Can a mixture of Hermetia illucens and Tenebrio molitor meals be feasible to feed broiler chickens? A focus on bird productive performance, nutrient digestibility, and meat quality

Hermetia illucens (HI) and Tenebrio molitor (TM) meals have widely been used in broiler chickens, but their mixture has never been tested. This study investigated the effects of HI and TM meals – alone and as a mixture (MIX, 1:1) – on productive performance, nutrient digestibility, carcass traits, and meat quality of broiler chickens. After assessing the nutrient digestibility of the insect meals (72 26-day-old male broilers, 4 treatments, 9 cages/treatment, 2 birds/cage), a total of 420 1-day-old male broiler chicks were allotted to 7 diets for 37 days (6 pens/diet, 10 birds/pen): C (control), HI5 (5 % HI), HI10 (10 % HI), TM5 (5 % TM), TM10 (10 % TM), MIX5 (5 % MIX), and MIX10 (10 % MIX). In the whole experimental period, better feed efficiency was observed in TM5, TM10 and MIX5 than C, HI10 and MIX10 birds (P < 0.001). Overall, TM5 and MIX5 groups showed the highest slaughtering, ready-to-cook carcass, and chilled carcass weights, while the lowest values were observed in HI10 and MIX10 (P < 0.001). Meat pH and color were limitedly influenced by dietary insect meal inclusion, while higher breast cooking losses were observed in HI10 birds than C, HI5 and MIX5 (P < 0.001). Higher breast dry matter was observed in HI5 birds than TM5 and HI10 (P < 0.001), with the same broilers displaying greater breast crude protein than TM5 (P < 0.001). The highest and lowest percentage of monounsaturated and polyunsaturated fatty acids, respectively, were observed in TM10 birds, along with the lowest polyunsaturated:saturated fatty acids ratio (P < 0.001). The TM5, HI5 and HI10 meat displayed lower tenderness than C meat (P = 0.001), with lower juiciness and overall liking being also overall identified for TM5 (P < 0.05). In conclusion, including 5 % of TM and MIX meals in diets for broiler chickens improved growth performance and carcass traits, while the 10 % inclusion level of HI and MIX meals was associated with the worst outcomes. Including 10 % of HI meal or using TM meal (mainly 5 %) also worsened meat quality and consumer perception.