Chemical and Microbiological characteristics of Hermetia Illucens meal as Fish Meal Replacement for Sparus Aurata L. on farm. Part I.

Among the various insect species considered for possible use in fish feeding (Regulation 2017/893/EC), Hermetia illucens seems to be one of the most promising for its chemical composition which, however, is variable depending on the processing technology and growth substrate. Aim of this study was a chemical and microbiological characterization of Hermetia illucens meal (HIM) for the preparation of a diet formulated to satisfy the nutritional needs of Sparus aurata L. farmed offshore. Proximate composition was analyzed using AOAC methods, fatty acids and amino acids by gas chromatography, minerals via ICP-MS, aflatoxins by liquid chromatography, microbial flora following the ISO methods. Proximate composition (g/100g, as fed) was: moisture 5.6, crude protein 54, crude lipid 10, crude fiber 10 and ash 7. Fatty acid classes showed a high SFA content (69%), mainly represented by C12:0 (41%), followed by MUFA (14%), mainly represented by C18:1 (10%), n6-PUFA (16%), mainly represented by C18:2n6 (15%) and n3-PUFA (1.5%), mainly represented by C18:3n3 (1.3%). EPA content was 0.11% while DHA was not identified. Ten indispensable (EAA) and ten dispensable amino acids (NEAA) were identified; among the EAA, the highest levels were observed for lysine (5%) and leucine (4.5%), phenylalanine (3.5%) valine (3.3%) and arginine (3.2%). The EAA/NEAA ratio was 1.15. Arsenic, cadmium, mercury and lead were below the limit of quantification (0.1 ppm). Total aflatoxins (B1, B2, G1 and G2) and aflatoxin B1 were below the limit of detection (0.15 ppb). An aerobic mesophilic bacteria count of 3.9 Log CFU/g was observed; Enterobacteriaceae, coliforms, clostridia, yeast and molds, Salmonella spp. and Listeria monocytogenes were not detected. The chemical characteristics of HIM allow it to be considered a valuable alternative protein source, especially for carnivorous fish species. Heavy metals and microbiological quality confirm the safety of insects as animal feed. Project “FIFA - Feed Insects For Aquaculture”, PO FEAMP 2014-2020 mis. 2.47 CUP J46C18000570006.