Co-evolution of Specific Gut Microbiota with Host Cold Adaptation Through Enhanced Vitamin B1 Synthesis

Min pigs exhibit remarkable cold tolerance, where Vitamin B1 synthesis by gut microbiota is crucial for the host energy metabolism. However, the underlying mechanisms of this synthesis and its role in cold adaptation are not fully understood. This study utilized amplicon and metagenomic sequencing to examine seasonal variations in the gut microbiota of Min pigs. Results indicated a significant winter increase in microbial diversity, with the Bacteroidetes group being the most notably increased. The B1 biosynthetic pathway was significantly enriched during winter, with six key genes (ThiC, ThiD, ThiE, ThiG, ThiH, and ThiL) showing strong evidence of purifying selection. Notably, ThiE appeared to experience a relaxation in selective pressure after undergoing this purifying selection. Sequences of these six B1 synthesis genes from various species revealed that the top ten with the greatest seasonal abundance differences were uniquely prevalent in Min pigs, possessing significantly lower substrate binding energies compared to those with minimal differences. Bacteroidetes and Bacteroidales were identified as the primary contributors to these gene sequences. This research provides valuable insights for developing innovative cold-resistant feed and probiotics.