A note on sampling digesta from the ileum of broilers in phosphorus digestibility studies

Area of Science:

• Animal Nutrition
• Poultry Science
• Digestive Physiology

Background:

• Dietary phosphorus (P) is essential for broiler growth and skeletal development.
• Accurate assessment of P utilization is critical for formulating cost-effective and environmentally sound diets.
• Prececal digestibility measurements are key to understanding nutrient absorption in the small intestine.

Purpose of the Study:

• To investigate the responses of broilers to increasing dietary phosphorus (P) concentrations.
• To compare P retention and P prececal digestibility across various P intake levels.
• To determine optimal digesta collection sites in the ileum for accurate P digestibility determination.

Main Methods:

• Two experiments were conducted with Ross 308 broilers at four weeks of age.
• Diets were supplemented with monobasic calcium phosphate at graded levels, with titanium dioxide as an indigestible marker.
• Ileal digesta was collected from different sections for P flow and prececal digestibility analysis.

Main Results:

• Phosphorus (P) excretion increased linearly up to 5.2 g P/kg diet and nonlinearly thereafter.
• Ileal P flow demonstrated a linear increase across the entire P intake range.
• Calculated P prececal digestibility varied significantly between ileal subsections, especially at lower P levels.

Conclusions:

• The response of P prececal digestibility to dietary P concentration is linear over a broader range than P retention.
• For accurate P prececal digestibility determination, digesta collection should exclude the initial third of the ileum.