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.