Changes of fecal microbiota with supplementation of <i>Acremonium terricola</i> culture and yeast culture in ewes during lactation

Ruminant physiology and nutrition undergo significant changes during lactation. This study aimed to investigate alterations in gut microbiota throughout lactation and examined the impact of supplementation with Acremonium terricola culture (ATC) and yeast culture (YC) on the gut microbiota of lactating ewes. Forty-five healthy Hu sheep ewes in late pregnancy (approximately 80 d of gestation) were randomly assigned to 3 groups. The control group (CON) was fed a basic diet, while the experimental groups received the same diet plus an extra 9 g/d of ATC (ATC) or 20 g/d of YC (YC). A total of 108 fecal microbial samples were collected from ewes at 1, 7, 30, and 45 d postpartum respectively. The samples were subjected to microbial sequencing utilizing the Illumina MiSeq-PE300 platform. The results indicated that the diversity of the fecal microbiota exhibited a pattern of initial increase, followed by a decrease, and then stabilization after parturition. The highest diversity of the microbiota was observed on the 7th day postpartum in the ewes. Supplementation with YC improved the fecal microbiota structure in lactating ewes, reduced the fecal alpha index, increased Firmicutes abundance, and decreased potentially harmful Spirochaetota bacteria (P < 0.05). Additionally, the inclusion of ATC and YC positively affected the relative abundance of specific bacterial genera, such as the Eubacterium coprostanoligenes group, Clostridia UCG-014, and Lachnospiraceae NK4A136 group (P < 0.05). The outcomes of the functional prediction analysis indicated that ATC and YC predominantly influence health status and bodily metabolism through their involvement in metabolic processes and the processing of genetic information. This includes reducing the biosynthesis and metabolism of lipopolysaccharides, enhancing key metabolic pathways, such as amino acids, and improving nicotinic acid/niacinamide metabolism (P < 0.05). In conclusion, the critical window for modulating the gut microbiota of lactating ewes is within the first 7 d postpartum. Supplementation with ATC and YC can adjust fecal microbial structure and function, positively impacting overall health. YC is more effective than ATC in these aspects. These results offer new insights into the regulation of intestinal microbiota during lactation and help identify the optimal timing for such interventions.