Changes in bacterial community and expression of genes involved in intestinal innate immunity in the jejunum of newborn lambs during the first 24 hours of life

Abstract

The newborn gut undergoes rapid colonization by commensal microorganisms and possible exposure to pathogens. The contribution of colostrum intake to host protection is well known; however, limited research exists on the intestinal innate immunity corresponding to colostrum intake during the passive immune transfer period in newborn ruminants. The aim of this study was to investigate the changes in bacterial community and expression of genes encoding toll-like receptors (TLR), mucins (MUC), antimicrobial peptides, and tight junctions in the jejunum of lambs that were fed colostrum during the first 24 h of life. Twenty-seven newborn lambs were used in this study, of which 18 lambs were bottle-fed pooled bovine colostrum within the first 2 h after birth to obtain an intake of approximately 8% of body weight. Lambs were slaughtered at 12 (n = 9) and 24 h (n = 9) after birth. The remaining 9 lambs without any feeding were slaughtered at 30 min after birth (0 h). Tissue and ligated segment samples from the jejunum were collected immediately after the lambs were slaughtered. The bacterial profile in the ligated jejunum segment was assessed using amplicon sequencing. The gene expression in the jejunum tissue was determined using quantitative real-time PCR. The relative abundances of Escherichia-Shigella, Lactobacillus, Lactococcus, and Streptococcus increased, whereas those of Sphingomonas, Phyllobacterium, Bradyrhizobium, and Rudaea decreased during the first 24 h of life. Expression of TLR2 and β-defensin 109-like was upregulated at 12 h after birth, but a recovery was detected at 24 h; TLR3, TLR5, LYZ, MUC1, MUC13, MUC20, and CLDN7 showed a higher expression level in samples taken at 24 h than in those taken at 0 h. In addition, expression level of CLDN1, CLDN4, and the junctional adhesion molecule-1 tended to be higher at 24 h than at 0 h after birth. Correlation analysis indicated that TLR2 expression was negatively correlated with the relative abundance of Lactobacillus and Bradyrhizobium, whereas TLR5 expression was positively correlated with the relative abundance of Escherichia-Shigella and Pelagibacterium. These results suggest that TLR, MUC, antimicrobial peptides, and CLDN act together and play an important role in intestinal defense during the passive immune transfer period. They are potentially associated with microbial colonization. The findings from this study provide novel information to elucidate the role of colostrum components in regulating the development of the intestinal mucosal immune barrier in newborn lambs during the passive immune transfer period.

Maternal Supply of Ruminally-Protected Lysine and Methionine During Close-Up Period Enhances Immunity and Growth Rate of Neonatal Calves

“…Provision of adequate immunoglobulin (Ig) mass to calves is essential for survival, health, and future productivity ( 16 ). Colostrum components also participate in regulating the development of the intestinal mucosal immune barrier in newborn lambs during the passive immune transfer period ( 17 ). However, failed passive transfer (FPT) is a common problem in newborn calves ( 18 ), causing increased mortality, diarrhea, respiratory diseases, and septicemia in young calves ( 19 – 21 ), and even decreasing their first lactation milk yield ( 22 , 23 ).…”

Shifts in intestinal microbiota and improvement of sheep immune response to resist Salmonella infection using Toll-like receptor 4 (TLR4) overexpression

“…The TLRs are associated with microbial colonization. The expression of TLR2, TLR4, and TLR5 in the jejunum of newborn ruminants was significantly correlated with the relative abundance of bacteria, which play an important role in intestinal defense during the passive immune transfer period ( Zhu et al, 2021 ). Correlation analysis indicated that TLR4 expression was negatively correlated with the relative abundance of Bradyrhizobium and Rudaea.…”

Colostrum Induced Passive Immune Transfer in Lambs

“…Pinocytosis of enterocytes also have a role in that maternal antibody absorbtion by the newborn [37]. PIT is a complex of reactions by acting together Toll-Like Receptors, Mucins, antimicrobial peptides, and Claudins in intestinal defense during the PIT in newborn lambs [38]. On the other hand, Fc receptor mediated pathways are key mechanism in IgG metabolism [39].…”