Effect of energy enrichment of dairy cattle manure on the productive performance and nutritional characterization of Musca domestica larval meal Efeito do enriquecimento energético do esterco de bovinos leiteiros no desempenho produtivo e na caracterização nutricional da farinha de larvas de Musca domestica

Insect larva production for animal feed represents a sustainable alternative to the growing demand for protein. This research evaluated the productive performance of housefly (Musca domestica) larvae reared on dairy cattle manure (DCM) under different levels of energy enrichment, alongside a nutritional characterization of the basal meal. A completely randomized design was employed with four treatments for productive variables: pure DCM (T0), DCM + 5% oil (T1), DCM + 5% molasses (T2), and DCM + 5% oil + 5% molasses (T3). Following bioconversion, the pure substrate (T0) exhibited a marginal reduction of 8% in both crude protein and crude fat, while nitrogen-free extract decreased by 22%. Individual weight and biomass production increased significantly (P < 0.01) with energy enrichment; T3 stood out with a larval weight of 17.19 mg and a productivity of 9.15 g/kg of substrate, representing increases of 123% and 244% compared to the control, respectively. A descriptive nutritional characterization was performed on the housefly larval meal (HFLM) produced from the basal substrate (T0), which presented 55.7% crude protein and 28.30 g/100g total fat. The amino acid profile was competitive against conventional sources, highlighting high levels of arginine (6.99 g/100g) and lysine (3.55 g/100g). The lipid profile was predominantly polyunsaturated, with an omega-6:omega-3 ratio of 1.4:1. Regarding minerals, HFLM proved to be rich in phosphorus (0.93 g/100g) but limited in calcium (0.14 g/100g). Microbiological analysis showed the absence of Salmonella spp., although levels of coliforms (1.1 x 103 CFU/g) and Clostridium perfringens (250 CFU/g) exceeded sanitary limits. It is concluded that manure enrichment improves larval productive indicators; however, the resulting meal requires strict sanitization protocols to guarantee its safety, and its potential as a protein source is supported by the competitive nutritional profile of the basal HFLM.