Effect of the Rearing Substrate on Total Protein and Amino Acid Composition in Black Soldier Fly

Abstract

Insects are becoming increasingly relevant as protein sources in food and feed. The Black Soldier Fly (BSF) is one of the most utilized, thanks to its ability to live on many leftovers. Vegetable processing industries produce huge amounts of by-products, and it is important to efficiently rear BSF on different substrates to assure an economical advantage in bioconversion and to overcome the seasonality of some leftovers. This work evaluated how different substrates affect the protein and amino acid content of BSF. BSF prepupae reared on different substrates showed total protein content varying between 35% and 49% on dry matter. Significant lower protein contents were detected in BSF grown on fruit by-products, while higher contents were observed when autumnal leftovers were employed. BSF protein content was mainly correlated to fibre and protein content in the diet. Among amino acids, lysine, valine and leucine were most affected by the diet. Essential amino acids satisfied the Food and Agricultural Organization (FAO) requirements for human nutrition, except for lysine in few cases. BSF could be a flexible tool to bio-convert a wide range of vegetable by-products of different seasonality in a high-quality protein-rich biomass, even if significant differences in the protein fraction were observed according to the rearing substrate.

Towards Functional Insect Feeds: Agri-Food By-Products Enriched with Post-Distillation Residues of Medicinal Aromatic Plants in Tenebrio molitor (Coleoptera: Tenebrionidae) Breeding

“…Especially since insect meals are marketed as a protein source, rich content is essential. In the literature, insect protein content has been correlated with the dietary protein [ 39 ], and dietary fat and fiber [ 70 ]. In this study, protein content did not correlate with the substrates’ proximate composition, leading to the assumption that TML adapted their substrate consumption to maximize nutrient intake regardless of the different dietary composition.…”

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“…The imbalance between oxidants and antioxidants can lead to oxidative damage products [75][76][77]. So, the use of insect to convert organic waste into biomass, which can then be used for an innovative purpose, were studied in various studies [65,[78][79][80][81][82][83][84][85], however, the ability to use insect as a bioremediation agent of pollutants contamination is still needed more studies and clarifications mechanisms [86,87].…”

Genotype-by-Diet Interactions for Larval Performance and Body Composition Traits in the Black Soldier Fly, Hermetia illucens

“…The summed AA contents, including proxies for Trp , allowed enumerating specific protein (SP) concentrations (g/kg DM). Accordingly, profiles of individual AA (g/100 g protein) for BSFL were calculated by accounting for a general literature-based proxy for Trp of 1.8 g/100 g protein in BSFL [ 25 , 36 , 37 , 38 , 76 ]. Similarly, a common constant of 1.2 g Trp /100 g protein was applied to all diets (e.g., [ 36 , 79 ]) to provide merely informative specific protein concentrations of different diets.…”

“…Performance on seemingly comparable diets across different studies nevertheless documents notable variation [ 5 , 6 , 33 ]. The same is true for compositional characteristics: individual studies not only detected substantial variation in the proximate composition of BSFL, including crude protein, lipids, and total ash but also subtle yet highly important variability in amino acid and fatty acid profiles [ 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. Similarly, while nutrition is indicated to be a major driver of variation in BSFL body composition [ 22 ], available reviews across settings worldwide further reveal that differences other than the developmental stage at harvest [ 41 ] may not solely be related to diets [ 6 , 22 , 42 , 43 ] but also involve other factors.…”