Dynamic Changes in the Nutrient Digestibility, Rumen Fermentation, Serum Parameters of Perinatal Ewes and Their Relationship with Rumen Microbiota.

Changes in physiological and biochemical parameters are crucial for the reproductive performance and health of perinatal ewes. This study investigated the temporal variations in feed intake, nutrient digestibility, serum parameters, and ruminal fermentation on days 21, 14, and 7 before lambing (Q21, Q14, and Q7) and days 3, 7, and 14 after lambing (H3, H7, and H14). The results showed that dry matter intake (DMI) and glucose (Glu) gradually decreased ( < 0.05) before lambing and increased ( < 0.05) after lambing. The digestibility of dry matter (DMD), crude protein (CPD), and acid detergent fiber (ADFD) increased ( < 0.05) before lambing, then decreased ( < 0.05) on day H3, and then increased ( < 0.05) on day H14. The rumen pH, NH-N, and triglycerides (TG) gradually increased ( < 0.05) before lambing and were higher ( < 0.05) on day Q7 than after lambing. The concentrations of acetate, butyrate, and total volatile fatty acids (T-VFA) were lower ( < 0.05) on day Q7 than those on days Q21 and Q14, then increased ( < 0.05) after lambing. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) concentrations gradually decreased ( < 0.05) in perinatal ewes. BHBA and NEFA concentrations were lower ( < 0.05) on day Q21 than those from days Q14 to H14. The rumen microbiota compositions were different ( < 0.05) in perinatal ewes, and , , and were positively correlated ( < 0.05) with DMI, Glu, acetate, propionate, and T-VFA, and negatively correlated ( < 0.05) with LDL-C. was negatively correlated ( < 0.05) with DMI, Glu, acetate, propionate, butyrate, and T-VFA, but positively correlated ( < 0.05) with rumen pH and LDL-C. In summary, the DMI, nutrient digestibility, rumen fermentation, and serum parameters changed during the perinatal period of ewes, and the changes in DMI, serum glucose, acetate, propionate, and T-VFA were related to the rumen bacteria.