The relative biological value of feed phosphates for chicks

Area of Science:

• Animal Nutrition
• Nutrient Bioavailability
• Feed Science

Background:

• Phosphorus is an essential nutrient for broiler growth and bone development.
• Accurate assessment of phosphorus bioavailability from feed phosphates is crucial for optimizing poultry diets.
• Nonphytate phosphorus is the primary form of digestible phosphorus in plant-based feed ingredients.

Purpose of the Study:

• To determine the relative biological values (BV) of various feed phosphates.
• To compare the phosphorus bioavailability of commercial phosphate supplements.
• To establish a reliable method for assessing phosphorus efficacy in broiler diets.

Main Methods:

• Two replicated experiments using broiler cockerels fed corn-soybean meal-based diets.
• Inclusion of anhydrous, reagent-grade, dibasic calcium phosphate (AR-DCP) as a reference standard at five phosphorus levels.
• Calculation of a regression equation based on bone ash percentage and nonphytate phosphorus intake.
• Determination of biological values using nonphytate phosphorus equivalents derived from test phosphate diets.

Main Results:

• Dibasic calcium phosphate exhibited high biological values (106 and 104).
• Monobasic calcium phosphate also demonstrated high bioavailability (102 and 104).
• Defluorinated phosphate (DFP)-1 showed lower biological values (88 and 90), while DFP-2 had a BV of 100.

Conclusions:

• The study provides comparative biological values for common feed phosphates used in poultry nutrition.
• Dibasic and monobasic calcium phosphates are highly bioavailable sources of phosphorus.
• DFP-1 may be less effective in meeting broiler phosphorus requirements compared to other tested phosphates.