College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China.
Poult Sci. 2019 Jul 1;98(7):2927-2932. doi: 10.3382/ps/pez041.
This experiment was conducted to evaluate the effects of lysine deficiency or excess on growth and the expression of lipid metabolism genes in slow-growing birds. A total of 360 one-day-old chicks were randomly divided into 3 groups, with 6 replicates of 20 birds each. The birds fed the basal diet with a total lysine 0.60% (LL), 1.00% (ML), or 1.40% (HL). The amount of lysine (ML) as the control group, LL and HL as the experimental group, the trial period last 3 wk. The results showed that compared with ML, LL significantly decreased average daily gain and average daily feed intake and remarkably increased feed conversion ratio of birds at 21 day old (P < 0.01), while the above indices in HL had no significant effects (P > 0.05). Besides, LL reduced the pectoral muscle rate (P < 0.01) and decreased the percentage of abdominal fat significantly (P < 0.05). In addition, compared with ML, the expression of fatty acid binding protein 1 (FABP1), acetyl-CoA carboxylase (ACC), malic enzyme (ME), and sterol regulatory element binding protein 1 (SREBP1c) mRNA of liver in LL was significantly decreased (P < 0.05), and the expression of cholesteryl ester transfer protein (CETP) mRNA was significantly increased (P < 0.01), whereas LL had no significant effects on the expression of peroxisome proliferator activated receptor alpha (PPARα) mRNA (P > 0.05). Moreover, compared with ML, HL significantly reduced the expression of FABP1, ACC, ME, SREBP-1c, and PPARα mRNA in the liver (P < 0.05), and had no significant effects on the expression of CETP mRNA (P > 0.05). The results of current research suggest that dietary lysine deficiency could reduce the growth and fat deposition of slow-growing broilers mainly by downregulating the expression of lipid synthesis genes.
本实验旨在评估赖氨酸缺乏或过量对生长缓慢的鸟类生长和脂质代谢基因表达的影响。将 360 只 1 日龄雏鸡随机分为 3 组，每组 6 个重复，每个重复 20 只鸡。鸡饲喂基础日粮，总赖氨酸 0.60%（LL）、1.00%（ML）或 1.40%（HL）。赖氨酸（ML）作为对照组，LL 和 HL 作为实验组，试验期为 3 周。结果表明：与 ML 相比，LL 显著降低了 21 日龄鸡的平均日增重和平均日采食量，极显著提高了料重比（P < 0.01），而 HL 组上述指标均无显著影响（P > 0.05）；LL 降低了胸肌率（P < 0.01），显著降低了腹脂率（P < 0.05）。此外，与 ML 相比，LL 显著降低了肝脏脂肪酸结合蛋白 1（FABP1）、乙酰辅酶 A 羧化酶（ACC）、苹果酸酶（ME）和固醇调节元件结合蛋白 1c（SREBP1c）mRNA 的表达（P < 0.05），显著增加了胆固醇酯转移蛋白（CETP）mRNA 的表达（P < 0.01），而对过氧化物酶体增殖物激活受体α（PPARα）mRNA 的表达无显著影响（P > 0.05）。此外，与 ML 相比，HL 显著降低了肝脏 FABP1、ACC、ME、SREBP-1c 和 PPARα mRNA 的表达（P < 0.05），对 CETP mRNA 的表达无显著影响（P > 0.05）。本研究结果表明，饲粮赖氨酸缺乏可通过下调脂质合成基因的表达来降低生长缓慢肉鸡的生长和脂肪沉积。
