Yu Yan, Qiu Jingyun, Cao Jincheng, Guo Yingying, Bai Hui, Wei Shengjuan, Yan Peishi
Department of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Anim Biosci. 2021 Sep;34(9):1569-1578. doi: 10.5713/ab.20.0750. Epub 2021 Feb 15.
This study was conducted to investigate the potential effects of prolonged photoperiod on the serum lipids, carcass traits, and meat quality of Jinjiang cattle during winter.
Thirty-four Jinjiang bulls aged between 14 and 16 months were randomly assigned to two groups that were alternatively subjected to either natural daylight +4 h supplemental light (long photoperiod, LP) or natural daylight (natural photoperiod, NP) for 96 days. The potential effects on the levels of serum lipids, carcass traits, meat quality, and genes regulating lipid metabolism in the intramuscular fat (IMF) of the cattle were evaluated.
Jinjiang cattle kept under LP showed significant increase in both dry matter intake and backfat thickness. the serum glucose and the plasma leptin levels were significantly reduced, while that of melatonin and insulin were observed to be increased. The crude fat contents of biceps femoris muscle and longissimus dorsi muscle were higher in LP than in NP group. In longissimus dorsi muscle, the proportions of C17:0 and C18:0 were significantly higher but that of the C16:1 was found to be significantly lower in LP group. The relative mRNA expressions in IMF of longissimus dorsi muscle, the lipid synthesis genes (proliferatoractivated receptor gamma, fatty acid-binding protein) and the fatty acid synthesis genes (acetyl-coa carboxylase, fatty acid synthetase, 1-acylglycerol-3-phosphate acyltransferase) were significantly up-regulated in LP group (p<0.05); whereas the hormone-sensitive lipase and stearoyl-CoA desaturase 1 were significantly down-regulated in LP than in NP group.
Prolonged photoperiod significantly altered the growth performance, hormonal levels, gene expression and fat deposition in Jinjiang cattle. It suggested that the LP improved the fat deposition by regulating the levels of different hormones and genes related to lipid metabolism, thereby improving the fattening of Jinjiang cattle during winter.
本研究旨在探讨延长光照周期对冬季晋江牛血清脂质、胴体性状和肉质的潜在影响。
将34头14至16月龄的晋江公牛随机分为两组，分别接受自然光+4小时补充光照（长光照周期，LP）或自然光（自然光照周期，NP），持续96天。评估其对牛血清脂质水平、胴体性状、肉质以及肌肉内脂肪（IMF）中脂质代谢调节基因的潜在影响。
处于LP条件下的晋江牛干物质摄入量和背膘厚度显著增加。血清葡萄糖和血浆瘦素水平显著降低，而褪黑素和胰岛素水平则升高。LP组的股二头肌和背最长肌粗脂肪含量高于NP组。在背最长肌中，LP组C17:0和C18:0的比例显著较高，但C16:1的比例显著较低。LP组背最长肌IMF中脂质合成基因（增殖激活受体γ、脂肪酸结合蛋白）和脂肪酸合成基因（乙酰辅酶A羧化酶、脂肪酸合成酶、1-酰基甘油-3-磷酸酰基转移酶）的相对mRNA表达显著上调（p<0.05）；而激素敏感性脂肪酶和硬脂酰辅酶A去饱和酶1在LP组中的表达显著低于NP组。
延长光照周期显著改变了晋江牛的生长性能、激素水平、基因表达和脂肪沉积。这表明LP通过调节与脂质代谢相关的不同激素和基因水平来改善脂肪沉积，从而提高冬季晋江牛的育肥效果。
