In vivo study of a high fiber cereal-legume derived syrup on Drosophila melanogaster life span and gut microbiota

It is well known that high fibre consumption has multiple positive effects on health, well-being, and healthy aging due to multiple factors (including positive gut microbiota modification)1. A high-fibre commercial natural syrup (MELTEC®, Hi-Food S.p.a) derived from legumes and cereals, was evaluated for its effect on life-spam and gut microbiota in a Drosophila melanogaster (fruit flies) model system. D. melanogaster flies were fed with a standard diet with or without a 0.25% MELTEC® supplementation. Gender effect was also accounted for. Life spam of D. melanogaster, kept at 25 °C with 12-hour light/dark cycles, was evaluated by recording the mortality rate every 3 days. Gut microbiota composition was analysed by 16S Miseq, starting 2 weeks after MELTEC® diet supply. MELTEC® supplementation was found to significantly extend life-spam of female flies as well as positively modify the intestinal microbiota. In particular, an increase in Bifidobacteria, Veillonella, Asaia and a decrease in Listeria species were observed. Conversely, no significant effect was found in male specimens both in respect of life-spam extension or microbiota composition, possibly due to the marked predominance of Acetobacter that may have hindered the proliferation of other bacteria species. This study indicates a positive effect of MELTEC® supplementation in female D. melanogaster, suggesting its potential role as prebiotic fibres and corroborating the need of taking into account gender differences in nutritional studies. Further studies to better assess MELTEC® positive effects in D. melanogaster and humans will be engaged in the next future