Valorisation of Insect Farming By-Products into Chitosan: Chemical Characterisation and Bioactivity for Veterinary Use

Insect-farming by-products provide an alternative source for chitin and chitosan production, adding value to existing protein-production systems. This narrative review examines extraction, physicochemical characterisation and bioactivity from documented by-products of Hermetia illucens and Tenebrio molitor. Veterinary applications are discussed separately, drawing on studies using chitosan of other or unspecified origins to identify potential uses and the evidence needed for insect-derived materials. Exuviae, empty puparia and documented adult residues are distinguished from whole-insect materials used as methodological comparators. Chemical, enzyme-assisted and intensified processes produce materials with different degrees of deacetylation, molecular weights, residual components and recoveries; yields relative to biomass are distinguished from conversion yields relative to isolated chitin. Direct insect-derived evidence consisted mainly of in vitro antimicrobial, antioxidant, epithelial-response, haemocompatibility and degradation assays, with limited preclinical haemostatic testing. No veterinary clinical or field study using a defined insect-derived chitosan product was identified. Studies of wound management, tissue repair, delivery systems and dietary supplementation showed formulation-, dose- and species-dependent responses, without establishing equivalence between chitosan sources. Veterinary translation requires traceable sources, reproducible processing, validated characterisation, contaminant control and product-specific safety and efficacy studies. Environmental and economic benefits also require comparative assessment. Insect-derived chitosan therefore warrants further investigation as a veterinary biomaterial, with suitability demonstrated for each preparation and application.