Comparative Analysis of Microbial Community Structure and Function in the Gut of South China Tigers Under Different Dietary Treatments

The gut microbiota is a crucial component of a tiger's health and plays a significant role in adapting to changes in food and the environment. Although extensive studies have been carried out on the gut microbiota of tigers, investigating the responses of gut microbial composition and function to preadaptation to wild predation patterns under captive conditions is particularly significant for South China tigers, given that it is the only tiger subspecies existing solely in captive settings at present. Here, we performed shotgun metagenomic sequencing for a comprehensive analysis of the gut microbiota of South China tigers assigned to two dietary groups (live prey group, LP group; frozen meat group, FM group), thereby generating abundant valuable data for this endangered subspecies. The results indicated that the core intestinal microbial composition was similar between the two dietary groups. Differential analysis revealed associations between dietary treatments and microbial abundance in the intestines of South China tigers. Functional gene analysis revealed that the LP group exhibited upregulation of genes and pathways related to antimicrobial resistance, bacterial infection-related disease, cell motility and proliferation, while the FM group displayed efficient energy metabolism. A total of 1251 antibiotic resistance genes (ARGs) were identified in the gut microbiome of South China tigers. The core resistome mainly included resistance to peptides, glycopeptides, tetracyclines, fluoroquinolones, and macrolides. In addition, the differences in ARGs between the LP group and FM group may be related to a broader range of animal tissues of live prey and the processing conditions of frozen meat. In summary, although feeding live prey did not change the core framework of the gut microbiota in South China tigers, it was associated with differences in microbial abundance, metabolic pathways, and antibiotic resistance gene profiles.