Long-Term Dietary Fish Meal Substitution with the Black Soldier Fly Larval Meal Modifies the Caecal Microbiota and Microbial Pathway in Laying Hens.

Feeding laying hens with black soldier fly larval (BSFL) meal improves their performance. However, the beneficial mechanism of BSFL meals in improving the performance of laying hens remains unclear. This study investigated the effects of the BSFL diet on liver metabolism, gut physiology, and gut microbiota in laying hens. Eighty-seven Julia hens were randomly assigned to three groups based on their diets and fed maize grain-and soybean meal-based diets mixed with either 3% fish meal (control diet), 1.5% fish and 1.5% BSFL meals, or 3% BSFL meal for 52 weeks. No significant differences were observed in biochemical parameters, hepatic amino acid and saturated fatty acid contents, intestinal mucosal disaccharidase activity, and intestinal morphology between BSFL diet-fed and control diet-fed laying hens. However, the BSFL diet significantly increased the abundance of acetic and propionic acid-producing bacteria, caecal short-chain fatty acids, and modified the caecal microbial pathways that are associated with bile acid metabolism. These findings indicate that consuming a diet containing BSFL meal has minimal effects on plasma and liver nutritional metabolism in laying hens; however, it can alter the gut microbiota associated with short-chain fatty acid production as well as the microbial pathways involved in intestinal fat metabolism. In conclusion, this study provides evidence that BSFL can enhance enterocyte metabolism and gut homeostasis in laying hens.

Egg quality and laying performance of Julia laying hens fed with black soldier fly (Hermetia illucens) larvae meal as a long-term substitute for fish meal.

The use of insects in animal feed appears to be an efficient approach that contributes to solving the environmental issues related to leftover disposal; however, it has not been approved in some countries due to concerns about pathogenic infections. This study aimed to evaluate the feasibility of long-term substitution of fish meal in poultry feed with organic defatted black soldier fly larvae (BSFL) meal prepared from BSFL raised on leftovers. The 87 Julia laying hens (178-day-old) were allotted in a completely randomized design with three treatments (29 layers in each treatment). The laying hens were fed maize grain and soybean meal-based diet containing either 3% fish meal, 1.5% fish meal and 1.5% BSFL meal, or 3% BSFL meal supplements for 52 wk (541-day-old). Results showed that substituting fish meal with BSFL meal had no effect on the laying rate, feed intake, and feed conversion ratio of laying hens, and only the complete replacement (3% BSFL meal) significantly increased the body weight of laying hens. In terms of egg quality, there was no significant effect on eggshell parameters (weight, thickness, and strength), albumen weight, yolk height, yolk color, and Haugh unit. However, both half (1.5% fish meal and 1.5% BSFL meal) and complete substitution of fish meal increased yolk weight (P < 0.01) and egg weight (P < 0.05). In conclusion, even if BSFL were fed leftovers and the meal was defatted with organic solvents, it can be used as a poultry feed ingredient without any adverse effect. Moreover, the complete substitution of fish meal with BSFL meal may be a feasible way to effectively contribute to the laying hens' performances and poultry farming costs. In addition to fish meal, the replacement of soybean meal with BSFL meal may also needs to be further studied for the extensive BSFL meal application in poultry feed.