由可知温度和RH对山羊的尿常规中尿酸碱度的影响有显著的交互作用（P<0.05）,在26℃、30℃和34℃下时尿酸碱度不随湿度的升高而显著变化,而到38℃,80%RH时,尿酸碱度显著降低（P<0.05）。温度和RH对山羊平均日干粪量、平均日排尿量和尿常规中尿比重的影响无显著的交互作用（P>0.05）。温度对山羊的平均日干粪量、平均日排尿量及尿常规中尿比重和尿酸碱度均有显著影响（P<0.05）,34℃和38℃山羊平均日干粪量显著低于26℃和30℃（P<0.05）;34℃和38℃山羊平均日排尿量显著高于26℃（P<0.05）;38℃山羊尿比重显著低于26℃和30℃（P<0.05）。温度的升高,平均日干粪量和尿常规中尿比重降低,平均日排尿量升高,尿酸碱度先升后降。RH对山羊的平均日干粪量有显著影响（P<0.05）,而对平均日排尿量和尿比重影响不显著（P>0.05）。RH为80%时平均日干粪量显著低于RH为35%、50%和65%时（P<0.05）。随着RH升高,平均日干粪量和尿酸碱度减少,平均日排尿量先减少后增加。
Table 2
表2
表2温度和RH对山羊干粪量、排尿量、尿比重、尿酸碱度的影响
Table 2
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由和可知,温度和RH对山羊血液中WBC、RBC、Hb、HCT、MCHC、MCH、MCV和RDW的影响在试验第3天和第5天时均无显著交互作用（P>0.05）。温度对试验第3天和第5天山羊血液中WBC均有显著影响（P<0.05）,而对试验第3和5天山羊血液中RBC、Hb、HCT、MCHC、MCH、MCV和RDW均无显著影响（P>0.05）。38℃试验第3天山羊血液中WBC显著低于26℃和30℃（P<0.05）;34℃和38℃试验第5天山羊血液中WBC显著低于26℃（P<0.05）。随着温度的升高,山羊血液中WBC和MCV降低,RBC、Hb和RDW升高。RH对试验第3天山羊血液中WBC和Hb及第5天WBC均有显著影响（P<0.05）,而对试验第3和5天血液中RBC、HCT、MCHC、MCH、MCV和RDW均无显著影响（P>0.05）。RH为65%和80%时山羊血液中WBC显著低于RH为35%时（P<0.05）;RH为65%和80%时试验第3天山羊血液中Hb含量显著高于RH为35%时（P<0.05）。随着RH的升高山羊血液中RBC和Hb升高,WBC、MCHC先降低后升高,RDW先升高后降低。试验第5天山羊血液中WBC、RBC、Hb和HCT低于第3天,而试验第5天MCHC高于第3天,MCH、MCV和RDW 随时间的延长基本不变。
Table 3
表3
表3温度和RH对山羊血液血常规指标的影响Ⅰ
Table 3
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Table 4
表4
表4温度和RH对山羊血液血常规指标的影响Ⅱ
Table 4
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由和可知,温度和RH对试验第5天山羊血清TP、ALB、GLO和BUN含量的影响有显著的交互作用（P<0.05）。在35%和50%RH下时ALB不随温度的升高而降低,而在65%RH下时30℃降低。在35%和50%RH下时GLO和BUN不随温度的升高而降低,而在65%和80%RH下时GLO随温度的升高而降低,而BUN在30℃降低。温度和RH对GLU、TC和TG含量的影响在试验第3和5天时均无显著交互作用（P>0.05）。温度对山羊血清GLU和试验第3天GLO和BUN有显著影响（P<0.05）。38℃试验第3天山羊血清GLO和GLU含量显著低于26和30℃（P<0.05）;38℃试验第5天山羊血清GLU含量显著低于26℃（P<0.05）;38℃试验第3天山羊血清BUN显著低于26℃、30℃和34℃（P<0.05）。温度升高,山羊血清TP、GLO、BUN、GLU以及第5天ALB、TG降低,而第3天ALB和TC升高。RH对试验第3天山羊血清GLU和BUN及第5天GLU含量均有显著影响（P<0.05）。RH为80%时试验第3天山羊血清GLU和BUN及第5天GLU含量显著低于RH为35%时（P<0.05）。RH升高,山羊血清TP升高,GLU及第3天BUN降低,GLO及第5天TG先升高后降低,第3天TC和TG先降低后升高。除26℃,65%这一组外,其他各组试验第5天山羊血清中TP、ALB、GLO、BUN、GLU、TC和TG含量均低于试验第3天。
