This research is aimed at improving the fatty acid profile of Hermetia illucens larvae and evaluating the effect of its inclusion on the apparent nutrient digestibility, feed choice, growth performance and slaughter traits of growing broiler quails (Coturnix coturnix japonica). H. illucens larvae (IM) were reared on two different substrates: layer mash (IM1) and 50:50 layer mash:fish offal (IM2). For the digestibility and feed choice trials, a total of sixty 16-day-old quails were assigned to three dietary groups: commercial diet (Control=C), a diet including 10% IM1 (IM1D), and a diet including 10% IM2 (IM2D). For the growth performance trial, a total of three hundred 10-day-old birds were allocated to the three dietary groups and fed the experimental diets until slaughter. Results of the digestibility trial showed a higher apparent metabolisable energy for larvae fed quail (14.0 and 13.9 MJ/kg DM vs 12.9 MJ/kg DM, (P<0.001). The IM2D quails also showed higher apparent digestibility for dry matter and organic matter. Feed choice results indicated that quails preferred the C diet compared to diets including H. illucens dried larvae. Productive performance, mortality and carcass traits were in line with commercial standards except for the IM2 quails which exhibited lower slaughter weight compared to C and IM1 fed quails. Based on the results of the present study, a 10% dietary inclusion of H. illucens larvae reared on a substrate rich in n-3 fatty acids did not negatively affect the apparent digestibility of nutrients, mortality, nor carcass yield. However, feed choice, growth rate and final carcass weight were negatively influenced by the IM2 diet. This result requires further investigations which should include the addition of an anti-oxidant.