Alterations of endotoxin distribution across different biofluids and relevant inflammatory responses by supplementing L-theanine in dairy cows during heat stress

Zuo Wang; Lingmei Zhang; Zhicai Li; Yuannian Yu; Lingyuan Yang; Peihua Zhang; Weijun Shen; Fachun Wan; Jianhua He; Wenjun Xiao; Dasheng Yang; Zhiliang Tan; Shaoxun Tang

doi:10.1016/j.aninu.2021.03.012

Alterations of endotoxin distribution across different biofluids and relevant inflammatory responses by supplementing L-theanine in dairy cows during heat stress

Anim Nutr. 2021 Dec;7(4):1253-1257. doi: 10.1016/j.aninu.2021.03.012. Epub 2021 Sep 23.

Authors

Zuo Wang¹, Lingmei Zhang¹, Zhicai Li², Yuannian Yu¹, Lingyuan Yang¹, Peihua Zhang¹, Weijun Shen¹, Fachun Wan¹, Jianhua He¹, Wenjun Xiao³, Dasheng Yang⁴, Zhiliang Tan⁴, Shaoxun Tang⁴

Affiliations

¹ College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, 410128, China.
² Deren Dairy Co. Ltd., Changde, Hunan, 415921, China.
³ College of Horticulture, Hunan Agricultural University, Changsha, Hunan, 410128, China.
⁴ 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 Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China.

Abstract

The present trial was performed to reveal the regulatory effects of L-theanine on the levels of lipopolysaccharide (LPS) endotoxin within different biofluids, as well as relevant inflammatory responses of dairy cattle under heat stress conditions. Thirty lactating Chinese Holstein dairy cattle (189 ± 47 days in milk, and 2 ± 1 parities) were allocated in a completely randomized design to each of 3 dietary treatments: the control (CON, 0 g/d per cow L-theanine), the low L-theanine dosage treatment (LL, 16 g/d per cow L-theanine), and the high L-theanine dosage treatment (HL, 32 g/d per cow L-theanine). This trial consisted of 38 d (7 d for adaption and 31 d for data and sample collection), and sample collection for rumen liquid, blood plasma or serum, and milk were conducted on the d 27 and 38, respectively. Dairy cattle were constantly exposed to environmental heat stress during this experiment according to the recorded temperature-humidity index (THI). In the LL treatment, LPS concentration in rumen liquid was higher (P < 0.05), whilst LPS densities in plasma and milk were lower (P < 0.05) than those of the CON. Supplementing L-theanine at 2 dosages both significantly lowered (P < 0.05) the level of interleukin (IL)-1β in the serum. Results of the present study suggested that L-theanine could be a promising additive in reducing the detrimental effects of heat stress on dairy cows, and L-theanine supplementation at 16 g/d per cow is preferred because it reduced the LPS translocation into the peripheral blood and LPS accumulation in the milk, as well as mitigated LPS-induced inflammatory reactions in dairy cows during heat stress. Further studies are necessitated to investigate the underlying mechanisms of L-theanine in LPS alteration and inflammation alleviation.

Keywords: Endotoxin; Heat stress; Inflammation; L-theanine.