Changes in Intestinal Microflora Diversity of Diarrhea Calves among Different Seasons using Metagenomic Sequencing Analysisor

Abstract

Background: To improve the prevention and control of diseases and level of feeding management of newborn calves, diversity analysis of their gut microbiota was conducted to explore the changes in their gut microbiota during different seasons. Methods: Based on metagenomic sequencing and high-throughput sequencing techniques, the diversity of gut microbiota, functional abundance, and differences in resistance genes of diarrhea calves in different seasons were analyzed. Result: At the phylum level, Firmicutes and Actinobacteria have always been significant dominant microbiota in the four seasons; at the genus level, Bacteroides exists in all four seasons; the variation pattern of microbial communities in different seasons and the relative abundance will change in different seasons. The analysis of Beta diversity shows that compared to the gut microbiota of calves in summer and autumn, the diversity and richness of the microbiota in winter and spring are relatively high. The annotation of the gut microbiota of diarrhea calves through the KEGG database showed that the proportion of genes with metabolic function (Metabolism) was the highest. The annotation gene results showed that amino acid metabolism was the most abundant among metabolic functions. Through functional annotation of CARD, it was found that the types and numbers of antibiotic resistance genes corresponding to the gut microbiota of calves vary in different seasons, with tetW/N/W (the gene name should be in italics) being the main enriched antibiotic resistance gene type. At the same time, potential pathogenicity prediction also found a significant increase in disease risk in the winter group. Spring and winter being the seasons with high incidence of digestive tract diseases in calves.