| In order to investigate the effects of calcitonin recombination expression plasmid on the calcium metabolism with old layers. First prepared calcitonin eukaryotic expression plasmid (pCEP4-CT) 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, eggshell quality and micro-structure with each layers injected 200μg calcitonin gene plasmid under the different level of calcium in diet (3.5 % and 2.5 %). The results showed that, the pCEP4-CT plasmid prepared succeed by the results of dual-enzyme electrophoresis and sequencing; the pCEP4-CT 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-CT plasmid could significantly increase the parathyroid hormone and alkaline phosphatase (P<0.05), and significantly lowering blood calcium and osteocalcin levels (P<0.05), but not affect the estradiol and phosphorus content; pCEP4-CT can improve the bone quality in aging layers, significantly enhance the tibia index number and bone density (P<0.05), and promotion of bone calcium and bone phosphorus deposition; pCEP4-CT plasmid can improve thedeposition of calcium in aging layers, improve the eggshell quality and micro-structure. 15 ~ 28 d , pCEP4-CT plasmid injection had no significant impact on each indicator. In summary, pCEP4-CT eukaryotic expression vector can promote calciummetabolism of laying hens , bone calcium deposition benefit, also improve the eggshell quality and micro-structure. Feeding low calcium (2.5 %) diet, pCEP4-CT plasmid could improve the calcium utilization of aging layers, promote eggshell form, and lower the onset risk of osteoporosis.
|
PDF Full Text Request