Effect of black soldier fly (Hermetia illucens) larvae meal and oil on the performance, biochemical profile, intestinal health and gut microbial dynamics in laying hens

This study investigated the effect of incorporating black soldier fly (BSF) larvae meal and oil on laying hens' performance, egg quality, serum profile, intestinal structure, and gut health. A total of 378 Lohmann laying hens (age 48 wk) were randomly assigned to 6 treatments with 3 replicates of 21 hens each. Following 7 d acclimation, the trail was conducted for 8 weeks. The dietary groups include: basal corn-soybean meal diet (S) without BSF (BSO) oil (S+BSO 0), S with BSF oil (S+BSO 100), BSF meal (9 %) without BSF oil (BSF 9+BSO 0), BSF meal (9 %) with BSF oil (BSF 9+BSO 100), BSF meal (18 %) without BSF oil (BSF 18+BSO 0), and BSF meal (18 %) with BSF oil (BSF 18+BSO 100). The results showed that the BSF 18 + BSO 100 diet significantly reduced egg weight (P < 0.001) compared to other dietary treatments. The addition of BSF meal reduced feed intake (P < 0.001) and the Haugh units (P < 0.05) in hens fed 18 % BSF meal with and without BSO. The jejunum villus area, crypt depth, and intestinal wall thickness increased with the increase in the inclusion of BSF larvae meal (P < 0.001). The ileum villus height, crypt depth and intestinal wall thickness increased (P < 0.001) at 9 % BSF meal and then decreased at 18 % BSF meal with and without BSF oil. The bacteria genera Ruminococcus, Clostridiales, Bacteroidales, Ruminococcus torques, and Intestinimonas were positively associated with the dietary treatments, while Prevotellaceae UCG-001, Clostridium, and Faecalibacterium were negatively associated with the dietary treatments. The inclusion of BSF meal and oil enriched the functional network of several pathways, including ascorbate and aldarate metabolism, D-arginine and D-ornithine metabolism, and fatty acid metabolism, highlighting the positive effects of BSF larvae meal and oil on the chicken gut microbiota. In conclusion, BSF meal at 9 % with BSF oil and BSF meal at 18 % without BSF oil can be incorporated into the diet without impairing the performance and gut health of laying hens.