Effects Of Different Phosphorus Level Of Ration On Growth, Bone Development, Laying Performance Of Laying Type Chickens And Efficacy Of Phytase Supplementation

Experiment 1 Effect of dietary non-phytate phosphorus levels on growth, bone development, phosphorus and calcium deposition in tissue of chicksNinety-six one-day-old commercial Lohmann chicks were allocatted into four groups randomly, fed the diets with 0.11%, 0.20%, 0.40% and 0.60% non-phytate phosphorus, respectively, for thirty day.The results indicated that the low-P and high-P diets decreased gain weight and feed consumption significantly (P<0.05), The appetite drop and growth retardation was intrinsic symptoms. The low-P diets (non-phytate P: 0.11%) could cause phosphorus deficiency and high mortality of chicks. The sternum bending were the earliest symptoms of phosphorus deficiency. The low-P diets decreased plasma phosphorus content significantly on day 30(P<0.05). Low-P diets decreased tibia phosphorus content on day 20 and day30(P<0.05). The tibia phosphorus content could be used as idices of diagnosis in chicks phosphorus deficiency. Low-P diets injured kidney critically. The 0.11% non-phytate phosphorus of the ration caused phosphorus deficiency. 0.20% non-phytate phosphorus of the ration was unsuccessful with chicken.Experiment 2 Effect of dietary non-phytate phosphorus levels on growth, bone development and mineral deposition in tissue of pullets and performance during laying period of pulletsForty-eight 78-day-old commercial Lohmann pullets, were allocatted into four groups randomly, fed diets with 0.10%, 0.20%, 0.30% and 0.40% non-phytate P, respectively. During the sixty-day experiment, the results indicated that the low-P diets decreased gain weight(P<0.05). The appetite drop and growth retardation was intrinsic symptoms of phosphorus deficiency. Feeding the diets with 0.1% non-phytate phosphorus P, the hens presented sternum bending and thoracic cyst. It was the earliest clinical symptoms of diagnosis. The low-P diets decreased plasma, blood, feather, tibia, kidney phosphorus content(P<0.05). The tibia,phosphorus content could be used as indices of diagnosis in phosphorus deficiency. The 0.10% non-phytate phosphorus of the ration caused phosphorus deficiency. 0.20% non-phytate phosphorus of the ration was was unsuccessful with pullets. As dietary phosphorus level increased, the manganese in feather liver, heart and kidney was decreased significantly (P<0.05). High phosphorus in diets have an adverse effect on resorption of manganese in pullets. As the calcium of the ration was low, the laying rate of the low-P ration was higher than normal and high phosphorus ration. As the calcium of the ration was normal, the laying rate of the low-P ration was lower than normal and high phosphorus ration. It show that calcium and phosphorus ratio was important factor affected laying rate.Experiment 3 Effect of dietary non-phytate phosphorus levels on laying performance, phosphorus and calcium deposition in tissue of laying hensForty-eight 178-day-old Lohmann commercial laying hens were allocatted into four groups randomly, fed with 0.08%, 0.12%,0.15% and 0.25% non-phytate P, respectivel,.for sixty days. The results indicated that the low-P diets decreased egg production, feed consumption and gain weight(P<0.05). The 0.12% -0.15% non-phytate phosphorus P diets increased egg shell thickness (P<0.05). The appetite drop and laying rate drop was intrinsic symptoms of phosphorus deficiency. Feeding the diets with 0.08% non-phytate P, the hens presented sternum bending up to forty-five day, appeared palsy up to fifty day. The earliest symptom in laying hens phosphorus deficiency was decreased egg production. The sternum bending and paresis wereearliest clinical diadynamic criteria. The low-P diets decreased plasma, blood, tibia, liver, heart, kidney, and yolk phosphorus content(P<0.05). It can be used as a laboratory diadynamic criteria. Yolk phosphorus content had dignosis meaning in early stage of laying hens phosphorus deficiency. Their critical value was 1.0%. The 0.12% non-phytate phosphorus of the ration caused phosphorus deficiency. 0.15% non-phytate phosphorus of the ration was was unsuccessful...