Evaluation of the effect of black soldier fly (Hermetia illucens L.) larvae meal in the diet of red drum (Sciaenops ocellatus) juveniles on production performance and feed palatability

Authors: PAREDES, JUAN - Harbor Branch Oceanographic Institute; RICHE, MARTY - Harbor Branch Oceanographic Institute; BRADSHAW, DAVID - Harbor Branch Oceanographic Institute; MEJRI, SAHAR - Nofima; CHIN, LI - Harbor Branch Oceanographic Institute; PEREZ, JASMINE - Indian River State College; POPA, RADU - Stratium; Romano, Nicholas; WILLS, PAUL - Harbor Branch Oceanographic Institute

Submitted to: Frontiers in Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2025
Publication Date: 7/2/2025
Citation: Paredes, J.F., Riche, M., Bradshaw, D., Mejri, S., Chin, L.S., Perez, J., Popa, R., Romano, N.P., Wills, P.S. Evaluation of the effect of black soldier fly (Hermetia illucens L.) larvae meal in the diet of red drum (Sciaenops ocellatus) juveniles on production performance and feed palatability. Frontiers in Aquaculture. 4:1619878. 2025. https://doi.org/10.3389/faquc.2025.1619878.
DOI: https://doi.org/10.3389/faquc.2025.1619878

Interpretive Summary: Black soldier fly (Hermetia illucens) larvae are insects capable of converting various waste streams, such as agricultural by-products/waste, into high quality protein that has the potential to replace expensive fish meal (FM) in the diets of fish. The feasibility of replacing FM with black soldier fly meal (BSFM) in the diets of Red drum (Sciaenops ocellatus) juveniles were evaluated in a two-part study. The first part was a palatability (taste) trial to observe if the fish would actually consume or reject the BSFM feeds. The second part was an 8-week feeding trial to observe how fast the fish grew, if feeding efficiency was affected and morphological responses of the liver and intestine. Results showed that Red drum readily accepted diets with BSFM without any need for feeding attractants. The feeding trial showed that BSFM when replacing 25% FM could improve Red drum growth, possibly due to bioactive compounds within the BSFM. Replacing 50% FM with BSFL led to similar growth compared to the FM-based control diet. Intestinal bacteria showed Red drum likely adapted to the diets by increasing abundance of bacteria capable of digesting lipids and chitin. Higher FM replacement of 75% and higher led to some adverse responses in the liver and intestine as well as lower growth. The inclusion of BSFM to replace FM can substantially improve aquaculture sustainability and has the potential to reduce feeding costs.

Technical Abstract: Black soldier fly (Hermetia illucens) larvae are insects that capable of valorizinge various waste streams into protein that has the potential to replace fish meal (FM) in fish diets. To evaluate the feasibility of replacing FM with black soldier fly meal (BSFM) in the diets of Red drum (Sciaenops ocellatus) juveniles, a two-part study was conducted that included a palatability trial followed by an 8-week feeding trial with isonitrogenous and isoenergetic formulations. Palatability trial was conducted with BSFM replacing FM in diets at 0% (Control), 25% (BSFM25), 50% (BSFM50) and 100% (BSFM100) levels. Palatability assessment showed that Red drum feeding response was statistically similar between the Control and BSFM25 diets. The feeding trial included diets above plus BSFM replacing FM at 75% (BSFM75) and the effects on growth, feeding efficiency, whole-body biochemical composition, intestinal/liver histomorphology, and intestinal microbiome were assessed. Significantly better growth and feeding efficiency (P<0.05) were observed in fish fed BSFM25 diet compared to those fed BSFM50, BSFM75 and BSFM100 diets. Whole-body saturated fatty acids increased with higher level of BSFM in diets while levels of arachidonic acid (ARA), eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA) remained statistically similar in BSFM25 and BSFM50 compared to the Control. Liver histomorphology revealed increased hepatic that hepatocytes had increased vacuolization with increasing levels of BSFM. Intestinal microbiota presented high alpha diversity abundance among treatments, but fish fed BSFM diets tended to have genera associated with chitinase and lipase activity. Overall, dietary FM replacement with BSFM is an adequate alternative protein source considering a replacement up to 50%, but levels over 75% caused reduction in growth and hepatic lipid liver accumulation.