铜、维生素A及互作效应对肉仔鸡肠壁组织结构、肠道微生物和血清生长激素的影响

 【目的】研究日粮中添加铜和维生素A及互作效应对肉仔鸡小肠各段肠壁厚度和绒毛高度、盲肠主要微生物、血清生长激素（GH）的影响。【方法】采用4×2(Cu×VA)完全随机试验设计，日粮Cu水平为0、8、150、225 mg?kg-1，VA水平为1 500、5 000 IU?kg-1，生长阶段分为前期（0～4 w）和后期（4～7 w）。选用1 d艾维茵肉仔鸡448只，随机分为8组，每组4个重复，每重复14只鸡，公母比为1﹕1。【结果】①前期添加Cu（8 mg?kg-1）生产性能较好，后期不添加Cu生产性能较好。②添加Cu 225 mg?kg-1明显降低生长前期肉仔鸡回肠肠壁厚度，添加Cu 150 mg?kg-1使生长后期肉仔鸡小肠各段肠壁厚度明显较低，在整个生长期，高铜对绒毛高度无影响;日粮添加Cu 150 mg?kg-1显著提高盲肠乳酸杆菌和双歧杆菌数量，降低大肠杆菌数量，添加Cu 225 mg?kg-1显著降低盲肠乳酸杆菌和双歧杆菌数量，增加大肠杆菌数量;Cu 8 mg?kg-1组盲肠沙门氏菌数量最低。③日粮中添加VA5 000 IU?kg-1显著降低前期小肠各段肠壁厚度和后期空肠肠壁厚度、提高前期十二指肠绒毛高度;显著增加盲肠大肠杆菌、乳酸杆菌、前期沙门氏菌和双歧杆菌的数量;④Cu和VA交互作用显著影响前期回肠肠壁厚度、后期空肠肠壁厚度(P＜0.05);极显著影响前期十二指肠绒毛高度、后期十二指肠和回肠绒毛高度、前后期盲肠内乳酸杆菌、双歧杆菌、大肠杆菌和沙门氏菌数量(P＜0.01);⑤Cu、VA及互作对血清GH无影响(P＞0.05)，前期GH平均水平高于后期。【结论】日粮添加Cu 150 mg?kg-1和VA 5 000 IU?kg-1有益于肉仔鸡小肠肠道形态和盲肠肠道菌群平衡;Cu和VA存在互作效应。

Influence of Various dietary Copper and Vitamin A Levels on Intestinal Wall Structure, Cecal Gut Flora and GH in Serum in Broilers

【Objective】 A 4×2 (Cu×VA) experiment with replicates was designed to investigate the influence of various dietary Cu and vitamin A levels on performance, intestinal wall thickness and villus height, cecal gut flora, growth hormone in serum in broilers of different stage (0-4 and 4-7 weeks). 【Method】 The dietary Cu at 0, 8, 150, 225 mg?kg-1 diet and vitamin A at 1 500, 5 000 IU?kg-1 diet were used. Four hundred and fourty-eight avin broilers of 1 day old were randomly allotted to 8 groups, each of which was replicated four times with fourteen broilers per replicate. 【Result】 The performance from 0-4 weeks in group with 8mg?kg-1 copper was better, but from 4-7 weeks group with 0 copper was better. Dietary copper level (225 mg?kg-1 diet) only decreased the ileac wall thickness at the end of week 4, dietary copper level (150 mg?kg-1) significantly decreased the wall thickness of various parts of small intestine at the end of week 7, high copper levels had no effect on villus height in the whole period. When copper supplemental level was 150 mg?kg-1 diet, the amounts of Lactobaccilus and Bifidobacterium significantly increased, and the amounts of E.coli decreased. When copper level was 225 mg?kg-1, the amounts of E.coli significantly increased, and the amounts of Lactobaccilus and Bifidobacterium decreased, the amounts of Salmonella were the least in group with 8 mg?kg-1, copper. Supplement with 5 000 IU?kg-1 VA decreased the intestinal wall thickness at the early stage and the jejunal wall thickness at the later stage significantly, but increased the villus height of duodenum, increased the amounts of Lactobaccilus and E.coli in the whole period and the amounts of Bifidobacterium and Salmonella at the early stage. The interaction of Cu and VA significantly affected the ileac intestinal wall thickness at the early stage, jejunal intestinal wall thickness at the later stage (P＜0.05), duodenal villus height at the early stage, villlus height of duodenum and ileum at the later stage (P＜0.01), the amounts of Lactobaccilus, Bifidobac- terium, E.coli and Salmonella through the whole period (P＜0.01). The level of dietary copper and VA had no effect on GH in serum (P＞0.05), the concentration at the early stage was higher. 【Conclusion】 Dietary copper level (150 mg?kg-1) and dietary VA level (5 000 IU?kg-1) is beneficial to the absorption of nutritive materials and the balance of gut flora. The interaction between dietary copper and VA existed.