Age-Related Differences in the Gut Microbiota of Pigs Influence Fat Deposition in the Mouse.

Background: The gut microbiota significantly influences lipid metabolism, but the impact of its developmental patterns at different growth stages on fat deposition remains unclear.

Objectives: This study aimed to explore the dynamic changes in microbial diversity and composition during the growth of pig models and assess their involvement in fat deposition.

Methods: Forty-five Duroc-Landrace-Yorkshire (DLY) crossbred pigs were killed at 5 ages: 90, 120, 150, 180, and 210 d of age (n = 9). Fecal samples were collected 1 and 15 d before each killing, and the fecal microbiota were detected by 16S rRNA sequencing. The backfat thickness, serum lipid concentrations, intramuscular fat, and fatty acid content in the longissimus dorsi muscle of pigs were measured to assess lipid metabolism. Fecal microbiota transplantation (FMT) from DLY pigs of different ages to antibiotics-challenged mice (n = 8) was used to confirm the effects of microbial development on fat deposition. Metagenomic sequencing was conducted on feces from pigs aged 150 and 180 d and their corresponding transplanted mice to identify key strains involved in fat deposition.

Results: We observed marked alterations and an increase in intestinal microbial α-diversity with age, peaking at 150 d of age in DLY pigs (P < 0.05). Spearman correlation analyses indicated that 20 genera significantly correlated with the muscle fatty acid contents (P < 0.05). FMT further confirmed that the developmental patterns of the gut microbiota affected host fat deposition, with notable differences observed between the fecal microbiota at day 150 and 180 of age in pigs. Schaalia canis was identified as a potential key microbial strain involved in the developmental patterns of the gut microbiota-governed fat deposition, and its colonization in mice reduced fat deposition by downregulating of LXRα/β gene expressions (P < 0.05).

Conclusions: Gut microbiota development impacts fat deposition in pigs, with S canis capable of inhibiting fat deposition.