Influence of dietary calcium on bone calcium utilization

Area of Science:

• Animal Nutrition
• Poultry Science
• Calcium Metabolism

Background:

• Eggshell formation is a critical process in poultry production.
• Calcium is an essential nutrient for eggshell integrity.
• Understanding calcium utilization is key to optimizing laying hen diets.

Purpose of the Study:

• To investigate the impact of dietary calcium levels on eggshell formation and calcium deposition in hens.
• To determine the rate of shell calcification throughout the egg formation cycle.
• To quantify the contribution of skeletal calcium to eggshell formation.

Main Methods:

• Experiment 1: Hens were administered 45Ca and fed varying dietary calcium levels (.08-3.75%).
• Experiment 2: Hens were sampled at different time points post-oviposition to assess shell calcification rates.
• Experiment 4: Hens with labeled skeletal calcium were fed different diets and sampled to measure calcium utilization.

Main Results:

• Increased dietary calcium led to heavier eggshells and reduced 45Ca accumulation in shells.
• Skeletal calcium contributed significantly (28-96%) to eggshell formation.
• Shell calcification rate was not constant, varying significantly over time.

Conclusions:

• Dietary calcium levels directly influence eggshell weight and calcium incorporation.
• Laying hens dynamically utilize both dietary and skeletal calcium for eggshell synthesis.
• The timing of calcium deposition is crucial for efficient shell formation.