Phytate Degradation Transcellular Mineral Transporters and Mineral Utilization by Two Strains of Laying Hens as Affected by Dietary Phosphorus and Calcium

摘要

Phosphorus is stored as phytate in plant seeds, which are the main components of poultry feed. Poultry can utilize phytate phosphorus after its cleavage catalyzed by enzymes. These enzymes are inhibited by high concentrations of calcium and phosphorus in diets. As laying hens require a high calcium concentration for eggshell production, the inhibition of enzymes might be high. Therefore, the objective of this study was to characterize the degradation of phytate and the utilization of phosphorus and calcium by two laying hen strains supplied with standard or reduced levels of dietary calcium and phosphorus at the egg production peak. The calcium level had a clear effect on phytate degradation products and mineral utilization. The phosphorus level had no effect on these traits, suggesting that actual recommendations for phosphorus supply of laying hens are too high. Differences were noted between the two hen strains and among individual hens regarding calcium and phosphorus metabolism. This is a first step in identifying individual birds that are more capable than others in using phytate phosphorus under challenging conditions. In the long term, our results could help to further reduce the mineral content of laying hen diets.