Table 5
表5
表5温度和RH对山羊血清生化指标的影响Ⅰ
Table 5
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Table 6
表6
表6温度和RH对山羊血清生化指标的影响Ⅱ
Table 6
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由可知,温度和RH对试验第3天山羊血清K含量和第5天Ca、P和Na含量有显著的交互作用（P<0.05）。在35%和50%RH下时K不随温度的升高而降低,65%和80%下时随温度升高而降低。在35%、50%、60%RH下时Na随温度的升高变化无规律,80%RH下30℃时降低。在26℃和30℃时P随RH的升高变化无规律,34℃和38℃下时随RH升高而降低。试验第3天,38℃,80%RH血清K含量显著低于26℃各处理组。温度和RH对Cl含量的影响在试验第3和5天时均无显著交互作用（P>0.05）。温度对试验第3天山羊血清Ca和第5天Na、K和Cl含量均有显著影响（P<0.05）。38℃试验第3天山羊血清Ca含量显著低于26℃、30℃和34℃（P<0.05）;34℃和38℃试验第5天山羊血清K和Cl含量显著低于26℃和30℃（P<0.05）。温度升高,山羊血清中第3天Cl和第5天Ca、Na含量降低,血清K及第3天Ca、P和第5天Cl含量先升高后降低。RH对试验第5天K和Cl含量均有显著影响（P<0.05）。RH为65%和80%时,试验第5天山羊血清K和Cl含量显著低于RH为35%时（P<0.05）。RH升高,血清Cl含量下降,而第5天K含量升高。试验第5天山羊血清中Ca和P含量均低于试验第3天,而时间的延长对血清中Na、K和Cl含量影响不大。
Table 7
表7
表7温度和RH对山羊血清无机离子的影响
Table 7
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由可知,温度和RH对试验第3天山羊血清ALT和AST和第5天LDH活性有显著的交互作用（P<0.05）。在26℃和30℃时ALT在65%时开始降低,而在34℃和38℃时ALT在50%时开始降低。在35%和50%RH下时AST不随温度的升高而降低,65%RH下时30℃即降低。在35%、50%和65%RH下时LDH不随温度的升高而降低,80%RH下时随温度升高而降低。试验第3天,38℃,50%RH、38℃,65%RH和38℃,80%RH组ALT活性显著低于26℃,35%RH和26℃,50%RH处理组（P<0.05）;温度和RH对ALP和CK活性的影响在试验第3和5天时均无显著交互作用（P>0.05）。温度对试验第3天山羊血清ALP和第5天ALT、AST、ALP和CK活性均有显著影响（P<0.05）。38℃试验第3天山羊血清ALP活性显著低于26℃和30℃（P<0.05）;34℃和38℃试验第5天ALT、AST和CK活性显著低于26℃（P<0.05）。温度升高,山羊血清ALT、第3天AST、CK及第5天ALP、LDH活性降低,而第5天AST和CK先降低后升高。RH升高,山羊血清ALP及第3天CK活性降低,LDH及第5天AST和CK升高,第3天ALT和AST先降低后升高。试验第5天山羊血清中ALT和AST活性均低于试验第3天,除26℃,80%组试验第5天山羊血清中ALP和LDH活性均低于试验第3天,而血清CK活性大部分处理组第5天活性要低于第3天。
Table 8
表8
