高精料日粮对山羊肝脏糖脂代谢的影响及其机制研究
发布时间：2018-08-27 12:46
【摘要】：生产中给奶畜饲喂高精料日粮来满足反刍动物泌乳期能量需求的饲喂模式已成为一种流行趋势。但是,奶畜摄入高精料日粮可导致瘤胃中挥发性脂肪酸的沉积和瘤胃液中异常代谢产物脂多糖的释放增加,进而转移入血液,经门静脉入肝脏,从而影响肝脏基因表达和营养重分配,然而其具体影响的途径和机制尚不清楚。本研究以关中奶山羊为动物模型,模拟实际生产中的喂养模式,通过在日粮中添加高比例的精料来揭示长期饲喂高精料日粮对关中奶山羊血液生化指标和肝脏糖脂代谢的影响,为科学饲养泌乳期的奶山羊提供理论基础。本课题的研究内容和结果如下:本试验选用14头体重相近、健康状况良好,泌乳初期的经产2~3胎的关中奶山羊,随机分为2组,对照组为6只,试验组为8只,其中对照组的奶山羊被饲喂精粗比为35:65的日粮,试验组的奶山羊被饲喂精粗比为65:35(高精料组)的日粮,试验期为19周,在试验期间可自由饮水,每日活动两次。1.采取颈静脉血测定血液生化参数,结果表明,饲喂高精料日粮的试验组奶山羊血浆中谷丙转氨酶浓度显著升高(P0.05),甘油三酯有下降的趋势(P=0.099),但是,在长期饲喂高精料日粮的条件下,血液中大部分的生化指标并没有发生显著性的变化(P0.05)。2.运用经典的HE染色,染色结果显示高精料日粮可以引起奶山羊肝细胞高度肿胀,体积变大,胞浆溶解,肝细胞呈肿胀变性或空泡样变性。3.通过Real-time PCR检测肝脏脂代谢相关基因表达,结果显示,长期饲喂高精料日粮的试验组奶山羊肝脏脂代谢关键基因的表达均未发生显著性变化(P0.05)。虽然,在长期饲喂高精料日粮的条件下,实验组肝脏脂代谢相关基因LPL、SCD、FADS2 mRNA的表达量有所升高,但是却没有达到显著的水平。4.Real-time PCR检测肝脏糖异生关键酶的表达,结果显示,肝脏糖异生关键基因PEPCK-c和Fbp1的mRNA的表达均显著下降(P0.05),说明高精料日粮抑制了肝脏的糖异生作用。5.免疫印迹结果表明Fbp1的蛋白表达显著下降(P0.05);但是,酶活性测定结果显示Fbp1的活性显著升高(P0.05)。6.通过Real-time PCR检测肝脏转录相关调控因子的表达,结果显示,试验组奶山羊肝脏肝X受体和视黄醇γ受体mRNA的表达显著降低(P0.05)。本研究结果显示,长期饲喂高精料日粮可导致血液中谷丙转氨酶升高,提示这可能与肝细胞受损有关,但是脂类代谢的相关基因表达均没有发生显著变化。肝细胞损伤可能抑制了肝脏转录相关基因的表达,进而抑制了肝脏糖异生作用。
[Abstract]:It has become a popular trend to feed dairy animals with high concentrate diets to meet the energy requirements of ruminants during lactation. However, intake of high concentrate diet led to the accumulation of volatile fatty acids in rumen and the release of abnormal metabolite lipopolysaccharide from rumen fluid, and then transferred into blood and liver through portal vein. Thus affecting liver gene expression and nutrient redistribution, however, the specific impact of the pathway and mechanism is not clear. In this study, Guanzhong dairy goat was used as an animal model to simulate the feeding mode in actual production. The effect of long-term feeding high concentrate diet on blood biochemical index and hepatic glucose and lipid metabolism of Guanzhong dairy goat was revealed by adding a high proportion of concentrate to the diet. To provide a theoretical basis for the scientific feeding of dairy goats during lactation. The research contents and results are as follows: 14 Guanzhong dairy goats with similar body weight and good health were randomly divided into two groups: control group (n = 6) and experimental group (n = 8). The milk goats of the control group were fed the diet of 35:65, and the dairy goats of the test group were fed the diet of 65:35 (high concentrate group) for 19 weeks. During the trial period, they were free to drink water and exercise twice a day. The blood biochemical parameters were measured by jugular vein blood. The results showed that the plasma concentration of alanine aminotransferase in dairy goats fed high concentrate diet was significantly increased (P0.05), and triglyceride decreased (P0. 099). Under the condition of feeding high concentrate diet for a long time, most of the biochemical indexes in blood did not change significantly (P0.05). 2. The results of classical HE staining showed that high concentrate diet could cause high swelling of hepatocytes, large volume, cytoplasmic dissolution, swelling or vacuolar degeneration of liver cells. The expression of liver lipid metabolism related genes was detected by Real-time PCR. The results showed that there was no significant change in the expression of key genes of liver lipid metabolism in dairy goats fed with high concentrate diet for a long time (P0.05). Although the expression of liver lipid metabolism-related gene LPL,SCD,FADS2 mRNA was increased in the experimental group under the condition of high concentrate diet for a long time, it did not reach a significant level. 4. Real-time PCR was used to detect the expression of hepatic glycosylated key enzymes. The expression of mRNA in PEPCK-c and Fbp1 decreased significantly (P0.05), which indicated that high concentrate diet inhibited hepatic glycosylation. 5. Western blotting showed that the protein expression of Fbp1 decreased significantly (P0.05), but the activity of Fbp1 increased significantly (P0.05). The expression of transcription-related regulatory factors in liver was detected by Real-time PCR. The results showed that the expression of X receptor and retinol 纬 receptor mRNA in liver of dairy goats in the experimental group was significantly lower than that in the control group (P0.05). The results showed that long-term feeding of high concentrate diet led to the increase of blood alanine aminotransferase, suggesting that this may be related to the damage of hepatocytes, but the expression of genes related to lipid metabolism did not change significantly. Hepatocyte injury may inhibit the expression of transcriptional genes in the liver and thus inhibit the hepatic glycosylation.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S827.5
