Preliminary assessment of the nutritive value of dietary exuviae from black soldier fly (Hermetia illucens) pupae in Mozambique tilapia

Authors: Romano, Nicholas; DATTA, SURJYA - Guru Angad Dev Veterinary & Animal Sciences University; PANDE, GDE S - Udayana University; SINHA, AMIT - University Of Arkansas At Pine Bluff; YAMAMOTO, F. - Mississippi State University; Rawles, Steven; Webster, Carl

Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2025
Publication Date: 5/14/2025
Citation: Romano, N.P., Datta, S.N., Pande, G.J., Sinha, A.K., Yamamoto, F., Rawles, S.D., Webster, C.D. Preliminary assessment of the nutritive value of dietary exuviae from black soldier fly (Hermetia illucens) pupae in Mozambique tilapia. Journal of the World Aquaculture Society. 56(3):e70027. 2025. https://doi.org/10.1111/jwas.70027.
DOI: https://doi.org/10.1111/jwas.70027

Interpretive Summary: Insect farming is gaining popularity as a sustainable means to produce protein and lipids as ingredients. It is expected that insect farming, particularly from black soldier fly larvae (BSFL) will increase because they can thrive on various organic waste that are unsuitable for human consumption. As BSFL farming increases, so too will their by-products. One of these by-products is the shell of the larvae called “exuviae” that contains nutrients but also chitin, which is believed to act as an antinutrient. In this 8-week trial, tilapia were fed diets with increasing amounts of BSFL exuviae at 0, 0.05, 0.1 or 0.5% and the growth, biochemical composition, hepatic expression set of genes related to metabolism and liver/intestinal histomorphology were examined. Results showed that while growth was unaffected, there were adverse effects to the morphology of the liver that included necrosis and hemorrhaging with increased exuviae content. This suggests that, for tilapia, BSFL chitin can become harmful and ways to reduce the chitin content of BSFL meal should be explored to potentially reduce liver pathologies and enhance fish production.

Technical Abstract: A by-product of black soldier fly (Hermetia illucens) larvae (BSFL) farming is the chitin-rich ‘exuviae’ (exoskeleton shell) that is the left behind after the prepupae larvae metamorphose into adults. Moreover, exuviae is present in BSFL meal and frass. In this 8-week trial, tilapia (initial weight of 2.93 g) were fed diets with increasing inclusions of dietary BSFL exuviae (0, 0.05, 0.1 or 0.5%) and the growth, biochemical composition, hepatic expression set of genes related to metabolism and liver/intestinal histomorphology were examined. Growth metrics tended (P = 0.066) to increase linearly with increasing exuviae level with 100% survival among all treatments, although feed conversion ratio was unaffected. Muscle P and Zn content were significantly linear and/or quadratic with respect to diet exuviae level and were highest in fish fed the control diet and lower in fish fed diets with exuviae. Dietary BSFL exuviae at 0.1 and 0.5% significantly downregulated the hepatic expression of lipoprotein lipase, trypsinogen, and cytochrome P450 1A (CYP1A) genes relative to control. Liver histology and scoring revealed mild to severe changes ranging from localized inflammation to necrosis and hemorrhaging with increasing exuviae content, while intestinal histology appeared similar among treatments. Muscle protein and amino acids decreased either linearly or quadratically with increasing BSFL exuviae. Muscle lipid and fatty acid profiles were not significantly impacted by dietary treatments. Results suggest that dietary inclusion of BSFL exuviae up to 0.5% of diet did not limit tilapia performance but further research is needed on treatments of BSFL meal or exuviae prior to diet inclusion to reduce liver pathologies and potentially enhance fish production.