表8温度和RH对山羊血清酶活性的影响
Table 8
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由可知,温度和RH对试验第3天和第5天山羊血清T-AOC、SOD、GSH-Px和CAT浓度均有显著的交互作用（P<0.05）。第3天,在35%RH下温度为34℃时T-AOC和GSH-Px开始降低,而在50%、65%和80%RH时温度在30℃即降低;第5天,在35%和50%RH下T-AOC不随温度升高而降低,而在65%和80%RH时温度在34℃降低。在35%和50%RH下CAT不随温度升高而降低,而在65%和80%RH下在34℃开始降低。在相同湿度下,山羊血清SOD随温度的升高而降低,温度越高,RH越高,SOD浓度越低。试验第3天时,34和38℃各处理组T-AOC和SOD活性显著低于26℃各处理组（P<0.05）;38℃,65%RH和38℃,80%RH组GSH-Px活性显著低于26℃各处理组（P<0.05）;38℃,80%RH组CAT活性显著低于26℃和30℃各处理组（P<0.05）。试验第5天,38℃,80%RH组T-AOC活性显著低于其他处理组;38℃,50%RH、38℃,65%RH、38℃,80%RH和34℃,80%RH组SOD活性显著低于26和30℃各处理组（P<0.05）;38℃,80%RH组GSH-Px活性显著低于26℃各处理组（P<0.05）;38℃,65%RH和38℃,65%RH组CAT活性显著低于其他处理组（P<0.05）。温度和RH对试验第3天和第5天山羊血清MDA无显著的交互作用（P<0.05）。温度对试验第3天和第5天山羊血清MDA均有显著影响（P<0.05）。34℃和38℃血清MDA浓度显著高于26℃（P<0.05）。温度升高,MDA浓度升高,T-AOC、SOD、CAT及第3天GSH-Px浓度降低。RH对试验第5天山羊血清MDA有显著影响（P<0.05）。RH为80%时MDA浓度显著高于RH为35%和50%时（P<0.05）。RH升高,MDA浓度升高,T-AOC、GSH-Px及第5天SOD浓度降低。试验第5天山羊血清中MDA浓度高于试验第3天,试验第5天山羊血清中T-AOC、SOD、GSH-Px和CAT浓度在26℃和30℃处理组大部分低于第3天,34℃和38℃处理组大部分高于第3天。
Table 9
表9
表9温度和RH对山羊血清抗氧化指标的影响
Table 9
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环境温度和RH是动物与其生存环境保持平衡的重要因素,动物在适宜环境范围中,能维持正常生长性能。当环境温度逐渐升高或环境温度与RH都较高时,畜禽的采食中枢受到抑制,维持需要的能量降低,从而导致采食量下降,以此来维持机体热平衡[]。同时,活动减少,饮水量增加,生长缓慢,甚至出现负增长等反应。
有研究发现,热应激期内西杂牛、地方黄牛和犏牛单位体重干物质采食量和平均日增重均有不同程度的降低[]。CHAIDANYA等 []研究发现,与21℃相比,27℃持续六周能显著降低山羊的体重,但对日采食量无显著影响。马燕芬等[]研究发现,热应激显著降低奶山羊干物质采食量、乳品质及其生长性能。本试验研究发现,温度和RH对山羊的平均日采食量和平均日饮水量的影响有显著的交互作用。随着温度和RH的升高,山羊的平均日采食量显著降低,30℃,80%RH平均日采食量开始下降明显,平均日增重也降低甚至出现负增长,而料重比的变化不显著。本试验结果与热应激处理结果基本一致。造成采食量减少的原因可能是其为了减少因采食带来的热增耗而自觉的减少采食[,]。另外,本研究还发现,温度和RH对山羊饮水量影响显著,温度升高,平均日饮水量增多,RH升高,平均日饮水量先减少后增多,这可能是其通过调节饮水量来缓解温度和RH带来的应激。