本文编号：2207328
[Abstract]:It has become a popular trend to feed dairy animals with high concentrate diets to meet the energy requirements of ruminants during lactation. However, intake of high concentrate diet led to the accumulation of volatile fatty acids in rumen and the release of abnormal metabolite lipopolysaccharide from rumen fluid, and then transferred into blood and liver through portal vein. Thus affecting liver gene expression and nutrient redistribution, however, the specific impact of the pathway and mechanism is not clear. In this study, Guanzhong dairy goat was used as an animal model to simulate the feeding mode in actual production. The effect of long-term feeding high concentrate diet on blood biochemical index and hepatic glucose and lipid metabolism of Guanzhong dairy goat was revealed by adding a high proportion of concentrate to the diet. To provide a theoretical basis for the scientific feeding of dairy goats during lactation. The research contents and results are as follows: 14 Guanzhong dairy goats with similar body weight and good health were randomly divided into two groups: control group (n = 6) and experimental group (n = 8). The milk goats of the control group were fed the diet of 35:65, and the dairy goats of the test group were fed the diet of 65:35 (high concentrate group) for 19 weeks. During the trial period, they were free to drink water and exercise twice a day. The blood biochemical parameters were measured by jugular vein blood. The results showed that the plasma concentration of alanine aminotransferase in dairy goats fed high concentrate diet was significantly increased (P0.05), and triglyceride decreased (P0. 099). Under the condition of feeding high concentrate diet for a long time, most of the biochemical indexes in blood did not change significantly (P0.05). 2. The results of classical HE staining showed that high concentrate diet could cause high swelling of hepatocytes, large volume, cytoplasmic dissolution, swelling or vacuolar degeneration of liver cells. The expression of liver lipid metabolism related genes was detected by Real-time PCR. The results showed that there was no significant change in the expression of key genes of liver lipid metabolism in dairy goats fed with high concentrate diet for a long time (P0.05). Although the expression of liver lipid metabolism-related gene LPL,SCD,FADS2 mRNA was increased in the experimental group under the condition of high concentrate diet for a long time, it did not reach a significant level. 4. Real-time PCR was used to detect the expression of hepatic glycosylated key enzymes. The expression of mRNA in PEPCK-c and Fbp1 decreased significantly (P0.05), which indicated that high concentrate diet inhibited hepatic glycosylation. 5. Western blotting showed that the protein expression of Fbp1 decreased significantly (P0.05), but the activity of Fbp1 increased significantly (P0.05). The expression of transcription-related regulatory factors in liver was detected by Real-time PCR. The results showed that the expression of X receptor and retinol 纬 receptor mRNA in liver of dairy goats in the experimental group was significantly lower than that in the control group (P0.05). The results showed that long-term feeding of high concentrate diet led to the increase of blood alanine aminotransferase, suggesting that this may be related to the damage of hepatocytes, but the expression of genes related to lipid metabolism did not change significantly. Hepatocyte injury may inhibit the expression of transcriptional genes in the liver and thus inhibit the hepatic glycosylation.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S827.5
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