Effects of continuous feeding of low-phosphorus diets with and without phytase during the growing and laying periods on performance of two strains of Leghorns

K. Keshavarz
2003 Poultry Science  
An experiment was conducted to determine the minimum levels of nonphytate P (NPP) with and without phytase that can be continuously and safely used during the growing and laying periods for diminishing P excretion to the environment. The experiment consisted of a 2 × 8 factorial arrangement of the treatments with two strains (Babcock B-300 and Hy-Line W-98) and eight diets. The birds of the control group (T 1 ) were fed a determined NPP regimen of 0.34-0.30-0.23% for the periods of 0 to 6 wk
more » ... 34%), 6 to 12 wk (0.30%), and 12 to 18 wk (0.23%) of age and 0.39% determined NPP during the laying period (18 to 26 wk of age). The dietary NPP regimens during the growing and laying periods for T 2 to T 5 were as follows: T 2 , 0.25-0.20-0.16 and 0.29%; T 3 , 0.15-0.10-0.08 and 0.18%; T 4 , 0.12-0.07-0.08 and 0.12%; and T 5 , 0.08-0.07-0.08, and 0.08%. The birds of T 6 to T 8 were fed diets similar to T 3 to T 5 plus 300 U phytase/kg of diet. The growth parameters and egg production performance of birds of T 2 , which were fed the NPP regimen of 0.25-0.20-0.16% during the growing period and 0.29% (Body weight at 26 wk of age, egg production, egg weight, feed intake, egg mass, feed conversion, specific gravity, and mortality of birds fed a NPP regimen of 0.25-
doi:10.1093/ps/82.9.1444 pmid:12967259 fatcat:rg6pynbl5ja2dkrmx3xbrbo6zq