AUTHOR=Liu En , Sun Mengxue , He Chenxin , Mao Kang , Li Qin , Zhang Jianhong , Wu Deyong , Wang Shuzhen , Zheng Chuanxia , Li Wenbin , Gong Shimin , Xue Fuguang , Wu Huadong 

TITLE=Rumen Microbial Metabolic Responses of Dairy Cows to the Honeycomb Flavonoids Supplement Under Heat-Stress Conditions

JOURNAL=Frontiers in Veterinary Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.845911

DOI=10.3389/fvets.2022.845911

ISSN=2297-1769

ABSTRACT=Flavonoids expressed critical roles in stabilizing microbial homoeostasis when animals suffered exoteric stresses. However, whether flavonoids attenuated dairy cows under heat stress is still not clear. Therefore, in the present article, flavonoids extraced from honeycomb were supplemented to investigate the productive, and rumen microbial metabolism responses of cows under heat stress contion. Total of 600 multiparous dairy herds were randomly alloted into the control treatment (CON), the heat stress (HS) treatment, and honeycomb flavonoids supplement (HF) treatment for a 30-days-long trial. Each treatment contains 4 replicates, with 50 cows in each replicate. Production performances including dry matter intake (DMI), milk production, and milk quality were measured on the basis of replicate. Further, 2 cows of each relicate were selectred for the measurement of ruminal fermentable parameters including ruminal pH, volatile fatty acids (VFAs), and ammonia-N, rumen microbial communities, and rumen metabolites. Results showed that, HF effectively increased DMI, milk yield, milk fat, and ruminal acetate content (P<0.05). Further, relative abundances of rumen microbial diversities especially Succiniclasticum, Pseudobutyrivibrio, Acetitomaculum, Streptococcus and Succinivibrio which mainly participated in energy metabolism significant improved after HF supplement. Metabolomic investigation indicated that HF supplement significantly up-regulated relative content of lipometabolic related metabolites such as phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylserine (PS), and phosphatidylethanolamine (PE), while down-regulated biogenic amines. In summary, HF supplement help proliferated microbial abundances and further promoted nutrients degradability and energy providation, which may ultimately enhance the production performances of dairy cows under heat stress condition.