Effect of feeding broilers diets differing in susceptible phytate content

Area of Science:

• Animal Nutrition
• Poultry Science
• Biochemistry

Background:

• Total phytate phosphorus measurements can be misleading for assessing phosphorus availability.
• Phytate's susceptibility to phytase may be a more accurate indicator of phosphorus (P) bioavailability.

Purpose of the Study:

• To compare diets with high vs. low susceptible phytate, with or without phytase supplementation.
• To determine if susceptible phytate measurements are a better predictor of P availability than total phytate.

Main Methods:

• A 2x2 factorial experiment using 240 Ross 308 broilers fed diets varying in susceptible phytate and phytase levels (0 or 500 FTU/kg).
• Susceptible phytate was quantified by simulating gastrointestinal tract conditions (pH 4.5, 37°C) and measuring dissolved phytate.
• Evaluated phytate hydrolysis, P solubility, bone mineral content, and pepsin activity throughout the digestive tract.

Main Results:

• Diets high in susceptible phytate increased phytate hydrolysis, P solubility, and bone mineral content, leading to improved body weight gain (BWG) and feed conversion ratio (FCR).
• Phytase supplementation significantly enhanced BWG, FCR, P solubility, and bone parameters.
• Susceptible phytate was fully degraded in the gut without supplemental phytase, validating the assay's effectiveness.

Conclusions:

• Susceptible phytate is a more meaningful measure of dietary P availability for broilers than total phytate.
• Diet formulation focusing on susceptible phytate can optimize P utilization and broiler performance.
• Both susceptible phytate content and phytase supplementation play crucial roles in enhancing nutrient availability and broiler health.