Utilisation of different phosphorus sources in relation to their fluorine content for broilers and layers

1. The relative utilisation of different phosphorus sources in relation to their fluorine (F) content was studied in commercial broilers (5 to 40 d) a nd White Leghorn layers (252 to 364 d). The phosphorus (P) sources tested w ere bonemeal (BM), low fluorine (LFRP) and high fluorine (HFRP) rock phosph ates and a commercial mineral mixture (CMM). The P sources were incorporate d in broiler and layer diets by replacing dicalcium phosphate (DCP) on a P basis. 2. The F contents of diets based on BM, LFRP, CMM and HFRP were 53, 365, 62 2 and 1383 mg/kg in the broiler experiment and 34, 242, 437 and 967 mg/kg i n the layer experiment, respectively. F was not detected in DCP based diets . 3. In broilers, body weight gain, food intake, gain: food, P retention and serum inorganic P content on P sources (BM and LFRP) containing F up to 365 mg/kg diet were similar to those on DCP. Body weight gain, food intake, se rum calcium and inorganic P contents and retention of P were depressed in g roups fed on CMM and HFRP, which may have been due to the toxic effects of F (622 and 1383 mg/kg) present in diets based on these P sources. 4. Bone ash and its P content were not affected by feeding diets containing F up to 1383 mg/kg from various P sources. The amount of F deposited in ti bia increased significantly with increases in dietary F concentration. 5. In layers, egg production and food intake were not affected by F up to 4 37 mg/kg in diets containing BM, LFRP or CMM as the sole source of suppleme ntal P. Egg production and food intake were depressed significantly in laye rs given the diet containing 967 mg F/kg from HFRP. 6. Egg mass: food, egg weight, shell quality (shell thickness and shell wei ght) and serum calcium and inorganic P levels were not affected by F up to 967 mg/kg in diets containing different P sources. 7. It may be concluded that the performance of broilers and layers was not affected by feeding various P supplements with dietary levels of F up to 36 5 and 437 mg/kg, respectively. The reduced performance in broilers and laye rs observed with some of the P sources may have been due to poor availabili ty of P and/or toxic effects of F (622 and 967 mg/kg, respectively).