title: Age-related influence of a cocktail of xylanase, amylase, and protease or phytase individually or in combination in broilers.
abstract: This 21-d experiment was conducted to determine if the response of chicks to a cocktail of xylanase, amylase, and protease (XAP) or Escherichia coli-derived phytase individually or in combination when fed a nutritionally marginal corn-soybean meal diet is age-dependent. Six hundred 1-d-old chicks were allocated to 5 dietary treatments in a randomized complete block design. The treatments were as follows: 1) positive control with supplemental inorganic P; 2) negative control (NC) marginal in P and ME; 3) NC plus XAP to provide (per kg of diet) 650, 1,650, and 4,000 U of xylanase, amylase, and protease, respectively; 4) NC plus phytase added to provide 1,000 phytase units/kg; and 5) NC plus a combination of XAP and phytase. Low ME and P in the NC diet depressed weight gain and gain:feed (P < 0.001). A cocktail of XAP alone did not improve performance, but phytase supplementation improved (P < 0.001) weight gain. The enzymes were additive in their effects on growth performance. The enzymes had no effect on ileal digestible energy. Ileal N digestibility was higher (P < 0.05) in diet with XAP or phytase individually compared with NC. Both phytase and XAP individually and in combination improved (P < 0.01) ileal P digestibility compared with NC. Total tract nutrient retention and ME increased (P < 0.01) as the birds grew older. There were age x diet interactions (P < 0.001) on total tract retention of P and Ca; improvement in P retention due to phytase use decreased by 50% as the chicks matured. The current study shows that a combination of XAP and phytase improved performance, but the enhancement in performance appears to be mainly from phytase. Both XAP and phytase were effective in improving P digestibility and retention of chicks receiving nutritionally marginal corn-soybean meal. The data also shows that the chicks benefited more from the enzyme addition at a younger age and that the contribution of the enzymes to nutrient retention decreased with age in chickens.
authors.affiliation: Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: O A
authors.initials: OA
authors.lastname: Olukosi
authors.forename: A J
authors.initials: AJ
authors.lastname: Cowieson
authors.forename: O
authors.initials: O
authors.lastname: Adeola
mesh_terms: D010832:6-Phytase / Q000008:administration & dosage / Q000494:pharmacology*; D000375:Aging / Q000502:physiology*; D000681:Amylases / Q000008:administration & dosage / Q000494:pharmacology*; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects; D000818:Animals; D002645:Chickens / Q000254:growth & development*; D004032:Diet / Q000662:veterinary; D004063:Digestion / Q000187:drug effects*; D004359:Drug Therapy, Combination; D004734:Energy Metabolism; D008297:Male; D010447:Peptide Hydrolases / Q000008:administration & dosage / Q000494:pharmacology*; D015430:Weight Gain; D014995:Xylosidases / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D010832:6-Phytase; D000681:Amylases; D014995:Xylosidases; D010447:Peptide Hydrolases