Probiotic effects of Lactococcus lactis and Leuconostoc mesenteroides on morphology, fecundity, and longevity in Caenorhabditis elegans

Probiotic supplementation has been widely studied showing that it can sustain significant therapeutic benefits to overall health, which depends on the overall composition of the microbiome. In this study, we investigated the supplementation of potential probiotic lactic acid bacteria Lactococcus lactis and Leuconostoc mesenteroides in the gut of Caenorhabditis elegans and observed their effects in survival, size and morphology, and fecundity. Survival assays were used to analyze median and total lifespan, where analysis was performed until death. Fecundity assays were performed with the number of progenies counted daily. Body morphometrics were analyzed where length, width, area, and speed were recorded. Intestinal permeability was also evaluated using a dye-leakage assay (Smurf). Survival analysis using CeMbio, a C. elegans natural microbiome, demonstrated a decrease in survival when supplemented with L. lactis and L. mesenteroides, compared to the supplementation of the standard E. coli OP50 diet. In terms of morphometrics, OP50-fed C. elegans supplemented with L. mesenteroides were smaller and slower when compared to L. lactis-supplemented OP50, which were larger and faster. Fecundity showed that OP50 supplementation with L. mesenteroides or L. lactis produced higher amounts of progeny than the L. mesenteroides or L. lactis monocultures. Intestinal permeability was shown to be higher in both L. lactis and L. mesenteroides, which also show to have an increase in longevity when compared to OP50. These results highlight the potential and beneficial applications for these lactic acid bacteria as a therapeutic probiotic. Our study indicates that both L. lactis and L. mesenteroides when supplemented with OP50 has a positive influence on the overall health and longevity of C. elegans.