Calcium And Phosphorus Requirements Of Broilers From 3 To 6 Week Of Age

The experiments were conducted to determine calcium and nonphytate phosphorus requirements for broilers, and to estimate effects of calcium and phosphorus levels on growth performance and bone healthy of broilers. Eight hundred 1-day-old AA+ broilers with similar body weight were randomly alloted into 20 experimental treatments with 4 replicates of 10 broilers each. Experiments had a 5×4 factorial arrangment of treatments with Ca at 0.6%, 0.8%, 1.0%, 1.2%, 1.5% and NPP at 0.35%, 0.45%, 0.55%, 0.65%. And these broilers were raised with experimental diets from 0 to 3 weeks and 4 to 6 weeks of age. The results were as follws:1. Calcium and nonphytate phosphorus levels of diets and its interaction had significantly effects on weight gain, feed intake and feed conversion. The daily weight gain and feed intake exhibited quadratic trend with dietary calcium and phosphorus increased. The higher level of Ca(1.5%) and the lower level of NPP(0.35%) decreased feed consumption and weight gain.2. Weight gain are sensitive indictors for the determination of the requirements of diet Ca and P for broilers. The tibia ash and tibia strength prediction equation between weeks 0 to 3 and 4 to 6 were as follows:The requirements of Ca and NPP, for maximum growth, were 0.82% and 0.61% in the period between weeks 0 to 3, 0.96% and 0.56% in the period between weeks 4 to 6, respectively, as determined by regression analysis of body weight gain against Ca and NNP levels in the diet.3.Tibia breaking strength, tibia ash content, Ca and P content of tibia were increased significantily with the levels of diets calcium and nonphytate phosphorus increasing, respectively. There were no effects on Ca content of tibia from 4 to 6.w. The levels of calcium 1.5%, 0.6% and nonphytate phosphorus 0.35% had negative effects on tibia strength, tibia ash content, Ca and P content of tibia.4. The tibia ash and tibia strength prediction equation between from 0 to 3 w were as follows:The tibia ash and tibia strength prediction equation between weeks 4 to 6 were as follows: The optimal requirements of Ca and NPP, for maximum tibia ash content and tibia breaking strength were 0.98% and 0.53%, 1.06% and 0.55% in the period between weeks 0 to 3, 0.99% and 0.55%,1.02% and 0.55% in the period between weeks 4 to 6, respectively, as determined by regression analysis of tibia ash content and tibia breaking strength against Ca and NNP levels in the diet.