The Cholecalciferol Requirement Of White Pekin Duckings And The Effect Of Dietary Cholecalciferol On Calcium And Phosphorus Metabolism

One experiment was conducted to research the effect of dietary calcium/ phosphorus and cholecalciferol levels on growth performance and tibia quality of White Pekin Duckings through the methods of feeding trial, slaughter test and biochemistry analysis, and got the requirement of cholecalciferol to provide the reference for the diet dispengsing of White Pekin Duckings. A 2×6 factorial arrangement experiment was designed with two calcium/ Non-phytate phosphorus levels (0.8%/0.4%,0.4%/0.2%) and six cholecalciferol levels (0,250.,500,1000,2000 and 3000 IU/kg). A total of 720 one-day-old male white pekin duckings with similar body weight were randomly assigned to 12 treatments with 6 replicates of 10 duckings each.These birds were fed radomly experiment diets for 21 days.Then the duckings were killed and blood and tibia were separated to keep in the fridge.The result was followed:1. Effect of dietary calcium/ phosphorus and cholecalciferol levels on growth performance of White Pekin Duckings :(1) Supplementation of cholecalciferol in diet could alleviate the death of duckings caused by the low dietary calcium/phosphorus levels.(2) Compared with low calcium/phosphorus (0.4% / 0.2%) diet, high calcium/phosphorus (0.8% / 0.4%) diet significantly increased the feed intake, weight gain and feed efficiency of 14 days old White Pekin Duckings. Supplementation of cholecalciferol in low calcium/phosphorus diet improved significantly the feed intake, weight gain and feed efficiency of 14 days old White Pekin Duckings. And this had no effects on growth performance of ducklings with high alcium/phosphorus diet. The cholecalciferol requirement of 14 days old White Pekin Duckings was 2391 IU/kg for optimal weight gain when the calcium/ Non-phytate phosphorus levels was 0.4%/0.2%.(3) Supplementation of cholecalciferol in high calcium/phosphorus diet improved significantly the feed intake, weight gain and feed efficiency of 21 days old White Pekin Duckings. The cholecalciferol requirement of White Pekin Duckings was 1088IU/kg for optimal weight gain when the calcium/ Non-phytate phosphorus levels was 0.8%/0.4%.2. Effect of dietary calcium/ phosphorus and cholecalciferol levels on blood biochemistry and bone quality of White Pekin Duckings:(1) Elevated levels of dietary calcium and phosphorus significantly increased the plasma calcium and phosphorus content of White Pekin Duckings,decreased alkaline phosphatase activity of 14 days old White Pekin Duckings,and had no effects on plasma calcium content of 21 days old White Pekin Duckings.As the increasing of cholecalciferol levels in diet, plasma calcium increased significantly, plasma phosphorus content and alkaline phosphatase activity decreased on 14 days old White Pekin Duckings ,and had no effect on plasma phosphorus content on 21 days old White Pekin Duckings.(2) When calcium and phosphorus were insufficient in diet, tibia length and weight of 14 days old White Pekin Duckings was affected severity ,and tibia ash,tibia calcium , tibia phosphorus were much more lower than the groups with high calcium and phosphorus. Supplementation of cholecalciferol increased significantly tibia length,tibia weight and tibia ash,howerer there was a slope when cholecalciferol was over 2000 IU/kg.(3)Conclusion:Dietary cholecalciferol can raise plasma calcium content, and promote the growth of bone and increase feed intake and weight gain at low calcium/phosphorus levels. Cholecalciferol can improve bone quality and growth performance of White Pekin Duckings at suitable calcium/phosphorus levels. The cholecalciferol requirement of 14 days old White Pekin Duckings was 2391 IU/kg for optimal weight gain when the calcium/ Non-phytate phosphorus levels was 0.4%/0.2%.The cholecalciferol requirement of 21 days old White Pekin Duckings was 1088IU/kg for optimal weight gain when the calcium/ Non-phytate phosphorus levels was 0.8%/0.4%.