From Wild to Farm: Gut Bacteriome Differences and Probiotic Potential of Pantoea Agglomerans in Two-Spotted Cricket (Gryllus Bimaculatus) Rearing

The gut microbiome plays a crucial role in insect nutrition and performance, yet its targeted exploitation in cricket farming remains underexplored. Here, we combined gut microbiota profiling of wild and farmed Gryllus bimaculatus with probiotic testing of host-derived bacterial isolates to explore microbiome-informed strategies for sustainable cricket farming. Wild crickets exhibited higher Shannon diversity but lower phylogenetic diversity than farmed counterparts. Wild populations were enriched in Oscillospiraceae and Christensenellaceae families, while farmed crickets showed higher abundance of Parabacteroides. From 199 bacterial isolates, wild populations showed higher frequencies of uricolytic capabilities (44% vs. 31%), related to nitrogen recycling, while farmed crickets had more pectinolytic isolates (70% vs. 50%), linked to plant fiber degradation. Pantoea agglomerans I53BLB, which demonstrated broad enzymatic capabilities, was selected for probiotic evaluation; we further provide its genome sequence and analysis to contextualize its metabolic and probiotic potential. A feeding experiment with a 2 × 3 factorial design (two diets × three probiotic treatments, n = 10 replicates per group) compared control chicken feed versus a high-fiber diet formulated with agricultural by-products, each supplemented with water, live or heat-inactivated P. agglomerans. A significant diet × probiotic interaction was observed for weight gain (χ² = 18.8, p = 0.0021) and adult emergence (χ² = 17.7, p = 0.0033). Live P. agglomerans enhanced performance only when combined with the high-fiber diet, with individuals reaching a mean wet weight of 0.602 g compared to 0.451 g (heat-inactivated, p = 0.035) and 0.427 g (water control, p = 0.003), and a significantly higher adult emergence rate (37%) compared to all other treatment combinations (13%, p < 0.05), suggesting a symbiotic effect likely related with carbohydrate digestion. No effects were observed on survival or reproductive output. Notably, the high-fiber diet alone performed comparably to commercial feed, suggesting potential for sustainable cricket production using agricultural by-products. These findings demonstrate the feasibility of microbiome informed probiotic strategies to enhance cricket farming efficiency while reducing feed costs.