Nutritional value of frass from black soldier fly larvae, Hermetia illucens, in a channel catfish, Ictalurus punctatus, diet

Authors: Aksoy, Mediha; Eljack, Rashida; Beck, Benjamin

Submitted to: Aquaculture Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2019
Publication Date: 1/30/2020
Publication URL: https://handle.nal.usda.gov/10113/6862084
Citation: Aksoy, M., Eljack, R.M., Beck, B.H. 2020. Nutritional value of frass from black soldier fly larvae, Hermetia illucens, in a channel catfish, Ictalurus punctatus, diet. Aquaculture Nutrition. 00:1-8. https://doi.org/10.1111/anu.13040.
DOI: https://doi.org/10.1111/anu.13040

Interpretive Summary: Frass is the by-product of the larva meal industry, including larvae waste, exoskeleton sheds, and remaining feed ingredients. Experimental frass was derived from the larvae of black solder flies fed Distillers’ dried grains with solubles had a protein and fat content of approximately 21.6% and 6%, respectively. A 10-week study was conducted to evaluate the effect of dietary levels of frass from black soldier fly larvae on growth, feed utilization, body proximate and mineral composition of channel catfish, Ictalurus punctatus. Five diets containing frass at levels of 0, 5, 10, 20, and 30% as partial replacements of a combination of soybean meal (SBM), wheat short (WS) and corn meal (CM) on an equal protein basis were fed to juvenile channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. Final weight gain was significantly increased in fish fed diet including frass at levels from 10% to 30%. Fish fed diets without and with 30% frass significantly lowest and highest feed intake, respectively. Feed and protein efficiencies, however, were significantly lower in fish fed dietary frass at levels of 20% and higher than that of fish fed the control diet. Survival was not affected by dietary levels of frass. Whole-body composition and mineral content were not affected by dietary treatment. Liver of fish fed 30% dietary frass had significantly higher iron content then that of fish fed other treatments. Frass has specific growth promoting effects through increased feed intake. Frass from the larvae of black solder has the potential for use as a source of protein or as an ingredient for enhancing palatability of the diet of channel catfish.

Technical Abstract: Frass is the byproduct of the larval meal industry and includes larval waste, exoskeleton sheds and residual feed ingredients. Experimental frass was derived from the larvae of black solder flies fed Distillers’ dried grains with solubles and had a protein and fat content of 216 g kg-1 and 60 g kg-1, respectively. A 10-week study was conducted to evaluate the effect of dietary levels of frass on growth, feed utilization, and body proximate and mineral composition of channel catfish, Ictalurus punctatus. Five diets containing 0, 50, 100, 200, and 300 g frass kg-1 diet were fed to channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. Final weight gain was significantly increased in fish fed diets containing frass at levels from 100 to 300 g kg-1. Fish fed diets without frass, and with 30 g kg-1 frass, showed the lowest and highest feed intake, respectively. Feed and protein efficiencies, however, were significantly lower in fish fed frass at levels of 20 g kg-1 and higher compared to the control diet. Survival, whole-body composition and mineral content were not affected by frass. In summary, black soldier fly larval frass has potential as a protein source or just an ingredient for enhancing palatability of catfish diets.