Lactobacillus fermentum CECT5716 supplementation in rats during pregnancy and lactation affects mammary milk composition.

Lactobacillus fermentum CECT5716 has shown immunomodulatory action and reduction of infections; therefore, it is suggested to be appropriate for use in early life. The present study aimed to assess the effects of the supplementation of L. fermentum CECT5716 in rats during gestation and lactation periods on the composition of some mammary milk components such as microbiota, fatty acid (FA) profile, and immunoglobulins. Wistar rats were supplemented by oral gavage with 10 cfu/d of Lactobacillus fermentum CECT5716 (n = 6) or vehicle (n = 6) for 5 wk, comprising the 3 wk of gestation and the first 2 wk of lactation. At the end of the intervention, milk, mammary glands, and cecal contents were obtained for the tracking of the probiotic strain by nested PCR-quantitative PCR. Additionally, milk samples were used for the analysis of microbiota by 16S rRNA sequencing, FA by gas chromatography-flame ionization detector, and immunoglobulin by Luminex (Luminex Corporation, Austin, TX). Although L. fermentum CECT5716 administration did not modify the overall composition of milk microbiota, the strain was detected in 50% of the milk samples of rats supplemented with the probiotic. Moreover, probiotic administration induced beneficial changes in the FA composition of milk by increasing total PUFA, including linoleic and α-linolenic acids, and decreasing the proportion of palmitic acid. Finally, the milk of the rats treated with the probiotic showed a 2-fold increase of IgA levels. The supplementation with L. fermentum CECT5716 during pregnancy and lactation periods improved the milk composition of FA and immunoglobulins. These effects were not linked to the presence of the strain in milk, thus suggesting that the mechanism is connected to intestinal compartment. These findings provide novel insight into a potential new approach for infants to benefit from better nutrition, development of a healthy immune system and microbiota, and protection from gastrointestinal infections.