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Unformatted text preview: METABOLISM AND NUTRITION Carbohydrases, Protease, and Phytase Have an Additive Beneficial Effect in Nutritionally Marginal Diets for Broiler Chicks A. J. Cowieson* ,1 and O. Adeola† ,2 †Department of Animal Sciences, Purdue University, West Lafayette 47907 *Danisco Animal Nutrition, Marlborough, Wiltshire, UK ABSTRACT To investigate the additive effects of xyla- nase, amylase, protease, and phytase in the diets of broiler chickens, a study was conducted using 1,152 growing broiler chicks (8 treatments with 12 replicate pens of 12 chicks). The birds were fed a corn/soybean-based nega- tive control (NC) diet that was formulated to be nutri- tionally marginal in terms of metabolizable energy, Ca, and P. A nutritionally adequate positive control (PC) diet was fed for comparison. The NC diet was supplemented with phytase; a cocktail of xylanase, amylase, and prote- ase (XAP); or a combination of phytase and XAP at 100 or 200 mg of each enzyme/kg (200 mg of XAP/kg pro- vided a guaranteed minimum of 300 U of xylanase, 400 U of amylase, and 4,000 U of protease/kg; 200 mg of phytase/kg provided a guaranteed minimum of 1,000 U of phytase/kg). Growth performance, ileal digestible energy (IDE), and the digestibility coefficients of N, Ca, P, and DM were calculated. Individually and in combina- ( Key words : broiler, enzyme combination, nutrient utilization, phytase) 2005 Poultry Science 84:1860–1867 INTRODUCTION The use of exogenous enzymes to improve the perfor- mance of farmed poultry is not a new concept and has been extensively studied and reviewed (Bedford, 2000; Selle et al., 2000; Acamovic, 2001; Cowieson, 2005). How- ever, although the efficacy of carbohydrases, proteases, and phytases in the diets of poultry has been well estab- lished, there is still a great deal of uncertainty regarding the modes of action of exogenous enzymes. Furthermore, the countless interactions between enzymes and the host animal, its microflora, and also dietary ingredients are not fully understood (Bedford, 2002). One area that has received relatively little attention in the literature is the use of combinations of enzymes such as carbohydrases, 2005 Poultry Science Association, Inc. Received March 8, 2005. Accepted September 10, 2005. 1 Corresponding author: email@example.com 2 Journal paper number 2005-17618 of the Purdue University Agricul- tural Research Program. 1860 tion, both phytase and XAP improved ( P &lt; 0.05) gain-to- feed ratio compared with the NC diet, particularly at the highest inclusion concentration. Body weight gain followed a similar trend, showing an improvement of approximately 6 to 7% with either enzyme individually and a 14% improvement with a combination of phytase and XAP. The effect of enzymes on IDE and nutrient digestibility coefficients was not as marked, but a 165- kcal/kg reduction in IDE was noted between the NC and PC diets, and a combination of phytase and XAP improved IDE by &gt; 100 kcal/kg. It can be concluded that the use of phytase and XAP individually in a corn/soy-...
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This note was uploaded on 07/28/2011 for the course VET 4335 taught by Professor Sakomura during the Spring '11 term at University of South Pacific.
- Spring '11