Physiological and Microbial Community Dynamics in Does During Mid-Gestation to Lactation and Their Impact on the Growth, Immune Function, and Microbiome Transmission of Offspring Kids.

This study investigated changes in physiological processes and rumen microbial communities in does from mid-gestation to lactation and identified potential associations between these physiological changes and the rumen microbiome. Additionally, we studied the transmission mechanisms of microorganisms between the dam and offspring. Our study demonstrates significant changes in maternal physiological metabolism, immune status, and rumen microbiota from mid-pregnancy through lactation. We identified potential associations between these physiological changes and the rumen microbiome. Moreover, the findings highlight that alterations in maternal physiological metabolism and immune status significantly influence the growth and immune development of offspring kids. Additionally, we observed that the maternal microbiota serves as a key source of gastrointestinal microbial communities in young animals, with early colonization of maternally derived microbes in the offspring's gastrointestinal tract playing a role in shaping their immune system development. The results for primary outcomes are as follows: The serum levels of estrogen and progesterone in pregnant does were greater than those observed during lactation, while the concentration of growth hormone, triiodothyronine, and glucose exhibited an upward trend during lactation. During late gestation, the serum IL-10 concentration in does decreased, while the TNF-α concentration increased. Additionally, on day 140 of gestation, does showed a significant decrease in IgG, total protein, and globulin levels. From mid-gestation to lactation, the abundance of dominant phyla and genera, including Firmicutes, Bacteroidetes, , , , , and , in the rumen of does underwent significant changes. LEfSe analysis identified a series of marker microorganisms in the rumen of does at different physiological stages. A correlation was observed between these dominant bacteria and the serum physiological indicators of the does. Notably, rumen volatile fatty acids also exhibited a correlation with serum physiological indicators. In addition, serum physiological indicators of does were significantly correlated with the growth and immune indicators of their kids. Microbiological origin analysis revealed that the gastrointestinal microbiome of kids primarily originated from the rumen, birth canal, and milk of does. Further analysis identified a correlation between the kids' serum immunometric indicators and certain gastrointestinal microorganisms. In particular, the jejunum microbiota of 28-day-old lactating kids, including , , and , showed a significant positive correlation with serum IL-6 and IL-10 levels. Meanwhile, these genera were dominant in the saliva and milk of does, suggesting a direct microbial transfer from dam to offspring. These microbial communities may play a significant role in modulating the metabolism and immune responses of the offspring, thereby influencing their immune system development.