【作者】 王鹏；

【导师】 周忠新；

【作者基本信息】 华中农业大学 ， 农业硕士（专业学位）， 2018， 硕士

【摘要】 运输应激会造成生猪下丘脑—垂体—肾上腺轴过度激活,产生大量应激激素,同时常常伴随机体氧化还原失衡—机体处在氧化应激状态,进而提高运输失重、损伤肉质、降低动物福利,甚至死亡。本试验旨在研究日粮中短期添加牛至精油和色氨酸组合是否可以通过靶向调节丘脑—垂体—肾上腺轴以及机体氧化还原平衡,缓解育肥猪运输应激。本试验选取360头、体重相近的二元杂交(长白×大白)生长育肥猪,按体重性别一致原则随机分为4组(非运输组(Blank)、对照组(Control)、处理一组、处理二组),每组4栏共计90头,每栏保证公母各半,饲喂8天后运输、屠宰、取样、测试、分析。非运输组—饲喂基础日粮,对照组—“饲喂基础日粮+长时间(5h)高密度(325kg/m~2)运输”,处理一组(0.3%OT组)—“饲喂基础日粮+(0.3%色氨酸+0.025‰牛至精油)+长时间(5h)高密度(325kg/m~2)运输”,处理二组(0.6%OT组)—“饲喂基础日粮+(0.6%色氨酸+0.025‰牛至精油)+长时间(5h)高密度(325kg/m~2)运输”。结果表明:1.与非运输组相比,对照组下丘脑5-羟色胺(5-Hydroxytryptamine,5-HT)浓度显著降低(P<0.01),5-羟吲哚乙酸(5-Hydroxyindoleacetic acid,5-HIAA)浓度无变化(P>0.05);血清5-HT、5-HIAA含量均没有显著差异(P>0.1)。与对照组比,日粮添加0.6%OT或0.3%OT使运输猪下丘脑5-HT(P<0.05)和5-HIAA(P<0.05)浓度显著升高,0.6%OT组的5-HT浓度比0.3%OT组高(P<0.05);添加0.6%OT可使运输猪血清5-HT浓度显著升高(P<0.05),0.3%OT则差异不显著(P>0.05),但日粮添加0.6%OT或0.3%OT都显著提高血清5-HIAA浓度(P<0.05)并且0.6%OT比0.3%OT具有更好的效果(P<0.05)。2.与非运输组相比,对照组血清皮质醇、促肾上腺皮质激素(Adrenocorticotropic hormone,ACTH)浓度均显著升高(P<0.05),血清中肌酸激酶(Creatine kinase,CK)、血浆尿素氮(Plasma urea nitrogen,PUN)和热休克蛋白70(Heat shock protein70,HSP70)含量显著性升高(P<0.01),乳酸脱氢酶(Lactate dehydrogenase,LDH)也有变化(P=0.97)。与对照组相比,添加0.6%OT或0.3%OT均可显著降低(P<0.01)血清中ACTH和皮质醇激素浓度,以及血清中CK含量(P<0.05),0.6%OT组比0.3%OT组具有更好的效果(P<0.05);同时,添加0.6%OT可以使血清中PUN、LDH、HSP70含量显著性下调(P<0.05),添加0.3%OT对上述3种物质浓度影响不显著(P>0.05)。3.与非运输组相比,对照组血清、肌肉组织和空肠组织总超氧化歧化酶(Superoxide dismutase,T-SOD)(P<0.05)含量,血清中谷胱甘肽过氧化物酶(Glutamine peroxidase,GSH-Px)(P<0.01)的含量显著下调,肌肉组织样活性氧自由基(Reactive oxygen species,ROS)水平显著上调(P<0.05),血清ROS含量上升(P=0.06),空肠组织样丙二醛(Malondialdehyde,MDA)水平升高(P<0.05);血清ROS和MDA,肌肉组织MDA,以及空肠组织ROS和抗氧化酶GSH-Px差异不显著(P>0.05)。与对照组相比,添加0.3%OT或0.6%均可使血液、肌肉、空肠中ROS含量显著下调(P<0.05),同时0.6%OT组可以有效降低血液、肌肉、空肠中脂质过氧化物MDA水平(P<0.05),提高机体抗氧化酶T-SOD和GSH-Px水平(P<0.05),但0.3%OT组对血清和肌肉组织MDA影响不显著(P>0.05)。4.与空白相比,对照组空肠粘膜白细胞介素6(Interleukin-6,IL-6)的mRNA相对表达量显著升高(P<0.05),白细胞介素—1β(Interleukin-1β,IL-1β)的mRNA相对表达量有上升的趋势(P=0.08),同时肿瘤坏死因子-α(Tumor necrosis factorα,TNF-α)的mRNA相对表达量上升(P=0.47)。与对照组相比,添加0.6%OT或0.3%OT均可显著降低空肠粘膜TNF-α、IL-1β、IL-6的mRNA相对表达量(P<0.05)。5.与非运输组相比,对照组空肠粘膜闭锁蛋白ZO-1的mRNA相对表达量显著降低(P<0.01),咬合蛋白Occludin的mRNA相对表达量有下降趋势(P=0.08),热休克蛋白HSP70的mRNA相对表达量上升(P=0.21)。与对照组相比,0.6%OT组和0.3%OT组空肠粘膜Occludin的mRNA相对表达量显著升高(P<0.05),而ZO-1 mRNA相对表达量差异均不显著(P=0.609)。0.3%OT组和0.6%OT组均可显著性降低空肠粘膜HSP70的mRNA相对表达量(P<0.05)。6.与非运输组相比,对照组宰后肌肉p Hi(45min)、p Hu(24h)值显著降低(P<0.05),肌肉滴水损失呈升高的趋势(P<0.05),对肉质检测的其它指标无影响(P>0.05)。与对照组相比,添加0.6%OT可以显著提高生猪宰后p Hu(24h)值(P<0.05),添加0.3%OT或0.6%OT均能显著性增加育肥猪背最长肌p Hi(45min)(P<0.05)值及降低生猪肌肉滴水损失(48h)(P<0.05)。商品猪失重率从高到低依次是:对照组(3.75%)、非运输组(1.91%)、0.3%OT组(1.33%)、0.6%OT组(0.50%)。综上所述,长时间(5h)、高密度(325kg/m~2)的运输使育肥猪下丘脑—垂体—肾上腺轴过度激活,增加下丘脑和血清中应激激素浓度,并伴随机体氧化还原失衡、肠粘膜炎性因子表达上调、肠上皮屏障功能受损、肉质损伤。在育肥猪宰前日粮中,短期添加(8天)0.025‰牛至精油和0.6%色氨酸组合,可以显著提高下丘脑中5-羟色胺的浓度(P<0.05),进而调节下丘脑—垂体—肾上腺轴的过度激活,显著减少释放到血液中的皮质醇(P<0.05)、促肾上腺皮质激素(P<0.05)等应激激素浓度;提高血液、肌肉、空肠组织超氧化物歧化酶和谷胱甘肽过氧化酶活力(P<0.05),同时降低这3个组织中的丙二醛含量(P<0.05),进而调节机体氧化还原平衡,降低机体活性氧自由基水平,达到有效缓解育肥猪运输应激及其导致的失重损失、肉质损伤的效果。本研究为缓解育肥猪运输应激及其引起的运输失重、肉质损伤、动物福利问题提供了一种短期营养调控处理措施。更多还原

