Tenebrio molitor and Zophobas morio Full-Fat Meals in Broiler Chicken Diets: Effects on Nutrients Digestibility, Digestive Enzyme Activities, and Cecal Microbiome

Simple Summary In animal nutrition, the links among health status, alimentary tract factors and gastrointestinal tract (GIT) integrity are increasing in importance. It has been documented that insects are useful as novel ingredients in poultry diets because they contain bioactive compounds such as chitin, melanin, and antimicrobial peptides, in addition to protein and dietary fat, and these bioactive compounds have been reported to modulate the GIT microbiome. From this perspective, insects could be promising functional feed additives to stimulate GIT health through inhibition of potentially pathogenic bacteria. Therefore, we evaluated the effect of the addition of a small amount of insects to the broiler chicken diet on the GIT microbiota composition and activity. Six experimental groups were used in the current study, i.e., two different levels (0.2% and 0.3%) of yellow mealworm and super mealworm full-fat meals, a positive control with salinomycin addition, and a negative control without any additives. Insect full-fat meals were capable of improving the health status of the birds by a positive reduction in potentially pathogenic bacteria in the cecal digesta and stimulation of the GIT microbiome to produce enzymes, especially glycolytic enzymes. Abstract This study was conducted to investigate the effect of insect full-fat meals added in relatively small amounts to a complete diet on the coefficients of apparent ileal digestibility, short-chain fatty acid (SCFA) concentrations, bacterial enzymes, and the microbiota community in the cecal digesta of broiler chickens. In total, 600 one-day-old female Ross 308 broiler chicks were randomly assigned to six dietary treatments with 10 replicate pens/treatment and 10 birds/pen. The groups consisted of a negative control (NC) with no additives; a positive control (PC; salinomycin 60 ppm), and supplementation with 0.2% or 0.3% Tenebrio molitor or Zophobas morio full-fat meals. Z. morio (0.2%) addition increased the activities of alpha- and beta-glucosidase and alpha-galactosidase. Dietary insects significantly decreased the cecal counts of the Bacteroides-Prevotella cluster in comparison to those in the NC and PC. Whereas, Clostridium perfringens counts were increased in the broiler chickens subjected to the 0.3% Z. morio treatment. In conclusion, small amounts of full-fat insect meals added to broiler diets were capable of reducing the abundance of potentially pathogenic bacteria, such as the Bacteroides-Prevotella cluster and Clostridium perfringens. In addition, this supplementation was able to stimulate the GIT microbiome to produce enzymes, especially glycolytic enzymes.