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ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #425658
Research Project: Maximizing Profitability and Fish Health in Catfish Aquaculture

Location: Warmwater Aquaculture Research Unit

Title: Dietary inclusion of frass from black soldier fly (Hermetia illucens) larvae modulates gut microbiota without compromising the growth performance and health status of catfish (Ictalurus punctatus) juveniles

Author
item DE SENHA FARIAS, ANA BEATRIZ - Mississippi State University
item SANTANA, THIAGO - Mississippi State University
item SILVIA, VITOR - Mississippi State University
item Older, Caitlin
item CONDE, CRYSTAL - Mississippi State University
item Romano, Nicholas
item GATLIN III, DELBERT - Texas A&M University
item GONCALVES, LIGIA - National Institute Of Amazonian Research
item YAMAMOTO, FERNANDO - Mississippi State University

Submitted to: Fish Physiology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2025
Publication Date: 8/5/2025
Citation: De Senha Farias, A., Santana, T.M., Silvia, V.F., Older, C.E., Conde, C.L., Romano, N.P., Gatlin Iii, D.M., Goncalves, L.U., Yamamoto, F.Y. 2025. Dietary inclusion of frass from black soldier fly (Hermetia illucens) larvae modulates gut microbiota without compromising the growth performance and health status of catfish (Ictalurus punctatus) juveniles. Aquaculture. 51(137). https://doi.org/10.1007/s10695-025-01552-5.
DOI: https://doi.org/10.1007/s10695-025-01552-5

Interpretive Summary: Black soldier fly larvae (BSFL) by-products have been recognized as potential alternative ingredients for many animal production industries. Waste from BSFL rearing, also known as frass, can have a favorable nutrient profile containing high levels of amino acids, lipids, and minerals. Researchers at Mississippi State University in Stoneville, MS, in collaboration with scientists from the USDA ARS, Texas A&M University, and the National Institute of Amazonian Research evaluated the inclusion of BSFL frass in juveniles catfish diets. BSFL frass was included in diets at 0%, 1.25,%, 2.5%, and 5%, and fed to fish for 60 days. Dietary BSFL frass did not affect growth performance, but the results suggest effects on liver metabolism and the bacterial communities present in the gut. Although BSFL frass appears to be safe for inclusion at levels up to 5% in juvenile channel catfish diets, these findings warrant further research to better understand which particular bacteria may benefit from BSFL frass, how these bacteria are utilizing the frass, and how liver metabolism is affected by this ingredient.

Technical Abstract: The present study evaluated the potential of BSFL frass (BF), a by-product composed of larval excretions, undigested substrate, and exoskeletons, as a dietary ingredient for juvenile channel catfish (Ictalurus punctatus). The experiment included a control diet and three test diets with BSFL frass 1.25% (BF1.25%), 2.5% (BF2.5%), and 5.0% (BF5.0%). All diets were isonitrogenous (37% crude protein), isolipidic (6% crude lipid), and isoenergetic (15 MJ gross energy/kg). Six hundred channel catfish juveniles (~'1.85 g) were equally distributed to 20 aquaria (30 fish/tank) in a recirculating aquaculture system and fed the experimental diets for 60 days. Dietary inclusion of BSFL frass did not significantly affect growth performance, viscerosomatic index, intraperitoneal fat, and hematological parameters. However, fish-fed BF5.0%diets showed a higher hepatosomatic index, suggesting effects on liver metabolism. No significant differences were observed in intestinal histomorphology. Fish-fed BF1.25% exhibited a higher relative abundance of Lactococcus spp. (~'47%), along with increases in Streptococcaceae, Lactobacillales, and Weissella, accompanied by reduced Cetobacterium spp. and Plesiomonas spp. BSFL frass did not improve performance but significantly altered the catfish gut microbiota. This finding warrants further research to better understand the components of the BSFL frass that can serve as a substrate for commensal bacteria and which bacterial species are benefiting from this supplementation. Additionally, evaluating the feasibility of BSFL frass as an unconventional ingredient in aquafeeds could provide insights into its potential functional benefits and practical application in sustainable fish nutrition.