تاثير مقادير مختلف كلسيم و فسفر قابل دسترس جيره بر عملكرد مرغان مادر بومي اصفهان

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<0.05) linear increase in egg production, egg weight and improvement in feed conversion. The results from this study showed that high egg production, maximum calcium retention in the shell and optimum feed conversion were observed in native breeder hens during late growing period with 1.96% calcium and 0.15% available phosphorus.