动物在适宜环境范围中,动物的粪尿量和尿常规处于正常的范围内,当受到外界刺激时,粪尿量和尿常规能够间接的反应动物的生理状态。温度和RH对动物的粪尿量和尿常规的影响的研究罕见。考虑到本试验的处理条件为不同温湿度,为减小试验误差,粪量为干粪量。随着温度和RH的升高,平均日干粪量显著降低,这可能与采食量的降低有关。温度和RH的交互作用对平均排尿量影响不大,但平均日排尿量随温度的升高显著升高,这可能与饮水量增加有关。温度和RH对山羊的尿常规中尿酸碱度的影响有显著的交互作用。尿比重随温度升高而降低,尿酸碱度随RH的升高而降低,这可能是因饮水量增加而产生的影响。尿常规中的其他指标未能检测,有待进一步地研究。
动物体内环境平衡与否、健康状态和生产性能高低等综合因素可以通过血常规来反映。一旦外界环境发生变化,就会迫使动物体内调节功能作出相应调节,从而引起血液成分的改变和一系列的代谢调整。热应激使动物体内平衡机制改变,导致红细胞生成受阻。高温环境动物通过增加呼吸频率增加耗氧量,进而增加血液中氧分压,减少红细胞生成,进而减少RBC、PCV和Hb含量[]。
有研究发现,在热应激状态下试验牛血液的RBC、MCH、PCV、MCHC、WBC等5项指标与无热应激差异显著[]。侯引绪等[]研究发现,在中度热应激下,荷斯坦牛RBC、MCHC、PCV与无热应激组差异显著,WBC、MCHC与无热应激组差异极显著。顾剑[]研究发现,热应激对长毛兔WBC和RBC影响不显著。有研究发现,热应激时,山羊WBC略有下降,RBC变化不显著[]。本试验发现,温度和RH及二者的相互作用对PCV、MCH、MCHC、MCV和RDW影响不显著。温度升高,山羊血液中WBC和MCV降低,RBC、Hb和RDW升高。38℃试验第3天山羊血液中WBC显著低于26℃和30℃（P<0.05）;34℃和38℃试验第5天山羊血液中WBC显著低于26℃（P<0.05）。RH升高山羊血液中WBC、MCHC先降低后升高,RBC和Hb升高,RDW先升高后降低。RH为65%和80%时,试验第3天和第5天山羊血液中WBC显著低于RH为35%时（P<0.05）;RH为65%和80%时,试验第3天山羊血液中Hb含量显著高于RH为35%时（P<0.05）。这与上述研究有差异,可能与物种、试验处理等不同有关系。另外,试验第5天山羊血液中WBC、RBC、Hb和HCT低于第3天,而试验第5天MCHC高于第3天。这说明热处理时间的长短也会对山羊的血液指标产生影响。
血清中的TP、ALB和GLO含量是反映机体非特异性体液免疫及功能的重要指标。本试验发现,温度和RH对试验第5天山羊血清TP、ALB和GLO含量的影响有显著的交互作用。温度升高,山羊血清TP、GLO以及第5天ALB降低,第3天ALB升高。温度对试验第3天山羊血清GLO含量有显著影响,38℃时山羊血清GLO含量显著低于26℃和30℃。RH升高,山羊血清TP升高。试验第5天山羊血清中TP、ALB和GLO含量大部分低于试验第3天。有研究表明,RH及温度和RH的交互作用对肉仔鸡血清蛋白含量的影响不显著,温度对试验第7天肉仔鸡的血清GLO含量有显著影响,26℃显著高于31℃[]。伍晓雄等[]研究发现,热应激对山羊血清中TP含量影响不显著。这与本试验结果基本一致。血清中TP、GLO和ALB的下降可能与高温高湿下山羊采食量减少,摄入蛋白含量不足,蛋白质代谢发生改变有关,这也可能成为山羊发病率提高的原因之一。
动物代谢活动时,GLU能快速有效的供能。正常情况下,动物体内的血糖含量处于稳定的动态平衡状态,受到应激时,血糖含量发生变化。另外,BUN是蛋白质分解代谢的产物,动物机体蛋白质的代谢变化的情况由血清中BUN含量直接反映出来,当蛋白质代谢良好时,其含量较低。血液中BUN的含量也与肾功能变化有重要关系,是检验肾功能的重要指标。有研究发现,热应激使肉牛血清中BUN含量降低[]。SCHARF等[]研究发现,在急性热应激时肉牛血清中GLU含量会升高,而在慢性热应激时会降低。伍晓雄等[]研究发现,热应激对山羊血清中GLU含量有一定程度的上升。本试验发现,温度和RH对试验第5天山羊血清BUN含量的影响有显著的交互作用;而对GLU含量的影响在试验第3和5天时均无显著交互作用（P>0.05）。温度对试验第3天和第5天山羊血清BUN和GLU含量均有显著影响,温度升高,山羊血清BUN、GLU降低。38℃时山羊血清BUN和GLU含量显著低于26℃;RH对试验第3天山羊血清BUN和GLU及第5天GLU含量均有显著影响,RH升高,山羊血清GLU及第3天BUN降低。RH为80%时显著低于RH为35%时。另外,试验第5天山羊血清中BUN和GLU含量大部分低于试验第3天。这可能是山羊在高温高湿状态下采食量降低引起的。同时,高温高湿的状态,山羊体内糖代谢增强,耗能加快,能量贮存减少,从而引起血糖降低,蛋白质代谢增强,BUN降低。
