Nutritional value of Tenebrio molitor larvae meal for broiler chickens: metabolizable energy and standardized ileal amino acid digestibility

Abstract

Summary Two experiments were conducted to determine the nitrogen-corrected apparent metabolizable energy (AMEn) (experiment 1) and the standardized ileal digestibility coefficients (SIDC) of amino acids (AA) (experiment 2) of Tenebrio molitor larvae meal (TM) for broilers. In experiment 1, 48 21-day-old male broilers were distributed in a completely randomized experimental design with 2 treatments (diets) and 6 replicates (metabolic cages)/treatment, with 4 birds each. Based on the total excreta collection method, cages were randomly assigned to 2 diets: a reference diet and a test diet prepared by substituting 300 g/kg of the reference diet with TM. Ferric oxide (1%) was added to the diets on the first and last day of excreta collection carried out from day 28 to 32, twice daily. In experiment 2, 120 one-day-old male broiler chicks were distributed in a completely randomized experimental design with 2 treatments (diets) and 6 replicates (pens)/treatment, with 10 birds each. At day 16, birds were assigned to 2 experimental diets: a semi-purified nitrogen free diet and a test diet with TM as the sole source of AA, formulated to be approximately 20% CP. Chromium oxide was used at 5 g/kg as an indigestible marker. On day 22, all birds were euthanized, and the contents of the distal ileum were collected. The determined AMEn for TM was 5,004 ± 121.2 kcal/kg DM, a value higher than that of common feed sources of animal and vegetable origin. The average SIDC of AA was 0.86, indicating a good availability of the nutrients for chickens. The values obtained for AMEn and SIDC of TM are comparable to those of other insect meals reported in the literature. Thus, AMEn and SIDC of AA of TM determined here might be applied as a guide to optimize poultry feed formulation using this ingredient.