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The effect of phytase enzyme and level on nutrient extraction by broilers.
F G Silversides1, T A Scott, M R Bedford
1Crops and Livestock Research Centre, Charlottetown, Prince Edward Island, Canada. silversidesf@agr.gc.ca
Poultry Science
|June 23, 2004
Summary
Phytase enzyme preparation B, produced in Pichia pastoris, improved broiler chick performance and nutrient digestibility after heat pelleting. Other tested phytase enzymes were inactivated by the pelleting process.
Area of Science:
- Animal Nutrition
- Enzymology
- Biotechnology
Background:
- Phytase enzymes are crucial for improving phosphorus availability in animal diets.
- The production host can influence enzyme stability and efficacy.
- Heat stability during feed processing is a critical factor for enzyme application.
Purpose of the Study:
- To compare the efficacy of three experimental phytase preparations (A, B, C) derived from the same gene but different hosts (Saccharomyces cerevisiae, Pichia pastoris, Pseudomonas fluorescens) against a commercial enzyme.
- To evaluate the impact of feed pelleting at temperatures above 80°C on the activity and performance of these phytase preparations in broiler diets.
- To assess the effects of enzyme B on broiler chick performance, nutrient digestibility, and apparent metabolizable energy (AME).
Main Methods:
- Three experimental phytase preparations (A, B, C) and one commercial enzyme were added to phosphorus-deficient wheat-soybean meal diets at three inclusion levels.
- Diets were pelleted at temperatures exceeding 80°C.
- Broiler chicks were fed the experimental diets from 4 to 21 days of age.
- Chick performance, nutrient digestibility (calcium, phosphorus), and AME were measured.
Main Results:
- Pelleting inactivated experimental enzymes A and C, and the commercial enzyme.
- Enzyme B, produced in Pichia pastoris, demonstrated significant positive effects on broiler performance, calcium, and phosphorus digestibility.
- Increasing levels of enzyme B resulted in progressively greater positive effects.
- Enzyme B also enhanced AME and protein digestibility compared to control diets.
- Enzyme B remained active after the high-temperature pelleting process.
Conclusions:
- Enzyme B exhibits superior heat stability during feed pelleting compared to enzymes A, C, and the commercial preparation.
- Pichia pastoris is a suitable host for producing thermostable phytase enzymes for animal feed.
- Enzyme B offers a viable solution for improving nutrient utilization and broiler performance in pelleted feed formulations.