The black soldier fly, Hermetia illucens (L. 1758), is an omnivorous saprophagous insect with a high potential for valorizing organic by-products rich in carbohydrates. Among carbohydrates, H. illucens relies on soluble sugars for the growth and storage lipid synthesis. This study aimed to assess the impact of common soluble sugars on the development, survival, and fatty acid composition of H. illucens. Monosaccharides and disaccharides were individually incorporated into a chicken feed diet. Cellulose was used as a control. Larvae fed glucose, fructose, sucrose, and maltose grew faster than control larvae. In contrast, lactose exhibited anti-nutritional effects on larvae, slowing down growth and reducing final individual weight. However, all soluble sugars produced larvae fatter than the control diet. Notably, the tested sugars shaped the fatty acid profile. Maltose and sucrose increased saturated fatty acid content compared to cellulose. Conversely, lactose increased the bioaccumulation of dietary unsaturated fatty acids. This study is the first to demonstrate the effect of soluble sugars on the fatty acid profile of H. illucens larvae. Our findings highlight that the tested carbohydrates have significant effects on black soldier fly fatty acid composition and can thus determine their final applications.

The interest in edible insects’ mass rearing has grown considerably in recent years, thereby highlighting the challenges of domesticating new animal species. Insects are being considered for use in the management of organic by-products from the agro-industry, synthetic by-products from the plastics industry including particular detoxification processes. The processes depend on the insect’s digestive system which is based on two components: an enzymatic intrinsic cargo to the insect species and another extrinsic cargo provided by the microbial community colonizing—associated with the insect host. Advances have been made in the identification of the origin of the digestive functions observed in the midgut. It is now evident that the community of microorganisms can adapt, improve, and extend the insect’s ability to digest and detoxify its food. Nevertheless, edible insect species such as Hermetia illucens and Tenebrio molitor are surprisingly autonomous, and no obligatory symbiosis with a microorganism has yet been uncovered for digestion. Conversely, the intestinal microbiota of a given species can take on different forms, which are largely influenced by the host’s environment and diet. This flexibility offers the potential for the development of novel associations between insects and microorganisms, which could result in the creation of synergies that would optimize or expand value chains for agro-industrial by-products, as well as for contaminants.

The increasing demand for animal‐based protein has led to biodiversity loss, deforestation, pollution, and extensive land use, mainly due to the rising production of soybean meal and fish meal used to feed livestock. Some edible insects, such as the black soldier fly, mealworm, and cricket, have emerged as a new sustainable source of protein. This review highlights that these edible insects can replace a significant portion of soybean meal and fish meal in monogastric animals (pigs and chickens) and aquaculture (fish and crustaceans). Their protein content, amino acid profile, and digestibility often meet the nutritional requirements of these animals. However, some indispensable amino acids require special attention. Overall, edible insect meals can be compared to those made from soybeans and fish. They can partially or fully replace these traditional protein sources in livestock farming.

The conversion of agro-industrial co-products and unsold organic plant-based residues into black soldier fly (BSF; Hermetia illucens (L. 1758)) proteins was assessed for use in organic post-weaning piglet diets in Belgium. A total of 72 crossbred female piglets (Landrace × Pietrain) were enrolled in a 5-week feeding trial. Experimental diets consisted of a common energy core (81.2% of the feed) and a protein core (18.8%) composed of organic soybean meal, pea meal, and potato protein, partially replaced by defatted BSF meal at inclusion levels of 15%, 25%, and 35%. All diets were formulated to be isoenergetic and isonitrogenous, with standardized ileal digestibility values for lysine, methionine, threonine, and tryptophan held constant. Incorporating 15% defatted BSF meal can substitute conventional organic protein sources without compromising growth performance in post-weaning piglets. However, economic modelling based on a cumulative feed conversion ratio expressed on a dry matter (DM) basis showed that break-even prices for organic BSF meal remained well below the price of the control protein nucleus (€1039·t⁻¹, excluding VAT), indicating that economic parity could not be achieved at typical market prices under the observed feed efficiency.

Biowaste and agro-industrial co-products continue to increase with population growth and rising living standards, calling for scalable valorization strategies that go beyond simple mineralization. The black soldier fly (BSF) has emerged as a practical bioconversion platform capable of channeling biodegradable organic waste into high-value proteins, lipids, and chitin. In parallel, microbial interventions are increasingly recognized as key levers for substrate conditioning, process stabilization, and performance optimization in BSF-based systems. In this review, we adopted a function-first perspective to examine how microbial processes shape and connect three major biological valorization routes: aerobic composting, anaerobic digestion (AD), and BSF bioconversion. Rather than focus on taxonomic inventories, we synthesized evidence on microbial functions that matter in practice, including extracellular hydrolysis of complex polymers, regulation of short-chain fatty acids, detoxification and pathogen suppression, and process stabilization. We further reviewed microbe-assisted strategies, such as lactic pre-fermentation, directed acidogenesis, and probiotic or defined consortia and their effects on waste reduction, conversion efficiency, product quality, and sanitary safety. Finally, we translated these microbial mechanisms into scalable design principles for configuring and operating integrated insect–microbe systems, highlighting how microbial functions underpin reproducible, enterprise-ready performance across composting, AD, and BSF-integrated workflows.