Effects of Dietary Betaine on Growth Performance, Digestive Function, Carcass Traits, and Meat Quality in Indigenous Yellow-Feathered Broilers under Long-Term Heat Stress
Effects of Dietary Betaine on Growth Performance, Digestive Function, Carcass Traits, and Meat Quality in Indigenous Yellow-Feathered Broilers under Long-Term Heat Stress
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DOI：
10.3390/ani9080506
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发表时间：
2019-08-01
期刊：
影响因子：
3
通讯作者：
An, Lilong
中科院分区：
文献类型：
--
作者：
Liu, Wenchao;Yuan, Yilin;An, Lilong
热应激是热带和亚热带地区的主要问题之一，对家禽生产产生不利影响。本研究旨在探讨甜菜碱对长期热应激下黄羽肉鸡生长性能、消化功能、胴体性状和肉品质的影响。结果表明，长期热暴露降低了生长性能、消化功能和胴体产量，饲粮中添加甜菜碱可部分缓解热应激对这些指标的不利影响。本研究结果可为黄羽肉鸡抗热应激饲料添加剂的开发提供参考。热应激对家禽的健康和生产力有着深远的影响。本研究旨在探讨甜菜碱是否能改善长期热应激对黄羽肉鸡生产性能的影响。试验选用5周龄肉仔鸡240只，随机分为5个处理，每个处理6个重复，每个重复8只肉仔鸡。试验设热中性区对照组（TN）、热应激对照组（HS）和分别添加500、1000、2000 mg/kg甜菜碱的HS对照组。在整个研究期间，TN组在26 +/- 1 ℃下升高，HS组从上午9：00至下午17：00暴露于32 +/- 1 ℃下8小时/天。结果表明，热应激使1-5、6-10、1-10周龄肉仔鸡的增重和采食量显著降低（p < 0.05）。热应激5周时，饲粮中添加甜菜碱有利于提高肉仔鸡的日增重和采食量（线性，p < 0.10），且在6-10周和1-10周时，饲粮中添加甜菜碱均能提高肉仔鸡的日增重和采食量（线性，p < 0.05）。热应激5周和10周后，氮沉积率显著降低（p < 0.05），而甜菜碱能显著提高热应激5周和10周后肉鸡的氮沉积率（线性，p < 0.05）。热应激5周后，空肠胰蛋白酶活性显著下降（p < 0.05），而甜菜碱对热应激肉鸡空肠胰蛋白酶活性的影响呈二次曲线关系（p < 0.05）。热应激10周后，十二指肠和空肠绒毛高度显著降低（p < 0.05），空肠绒毛高度与隐窝深度比值显著降低（p < 0.05）。添加甜菜碱可改善热应激对这些指标的不利影响（p < 0.05）。与TN组相比，10周热应激降低了肉仔鸡的胴体和胸肌产量（p < 0.05），添加甜菜碱提高了热应激肉仔鸡的胴体和胸肌产量（线性，p < 0.05）。综上所述，饲粮中添加甜菜碱可降低长期热应激对黄羽肉鸡生长性能、消化功能和胴体性状的不利影响。
Simple Summary Heat stress, one of the major problems in tropical and subtropical regions, adversely affects poultry production. This study was designed to evaluate the effects of dietary betaine on growth performance, digestive function, carcass traits, and meat quality in indigenous yellow-feathered broilers subjected to long-term heat stress. The results demonstrated that long-term heat exposure reduced the growth performance, digestive function, and carcass yield, and dietary betaine supplementation partially alleviated the adverse effects of heat stress on these parameters. These findings are useful for development of anti-heat stress feed additives in indigenous yellow-feathered broilers. Heat stress has a profound effect on poultry health and productivity. The present study evaluated whether feeding betaine could ameliorate long-term heat stress-induced impairment of productive performance in indigenous yellow-feathered broilers. A total of 240 five-week-old male broilers were randomly allocated to five treatments with six replicates of eight broilers each. The five treatments included a thermoneutral zone control group (TN, fed basal diet), a heat stress control group (HS, fed basal diet), and an HS control group supplemented 500, 1000, 2000 mg/kg betaine, respectively. The TN group was raised at 26 +/- 1 degrees C during the whole study, HS groups exposed to 32 +/- 1 degrees C for 8 h/day from 9:00 am to 17:00 pm. The results showed that heat stress decreased the body weight gain (BWG) and feed intake of broilers during 1-5, 6-10, and 1-10 weeks (p < 0.05). Dietary betaine tended to improve the BWG and feed intake of broilers under 5 weeks of heat stress (linear, p < 0.10), and betaine supplementation linearly increased the BWG and feed intake during 6-10 and 1-10 weeks (p < 0.05). Additionally, nitrogen retention was reduced by 5 weeks and 10 weeks of heat stress (p < 0.05), whereas dietary betaine could improve nitrogen retention in heat stressed broilers after both 5 and 10 weeks of heat stress (linear, p < 0.05). Moreover, this study observed that the trypsin activity of jejunum was decreased by 5 weeks of heat stress (p < 0.05), whereas betaine supplementation had quadratic effects on trypsin activity of jejunum in heat stressed broilers (p < 0.05). Furthermore, 10 weeks of heat stress induced a reduction of villus height of the duodenum and jejunum (p < 0.05), and decreased the villus height to crypt depth ratio of the jejunum (p < 0.05). Supplementation with betaine ameliorated the adverse effects of heat stress on these parameters (p < 0.05). Compared with the TN group, 10 weeks of heat stress reduced carcass and breast yield (p < 0.05) and betaine supplementation improved carcass and breast yield of heat stressed broilers (linear, p < 0.05). In conclusion, dietary supplementation of betaine could reduce the detrimental effects of long-term heat stress on growth performance, digestive function, and carcass traits in indigenous yellow-feathered broilers.