A multi-omic assessment of the mechanisms of intestinal microbes used to treat diarrhea in early-weaned lambs

Abstract

Transplant of donor microbiota can significantly alter the structure of the host's intestinal microbiota and alleviate early weaning stress. Screening for alternative-resistant products by transplanting fecal bacteria from healthy lambs is a current research trend in the livestock industry. In the present study, fecal microbiota transplantation was performed in lambs with diarrhea during early weaning. The transplanted fecal microbiota greatly reduced the diarrhea and serum inflammatory factor levels caused by early weaning. Transcriptome sequencing revealed that fecal microbiota transplantation alleviated colonic inflammation and increased the expression of colonic ion transport proteins. In addition, the levels of Streptococcus, Enterococcus, and Escherichia Shigella decreased in the jejunum, cecum, and colon of the lambs; meanwhile, the levels of Bifidobacterium and multiple secondary bile acids, such as ursodeoxycholic acid, increased in the colon. Furthermore, the abundance of Bifidobacterium was significantly negatively correlated with the diarrhea index. The fecal microbiota transplantation reshaped the intestinal microbiota of early-weaned lambs, protected the intestinal physiology and immune barrier, and reduced weaning stress. In addition to making available bacteriological products for controlling intestinal inflammation in young lambs, this study offers a theoretical framework and technical system for the mechanisms by which microbiota transplantation regulates intestinal health in young lambs.IMPORTANCEBefore weaning, the digestive system of lambs is not well developed; hence, its resistance to infectious diseases is weak. Under intensive feeding systems, lambs can easily be stressed and the risk of bacterial infection is high, which causes diarrhea, which in turn may cause mortality and significant economic losses to the livestock industry. With the elimination of antibiotics in animal feed, the incidence of mortality due to intestinal illnesses in lambs has gradually increased. There are several types of probiotics routinely used in young animals, but the effects and processes of their usage have only been assessed in monogastric animals. The lack of data on ruminants, particularly sheep, has severely hampered the process of efficient and healthy sheep breeding. Therefore, there is an urgent need to identify effective and safe functional supplements for lambs.

Keywords: diarrhea; early-weaning stress; fecal microbiota transplantation; lambs.

Fig 1

FMT alleviates stress in early-weaned lambs. Diarrhea in lambs in the (A) PBS, (B) ABX, (C) FMT, and (D) HEA groups. (E) Changes in the diarrhea index during the testing period. (F) Ion channel protein expression in the colon tissue. (G) Serum levels of inflammatory factors. Mean ± SEM is shown (n = 6). *P < 0.05, **P < 0.01, and ***P < 0.001. The letters (a, b, c, and d) in panel E represent the two sets of significant differences at different time periods.

Fig 2

FMT alters lamb colonic gene expression. Volcano map (A) and Kyoto Encylopedia of Genes and Genomes (KEGG) enrichment analysis (B) of the differential genes in the PBS vs HEA groups. Volcano map (C) and KEGG enrichment analysis (D) of the differential genes in the PBS vs FMT groups. (E) Changes in gene expression related to colonic inflammation. Mean ± SEM is shown (n = 4). *P < 0.05, **P < 0.01, and ***P < 0.001.

Fig 3

FMT alters the structure of the intestinal microbiota. Alpha diversity of the jejunum (A), cecum (B), and colon (C) contents. Beta diversity of the jejunum (D), cecum (E), and colon (F) contents. Phylum level abundance of the jejunum (G), cecum (H), and colon (I) contents. *P < 0.05.

Fig 4

FMT alters the abundance of intestinal bacteria. Genus-level abundance of jejunum (A), cecum (B), and colon (C) contents. ASV abundance in the jejunum (D), cecum (E), and colon (F) contents. ASVs are listed with the corresponding genus. *P < 0.05, **P < 0.01, and ***P < 0.001.

Fig 5

FMT varies the levels of colon metabolites. (A) PLS-DA analysis. (B) Impact on bile acid levels and effects on bile acid-related metabolites. (C) Correlation analysis of bile acid-related metabolites with significantly different bacteria at the genus level. Red indicates a positive correlation, and blue indicates a negative correlation. *P < 0.05, **P < 0.01, and ***P < 0.001.