【作者】 张根军；

【导师】 张宏福；

【作者基本信息】 中国农业科学院 ， 动物营养与饲料科学， 2004， 硕士

【摘要】 为给猪热应激监测提供科学依据，本研究利用人工气候舱，模拟典型的热应激环境，探讨高温应激对生长猪的血液生理生化指标的影响模型，并从中筛选可作为监测热应激的敏感指标，为动物生产中的福利和应激监测提供方法。 选择12头体重接近（25±1.12kg）、遗传基础相似的的健康安装颈静脉血导管的杜×长×大三元杂交阉公猪，首先研究某些生理生化指标和分子生物学指标的日变化规律，然后进行短期急性高温热应激和持续日变高温热应激试验测定这些指标变化规律，以期得到热应激监测的适宜指标。结果为： （一）、血液生理生化指标日变化规律 生长猪在18℃-26℃，相对湿度（RH）保持在50％-60％环境条件下的日变化规律测定结果表明：钾离子、氯离子在一昼夜内不同时间采样所测值差异显著（P＜0.05）：钙离子、磷离子、镁离子、GPT、GOT、LDH、CPK、COR、INS、T₃、T₄等在一昼夜内不同时间所测值差异未呈显著水平（P＞0.05）。但从测值看除INS、T₃、T₄、HSP70外血液生理生化指标测值的日变化似存在，而且以8：00和16：00测值较高，其他时间点测值较低。在自然日变温条件下（18℃-26℃，相对湿度（RH）保持在50％-60％）INS、T₃、T₄、HSP70测值基本稳定，变异很小。 （二）短期急性热应激 在半小时内温度从19℃升至40℃并保持3小时之后迅速降至19℃，相对湿度（RH）保持在50％-60％环境条件下短期急性热应激实验表明： （1）、生长猪血液无机离子中钾离子对短期急性热应激比较敏感，K⁺在升温半小时后即有明显降低（P＜0.01），直到降温后3天后仍低于升温前（P＜0.05）。热应激对钙、磷、镁、氯等离子浓度测值的影响未达显著水平（P＞0.05），但从测值平均值看也表现出与钾离子相似的变化趋势。 （2）、生长猪血液中GOT、LDH、CPK等酶对短期急性热应激比较敏感，CPK尤为敏感。GOT在升高温度1小时后即有显著升高（P＜0.05），最高时达应激前的1.79倍（P＜0.05）：LDH、CPK在升高温度1小时后即有升高（P＜0.01），至2小时达最高，分别是应激前的1.80倍（P＜0.01）和2.39倍（P＜0.01）；降温后逐渐下降恢复，但降温4小时后，CPK的活性还明显高于升温前（P＜0.05）。 （3）、生长猪血液几种激素中以COR对短期急性热应激比较敏感。COR在升高温度后即有升高（P＜0.05），1小时后升至最高（P＜0.01）；随后逐渐降低，降温4小时后，即恢复正常。表明COR测值可以及时反映热应激源的存在状况。 （4）、生长猪血液中HSP测值对短期急性热应激比较敏感，而且反应延续时间长。生长猪血液HSP在短期急性高温条件下，有升高趋势，在升高温度后立即升高（P＜0.01），降温5日后仍明显高于升温前（P＜0.01）。表明分子生物学指标HSP不仅能反映猪受热应激的状况，而且还能反映猪受热应激的后续效应。 （三）、持续日变高温热应激 对照组温度18℃一26℃日变，实验组25℃一37℃日变，相对湿度（RH）都保持在50%条件下进行两周实验表明: （1）、持续日变高温条件下，生长猪血液中钙、磷、镁、钾、抓等离子浓度无明显变化，在持续高温开始至实验结束与对照组相比都无显著差异（乃0.05）。表明从猪血液中电解质离子浓度角度看，该强度的热应激源对实验猪没有产生明显应激。并且表明血液中离子浓度不是反映猪受长期中低强度热应激的敏感指标。 （2）、持续高温条件下，生长猪血液中GPT、Gor、LDH、CPK等酶的活性明显升高，均随热应激时间延长而升高（只0.01）。并且与对照组相比差异达显著（只0.05）或极显著水平 （只0.01）:表明血液中各项酶指标测值都能较敏感地反映猪受热应激的状况，并且随应激时间延长各指标测值累进升高. （3）、持续高温条件下，生长猪血掖中COR测值先升后降，在持续高温开始第1日明显高于对照组（代0.05），随后逐渐下降，至第4日后降至低于对照组的水平，表明coR在持续应激的条件下有耗竭的趋势。 （4）、持续高温条件下，与对照组相比生长猪血液中HsP明显升高（只0.05），但在持续高温试验期内各次测值相对恒定，绝对值与短期急性热应激时侧值接近，表明”SP是一项定性监测动物受应橄与否的指标，而不能敏感地反映受应激的程度。 动物生理生化指标测值的日变化是客观存在的，同时由于应激监测指标的测值本身受多种因素的影响变异较大，因此研究应激反应模型，应激监测时采样时间点的控制十分重要。 血液中GPT、GOT、LDll、CPK等酶指标，COR等激素指标和HSP70等指标都能敏感的反映猪受热应激的状况，但各项指标的生物学表征意义有很大差别.其中GPT、GOT、LDH、C滩等酶指标能反映动物体受应傲源刺傲的累进程度，但应激源消失后，其测值迅速恢复正常，、Gor、LDll、CPK等是即时监测应激源及其刺激强度的敏感指标.而分子生物学指标HSP70测值却较为恒定，它能较准确反映动物受应激的状态，且应激源消失后仍保持较高的测值，因此HsP70是一种监测动物是否受过应激的良好指标。更多还原

