目的 探讨饲粮中添加牛至油对天露黄鸡腹脂沉积及脂肪代谢的影响，并通过模拟生产试验对牛至油降低肉鸡腹脂率效果进行验证。方法 实验室试验：选取24只65日龄雌性天露黄鸡，逐只称质量编号后，根据体质量相近的原则，随机分为3组，每组8只，单笼饲养；对照组饲喂基础饲粮(不含牛至油)，处理组分别饲喂含100和200 mg/kg牛至油的饲粮；试验开始前预饲喂3 d，正式试验时间为30 d，自由采食及饮水。模拟生产试验：选取270只65日龄雌性天露黄鸡，逐只称质量编号后，按照体质量相近的原则，随机分为3组，每组6次重复，每次重复15只，试验处理和饲养管理方法与实验室试验相同。实验室试验结束后称体质量计算生产性能指标，并屠宰，采集血液、肝脏、腹脂、胸肌、腿肌等样品，测定屠宰性能、血清生化指标和脂肪代谢相关基因的mRNA表达量。模拟生产试验结束后称体质量，并取样测定生产性能和屠宰性能，验证实验室试验结果。结果 实验室试验中，与对照组相比，饲粮添加200 mg/kg牛至油可显著提高天露黄鸡的平均日增体质量和胸肌率，显著降低天露黄鸡的耗料增重化和脂肪沉积，腹脂减少率达到23.51%；显著降低天露黄鸡肝脏中与脂肪合成相关基因的mRNA表达量，对肝脏中脂肪分解相关基因无明显影响。模拟生产试验结果与实验室试验相符，验证了牛至油具有降低天露黄鸡腹脂沉积的作用，与对照组相比，200 mg/kg牛至油添加组的腹脂减少率达到20.00%。结论 饲粮中添加200 mg/kg牛至油可显著降低天露黄鸡的腹脂沉积，其作用可能与降低肝脏脂肪酸的合成有关。
Objective To investigate the effects of oregano oil addition in the diet on abdominal fat deposition and fat metabolism of Tianlu yellow-feathered chicken, and verify the effect of oregano oil reducing abdominal fat rate of broiler through production simulation experiment.Method In laboratory experiment, twenty-four 65-day-old female Tianlu yellow-feathered chickens were selected. Each chicken was weighed and numbered, then randomly divided into three groups with eight chickens of each group according to the principle of weight similarity. Each chicken was fed in single cage. The control group was fed with basal diets (without oregano oil), while the other two groups were fed with diets containing 100 and 200 mg/kg oregano oil respectively for 30 days after 3 days’ pre-feeding. The chickens were fed by free eating and free drinking. In production simulation experiment, total 270 65-day-old female Tianlu yellow-feathered chickens were randomly divided into three groups according to the principle of weight similarity after weighing and numbering, with six replicates in each group and 15 chickens per replicate. All experiment protocols were the same as laboratory experiment. The chickens were weighed after the laboratory experiment to calculate production performance. Then the chickens were slaughtered to collect blood, liver, abdominal fat, breast muscle and leg muscle samples and determine slaughter performance, serum biochemical indicators and mRNA expression levels of fat metabolism related genes. After the production simulation experiment, the chickens were weighed and sampled to determine production and slaughter performances, and verify the results of the laboratory experiment. Result In laboratory experiment, compared with the control, 200 mg/kg oregano oil addition significantly increased Tianlu yellow-feathered chicken average daily weight gain and breast muscle rate, significantly reduced feed to gain ratio and abdominal fat deposition, with abdominal fat reduction rate of 23.51%. Adding 200 mg/kg oregano oil to the diets significantly reduced mRNA expression levels of fat synthesis related genes in liver of Tianlu yellow-feathered chicken, but had no obvious effect on fat decomposition related genes. The results of production simulation experiment conformed to those of laboratory experiment, and validated the effect of oregano oil reducing abdminal fat deposition. Compared with the control group, the abdominal fat reduction rate reached 20% in 200 mg/kg oregano oil addition group.Conclusion The 200 mg/kg oregano oil addition can significantly reduce abdominal fat deposition of Tianlu yellow-feathered chicken by reducing the synthesis of fatty acids in liver.