The use of calcium formate (Ca-formate) to partially or fully replace limestone in piglet diets is a nutritional strategy to reduce the dietary buffering capacity and lower stomach pH. Phytase activity is optimal at low pH, which raises the question of whether this strategy can also increase phytase efficiency. This was investigated in a piglet digestibility trial using Ca-formate or limestone as the main Ca source in diets with adequate or reduced Ca and P levels but containing 0, 750, 1,500, or 3,000 phytase units. In total, 10 diets were tested with 60 weaned piglets. Results indicated that the Ca-formate diets did not reduce stomach pH of piglets, had greater Ca but lower P digestibility, and rendered phytase less efficient compared with the limestone diets. This suggests the necessity of considering the digestibility of Ca when formulating piglet diets.

Read the full article in the Journal of Animal Science.