TG和TC是血脂的主要成分,机体内脂类代谢水平由血脂含量的高低来表现。有研究发现,热应激对长毛兔血清中TG和TC影响显著[]。本试验中温度、RH及二者的交互作用对山羊血清TG和TC影响不显著,温度升高,山羊血清第5天TG降低,第3天TC升高。试验第5天山羊血清中TC和TG含量大部分低于试验第3天。这可能是因为山羊与长毛兔相比,抗逆性比较强。另外,不同物种,不同处理方式和时间也会有影响。
血清中的无机离子对动物机体的内环境平衡、凝血、排泄等过程都有重要的意义。有研究发现,山羊在热应激下,血清Na+和K+含量升高[]。魏学良等[]研究发现,奶牛在热应激状态下,血清中Na+降低,Cl–和K+升高。SUNIL等[]研究发现,长期热应激使血清中K+含量下降。也有研究表明,高温可引起荷斯坦牛血清K和P水平明显上升,Na、Ca含量变化不显著[]。本试验发现,温度和RH对试验第3天山羊血清中K含量和第5天山羊血清Ca、P、Na和K含量的影响均有显著的交互作用;温度对试验第3天山羊血清Ca和第5天山羊血清Ca、Na、K和Cl含量有显著影响,温度升高,山羊血清Ca、P、Na、K和Cl含量呈降低趋势,且38℃时山羊血清Ca、P、Na、K和Cl含量显著低于26℃;RH升高,血清Cl含量下降,第5天K含量升高,RH对试验第5天山羊血清Cl含量影响显著,RH为65%和80%时显著低于RH为35%时。另外,试验第5天山羊血清中Ca和P含量均低于试验第3天。
血清中无机离子发生变化的原因可能是高温高湿使山羊的采食量显著下降、饮水量增加、排尿量明显增加引起的。另外,高温高湿干扰了小肠黏膜上皮对钙的转运[]。高温高湿时,由于动物血液中H+和HCO3– 浓度明显下降,造成酸碱平衡失调,大量有机酸由机体分泌,血液中的 pH值降低,有机酸与Ca、P等离子结合,最终使其浓度降低。环境温度突然升高,导致山羊机体的呼吸中枢兴奋,呼吸加快加深, CO2 排出量增多,最终发生呼吸性碱中毒。此时肾小管保酸排钾,细胞内的氢离子与细胞外的K+交换,导致K+含量稍微有所降低。
高温高湿可引起动物机体代谢机能和酶活性发生改变,造成机体组织不同程度的损伤。在正常情况下,细胞内酶由于细胞膜的屏障作用不易逸出, 处于较稳定的状态,由于细胞的不断更新破坏而少量释放进入血液[],而在应激情况下细胞受到损伤和刺激,细胞膜的通透性增大致使其释放进入血液的速度加快,血清酶含量发生变化。
ALT和AST不仅对氨基酸的合成与分解代谢非常重要,而且能够衡量肝脏的重要功能,有助于动物疾病的诊断。ALT和AST浓度与热应激程度关系密切[]。 在正常情况下,ALT和AST是在肝细胞内,不易逸出,当高温高湿时,由于畜禽机体内细胞受到损伤,细胞膜的通透性增大,ALT和AST渗透而进入血液。ALP的活性与骨骼形成关系密切,ALP的含量与成骨细胞的活性成正比,在正常情况下与骨胶原蛋白的形成、骨盐沉积以及动物生长发育有关,这是高温高湿导致畜禽生长性能下降的一个原因。LDH几乎存在于所有组织中,是体内代谢过程中一个很重要的酶。由于组织中的LDH的活力比血浆中高得多,因此少量组织受损伤时,LDH释放入血液使在血液中LDH活力升高。CK是反映动物热应激状态的敏感指标,当动物处于热应激状态时,肌肉能量供应不足、细胞膜磷脂层被氧化而使细胞膜通透性增加进而使CK溢于胞外,使外周血CK浓度明显增加。因此,LDH和CK可以用来诊断应激[]。
