TY - JOUR T1 - Effect of Different Levels of Dietary Calcium and Available Phosphorus on the Performance of Isfahan Native Breeder Hens TT - تأثیر مقادیر مختلف کلسیم و فسفر قابل دسترس جیره بر عملکرد مرغان مادر بومی اصفهان JF - JCPP JO - JCPP VL - 7 IS - 3 UR - http://jcpp.iut.ac.ir/article-1-452-en.html Y1 - 2003 SP - 163 EP - 172 KW - Calcium KW - Available phosphorus KW - Native breeder hens. N2 - In a 3×3 factorial experiment, 90 72-week-old native breeder hens of Isfahan were kept in cages (one bird/cage). The effect of three levels of dietary calcium (3.27, 2.62, and 1.96%) and three levels of dietary available phosphorus (0.25, 0.20, and 0.15%) on egg production and egg shell traits were investigated. Each treatment contained five replicates of two birds (10 birds per treatment). The experimental diets were fed 8 weeks (from 72 to 80 weeks of age). Dietary calcium and available phosphorus levels had no significant effects on feed consumption, shell thickness and shell breaking strength. Decreasing dietary calcium or available phosphorus levels (1.96% calcium and 0.15% available phosphorus) caused a significant (P M3 ER -