Dietary inclusion of live Hermetia illucens larvae in ISA Brown hens: effects on performance, egg quality and fatty acid profile

The increasing interest in sustainable feed resources for poultry production has highlighted insects as alternative dietary components. This study evaluated the effects of partially replacing conventional feed with live Hermetia illucens larvae in ISA Brown laying hens, focusing on performance, egg quality, proximate composition, health and behavioural observations, and whole egg fatty acid (FA) profile. Three independent 30-day trials were conducted across three experimental periods, using 24 first-laying-cycle hens per trial, aged 150-186 days at trial onset. In each trial, hens were allocated to a control group (CTR; 140 g/hen per day of commercial feed) or a treatment group (TRT), in which 40 g/hen per day of the commercial diet was replaced by 40 g/hen per day of live larvae, without increasing the total daily amount offered. Larvae inclusion did not affect most egg quality or proximate composition traits, and no adverse health or behavioural alterations were observed. However, egg weight was reduced in the TRT group in Trial 1 ( p < 0.001[jls-end-space/]), with a consistent numerical decrease observed across the trials. The whole egg FA profile was only marginally affected in Trials 1 and 2, whereas in Trial 3, larvae inclusion increased saturated and polyunsaturated FAs and reduced monounsaturated FAs ( p < 0.05[jls-end-space/]), with higher lauric acid (C12:0; p < 0.01[jls-end-space/]). These FA changes suggest a selective modulation of egg lipid composition, although their nutritional implications require further investigation. Overall, live H. illucens larvae were well tolerated, but further studies are needed to optimise inclusion strategies and avoid reductions in egg weight.