Evaluation of Enzymatically Hydrolyzed Hermetia illucens Larval Homogenate as a Dietary Supplement for 1–21-Day-Old Broilers: Growth Performance, Meat Quality, Serum Biochemical Indices and Intestinal Morphology

Conventional unprocessed black soldier fly larval meal often exerts inconsistent growth-promoting effects on broilers. This variability may arise from multiple factors, including dietary inclusion level, rearing substrate, processing method, defatting status, and nutritional composition; indigestible macromolecular proteins and chitin are among these contributing factors. Enzymatically hydrolyzed Hermetia illucens larval homogenate (EH-BSFLH) is rich in small peptides and lauric acid, which theoretically improve nutrient bioavailability and intestinal health, making it a promising novel functional feed additive. This study aimed to characterize the nutritional profile of a commercially available enzyme hydrolyzed Hermetia illucens larval homogenate (EH-BSFLH), and to explore the effects of 2% and 6% dietary EH-BSFLH supplementation on 1–21-day-old Arbor Acres (AA) broilers. A total of 126 one-day-old AA broilers were randomly assigned to three treatments in this 21-day starter feeding trial, with seven pens per treatment. Nutrient composition of EH-BSFLH and multiple phenotypic indicators of broilers were measured and statistically compared. EH-BSFLH utilized in this essay possessed unique nutritional characteristics, including high acid-soluble protein proportion (96.41% relative to total protein), abundant lauric acid (26.62% of total fatty acids), and a calcium-to-phosphorus (Ca/P) ratio of 3.10:1. The 6% EH-BSFLH supplementation increased (p < 0.02, FDR < 0.05) 21-d live weight, average daily feed intake (ADFI), average daily gain (ADG), eviscerated yield and semi-eviscerated yield relative to the control, while no significant difference in feed conversion ratio (FCR) was detected across treatments. Dietary EH-BSFLH at 2% and 6% increased (p < 0.02, FDR < 0.05) 24 h post-mortem pH of breast and thigh muscles, without affecting meat color or shear force. The 6% EH-BSFLH group elevated (p < 0.02, FDR < 0.05) 10 amino acids in thigh muscle, while maintaining stable essential amino acids/total amino acids (EAA/TAA) and essential amino acids/non-essential amino acids (EAA/NEAA) ratios. Moreover, 6% EH-BSFLH decreased duodenal crypt depth and increased Villus Height/Crypt Depth (VH/CD) ratios in duodenum and jejunum (p < 0.02, FDR < 0.05). Serum biochemical variables were generally comparable between groups, though differences were observed for glucose, albumin, alanine aminotransferase, aspartate aminotransferase, and total cholesterol (TCHO) (p < 0.02, FDR < 0.05). None of these values indicated obvious pathological alterations. This modified insect product exhibits promising application potential for young broiler feeding under the current trial conditions, and the observed shifts in serum metabolic indices may provide partial reference for balancing production performance and broiler physiological status in practical diet formulation.