Two experiments determined the quantitative relationships between dietary calcium, NPP (Nonphytate Phosphorus), vitamin D and phytase in diets for broiler chicks to 20 days of age. In experiment one, the NPP requirement was approximately 0.40% when the diet contained 0.90% calcium and 3000 ICU of vitamin D/kg. This was based on a linear response in chick weight, feed intake, bone ash and blood calcium and phosphorus to increasing dietary NPP. When the diet contained 0.70% calcium, bone ash and blood phosphorus had significant responses to added dietary NPP but other parameters had no significant responses. The NPP requirement was approximately 0.30% of the diet. Data from these experiments indicate the calcium: NPP ratio is approximately 2.25. Adding phytase at 773 or 1545 units per kg of diet gave responses of approximately 0.05% NPP per 773 units. In experiment two, vitamin D additions were 500, 2,500 or 12,500 ICU kg-1 of diet that contained 0.80% calcium. Between 500 and 2,500 ICU kg-1, the response was equal to approximately 0.013% NPP per 1000 ICU kg-1. Between 2,500 and 12,500 ICU kg-1 diet, the response was equal to approximately 0.003% NPP per 1000 ICU. The addition of 537 units of phytase kg-1 to a diet with 0.20% NPP caused a response equivalent to 0.05-0.07% NPP. Increasing the phytase to 1074 units per kg of diet gave no additional response. A discussion of the results suggests the importance of the solubility product and the common ion effect for explaining results in calcium and phosphorus nutrition.
J. David Latshaw and Aaron Pospisil. The Phosphorus Requirement of Broiler Chicks as Affected by Dietary Calcium
and Vitamin D and Phytase Supplementation.
DOI: https://doi.org/10.36478/rjpscience.2012.71.77
URL: https://www.makhillpublications.co/view-article/1993-5285/rjpscience.2012.71.77