Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, National Engineering Research Center of Biological Feed, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China.
Beijing Stockbreeding Station, Beijing 100026, P. R. China.
Poult Sci. 2019 Oct 1;98(10):4632-4639. doi: 10.3382/ps/pez161.
The effect of dietary conjugated linoleic acid (CLA) supplementation on lipid metabolism in laying hens was investigated. A total of 360 eighteen-wk-old Hy-Line Brown layers were randomly divided into 4 groups that consisted of 6 replicates with 15 birds each. Birds were fed basal diets with 0, 1%, 2%, and 4% CLA addition. The experiment lasted for 56 D after a 7-D adaptation period. Results showed that dietary CLA addition linearly reduced (P < 0.05) abdominal fat percentage but linearly increased (P < 0.05) relative liver weight of layers on day 56. A linear reduction (P < 0.05) in serum low-density lipoprotein cholesterol (LDL-C) level and a linear elevation (P < 0.05) in the ratio of serum high-density lipoprotein cholesterol level to LDL-C level of layers on both days 28 and 56 were observed with dietary CLA addition, which also linearly decreased (P < 0.05) cholesterol content in the liver of layers on day 56 as well as in eggs on both days 28 and 56. Besides, there were linear reductions (P < 0.05) in the gene expression and contents of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and cholesterol 7 alpha hydroxylase 1 (CYP7A1), along with a linear increase (P < 0.05) in the gene expression and content of hepatic low-density lipoprotein receptor (LDLR) in layers responded to dietary CLA addition. In conclusion, dietary CLA supplementation decreased the accumulation of lipids including abdominal fat and cholesterol in the liver and egg of laying hens, probably by upregulating hepatic LDLR expression and downregulating hepatic HMGR and CYP7A1 expression.
研究了饲粮共轭亚油酸（CLA）添加对产蛋鸡脂代谢的影响。将 360 只 18 周龄海兰褐蛋鸡随机分为 4 组，每组 6 个重复，每个重复 15 只鸡。鸡饲喂基础饲粮，添加 0、1%、2%和 4% CLA。试验期为 56d，适应期为 7d。结果表明：饲粮 CLA 添加线性降低（P＜0.05）了产蛋鸡第 56 天的腹脂率，但线性增加（P＜0.05）了其肝脏相对重量。饲粮 CLA 添加线性降低（P＜0.05）了产蛋鸡第 28 天和第 56 天血清低密度脂蛋白胆固醇（LDL-C）水平和血清高密度脂蛋白胆固醇水平与 LDL-C 水平的比值，还线性降低（P＜0.05）了第 56 天肝脏和第 28 天和第 56 天鸡蛋的胆固醇含量。此外，饲粮 CLA 添加还线性降低（P＜0.05）了产蛋鸡肝脏中 3-羟-3-甲基戊二酰辅酶 A 还原酶（HMGR）和胆固醇 7α羟化酶 1（CYP7A1）的基因表达和含量，以及肝脏低密度脂蛋白受体（LDLR）的基因表达和含量（P＜0.05）。综上所述，饲粮 CLA 补充可减少腹脂和肝脏及鸡蛋中胆固醇等脂质的积累，这可能是通过上调肝脏 LDLR 的表达和下调 HMGR 和 CYP7A1 的表达来实现的。
