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GHRP-2与半胱胺对生长迟缓牦牛的促生长作用机理研究

发布时间:2018-03-20 13:14

  本文选题:生长迟缓牦牛 切入点:瘤胃发酵 出处:《四川农业大学》2015年硕士论文 论文类型:学位论文


【摘要】:在青藏高原,牦牛生长迟缓形成“僵牛”的现象普遍存在,降低了牧民养殖生产综合效益。本文以青海高原型牦牛为研究对象,探讨了牦牛生长迟缓与生长轴激素分泌水平的关系,并研究了注射GHRP-2和日粮添加半胱胺提高牦牛“僵牛”生长性能的作用机理,为科学饲养牧区牦牛“僵牛”提供理论依据。论文分为两个试验:试验一牦牛体重与生长轴激素分泌水平关系的研究随机选取36头(体重38-83.2kg)1周岁青海高原型牦牛,预饲7d后进行空腹称重和采血,对牦牛群体体重与血清GHRH、GH和IGF-1进行相关分析。结果发现,牦牛血液GHRH、GH与IGF-1水平随体重增加而显著增加(P0.05)。体重偏低牦牛群体GHRH、GH和IGF-1与体重呈显著正相关性(P0.05),表明牦牛“僵牛”生长迟缓主要由生长轴激素分泌不足引起。试验二GHRP-2与半胱胺对牦牛“僵牛”生长性能,瘤胃发育和肌肉蛋白沉积的影响按低于同品种同龄牦牛群体平均体重1.5倍标准差的标准,选取15头1周岁青海高原型牦牛“僵牛”,平均体重54.8±9.24kg,按体重随机分为3组,每组5头牛。分别设为:僵牛对照组(负对照组),GHRP-2注射组(GHRP-2组)、半胱胺补饲组(半胱胺组);另选取1周岁正常青海高原型牦牛5头(75.3±2.43kg)设为正常组(正对照组)。其中负对照组每日投喂精补料和燕麦青干草的基础日粮;GHRP-2组在负对照组基础上于正式试验的第1-6d,11-16d,21-26d每天颈静脉注射12.5ug/kg体重GHRP-2,饲养方法同负对照组;半胱胺组在负对照组基础上于正式试验1-28d在精补料中添加半胱胺5g/头·d,29-84d饲养同负对照组;正对照组饲养同于负对照组。预饲期14d,正式试验84d,在正式试验的第0,28,56和84d对各组牦牛采血和称重,饲养试验结束后进行屠宰取样。结果如下:1) GHRP-2组和半胱胺组牦牛末重显著高于负对照组(P0.05),与正对照组差异不显著(P0.05)。GHRP-2组和半胱胺组全期(0-84d)ADG均显著高于正对照组和负对照组(P0.05)。试验第0-28d,GHRP-2组ADG显著高于其余三个处理组(P0.05);第29-84d,半胱胺组ADG显著高于其余三个处理组(P0.05)。2) GHRP-2和半胱胺显著促进牦牛“僵牛”瘤胃生长,提高瘤胃占复胃重比例(P0.05),半胱胺组优于GHRP-2组(P0.05)。GHRP-2与半胱胺显著提高了牦牛“僵牛”瘤胃乳头高度(P0.05)和宽度(P0.05),与正对照组差异不显著(P0.05)。3) GHRP-2与半胱胺显著提高牦牛“僵牛”瘤胃TVFA和乙酸浓度(P0.05)。GHRP-2显著提高瘤胃丙酸浓度(P0.05),半胱胺显著提高瘤胃丁酸浓度(P0.05)和乙酸/丙酸(P0.05)。GHRP-2组和半胱胺组牦牛瘤胃氨氮浓度显著低于正对照组(P0.05),但高于负对照组(P0.05),而MCP浓度显著高于负对照组(P0.05),且GHRP-2组高于半胱胺组(P0.05)。4) GHRP-2和半胱胺显著提高牦牛“僵牛”血清GLU和BUN浓度(P0.05),显著提高28d血清TP和56d血清ALB浓度(P0.05)5)试验28d,半胱胺显著提高牦牛“僵牛”血清GHRH水平(P0.05),显著降低SS水平(P0.05)。GHRP-2和半胱胺均显著提高牦牛“僵牛”血清GH和IGF-1水平(P0.05)。半胱胺组试验56d GHRH.GH和IGFBP-3最高(P0.05),84d GHRH和IGFBP-3最高(P0.05),SS显著最低(P0.05)。6) GHRP-2显著提高牦牛“僵牛”肝脏、背最长肌和半腱肌中GHR、IGF-1和IGF-1R基因表达量(P0.05),半胱胺显著降低下丘脑中SS基因表达量(P0.05)显著提高肝脏中GHR和IGF-1基因表达量(P0.05)。7) GHRP-2和半胱胺显著提高牦牛“僵牛”骨骼肌纤维直径(P0.05)、肌纤维面积(P0.05)以及蛋白质含量(P0.05)。8) GHRP-2显著提高骨骼肌中IRS-1、PI3K、AKt和mTOR基因表达量(P0.05),显著降低MuRF1基因表达量(P0.05)。半胱胺显著降低AMPK、Atrogin-1和MuRF1基因表达量(P0.05)。综上,生长轴激素分泌不足是造成牦牛“僵牛”原因之一。GHRP-2和半胱胺均可促进瘤胃生长与发酵,促进牦牛“僵牛”补偿生长,且后续效应持久。GHRP-2通过提高血清中GH和IGF-1水平,提高肝脏和肌肉中GHR、IGF-1及IGF-1R基因表达,进而上调骨骼肌蛋白合成通路中IRS-1、PI3K、AKt和mTOR基因表达,下调蛋白降解通路中MuRF1基因表达,从而提高骨骼肌纤维直径和面积,促进牦牛“僵牛”生长。半胱胺则通过提高血清GHRH、GH和IGF-1水平,降低SS水平,降低下丘脑中SS基因表达,提高肝脏中GHR和IGF-1基因表达,下调肌肉蛋白降解通路中AMPK、Atrogin-1和MuRF1基因表达,从而提高骨骼肌纤维直径和面积,促进牦牛“僵牛”生长。
[Abstract]:In the Qinghai Tibet Plateau, yak growth retardation to form a "universal stiff cow" phenomenon, reduce the comprehensive benefits of herdsmen aquaculture. Taking Qinghai Yaks of plateau type as the research object, discusses the relationship between yak growth retardation and growth hormone secretion, and the injection of GHRP-2 and dietary cysteamine improved yak "stiff cow" mechanism of growth performance, for scientific breeding yak "stiff cattle" and provide a theoretical basis. The thesis is divided into two test: a study of 36 pigs were randomly selected to test yak weight and growth hormone axis relationship (weight 38-83.2kg) 1 years of Qinghai plateau yak, pre feeding after fasting weighing 7d and the blood, body weight and serum levels of GHRH GH and IGF-1 yak populations, correlation analysis. The results showed that the yak blood GHRH, GH and IGF-1 levels increased significantly with the increase of body weight (P0.05). The low weight group