Effects of supplementation with defrosted full-fat black soldier fly (Hermetia illucens) larvae on growth performance and gut histology in broilers

Abstract The use of black soldier fly larvae (BSFL) as an alternative protein source in broiler nutrition has attracted increasing interest; however, information on the effects of defrosted full-fat BSFL supplementation remains limited. This study evaluated the dose-response effects of top-dressed defrosted full-fat BSFL (10 and 20% of the previous day’s feed intake) on growth performance, gut histology, and blood metabolic markers of Ross 308 broilers. A total of 150 one-day-old male broilers were randomly allocated to three groups. The control group (CON) received a commercial corn-soybean meal-based basal diet ad libitum , while the BSFL10 and BSFL20 groups received the same diet supplemented with 10% or 20% BSFL. Growth performance and blood samples were collected on days 21 and 35. The BSFL20 group exhibited a significant increase in average daily gain (ADG) during days 22–35 and 1–35 ( ). The observed linear increase in ADG was associated with a significant linear increase in the villus height-to-crypt depth ratio in the jejunum ( ). Furthermore, BSFL20 reduced circulating triglyceride, alkaline phosphatase (ALP), and D-lactate levels ( ). There were no significant effects on the heterophil:lymphocyte (H:L) ratio, or other standard haematological parameters ( ). In conclusion, supplementation of defrosted full-fat BSFL up to 20% of the diet enhanced growth performance, improved gut histology, and induced beneficial changes in blood lipid profiles and metabolic markers in broilers, supporting the use of BSFL as a sustainable and functional feed ingredient in broiler production.