College of Animal Science and Technology, Northwest A&F University, Yangling, China.
Nano Vitamin Engineering Research Center of Shaanxi Province, Xi'an, China.
Poult Sci. 2022 Oct;101(10):101935. doi: 10.1016/j.psj.2022.101935. Epub 2022 Apr 30.
Attaining the optimal feed conversion ratio is the unaltered goal for poultry breeding, meat yield is one of the vital reference indexes for that. Folic acid is involved in protein metabolism by acting as a transmitter of one carbon unit, and the detail mechanism for the high-dose folic acid on growth of broiler skeletal muscle is still unclarified. The present study was conducted to investigate the effect and regulatory mechanism of folic acid on deposition and metabolism of protein in broiler breast muscle. A total of 196 one-day-old AA broilers were randomly assigned to 2 treatment groups. The chicks were fed corn-soybean diet with folic acid levels of 1.3 mg/kg (CON) or 13 mg/kg (FA), respectively. The results showed that high dose of folic acid significantly increased the body weight gain, average daily gain, average daily feed intake, and feed conversion ratio of broilers during 1 to 42 d. Compared with control group, folic acid statistically augmented the breast muscle ratio of broilers at 42 d, abdominal fat percentage was also decreased in FA group. Folic acid significantly increased the gene expression of folate receptor (FR) in duodenum and jejunum at 21 d, and its relative expression in jejunum of broilers at 42 d. Furthermore, relative expression of myogenin in broiler breast muscle was upregulated in folic acid group. Folic acid supplementation significantly enhanced the protein expression of phosphorylated serine/threonine kinase (AKT) and ribosomal protein S6 kinase 1 (S6K1) in the breast muscle of broilers at 21 d and 42 d. In conclusion, the results proved that high-dose folic acid activated the AKT/mammalian target of rapamycin (mTOR) pathway and increased the activity of phosphorylation of S6K1, thereby regulating the protein deposition in breast muscle. Meanwhile, the gene expression of the myogenic determinant factor was upregulated by folic acid and then promoted the growth of breast muscle. Consequently, the growth performance, meat production and feeding efficiency were improved of broilers by adding folic acid at 13 mg/kg.
实现最佳饲料转化率是家禽养殖不变的目标，而肉产量是其中一个重要的参考指标。叶酸作为一碳单位的载体参与蛋白质代谢，高剂量叶酸对肉鸡骨骼肌生长的作用机制尚不清楚。本研究旨在探讨叶酸对肉鸡胸肌蛋白质沉积和代谢的影响及其调控机制。将 196 只 1 日龄 AA 肉鸡随机分为 2 个处理组，分别饲喂叶酸水平为 1.3 mg/kg（CON）或 13 mg/kg（FA）的玉米-豆粕日粮。结果表明，高剂量叶酸显著提高了肉鸡 1 至 42 日龄的体重增重、平均日增重、平均日采食量和饲料转化率。与对照组相比，叶酸组 42 日龄肉鸡的胸肌比例显著增加，腹脂率也降低。叶酸组在 21 日龄时十二指肠和空肠中叶酸受体（FR）基因表达显著增加，42 日龄时空肠中的相对表达量也增加。此外，叶酸组肉鸡胸肌中肌生成素基因的相对表达量上调。叶酸添加显著增强了肉鸡胸肌中磷酸化丝氨酸/苏氨酸激酶（AKT）和核糖体蛋白 S6 激酶 1（S6K1）的蛋白表达，分别在 21 日龄和 42 日龄时。综上所述，结果表明高剂量叶酸激活了 AKT/哺乳动物雷帕霉素靶蛋白（mTOR）通路，增加了 S6K1 的磷酸化活性，从而调节胸肌中的蛋白质沉积。同时，叶酸上调了肌源性决定因子的基因表达，进而促进了胸肌的生长。因此，在日粮中添加 13 mg/kg 叶酸可提高肉鸡的生长性能、产肉性能和饲料效率。
