Gut microbiota and blood metabolomics in weaning multiparous sows: Associations with oestrous

This study was conducted to detect the potential relationship between changed plasma metabolites, intestinal microbiota and the weaning-to-oestrous interval in multiparous sows after weaning. Multiparous sows were allocated to two groups after weaning: the oestrous group (n = 15) with a weaning-to-oestrous interval ≤7 days or the anoestrous group (n = 15) with a weaning-to-oestrous interval >14 days. The levels of plasma reproductive hormones: oestradiol, follicle-stimulating hormone and luteinizing hormone, plasma total protein; blood urea nitrogen; cholesterol; high-density lipoprotein; and ammonia (NH₃ ) were significantly lower in the anoestrous sows compared with the oestrous sows (p < .05). The plasma metabolomics analysis identified 14 metabolites (lactose, l-cysteine, cytosine, hydantoin, palmitoleic acid, arachidic acid, linoleic acid methyl ester, α-ketoglutaric acid, N(ε)-trimethyllysine, threo-β-hydroxyaspartate, 3-(3-hydroxyphenyl) propionic acid and others) with lower concentrations and 12 metabolites (noradrenaline, 5-dihydrocortisone, p-cresol, 1,4-cyclohexanedione, 2,3-dimethylsuccinic acid and others) with higher concentrations in the anoestrous group compared with the oestrous group (p < .05). The 16S rRNA pyrosequencing analysis showed the relative increase in abundance of the Prevotella and the Bacteroides at the genus level in the anoestrous group (p < .05). At the phylum level, lower proportions of Firmicutes and Lentisphaerae were observed in the anoestrous group (p < .05). This study provided a comprehensive assessment of metabolic differences in the blood and differences in the gut microbiome composition between anoestrous and oestrous sows. And suggesting that this profiling approach may offer new insights into explaining the alteration of the gut microbiota and blood metabolomics are correlated with sex hormone secretion and the weaning-to-oestrous interval of sows after weaning.