Research Note: Phosphorus digestibility in conventional canola meal determined using different balance assays

Area of Science:

• Animal Nutrition
• Nutrient Metabolism
• Feed Science

Background:

• Canola meal (CM) is a valuable protein source in animal diets.
• Phosphorus (P) is an essential mineral, and its digestibility in plant-based feed ingredients is crucial for optimizing animal nutrition and minimizing environmental impact.
• Understanding P digestibility and retention in CM is vital for formulating cost-effective and sustainable animal diets.

Purpose of the Study:

• To determine the ileal phosphorus (P) digestibility and excreta P retention values for canola meal (CM) in chicks.
• To evaluate the effects of phytase supplementation on P digestibility and retention in CM.
• To assess the impact of varying calcium (Ca) to nonphytate P ratios on P digestibility and retention in CM.

Main Methods:

• Three distinct chick assays were employed: ad libitum feeding with phytase, precision feeding, and ad libitum feeding with varying Ca:nonphytate P ratios.
• Ileal P digestibility and excreta P retention were measured in broiler chicks fed diets containing CM.
• Regression analysis was used to determine P digestibility and retention based on digesta and excreta P output relative to dietary P concentration.

Main Results:

• Phosphorus digestibility/retention values for CM ranged from 30% to 40% across the three balance assays.
• Phytase supplementation significantly increased both ileal P digestibility and excreta P retention.
• Increased dietary Ca:nonphytate P ratio negatively affected ileal P digestibility and, to a lesser extent, excreta P retention.

Conclusions:

• The three balance assays provided consistent estimates of P digestibility and retention in canola meal.
• Phytase is effective in enhancing P utilization from canola meal in poultry diets.
• Dietary calcium levels significantly influence phosphorus bioavailability from canola meal, necessitating careful formulation to optimize P absorption.