| 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 | O A Olukosi, A J Cowieson, O Adeola
(Affiliation: Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.)
|
| Journal | Poultry science
(Poult Sci)
Vol. 86
Issue 1
Pg. 77-86
(Jan 2007)
ISSN: 0032-5791 United States |
| PMID | 17179419
(Publication Type: Journal Article, Randomized Controlled Trial)
|
| Chemical References |
- 6-Phytase
- Amylases
- Xylosidases
- Peptide Hydrolases
|
| Topics |
- 6-Phytase
(administration & dosage, pharmacology)
- Aging
(physiology)
- Amylases
(administration & dosage, pharmacology)
- Animal Feed
- Animal Nutrition Physiology
(drug effects)
- Animals
- Chickens
(growth & development)
- Diet
(veterinary)
- Digestion
(drug effects)
- Drug Therapy, Combination
- Energy Metabolism
- Male
- Peptide Hydrolases
(administration & dosage, pharmacology)
- Weight Gain
- Xylosidases
(administration & dosage, pharmacology)
|
