Black soldier fly (Hermetia illucens) larvae exoskeleton as a potential source of chitin in diets for juvenile channel catfish (Ictalurus punctatus)

Authors: SANTANA, THIAGO - Mississippi State University; DE S. FARIAS, ANA - Mississippi State University; Older, Caitlin; Romano, Nicholas; GATLIN, DELBERT - Texas A&M University; GRIFFIN, MATT - Mississippi State University; YAMAMOTO, FERNANDO - Mississippi State University; GONCALVES, LIGIA - National Institute Of Amazonian Research

Submitted to: Fish Physiology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2025
Publication Date: 8/4/2025
Citation: Santana, T.M., De S. Farias, A.B., Older, C.E., Romano, N.P., Gatlin, D., Griffin, M.J., Yamamoto, F.Y., Goncalves, L.U. Black soldier fly (Hermetia illucens) larvae exoskeleton as a potential source of chitin in diets for juvenile channel catfish (Ictalurus punctatus). Fish Physiology and Biochemistry. 51:135. 2025. https://doi.org/10.1007/s10695-025-01551-6.
DOI: https://doi.org/10.1007/s10695-025-01551-6

Interpretive Summary: Black soldier fly larvae (BSFL) are insects that have gained interest as an ingredient in fish feeds. This is due to BSFL being able to thrive on various organic wastes that could otherwise be left in landfills but also BSFL has an elevated content of high quality proteins and lipids. Insects, like BSFL, contain chitin that is part of their shell. Often reports state that excessive chitin in BSFL can disrupt nutrient utilization and, in extreme cases, cause injury to internal organs. This study set out to determine whether the inclusion of BSFL exoskeleton (or exuviae) actually causes harm in catfish or could improve their growth and health, based on measuring immune markers in the blood and survival to disease. This was compared with diets containing the same amount of chitin by in the form of shrimp shell. Results of this study showed no influence of BSFL exoskeleton or shrimp chitin on catfish growth or health and may have in fact led to harm based on lower survival to disease exposure.

Technical Abstract: The aim of this study was to investigate the dietary supplementation of chitin from the exoskeleton (exuviae) of black soldier fly larvae (BSFL) and purified chitin (PC) from shrimp in the production performance, health related parameters, and disease resistance of channel catfish juveniles. Five experimental diets were formulated (37% crude protein and 19.7 MJ gross energy kg-1): BSFL and PC at two inclusion levels of chitin (500 and 1000 mg kg-1), and a diet devoid of chitin was used as a control (37% crude protein and 19.7 MJ gross energy kg-1). The feeding trial was performed with 1,000 channel catfish juveniles (1.82 ± 0.12 g), randomly distributed into 25 experimental units (110 L; 40 fish aquarium-1), in a recirculating aquaculture system. The fish were fed rations based on the tank biomass for 9 weeks. Data from production performance, whole-body proximate composition, whole-blood and plasma immunological responses, intestinal microbial community profiles, as well bacterial challenge resistance were analyzed by a two-way ANOVA, having a 2 × 3 factorial design (BSFL and chitin as main factors and 3 graded levels). There was no impact on production performance, health parameters, and intestinal microbial community profile of juvenile catfish. The BSFL500 diet required less digestive effort, resulting in a lower viscerosomatic index. After the feeding trial, the remaining fish were subjected to a bacterial challenge (Edwarsiella ictaluri) for 28 days. Fish fed BSFL1000 and PC500 showed a lower cumulative survival rate. Chitin, at the tested dietary levels, does not seem to serve as a substrate for the intestinal microbiota or as a modulator of the intestinal microbiota of juvenile catfish.