Impact of gestational antibiotics on maternal and offspring gut microbiota and growth in pigs

Maternal microbiota modulates the development of the microbiota in the offspring. Effects of gestational antibiotics are not well understood, as most studies have focused on the perinatal period. We treated sows with penicillin, tetracycline or saline on days 78-80 of the 114-119-day gestation, a critical period in the fetal immune system development. Microbiotas were analyzed by 16S rRNA gene amplicon sequencing in sow feces and vagina at days 77 and 113, in colostrum, and in piglet feces at three days, three weeks and ten weeks of age. Sow fecal microbiota changed during pregnancy, but less in antibiotic groups. No significant effects on sow microbiota remained on day 113. The piglets of the antibiotic-treated sows had lower Firmicutes+Actinobacteriota to Bacteroidota+Proteobacteria ratio, lower alpha diversity and higher relative abundance of Escherichia at three days. At ten weeks, they exhibited higher alpha diversity, had higher of Prevotella and Clostridium sp. CAG-127, and smaller increase of Limosilactobacillus than the control. Increased alpha diversity at 10 weeks was associated with lower weight gain during nursing. Oliverpabstia and Mitsuokella were positively associated with weight gain, while CAG-127 and Campylobacter B were negatively associated. Sow antibiotic treatment decreased the positive effect of Oliverpabstia and Mitsuokella and increased the negative effects of CAG-127 and Campylobacter B . Gestational antibiotics may have had adverse effects on microbiota and growth of the offspring, even if their effects on maternal microbiota were undetectable by parturition.