奶牛人工授精后7天阴道和粪便微生物组及靶向代谢组分析OA

This study aimed to investigate the differences and correlations in vaginal and fecal microbiota structure and blood metabolic profiles in dairy cows at different pregnancy states following timed artificial insemination(TAI).A total of 43 healthy cows were selected for synchronization treatment,and blood,vaginal,and fecal samples were collected on day 7 after TAI.The return-to-estrus cows were determined using pedometers from days 18 to 24 after TAI,and pregnancy diagnosis was conducted via ultrasonography at(33±3)days.The cows were divided into the return-to-estrus group(FQ),non-pregnant group(WRS),and pregnant group(RS).Six cows from each group were selected for 16S rRNA sequencing to characterize the vaginal and fecal microbiota.Plasma concentrations of bile acids and steroid hormones were measured using LC-MS targeted metabolomics,and the activities of total antioxidant capacity(T-AOC),superoxide dismutase(SOD),glutathione peroxidase(GSH-Px),and the contents of malondialdehyde(MDA)were detected using ELISA.The results showed that,on day 7 after TAI,1)the SOD levels were significantly higher in the pregnant and return-to-estrus cows than in the non-pregnant cows(P<0.05),and the MDA levels was significantly lower in the pregnant cows than in the non-pregnant cows;2)there were no significant differences of bile acids and steroid hormones in the plasma of the 3 groups(P>0.05);3)the Chao1 index of the fecal microbiota in the non-pregnant cows was significantly higher than that in the pregnant and return-to-estrus cows(P<0.05),and the Ace index was significantly higher than that in the return-to-estrus cows(P<0.05);4)at the genus level,the relative abundance of Anaerovibrio,Intestinibacter,and Eubacterium_hallii_group in the vaginal microbiota of the pregnant cows was significantly higher than that in the non-pregnant group,and the relative abundance of Lachnospiraceae_AC2044_group,Butyrivibrio,and Lachnospiraceae_UCG-007 in the fecal microbiota of the return-to-estrus cows were significantly higher than that in the pregnant cows;5)correlation analysis revealed that SOD in the plasma was significantly positively correlated with Anaerovibrio,Intestinibacter,and Eubacterium_hallii_group in the vaginal microbiota(P<0.05),these genera might contribute to embryonic development by providing lipid-derived energy substrates.In contrast,plasma SOD levels were significantly negatively correlated with relative abundance of Butyrivibrio and Proteiniphilum in feces(P<0.05),indicating that these genera might disrupt systemic oxidative balance and impair immune tolerance at the maternal-fetal interface.In summary,pregnant cows exhibited enhanced plasma antioxidant capacity on day 7 post-TAI.The correlations between SOD and specific microbial genera reveal a state of functional instability characterized by the coexistence of antioxidant compensation and metabolic dysbiosis in specific microbial communities.These findings provide new insights into the microbial-host interaction mechanisms underlying successful pregnancy establishment in dairy cows.