Effect of exogenous enzymes in maize-based diets varying in nutrient density for young broilers: growth performance and digestibility of energy, minerals and amino acids

1. A total of 192 male broilers (Cobb 500) were used in a growth and digestibility assay, involving a 2_2 factorial arrangement of treatments, to assess the effects of an enzyme cocktail of xylanase, amylase and protease in maize-based diets. 2. The following two diets were formulated: a positive control diet containing adequate nutrient concentrations for broiler starters as per breeder recommendations and a negative control diet to contain approximately 0_63 MJ/kg apparent metabolisable energy (AME) and 3% amino acids less than the positive control. 3. A further two dietary treatments were developed by supplementing each control diet with an enzyme product containing xylanase, amylase and protease. 4. Birds fed on the negative control diet had poorer weight gain and feed efficiency than those given the positive control diet. There was no effect of diet or enzyme on feed intake. The digestibility of nitrogen, calcium, phosphorus and most amino acids were unaffected by dietary nutrient density. 5. Supplementation of both the positive and negative control diets with the enzyme improved weight gain and feed efficiency compared with the unsupplemented diets. In the case of the negative control, supplemental enzyme improved performance to that of the unsupplemented positive control diet. There was no interaction between diet and enzyme for either weight gain or FCR, suggesting similar beneficial responses regardless of the nutrient density of the diet. 6. In both diets, enzyme supplementation improved AME by an average of 3% (0_35 MJ/kg DM) and nitrogen retention by an average of 11_7% (26 g/kg DM intake vs 29 g/kg DM intake). There was no interaction between diet and enzyme for AME or nitrogen retention. 7. Ileal digestibilities of calcium and phosphorus were not influenced by supplemental enzyme, whereas the digestibility of nitrogen and most amino acids was improved by enzyme addition compared with the unsupplemented control diets. There was no interaction between diet and enzyme for the ileal digestibility of nitrogen and amino acids. 8. These data demonstrate that it is possible to improve the nutritional value of a maize/soy-based diet for broiler starters through the use of exogenous enzymes. The nutrient density of the diet does not appear markedly to influence the response to enzyme, offering flexibility in the use of enzymes for maize-based diets. 9. It is concluded that the energy and amino acid values of maize-based diets for broilers can be enhanced by supplementation with an enzyme cocktail of xylanase, amylase and protease, offering potential economic benefits to producers

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Product / service:	Carbohydrases and Proteases
Publication date:	01/01/2008
Species:	Poultry, Broiler
Authors:	Cowieson AJ, Ravindran V
Doctype:	Publications & Citations
Publication / conference:	British Poultry Science, volume 49, issue 1
Regions and countries:	Global
Keywords:	ame, amino, acid, acids, amylase, apparent, metabolisable, energy, assay, birds, breeder, broiler, broilers, calcium, concentration, control, dan, diet, dietary, diets, digestibilities, digestibility, dm, effects, efficiency, enzyme, addition, cocktail, supplementation, enzymes, exogenous, fcr, feed, intake, gain, growth, performance, ileal, interaction, male, mineral, minerals, nitrogen, retention, nutrient, nutritional, value, per, phosphorus, protease, response, starter, treatment, weight, xylanase
Production challenge(s):	Gut health
Diets:	Maize, Mixed grain
Brands:	Axtra® AB, Axtra® XAP, Axtra® PHY, Optimize Feed, Phyzyme® XP, Phycheck, Danisco Xylanase, FASTKit assay
Resource ref:	9725
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Effect of exogenous enzymes in maize-based diets varying in nutrient density for young broilers: growth performance and digestibility of energy, minerals and amino acids

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