Rearing substrate impacts growth and macronutrient composition of Hermetia illucens (L.) (Diptera: Stratiomyidae) larvae produced at an industrial scale

Abstract

Organic waste is a rapidly increasing problem due to the growth of the agricultural production needed to meet global food demands. Development of sustainable waste management solutions is essential. Black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae) (BSF), larvae are voracious consumers of a wide range of organic materials ranging from fruits and vegetables to animal remains, and manure. Thanks to this ability and considering the larval high protein and lipid content, BSF larvae are a useful additive in animal feeds and biodiesel production. Unfortunately, the feasibility of using the black soldier fly as a tool for waste valorization and feed production has primarily been investigated at the benchtop scale. Thus, mobilization of current practices to an industrial scale is challenging because scaling up from small laboratory studies to large industrial studies is not necessarily linear. The goal of this study was to demonstrate the ability of the BSF to recycle organic waste at an industrial scale. To accomplish this goal, three organic waste streams were used (e.g., apples, bananas, and spent grain from a brewery) to test six diet treatments (1) apple, (2) banana, (3) spent grain, (4) apple and banana, (5) apple and spent grain, and (6) banana and spent grain. Working at scale of 10,000 BSF larvae life history traits, waste valorization, protein and lipid profiles were measured for each diet treatment. Differences were recorded across all variables, except substrate conversion, for larvae fed on fruit and spent grain (alone or with fruit). Growth rate significantly differed across treatments; larvae reared on spent grain grew twice as fast as those fed apples alone, but those reared on the apple and spent grain mixture produced twice as much insect biomass. However, it should be noted that larvae resulting from the apple diet contained 50% more fat than larvae fed the fruit and spent grain mixtures. Commonly-available organic wastes were successfully used at an industrial scale to produce BSF larvae that have the potential to substitute other sources of protein and lipids in different industrial applications. Industrialization efforts are encouraged to assess these impacts when integrating diverse ingredients into larval diets as a means to more precisely predict output, such as larval development time and final larval biomass.

Mechanical Processing of Hermetia illucens Larvae and Bombyx mori Pupae Produces Oils with Antimicrobial Activity

“…It is well-known that the insect species, the rearing substrate, and the extraction method have a great influence on the quantity and quality of the oil yield. The two insects selected for our study, although taxonomically different, have some similarities that facilitate a comparison: (1) they can be used in circular economy settings giving place to considerable economic outputs; (2) they can be reared on vegetable substrates, therefore their oil profile can be mostly composed of unsaturated fatty acids with very interesting properties, as shown in the present work ( Supplementary Material—Tables S1 and S3 ); (3) their rearing substrate can be modulated and enriched; in fact, different feeds have been tested for BSFL [ 10 , 19 , 20 ] and several artificial diets, with different compositions, were studied for the silkworm [ 21 , 22 , 23 ]; furthermore, different diet regimens affect the fatty acid composition of the two insects [ 24 , 25 ]; and (4) it has already been demonstrated they are rich of antimicrobial peptides and other compounds with pharmacological action [ 2 , 3 , 26 ].…”

Impact of Diets Including Agro-Industrial By-Products on the Fatty Acid and Sterol Profiles of Larvae Biomass from Ephestia kuehniella, Tenebrio molitor and Hermetia illucens

“…In the EU, the total amount of agroindustrial by-products is estimated to be around 16 million tons, where the top producers are Germany (3 million tons), the United Kingdom (2.6 million tons), Italy (1.9 million tons), France (1.8 million tons), and Spain (1.6 million tons) [2]. Notably, these by-products Insects 2021, 12, 672 2 of 13 are rich sources of bioactive compounds [3,4]. Therefore, developing eco-friendly solutions for their reuse and recycling is essential from economic and environmental perspectives.…”

Coprophilous fungi : Closing the loop: improving circularity with manure-loving mushrooms

“…Because of their high protein and lipid content, BSF larvae can be used as an additive in animal feeds and biodiesel production (Scala et al, 2020). Parodi et al (2020) showed that BSF has a preference for manure.…”