【Abstract】 12 duroc Iandrace yorkshare crossbred barrow pigs was fed in artificial climate chamber to study effects of heat stress on anhnal physiological and biochemical parameters, which expect to pick out the sensitive indexes to monitor status of heat stress for pig, and provide scientific bases for animal welfare. Three experiments were conducted after pigs were arranged into three groups at random after blood Cathers was surgically installed in the juguar vein for each pig.In Exp. 1 .physiological and biochemical parameters in a day were continuously determined during the experiment. Air temperature inside artificial climate chamber varied from 18 C to 26 C, and Relative humidity (RH) varied from 50% to 60%. The result showed that K+, Cl- changed significantly. Other parameters included, Ca2+ P, CL- Mg2+,Creatine PhosphoKinase, (CPK) .Glutamic-Pyruric Transaminase (GPT), Glutamic -Oxalacetic Transaminase (GOT), Lactate Dehydrogenase (LDH), Triodothyronime (T3), Thyroxine (T4), Cortisol (COR), Insulin(INS),Heat Shock Protein (HSP) did not change significantly in this experiment. However, these parameters maybe numerically have a diurnal variation except the. INS, T3, T4, HSP.In Exp.2, the effect of a short-term acute heat shock on pigs was studied by determining the physiological and biochemical parameters. The result showed that K+ decreased significantly after half an hour (p<0.01) and lasted up to 3 days (p<0.05), the effects on Ca2+,P,CL~ ,Mg2+ were not significant. But it had the same tendency with K+. GOT, which increased significantly as well as LDH and CPK after one hour (p<0.01). As the chamber temperature cooling down, then LDH and CPK gradually decreased except that CPK was still higher than previous value before the temperature elevated. COR increased after half an hour and reach peak value after one hour, then it gradually decreased. It restored to normal after cooling down in 4 hours. These results suggested that heat stress appeared under different chamber temperature and relative humidity.Serum HSP70 was quite sensitive to short time heat stress, and increased immediately once heat stress appeared (p<0.01). The duration of HSP70 change longed for 5 days when exposed to high temperature (p<0.05).In Exp.3, Diumal high temperature lasted 14 days were respectively assigned to 30 C-38 C and 18-23 C. Samples of plasma were taken on day1, day2, day4, day7, day10, and day14. The result showed that K+, C1-, Ca2+, P and Mg2+ did not change significantly in this experiment. With the heat stress going on, the activity of serum GPT, GOT, LDH, CPK increased significantly (p<0.01), this lasted up to 14 days. It can be sensitively reflected the state of the stress. COR in the duration heat stress group was higher than which in contrast group on dayl (p<0.05), then it gradually decreased up to day4. It was lower than which in contrast group. Serum HSP70 content of pigs in the duration heat stress increased significantly and was higher than which in contrast group(p<0.05). but it didn’t change significantly between 14days. It can be a preferable heat stressmonitoring index but it can not reflect the extent of the heat stress.The physiological and biochemical parameters of animals have a diurnal variation. The value of parameters was affected by many factors, so time of blood sampling has to be controlled in order to stud heat stress.The indexes in blood included, GPT, GOT,LDH,CPK,COR,HSP can reflect the state of the stress sensitively, but the biological meaning varies between different index-GOT, LDH, CPK can represent the accumulation of the stress. As the stress disappeared, the value of these physiological and biochemical parameters restored rapidly, so it can be sensitive indexes to monitor the source and the intensity of stress. The value of serum HSP70 kept continuously higher although source of stress disappeared for a long time. Serum HSP70 can be a preferable monitoring index to the existence of heat stress.更多还原