Doxycycline Attenuates Pig Intestinal Microbial Interactions and Changes Microbial Metabolic Pathways.

Area of Science:

• Veterinary Medicine
• Microbiology
• Animal Science

Background:

• Doxycycline is a widely used veterinary antibiotic in swine production.
• Understanding its impact on the gut microbiome and host physiology is crucial for responsible use.

Purpose of the Study:

• To investigate the effects of doxycycline administration on the intestinal microbial community structure and function in fattening pigs.
• To assess the impact of doxycycline on bacterial abundance, interactions, and metabolic pathways during medication and withdrawal periods.

Main Methods:

• Twenty-seven pigs were divided into three groups: control (0 mg/kg), low dose (3 mg/kg), and high dose (5 mg/kg) doxycycline.
• Medication was administered for 5 days, followed by a 28-day withdrawal period.
• Intestinal microbial community structure, abundance, co-occurrence networks, and metabolic pathways were analyzed.

Main Results:

• Doxycycline did not affect overall intestinal microbial diversity.
• Relative abundance of *Streptococcus* increased, while *Alishewanella*, *Vagococcus*, *Cloacibacterium*, and *Campylobacter* abundances correlated positively with doxycycline levels.
• High doxycycline concentrations weakened bacterial interactions, and altered cell membrane-related metabolic pathways.

Conclusions:

• Doxycycline use in pig breeding can alter bacterial abundance and interactions during the withdrawal period.
• The antibiotic may influence intestinal metabolic pathways, potentially affecting pig health and productivity.