【摘要】：奶牛在產(chǎn)后處于能量負(fù)平衡狀態(tài),使體脂大量動(dòng)員,進(jìn)而導(dǎo)致酮病。酮病牛生產(chǎn)、繁殖性能下降,甚至被淘汰。瘦素(Leptin)是由白色脂肪合成分泌的激素,能夠抑制攝食行為,參與能量平衡、脂肪代謝的調(diào)控。本研究旨在了解血漿Leptin水平與奶牛酮病的相互關(guān)系以及添加β-羥丁酸、Leptin.胰島素對脂肪Leptin相關(guān)基因轉(zhuǎn)錄的影響。實(shí)驗(yàn)選擇16頭待產(chǎn)母牛,自產(chǎn)前1周起至產(chǎn)后第7周逐周進(jìn)行血漿Leptin等血液指標(biāo)檢測,結(jié)果表明：酮病牛具有低血漿Leptin.低葡萄糖、高酮體、高游離脂肪酸水平的代謝特點(diǎn),與非酮病牛相比差異顯著。奶牛分娩后血漿Leptin水平逐漸升高,在產(chǎn)后第2周至第4周,酮病牛的Leptin含量超過非酮病牛,但差異不顯著。該時(shí)期酮病牛的酮體、游離脂肪酸水平極顯著高于非酮病牛的水平。體外實(shí)驗(yàn)對皮下脂肪、腸系膜脂肪和腎周脂肪組織分別添加不同濃度的β-羥丁酸(0.5、1.0、3.0、5 mM/L),Leptin(10.50、100ng/ml).和胰島素(10、50、100 nM/L),檢測Leptin及其三個(gè)受體(ObRa、ObRb. ObRc)的mRNA水平。結(jié)果表明：在三種脂肪中均未檢測到ObRa的表達(dá)。皮下脂肪對β-羥丁酸濃度變化最為敏感,低濃度的β-羥丁酸(0.5、1.0 mM/L)極顯著上調(diào)皮下脂肪Leptin、ObRb和ObRc轉(zhuǎn)錄水平；高濃度β-羥丁酸(3.0、5.0 mM/L)下調(diào)Leptin mRNA表達(dá),極顯著降低對ObRb和ObRc的上調(diào)作用。腎周脂肪中,β-羥丁酸濃度變化僅對ObRc mRNA有顯著作用。各濃度Leptin對皮下、腎周脂肪的Leptin及ObRb、ObRc mRNA水平有趨同效應(yīng)。皮下脂肪的Leptin及ObRb、ObRc mRNA隨胰島素濃度升高而降低,腎周脂肪則相反。三種藥物各濃度均下調(diào)腸系膜脂肪中的Leptin及其受體mRNA表達(dá),其中胰島素作用顯著。結(jié)論,低血漿Leptin水平與酮病有關(guān)。β-羥丁酸升高會影響Leptin及其受體mRNA的表達(dá)。不同部位脂肪的Leptin分泌與自身調(diào)節(jié)存在差異,皮下脂肪是最主要的Leptin分泌位點(diǎn),且對β-羥丁酸最為敏感。腎周脂肪Leptin相關(guān)基因的轉(zhuǎn)錄變化不大,維持在一定水平。
[Abstract]:Cows in postpartum negative energy balance, body fat mobilization, and then lead to ketosis. Ketosis cattle production, reproductive performance decline, or even be eliminated. Leptin (Leptin) is a hormone synthesized and secreted by white fat, which can inhibit feeding behavior, participate in the regulation of energy balance and fat metabolism. The purpose of this study was to investigate the relationship between plasma Leptin level and ketogenic disease in dairy cattle and to add 尾 -hydroxybutyric acid, Leptin.. Effects of insulin on the transcription of adipose Leptin related genes. Blood indexes such as plasma Leptin were measured from 1 week before delivery to 7 weeks postpartum. The results showed that ketosis cattle had low plasma Leptin.. The metabolic characteristics of low glucose, high ketone body and high free fatty acid levels were significantly different from those of non-ketosis cattle. The plasma Leptin level increased gradually after parturition, and the Leptin content of ketosis cattle was higher than that of non-ketosis cattle from the 2nd to 4th week postpartum, but the difference was not significant. The level of free fatty acids in ketosis cattle was significantly higher than that in non ketosis cattle. In vitro, subcutaneous fat, mesenteric fat and perirenal adipose tissue were supplemented with different concentrations of 尾 -hydroxybutyric acid (0.5 ~ 1.0 ~ 3.0 mM/L), Leptin (10.50100ng/ml). And insulin (1050100 nM/L). Leptin and its three receptors (ObRa,ObRb.) were detected. ObRc). The results showed that the expression of ObRa was not detected in all three fats. The subcutaneous fat was most sensitive to the change of 尾 -hydroxybutyric acid concentration, and the low concentration of 尾 -hydroxybutyric acid (0.5 ~ 1.0 mM/L) significantly upregulated the transcription levels of Leptin,ObRb and ObRc in subcutaneous fat. High concentration of 尾 -hydroxybutyric acid (3.0 mM/L) down-regulated the expression of Leptin mRNA, and significantly decreased the up-regulation of ObRb and ObRc. In perirenal fat, the change of 尾-hydroxybutyric acid concentration only had a significant effect on ObRc mRNA. The concentration of Leptin had a similar effect on the levels of Leptin and ObRb,ObRc mRNA in subcutaneous and perirenal fat. The Leptin and ObRb,ObRc mRNA of subcutaneous fat decreased with the increase of insulin concentration, whereas the perinephric fat decreased. All the three drugs down-regulated the expression of Leptin and its receptor mRNA in mesenteric fat, in which insulin played a significant role. Conclusion: low plasma Leptin level is associated with ketosis. 尾 -hydroxybutyric acid (尾 -hydroxybutyric acid) may affect the expression of Leptin and its receptor mRNA. The secretion of Leptin in different parts of fat was different from that of self-regulation. Subcutaneous fat was the most important Leptin secretion site, and was most sensitive to 尾 -hydroxybutyric acid (尾 -hydroxybutyric acid). The transcriptional changes of Leptin related genes in perirenal fat were not changed and maintained at a certain level.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S858.23

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本文編號：2398265