Egg production, eggshell quality and profitability of laying hens during first cycle with levels of calcium and available phosphorus

摘要

In order to evaluate the importance of calcium and phosphorus for egg shell quality, a trial was conducted using 480 Hy-Line 36 hens in a 3*4*3 factorial arrangement to evaluate three calcium (Ca) (3.2, 4.2 and 5.2 %) and four available phosphorus (Ap) levels (0.15, 0.20, 0.25 and 0.30 %) during 20 to 72 wk of age). Results showed an interaction (P<0.05) between Ca and Ap levels for feed intake (FI) and egg mass (EM). The FI (96.7 g) and EM (48.7 g) decreased with the highest Ca (5.2 %) and the lowest Ap (0.15 %) levels. Egg production and EM were lower (P<0.05) with the 0.15 % compared to the 0.3 % Ap level. Feed conversion was also affected by the Ap level having the best performance with 0.3 % (1.94), 0.20 % (1.96), 0.15 % (1.98) and 0.25 % (1.99). Egg weight was 0.7 and 0.8 g higher (P<0.05) with 3.2 % level compared to 4.2 and 5.2 % levels, respectively. Egg specific gravity was improved (P<0.05) when calcium level increased (1.080 vs 1.081 and 1.082) in the diet. It was concluded that, in order to get a good shell quality, 4.2 % calcium must be used, and a proportional increase of the Ap must be considered. The level of 0.15 % of available phosphorus is not enough for good egg production and optimal feed conversion.