【Abstract】 Transport stress can lead to hyperactivation of the hypothalamus-pituitary-adrenal axis of pigs,resulting in a large number of stress hormones.At the same time,it often accompanies the body’s oxidation-reduction imbalance,so that the body is in an oxidative stress state,thereby increasing transport weight loss,meat quality,and animal welfare.It even caused the transport to die.The purpose of this study was to determine whether the combination of oregano oil and tryptophan in the diet can target the regulation of the thalamo-pituitary-adrenal axis and regulate the redox balance of the organism,so as to effectively relieve the transport stress of pigs.In this experiment,360 pigs of two crossbreds(Landrace×Dabai)with similar weights were selected to grow and finish the pigs.They were randomly divided into 4groups(Blank group,control group,treatment group,and treatment group 2)according to the principle of uniform body weight and gender.Each group 4,There are altogether 90heads in the column.Each column guarantees half male and female half,feeds,slaughters,samples,tests and analyses after 8 days of feeding.Blank group-fed the basal diet,control group-"basal diet+long-term(5h)high-density(325kg/m~2)transport"to treat a group(0.3%OT group)-"feeding basal diet+(0.3%tryptophan+0.025‰to essential oil)+long-term(5h)high-density(325kg/m~2)transport",treatment two groups(0.6%OT group)-"basic diet fed+(0.6%Tryptophan+0.025‰oregano oil+long time(5h)high density(325kg/m~2)".1.Compared with the blank group,the concentration of 5-hydroxytryptamine(5-HT)in the hypothalamus was significantly lower in the control group(P<0.01),and there was no change in the concentration of 5-Hydroxyindoleacetic acid(5-HIAA).(P>0.05);There was no significant difference in serum 5-HT and 5-HIAA levels(P>0.1).Compared with the control group,dietary supplementation with 0.6%OT or 0.3%OT significantly increased 5-HT(P<0.05)and 5-HIAA(P<0.05)concentrations in the hypothalamus of transport pigs,and 5-HT in the 0.6%OT group.The concentration was higher than that of0.3%OT group(P<0.05).The addition of 0.6%OT significantly increased the serum5-HT concentration in transportation pigs(P<0.05),but there was no significant difference in 0.3%OT(P>0.05).The dietary supplementation with 0.6%OT or 0.3%OT significantly increased serum 5-HIAA concentration(P<0.05),and 0.6%OT had better effect than 0.3%OT(P<0.05).2.Compared with the blank group,the serum cortisol and Adrenocorticotropic hormone(ACTH)concentrations in the control group were significantly increased(P<0.05),serum creatine kinase(CK),plasma urea nitrogen(Plasma urea nitrogen(PUN)and heat shock protein 70(HSP70)levels were significantly increased(P<0.01),and lactate dehydrogenase(LDH)was also changed(P=0.97).Compared with the control group,the addition of 0.6%OT or 0.3%OT significantly decreased(P<0.01)serum ACTH and cortisol hormone concentrations,and serum CK levels(P<0.05),0.6%OT group compared to 0.3%The OT group had better results(P<0.05).At the same time,the addition of 0.6%OT could significantly decrease the levels of PUN,LDH,and HSP70 in the serum(P<0.05).The addition of 0.3%OT had no effect on the concentration of the above three substances.Significant(P>0.05).3.Compared with the blank group,the content of total superoxide dismutase(T-SOD)(P<0.05)in serum,muscle tissue and jejunum of the control group,and glutathione peroxidase(GSH-Px)(P<0.01)was significantly down-regulated,the level of reactive oxygen species(ROS)in muscle tissue was significantly up-regulated(P<0.05),the content of ROS in serum was increased(P=0.06),and the content of ROS in jejunum tissue was increased.Malondialdehyde(MDA)levels were elevated(P<0.05);serum ROS and MDA,muscle tissue MDA,and jejunum tissue ROS and antioxidant enzyme GSH-Px were not significantly different(P>0.05).Compared with the control group,the addition of 0.3%OT or 0.6%can significantly