| Summary: | Summary: Two experiments were carried out to determine the apparent metabolizable energy, nitrogen-corrected apparent metabolizable energy (AMEn), and the standardized ileal amino acid digestibility (SIAAD) and apparent ileal amino acid digestibility of corn distillers dried grains with solubles (corn-DDGS), without or with the singular supplementation of protease and phytase in broiler diets. One hundred sixty-eight male Cobb 500 broilers (experiment 1) were nutrient-properly fed to 13 D of age. At 14 D of age, broilers were fed one of four experimental diets (reference diet, reference diet + corn-DDGS, reference diet + corn-DDGS with 200 mg/kg of protease, or that with 100 mg/kg of phytase for 10 D). There was an effect (P < 0.05) of phytase and protease supplementation on the metabolizable coefficients of dry matter and crude protein. There was no effect (P > 0.05) of the supplementation with protease and phytase on AMEn values. In experiment 2, one hundred sixty-eight male Cobb 500 broiler chickens were nutrient-adequately fed from 1 to 24 D of age. On D 24, broilers were allocated to 4 treatments (nitrogen-free diet [NFD], NFD + corn-DDGS, NFD with corn-DDGS with 200 mg/kg of protease, or that with 100 mg/kg of phytase for 5 D) in a completely randomized design. The SIAAD of all amino acids was increased (P < 0.01) by the addition of protease. Phytase supplementation also improved SIAAD of (P < 0.01) lysine, methionine, cystine, aspartic acid, glycine, serine, and proline of corn-DDGS. Therefore, it is recommended to supplement protease and phytase in diets for broilers formulated with corn-DDGS to increase amino acid digestibility.
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