甜菜碱对热应激肉鸡生长性能、十二指肠消化酶活性及盲肠微生物区系的影响

摘要

The study was performed to explore the effects of betaine on growth performance, activities of duo-denum digestive enzymes and cecal mircoflora of heat-stressed broilers. A total of 270 14-day-old Arbor Acres ( AA) broilers were randomly divided into 6 groups with 3 replicates per group and 15 chicks per replicate. The experimental groups including normal temperature group, heat-stressed group, normal temperature+0.1% beta-ine group, heat-stressed+0.1% betaine group, heat-stressed+0.2% betaine group, and heat-stressed+0.4% be-taine group. Heat stressed broilers were reared in high ambient temperature at (32±1) ℃. The pre-test lasted for 7 d, and formal test lasted for 21 d. The results showed as follows:1) body weight of heat-stressed broilers aged from 28 to 42 days was significantly increased (P<0.01), and the ratio of feed to gain of heat-stressed broilers aged from 22 to 35 days was significantly decreased by diet supplemented betaine ( P<0.01) . 2) The activities of trypsinase, amylase and pancrelipase in duodenum of heat-stressed broilers aged 28, 35 and 42 days were significantly increased by betaine with different concentrations ( P<0.05 or P<0.01) , except trypsi-nase activity of heat-stressed broilers of 28 days old fed diet supplemented with 0.1% or 0.2% betaine and am-ylase activity of heat-stressed broilers of 35 days old fed diet supplemented with 0.1% betaine were no signifi-cantly difference (P>0.05). 3) Diet supplemented with betaine could significantly increase the numbers of Lactobacillus in cecum (P<0.01), and significantly reduce the numbers of Clostridium perfringens in cecum of heat-stressed broilers ( P<0.01) . In conclusion, the basal diet supplemented with betaine may improve the growth performance, increase the activities of duodenum digestive enzymes and maintain the stabilization of ce-cal microflora of heat-stressed AA broilers, then release heat stress hazard to broilers.%本试验通过在饲粮中添加不同剂量的甜菜碱研究其对热应激肉鸡生长性能、十二指肠消化酶活性及盲肠微生物区系的影响。选取270只14日龄爱拔益加( AA)肉鸡随机分成6组：常温组、热应激组,常温+0.1%甜菜碱组、热应激+0.1%甜菜碱组、热应激+0.2%甜菜碱、热应激+0.4%甜菜碱组。热应激肉鸡饲养在(32±1)℃的高温环境中。每组3个重复,每个重复15只。预试期7 d,正试期21 d。结果表明：1)饲粮添加甜菜碱可极显著增加28~42日龄热应激肉鸡的体重( P<0.01),极显著降低22~35日龄肉鸡料重比( P<0.01)；2)除添加0.1%和0.2%甜菜碱饲粮对28日龄热应激肉鸡胰蛋白酶活性无显著影响( P>0.05)和添加0.1%甜菜碱对35日龄热应激肉鸡淀粉酶活性无显著影响( P>0.05)外,不同浓度的甜菜碱均能显著或极显著增加28、35、42日龄热应激肉鸡十二指肠胰蛋白酶、淀粉酶和胰脂肪酶活性( P<0.05或P<0.01)；3)饲粮添加甜菜碱极显著提高了28、35、42日龄热应激肉鸡盲肠内乳酸杆菌的数量(P<0.01),极显著降低了产气荚膜梭菌的数量( P<0.01)。由此可见,热应激状态下,在基础饲粮中添加甜菜碱可改善AA肉鸡生长性能,提高十二指肠消化酶的活性,维持盲肠内微生物区系平衡,从而减轻热应激对肉鸡的危害。