Diet-Dependent Variations in the Gut Microbiota and Metabolic Pathways of the land slug Deroceras laeve

The slug Deroceras laeve has emerged as a valuable model for biological research, but limited knowledge exists of the microbiota that inhabit the digestive tract of this species. This study assessed the bacterial microbiota of the stomach and intestine of D. laeve fed either a diet formulated for rodents (RD) or a diet of fresh vegetables (VD). Pseudomonadota was the most abundant phylum in both digestive compartments, although it decreased in abundance with the VD diet. The genus Rahnella was the most abundant in both regions with a decrease caused by the VD diet and a concomitant increase in richness. Predicted metabolic pathways indicated that fatty acid biosynthesis predominated in the stomach of slugs fed the RD, whereas pyruvate fermentation and amino acid biosynthesis were enriched in VD animals. In the intestine, aerobic respiration, pyruvate fermentation, fatty acid and amino acid biosynthesis were identified as conserved pathways. Predictive functional profiling revealed that signaling and cellular processes, genetic information processing, and metabolism were predominant functions across all groups. These results reveal a more diverse microbiome in slugs fed VD, paralleling the findings in other animals and providing a good grounding for the study of ecological adaptations of this species to its environment.