The Effects Of Calcium-binding Protein D28k Eukaryotic Expression Vector By Intramuscular Injecting On The Regulation Of Calcium Metabolism And Eggshell Quality With Aging Layers

In order to investigate the effects of calcium-binding protein D28k recombination expression vector on the regulation of calcium metabolism and eggshell quality with old layers. First prepared calcium-binding protein D28k eukaryotic expression vector (pCEP4-CaBP-D28k) and identified, then chose 36 New Yangzhou layers in 70 weeks old, which randomly divided into 4 groups of 3 repeat, each repeat contained 3 layers. To study the effect of correlation factor of calcium metabolism, skeleton quality, nutrient appearance metabolic rate, laying performance, eggshell quality and micro-structure with each layers injected 200μg calcium-binding protein D28k gene plasmid under the different level of calcium in diet (3.5% and 2.5%). The results showed that, the pCEP4-CaBP-D28k plasmid prepared succeed by the results of dual-enzyme electrophoresis and sequencing; the pCEP4-CaBP-D28k recombination expression vector expressed well in vivo, between 0~14 d the expression level was highest, and the effect tapered with the experimental stage extend; 0~14 d under the same calcium level, pCEP4-CaBP-D28k plasmid could significantly increase the calcium and alkaline phosphatase in serum (P<0.05), but not affect the parathyroid hormone, calcitonin, estradiol, and phosphorus content; pCEP4-CaBP-D28k plasmid could promote the bone calcium metabolism in aging layers, significantly enhance the tibia index number and bone density (P<0.05), and not affect the secretion of osteocalcin and bone phosphorus deposition; pCEP4-CaBP-D28k plasmid did not have a significant impact on laying performance and weight, but could significantly improve the calcium absorption and utilization (P<0.05), promote deposition of calcium in eggshell, improve the eggshell quality and micro-structure. 15~28 d, pCEP4-CaBP-D28k plasmid injection had no significant impact on each indicator. So, pCEP4-CaBP-D28k eukaryotic expression vector could promote calcium absorption and metabolism, improve bone calcium deposition, also improve the eggshell quality and micro-structure. Feeding low calcium (2.5%) diet, pCEP4-CaBP-D28k plasmid could improve the calcium absorption and utilization of aging layers, promote eggshell form, and lower the onset risk of osteoporosis.