reduce the ROS content in blood,muscle,and jejunum(P<0.05),and 0.6%OT group can effectively reduce lipid peroxidation in blood,muscle,and jejunum.MDA levels(P<0.05)increased the levels of antioxidant enzymes T-SOD and GSH-Px in the body(P<0.05),but 0.3%OT group had no significant effect on serum and muscle MDA(P>0.05).4.Compared with the control group,the mRNA expression level of interleukin-6(IL-6)in the control group was significantly increased(P<0.05),and Interleukin-1β(IL-1β)was the interleukin-1β.The relative expression of mRNA increased(P=0.08),while the mRNA expression of tumor necrosis factor-α(TNF-α)increased(P=0.47).the relative expression of ZO-1 mRNA in the jejunum mucosa of the control group was significantly decreased(P<0.01),and the relative mRNA expression of the occluden protein Occludin was decreased(P=0.08).The relative mRNA expression of HSP70increased(P=0.21).Compared with the control group,0.6%OT or 0.3%OT significantly decreased the relative mRNA expression of TNF-α,IL-1βand IL-6 in jejunum mucosa(P<0.05).The relative mRNA expression of Occludin in the jejunum mucosa of 0.6%OT group and 0.3%OT group was significantly increased(P<0.05),while the relative expression level of ZO-1 mRNA was not significant(P=0.609).Both 0.3%OT group and0.6%OT group significantly decreased the relative mRNA expression of HSP70 in jejunum mucosa(P<0.05).5.Compared with the blank group,the p Hi(45min)and p Hu(24h)values of the post-slaughter muscle in the control group were significantly lower(P<0.05),and the muscle drip loss was increased(P<0.05).Compared with the control group,the addition of 0.6%OT significantly increased the postharvest p Hu(24h)value(P<0.05).Adding0.3%OT or 0.6%OT significantly increased the longissimus muscle p Hi(45min)in finishing pigs.(P<0.05)and decreased muscle drip loss(48h)(P<0.05).The weight loss rate of commodity hogs from high to low was:control group(3.75%),blank group(1.91%),0.3%OT group(1.33%),and 0.6%OT group(0.50%).The prolonged(5h),high-density(325kg/m2)transport overactivates the hypothalamic-pituitary-adrenal axis of fattening pigs,increases the concentration of stress hormones in the hypothalamus and serum,and is accompanied by the body’s redox imbalance and intestinal mucosal inflammation.Upregulation of factor expression,impaired intestinal epithelial barrier function,and meat damage.In the diet before fattening pigs,the short-term(8 days)combination of 0.025 calf to essential oil and 0.6%tryptophan can significantly increase the concentration of 5-hydroxytryptamine in the hypothalamus(P<0.05),thereby regulating the hypothalamus.Excessive activation of the pituitary-adrenal axis significantly reduces the concentration of cortisol(P<0.05),norepinephrine(P<0.05)and other stress hormones released into the blood,and increases the superoxide dismutation in blood,muscle,and jejunum.Enzyme and glutathione peroxidase activity(P<0.05),while reducing the content of malondialdehyde in these three tissues(P<0.05),thereby regulating the body’s redox balance and reducing the level of reactive oxygen species in the body,achieving Effectively relieve the transportation stress of fattening pigs and the loss of weight loss and meat damage.This study provided a short-term nutrition regulation and treatment measures to alleviate the transport stress of fattening pigs and the weightlessness,meat damage,and animal welfare caused by fattening pigs.更多还原