Dynamic changes in gut microbiota of three breeds of stud boars pre- and post-amoxicillin administration.

INTRODUCTION

Amoxicillin is a commonly used broad-spectrum antibiotic in pig farming, valued for its cost-effectiveness and efficacy in addressing prevalent swine ailments. However, the specific effects on the gut microbiota of stud boars and the trajectory of microbial recovery post-antibiotic withdrawal remain insufficiently elucidated.

METHOD: This study aimed to investigate the dynamic trajectory of gut microbiota in 40 Large White (LW), 47 Landrace (LAN), and 16 Duroc (DUR) stud boars before (D0), during (D7), and after (D14) amoxicillin administration (100 mg/kg of feed from D3 to D7) using 16S rRNA sequencing.

RESULTS

Amoxicillin significantly reduced alpha diversity (measured by observed species and the Shannon index) in LW and LAN stud boars at D7, with partial recovery by D14. In contrast, DUR stud boars showed no significant changes in diversity. Principal coordinate analysis revealed distinct microbial community structures across different time points, with samples from D7 forming a separate cluster, distinct from those collected on D0 and D14. At the genus level, Lactobacillus and Streptococcus were predominant in LW and LAN, with relative abundances increasing during amoxicillin treatment and decreasing post-withdrawal. In DUR stud boars, Prevotella and Lactobacillus were more abundant. Functional predictions indicated changes in KEGG pathways related to metabolism and drug resistance. These findings highlight the breed-specific responses of gut microbiota to amoxicillin. While LW and LAN showed signs of recovery after the withdrawal of the antibiotic, DUR exhibited resilience.

CONCLUSION

Taken together, this study aids in optimizing antibiotic use in pig farming, reducing resistance risks, and promoting sustainable animal health.