormone levels related to calcium and phosphorous metabolism in broilers.A total of three hundred and eighty-four 8-day-old Arbor Acre male broilers with similar body weight were randomly allotted into sixteen treatments with three replicates in every treatment and eight chickens each replicate.The trial lasted for five weeks.Broilers were fed four levels of dietary vitamin A(1 500,3 000,15 000 and 45 000 IU/kg) and four levels of vitamin D(500,1250,2 500 and 5 000 IU/kg) in a 4×4 factorial arrangement.The results showed that 45 000 IU/kg vitamin A group of chicken serum BGP concentration had the tendency to be significantly decreased compared with 1 500 IU/kg vitamin A group(P=0.08).Vitamin A decreased the content of CaBP and CT in serum of broilers in a linear dose-dependent manner(P=0.092,P=0.18),and the addition of 15 000 and 45 000 IU/kg vitamin A in the diet was more effective,and the addition of 45 000 IU/kg vitamin A in the diet was the most effective.Vitamin A depressed serum vitamin D3 content in a quadratic dose-dependent manner(P=0.12),and the supplementation of 15 000～45 000 mg/kg vitamin A in the diet was more effective.The results also showed that vitamin A improved serum PTH content in a linear dose-dependent manner(P=0.029),and the addition of 15 000 and 45 000 IU/kg vitamin A in the diet was higher,and the addition of 45 000 IU/kg vitamin A in the diet was the highest.The results also suggested that vitamin D improved theconcentrations vitamin D3 and BGP content in serum in a linear dose-dependent manner(P=0.093,P=0.14)while dietary vitamin D level was between 500 and 5 000 IU/kg,and the supplementation of 2 500~5 000 IU/kg vitamin D in the diet was more effective.The possible mechanism of excess vitamin A caused abnormal skeleton metabolism was that large amounts of vitamin A in diet reduced serum CaBP content and increased serum PTH content.It was probably related to antagonistic action of high levels of vitamin A on vitamin D.