Loss of probiotics from natural microbiome of the fousefly due to high-sucrose diet

We investigated how the rearing substrate affected the gut microbiota of housefly larvae across the course of thirteen consecutive generations. We tested a control substrate, a high-fat, and a high-sucrose substrate. We measured larval development and investigated the changes to microbiota. We found a significant effect of the high-sugar diet on the gut bacterial communities, in contrast to the high-fat diet. The high-sugar diet led to lower developmental success and less diverse gut bacterial communities, in which several Lactobacilli were replaced with bacteria phylogenetically related to the Weissella genus. Bacterial cultures with sucrose as the sole carbon source confirmed that a Weissela confusa strain, isolated from housefly larvae, could utilize sucrose more efficiently than other tested lactic acid bacteria. Enhancing the rearing substrate with Limosilactobacillus fermentum and Lactiniplantibacillus plantarum strains, which were isolated from the control larvae, could not only revert the bad effect of the high-sucrose diet on larval growth, but could also restore the richness of the larval gut bacterial community, as shown by bacterial survey.