Abstract
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.