Gut Microbiota and Mucin Composition in Female Broiler Chickens Fed Diets including Yellow Mealworm (Tenebrio molitor, L.)

Simple Summary Gut health evaluation is a topic of great research interest in animal production, since the intestinal features (such as the microbiota and the mucin composition, as well as the mucosal morphology) are usually diet dependent, thus also directly influencing the growth performance of the animals. Insects are currently considered a novel, promising alternative protein source for animal feeding due to their remarkable nutritional properties, low competitiveness with human food and environmental implications, but data regarding the gut health of insect-fed animals are still very limited. We herein demonstrated that yellow mealworm (Tenebrio molitor, TM) meal utilization at low inclusion rates (5%) represents the most feasible alternative in terms of gut microbiota characteristics (identification of a phylum profile with better feed digestion and higher capacity of harvesting) and mucin dynamics (higher mucin production) in broiler chickens. Abstract A total of 160 female broiler chickens were divided into four dietary treatments (control feed [C] and 5, 10 and 15% TM meal inclusion, respectively, with five replicate pens/treatment and eight birds/pen) to investigate the effects of Tenebrio molitor (TM) meal utilization on poultry gut microbiota and mucin composition. The cecal microbiota assessment displayed a shift in the beta diversity in chickens fed TM-based diets. The TM10 and TM15 birds showed a significant decrease in the relative abundance of Firmicutes phylum and lower Firmicutes:Bacteroidetes ratios (False Discovery Rate [FDR] < 0.05), respectively, than the TM5 group. The relative abundance of Clostridium, Alistipes and Sutterella genera significantly increased in TM chickens (FDR < 0.05), while birds fed TM-based diets displayed a significant decrease in the relative abundance of Ruminococcus genus in comparison with the C group (FDR < 0.05). Gut mucin composition evaluation revealed higher mucin staining intensity in the intestinal villi of TM5 birds than the other TM groups, as well as mucin reduction in the intestinal villi of TM10 birds when compared to the C group (p < 0.05). In conclusion, dietary TM meal utilization (especially the 10-15% inclusion levels) may negatively influence either the cecal microbiota or the intestinal mucin dynamics of broiler chickens.