ارزیابی ترکیب، محلولیت آزمایشگاهی و قابلیت هضم ظاهری کلسیم و فسفر منابع کلسیمی مختلف و اثر آن بر عملکرد و صفات استخوانی جوجه های گوشتی

Mineral composition and in vitro solubility rates for seven different Calcium (Ca) sources, and their feeding effects on performance and digestibility of calcium and phosphorous in broiler chickens were assessed. The experiment used a 6 × 2 factorial arrangement with 12 diets formulated to contain of 6 Ca sources and 2 levels of particle size (<0.05mm and > 1.0-2.0 mm) and one diet as a control contain oyster shell (<0.05mm). A total of 486 Ross 308 broilers were allocated to 13 dietary treatments with 3 pen (18 birds per cage) per treatment from d 1 to 42 post hatching Seven test Ca sources (six commercial limestone sources (GL) and oyster shell (OS) were separated into their particle size groups that ranged from <0.05mm, > 1.41-2.83 mm, and >2.83 mm. Average concentration of Ca was 36.2 g/kg in all Ca sources. In vitro solubility was dependent upon Ca source and particle size with small particle generally having a greater in vitro solubility than large particle at the same time. Dietary treatments had effect on the feed intake and body weight gain in starter period, but there was no difference in performance of different Ca sources and different particle in grower period in broiler chickens. Apparent Ca and P digestibility in Ca sources was greater (P < 0.05) for birds fed a diet with particle size of > 0.5 mm compared with those fed higher particle size. However, the bone ash, non-fat dry matter, Ca and P of were not affected by Ca sources and partile size. In conclusion, results of the present experiment demonstrated that performance and bone traits of broilers were not affected by Ca sources and particle sizes; and there was difference in in vitro solubility and Ca and P digestibility of different Ca sources in broiler chickens.