Nutritional value of two insect larval meals (Tenebrio molitor and Hermetia illucens) for broiler chickens: Apparent nutrient digestibility, apparent ileal amino acid digestibility and apparent metabolizable energy

The aim of this study was to determine the apparent digestibility coefficients of the total tract (CTTAD) of nutrients and the apparent metabolizable energy (AME and AMEn) of two insect larval meals (Tenebrio molitor and Hermetia illucens) for broiler chickens. The amino acid (AA) apparent ileal digestibility coefficients (AIDC) was also determined. The experimental diets were: a basal diet and two diets prepared by substituting 250 g/kg (w/w) of the basal diet with Tenebrio molitor meal (TM) or Hermetia illucens meal (HI). No statistical difference was found between the two insect larval meals for the CTTAD of the nutrients, except for the CTTAD for ether extract (P < 0.001) where the HI meal proved to be more digestible than the TM meal (0.99 and 0.88, respectively). The CTTAD for DM was 0.60 and 0.53; 0.66 and 0.66 for OM; 0.60 and 0.51 for CP, whereas it was 0.64 and 0.69 for GE, for TM and HI, respectively. No difference was observed between TM and HI (P > 0.05) for AME or AMEn (AME = 16.86 and 17.38 MJ/kg DM, respectively; AMEn = 16.02 and 16.60 MJ/kg DM, respectively). The average AIDC of the 17 analyzed AAs was higher (P < 0.001) in TM than in HI (0.86 and 0.68, respectively) because the AIDC of isoluecine, lysine, methionine, phenylalanine, valine, alanine, aspartic acid, glycine, glutamic acid and tyrosine was higher (P < 0.05) in TM than in HI. Overall, the present results have shown that TM and HI meals are excellent sources of AME for broilers and a valuable source of digestible AA, particularly as far as TM meal is concerned.