Thermophile-fermented feed modulates the gut microbiota related to lactate metabolism in pigs.

Aims: Extracts of fermented feed obtained via fermentation of marine animal resources with thermophilic Bacillaceae bacteria increase the fecundity of livestock. The intestinal bacterial profiles in response to long-term administration of this extract to pigs were investigated.

Methods and results: Half of a swine farm was supplied with potable water containing an extract of fermented feed for more than 2 years, whereas the other half was supplied with potable water without the extract. Feces from 6-month-old pigs rearing in these two areas were collected. 16S rRNA gene sequencing and isolation of lactic acid bacteria revealed an increase in the D/L-lactate-producing bacterium, Lactobacillus amylovorus, and a decrease in several members of Clostridiales following administration of fermented feed. A lactate-utilizing bacterium, Megasphaera elsdenii, was more abundant in the feces of pigs in the fermented feed group. All representative isolates of M. elsdenii showed rapid utilization of D-lactate relative to L-lactate, and butyrate and valerate were the main products.

Conclusion: The probiotic effect of fermented feed is associated with the modulation of lactate metabolism in the digestive organs of pigs.