Nutritional Evaluation of Black Soldier Fly Frass as an Ingredient in Florida Pompano (Trachinotus carolinus L.) Diets

Abstract

The aquaculture industry is in need of sustainable fish feed to reduce the use of expensive and environmentally invasive wild-caught fish currently fed to many carnivorous species. The black soldier fly (BSF) has become a popular sustainable alternative protein source; however, the nutritional waste byproduct of BSF, frass, has not been extensively studied as a feed replacement in carnivorous species. This study evaluates the potential of BSF frass on the growth, body composition, and intestinal microbiome of the Florida pompano, Trachinotus carolinus. Four experimental diets were formulated containing different levels of frass, replacing plant-based carbohydrate sources. As a result of this study, the frass did not improve the growth performance, resulting in a lower specific growth rate and higher feed conversion rate. While the frass diets did not alter the body composition, the visceral somatic index (VSI) significantly increased compared to the control diet and the hepatosomatic index (HIS) was lowered. The microbiome analysis showed high variation among the diets, with the control diet having the most distinct consortia, which may have been driven by the increased levels of starch compared to frass diets. This study indicates that BSF frass may not be a suitable feed replacement for carnivorous pompano; however, frass could still potentially be a replacement feed for herbivore or detritivore fish and should be further studied.

Opportunities and challenges in upcycling agri-food byproducts to generate insect manure (frass): A literature review

“…Currently, agriculture, horticulture and retail appear as the primary markets for frass applications as a fertilizer (Chavez and Uchanski 2021) , Larouche 2022. However, applications of frass as a potential ingredient in animal feed (fish , Banavar, Amirkolaei et al 2022), shrimp (Yildirim-Aksoy, Eljack et al 2022, rabbits (Radwan, Maggiolino et al 2023)), and/or secondary processing (feedstock for biomethanisation (Wedwitschka, Gallegos Ibanez and Jáquez 2023), for composting (Song, Ee et al 2021), or for biochar production (Yang, Chen et al 2019, Yang, Zhang et al 2019)) are emerging. Considering the strong growth of the edible insect sector, and the high ratio of frass production per tonne of edible insects harvested, it is therefore important to find value-added opportunities to consolidate the economic model of current and future insect productions.…”

Frass from Black Soldier Fly Larvae, Hermetia illucens, as a Possible Functional Dietary Ingredient in Channel Catfish Feed

“…We recently demonstrated that larval frass from the by-product of black soldier fly larvae (BSFL) has a growth-promoting effect on channel catfish through increasing palatability and feed intake [18]. Besides its promising value as a feed ingredient for several fish species, such as channel catfish (Ictalurus punctatus) [18,19], hybrid tilapia (Oreochromis niloticus × O. mozambique) [20], and Florida Pompano (Trachinotus carolinus L.) [21], frass contains abundant nutrients, chitin-a naturally occurring biopolymer from invertebrate shells-and beneficial microbes [22,23]. In fact, the use of frass in tilapia diets have shown to be beneficial by improving innate immune components and subsequently, the resistance of hybrid tilapia against bacterial infection [20] as well as increasing the serum antibacterial effect of Pacific white shrimp, Litopenaeus vannamei, against Vibrio parahemolyticus [24].…”

Effect of fatty acid-enriched black soldier fly larvae meal combined with chitinase on the metabolic processes of Nile tilapia

“…The gut microbiota modulation can also affect lipid metabolism and the balance of energy ( 18 ) . It also seems that certain BSF diets do not improve the microbiota diversity in carnivorous fish in a balanced way but could be more beneficial in herbivore and detritivore fish species ( 19 ) .…”