分娩前后荷斯坦奶牛血浆中非酯化脂肪酸和瘦素变化特点

Dynamic characterestics of plasma NEFA and leptin level in Holstein cows around calving

为探讨血浆非酯化脂肪酸(NEFA)和瘦素(Lep)水平在奶牛分娩前后的变化特点及其意义,在南宁某牛场随机选取30头荷斯坦奶牛,从产前1周到产后9周,每周采样检测血浆酮体、NEFA和Lep水平。26头酮体正常奶牛(除去4头酮病牛后)的285份血浆NEFA和Lep的平均水平分别为655.7±359.9μmol/L和7.5±4.4 ng/m L,血浆NEFA水平从产前1周开始上升,分娩当天达峰值,然后渐降至产后7周最低值,之后回升。血浆Lep从产前1周上升,产后4周达峰值,之后渐降至8周最低值,之后回升。NEFA与Lep水平呈显著正相关(n=285,R=0.1137;P<0.05)。Lep上升时NEFA水平较高(923.1±398.7μmol/L),Lep下降时,NEFA较低(334.9±313.3μmol/L)。结论:Lep可能参与奶牛体脂动员的调节,产前1周至产后4周Lep的升高可能促进体脂动员,之后Lep下降可能减少体脂动员,产后4周可能是Lep调节体脂动员的拐点,NEFA正常值对监控奶牛分娩前后体脂动员、维护奶牛健康具有重要意义。

To understand the change characters and significance of plasma NEFA and Leptin（ Lep） level in cows around calving,30 Holstein cows from a dairy farm in Nanning were randomly selected. Blood sample was collected every week from 1 wk prepartum to 9 wk postpartum,and plasma ketone body,NEFA and Lep were determined. The average plasma NEFA and Lep levels were 655. 7 ±359. 9μmol/L and 7. 5 ± 4. 4 ng/m L in 285 samples from 26 normoketonemia cows（ except 4 hyperketonemia cows）,respectively.Plasma NEFA began to increase at 1 wk prepartum and reached the peak at calving day,and then it decreased gradually and reached the minimum value at 7 wk postpartum,and afterward rebounded. Plasma Lep began to increase at 1 wk prepartum and reached the peak at 4 wk postpartum then it decreased gradually and reached the minimum value at 8 wk postpartum,and afterward rebounded.There was a positive correlation between NEFA and Lep（ n = 285,R = 0. 1137; P 0. 05）. Plasma NEFA level was higher when Lep increasing（ 923. 1 ± 398. 7μmol/L）,and it was lower when Lep decreasing（ 334. 9 ± 313. 3 μmol/L）. In conclusion,Lep may participate the regulation of body fat mobilization,Lep increasing from 1 wk before to 4 wk after calving might accelerate the body fat mobilization; Lep decreasing from 4 wk postpartum might alleviate body fat mobilization; 4 wk postpartum may be a turning point for body fat mobilization. It is important to monitor body fat mobilization of cows around calving by comparing with normal NEFA level.