Yang Lingyuan, Zhang Lingmei, Zhang Peihua, Zhou Yuli, Huang Xingguo, Yan Qiongxian, Tan Zhiliang, Tang Shaoxun, Wan Fachun
College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan 410128, China.
CAS Key Laboratory of Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Key Laboratory of Animal Nutrition & Physiology and Metabolism, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan 410125, China.
Anim Nutr. 2022 Aug 11;11:350-358. doi: 10.1016/j.aninu.2022.08.002. eCollection 2022 Dec.
The purpose of this study was to investigate the effects of dietary L-theanine supplementation on apparent nutrient digestibility, milk yield, milk composition, and blood biochemical indices of dairy cows under heat stress. Thirty Chinese Holstein cows (19.84 ± 2.42 kg milk/d, 192.36 ± 40.77 d in milk and 2 ± 0.93 parities) were divided into 3 groups of 10 animals each. The control group was fed a basal total mixed ration (TMR) diet, while treatment 1 (LTA16) and treatment 2 (LTA32) groups were fed a basal TMR diet supplemented with L-theanine at 16 and 32 g/cow per day, respectively. The results showed that feeding the dairy cows with LTA16 treatment decreased ( < 0.05) their rectal temperature, whereas feeding with LTA32 treatment decreased ( < 0.05) their rumen fluid ammonia nitrogen content. In comparison to the control group, the supplementation of L-theanine had no significant effect ( > 0.05) on the dry matter intake, nutrient digestibility, total volatile fatty acid (TVFA) concentration and molar proportion of volatile fatty acid, milk yield, milk composition, feed efficiency and antioxidant capacity of the dairy cows. The triglyceride (TG) content of the LTA32 group was significantly greater ( = 0.014) than that of the control group. With the increase in L-theanine dosage, the serum cholesterol (CHOL) content significantly increased ( = 0.013). The serum albumin (ALB; = 0.067), low-density lipoprotein cholesterol (LDL-C; = 0.053), and high-density lipoprotein cholesterol (HDL-C; = 0.067) contents showed an upward trend as L-theanine dosage increased. Ultimately, the results of this study show that supplementing dairy cow diet with L-theanine could decrease dairy cow rectal temperature, affect lipid metabolism, and potentially relieve the heat stress of dairy cows to some extent.
本研究旨在探讨在热应激条件下，日粮中添加L-茶氨酸对奶牛表观养分消化率、产奶量、乳成分及血液生化指标的影响。选取30头中国荷斯坦奶牛（日产奶量19.84±2.42 kg，泌乳天数192.36±40.77 d，胎次2±0.93），随机分为3组，每组10头。对照组饲喂基础全混合日粮（TMR），处理1组（LTA16）和处理2组（LTA32）分别在基础TMR日粮中添加16 g/头·天和32 g/头·天的L-茶氨酸。结果表明，LTA16处理组奶牛直肠温度降低（P<0.05），LTA32处理组奶牛瘤胃液氨氮含量降低（P<0.05）。与对照组相比，添加L-茶氨酸对奶牛干物质采食量、养分消化率、总挥发性脂肪酸（TVFA）浓度及挥发性脂肪酸摩尔比例、产奶量、乳成分、饲料效率和抗氧化能力均无显著影响（P>0.05）。LTA32组甘油三酯（TG）含量显著高于对照组（P=0.014）。随着L-茶氨酸添加量的增加，血清胆固醇（CHOL）含量显著升高（P=0.013）。血清白蛋白（ALB；P=0.067）、低密度脂蛋白胆固醇（LDL-C；P=0.053）和高密度脂蛋白胆固醇（HDL-C；P=0.067）含量随L-茶氨酸添加量增加呈上升趋势。本研究结果表明，在奶牛日粮中添加L-茶氨酸可降低奶牛直肠温度，影响脂质代谢，并在一定程度上缓解奶牛热应激。
