Assessing the effect of limited incorporation of black soldier fly larvae and prepupae meal on laying performance, egg characteristics and biological indicators in aged hens

This study evaluated the effects of including low percentages (1.25%, 2.5% and 3.75%) of black soldier fly (Hermetia illucens L.) larvae (BSFL) and prepupae (BSFP) meal in the diet of old laying hens (100–115 weeks), assessing production, egg quality, metabolic/physiological traits, sensory attributes and economic outcomes. The 252 Lohmann LSL-Classic hens were assigned to seven groups in a completely randomised design. The 3.75% BSFP group improved feed conversion ratio (FCR), while egg production index (EPI) tended to be higher versus control; feed intake, survival and body weight were not adversely affected. External shell traits (e.g. shell weight and SWUSA) were higher in BSF groups, particularly with 3.75% BSFL whereas internal quality (Haugh units, yolk index) was maintained. Sensory evaluation showed no differences among groups. Serum protein fractions were modulated without detrimental changes in hepatic/renal indices. Economically, BSF diets reduced feeding costs and improved efficiency versus control. Overall, BSFL/BSFP up to 3.75% may represent a promising low-level alternative to soybean meal in aged layers, supporting a more circular and sustainable supply chain.