of Yak GHRH, GH and IGF-1 were positively correlated with body weight (P0.05), showed that "stiff yak cow" growth retardation mainly by growth hormone secretion caused by insufficient test. Two GHRP-2 and Cysteamine on growth performance of yak "dead cow", affect rumen development and muscle protein deposition at low age in the same variety standard the average weight of 1.5 times the standard deviation of the yak populations, 15 piglets from 1 years of Qinghai Yaks of plateau type "dead cow", the average weight was 54.8 + 9.24kg, were randomly divided into 3 groups, each group of 5 cows. Cows were divided into control group: stiff (negative control group), GHRP-2 group (group GHRP-2). Cysteamine supplementation group (cysteamine group); another 1 years of normal Qinghai Yaks of plateau type 5 (75.3 + 2.43kg) as normal group (positive control group). The negative control group daily feeding fine feeding and oat hay based diet; GHRP-2 group in negative control group on the basis of the formal test The 1-6d, 11-16d, 21-26d daily intravenous injection 12.5ug/kg weight GHRP-2, feeding method with negative control group; cysteamine group in negative control group on the basis of the formal test of 1-28d in tonic cysteamine 5g/ head D material, 29-84d feeder with the negative control group; positive control group fed with negative control the pre feeding period. Group 14d, 84d in the formal test, formal test in 0,28,56 and 84d groups of yak blood sampling and weighing, after the end of the feeding trial were slaughtered. The results are as follows: 1) GHRP-2 group and cysteamine group yak final weight was significantly higher than the negative control group (P0.05), and positive control group were not was (P0.05).GHRP-2 group and cysteamine group whole period (0-84d) ADG were significantly higher than the positive control group and negative control group (P0.05). The 0-28d, ADG in GHRP-2 group was significantly higher than the other three groups (P0.05); 29-84d, cysteamine group ADG was significantly higher than the other three groups (P0.05).2) GH RP-2 and cysteamine significantly promote the growth of yak stiff cow rumen, improve rumen accounted for complex stomach weight ratio (P0.05), cysteamine group than in GHRP-2 group (P0.05.GHRP-2) and cysteamine significantly improved the yak "stiff cow rumen papillae height (P0.05) and width (P0.05), and positive control there were no significant differences (P0.05).3 GHRP-2) and cysteamine significantly improved yak stiff cow rumen TVFA and acetic acid concentration (P0.05) of.GHRP-2 significantly increased the rumen propionate concentration (P0.05), cysteamine significantly improved ruminal butyrate concentration (P0.05) and acetic acid / propionic acid (P0.05) in.GHRP-2 group and cysteamine group yak rumen ammonia concentration was significantly lower than the positive control group (P0.05), but higher than the negative control group (P0.05), and the concentration of MCP was significantly higher than the negative control group (P0.05), and GHRP-2 group was higher than that of cysteamine group (P0.05).4 GHRP-2) and cysteamine significantly improved the yak" stiff cow serum GLU and BUN concentration (P0.05, 28d) increased significantly 琛,

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