有研究发现,热应激状态下肉牛血清LDH活性显著升高,对ALT、AST、CK和ALP活性影响不显著[]。在泌乳期绵羊中发现,血清中的ALT、AST、CK和LDH在急性热应激时显著升高,然后恢复正常水平,CK未发生显著变化[]。HELAL等[]研究发现,热应激使ALP和LDH活性降低。SHARMA等[]研究发现,山羊受热应激时血清ALT含量降低,AST含量变化不显著。OCAK等[]研究发现,热应激对山羊血清AST含量影响不显著。本试验发现,温度和RH对试验第3天山羊血清ALT和AST活性和第5天LDH活性的影响有显著的交互作用,试验第3天,38℃,50%RH、38℃,65%RH和38℃、80%RH组ALT活性显著低于26℃,35%RH和26℃,50%RH处理组。温度对试验第3天山羊血清ALP和第5天ALT、AST、ALP和CK活性均有显著影响,温度升高,山羊血清ALT、第3天AST、CK及第5天ALP、LDH活性降低。38℃山羊血清ALP活性显著低于26℃和30℃;34℃和38℃ALT、AST和CK活性显著低于26℃。RH升高,山羊血清ALP及第3天CK活性降低,而LDH及第5天AST和CK升高。这说明高温高湿下,不同动物的机体组织受到影响程度不同。另外,试验第5天山羊血清中ALT、AST、ALP、LDH和CK活性大部分组低于试验第3天。
动物机体内活性氧（ROS）的产生、利用与清除维持着动态平衡,当机体ROS产生与抗氧化系统失衡时,可引起氧化应激,造成机体组织细胞及蛋白质和核酸等生物大分子损伤[]。当动物受到热应激侵害时,机体内的CAT、GSH-Px、SOD的活性受到影响,影响机体抗氧化系统,导致机体ROS的产生与抗氧化系统失衡[]。
T-AOC是机体防御体系的抗氧化能力,MDA是在脂质过氧化过程中产生的脂质过氧化产物, 二者是衡量机体抗氧化系统功能状况的综合性指标[]。SOD是对机体的氧化与抗氧化平衡起着关键作用的一种重金属酶。SOD和CAT、GSH-Px可以清除超氧阴离子自由基,起到抗炎作用,反映机体清除氧自由基的能力[]。有研究发现,夏季与冬季相比,血清中SOD和GSH-Px显著降低[]。在家禽的研究中表明,热应激会显著降低肉鸡血清中GSH-Px和T-AOC的活性[]。刁华杰等[]在日循环高温对蛋鸡的研究发现,低循环温度组仅显著影响血清T-AOC水平,而高循环温度组显著降低血清T-AOC水平以及血清中GSH-Px活性。热应激期,肉牛血清T-AOC、SOD及GSH-Px含量均降低,而MDA含量升高[]。KUMAR等[]研究发现,热应激使山羊血清SOD水平升高。本试验发现,温度和RH对试验第3天和第5天山羊血清T-AOC、SOD、GSH-Px和CAT均有显著的交互作用。试验第3天时,38℃,80%RH组T-AOC、SOD、GSH-Px和CAT显著低于26℃各处理组;试验第5天,38℃,80%RH组T-AOC、SOD、GSH-Px活性显著低于26℃各处理组。温度和RH对山羊血清MDA无显著的交互作用。温度升高,MDA浓度升高,T-AOC、SOD、CAT及第3天GSH-Px浓度降低,34℃和38℃血清MDA浓度显著高于26℃。RH升高,MDA浓度升高,T-AOC、GSH-Px及第5天SOD浓度降低,RH为80%时MDA浓度显著高于RH为35%和50%时。另外,试验第5天山羊血清中MDA浓度高于试验第3天。这说明山羊在高温高湿环境下抗氧化能力受到了影响,机体ROS的产生与抗氧化系统失衡。
4.1 温度、相对湿度及二者交互作用不同程度地影响山羊平均日采食量、平均日饮水量、血清生化指标和抗氧化指标。
4.2 温度升高,山羊平均日采食量、平均日增重、平均日干粪量、尿比重、血液中白细胞数和红细胞平均体积、血清总蛋白、球蛋白、尿素氮、葡萄糖、谷丙转氨酶、总抗氧化能力、超氧化物歧化酶、过氧化氢酶以及第3天Cl、谷草转氨酶、肌酸激酶、谷胱甘肽过氧化物酶和第5天白蛋白、甘油三酯、Ca、Na、碱性磷酸酶、乳酸脱氢酶降低,而平均日饮水量、平均日排尿量、血液中红细胞数、血红蛋白和红细胞体积分布宽度、血清中丙二醛及第3天白蛋白、总胆固醇升高。
4.3 相对湿度升高,平均日采食量、平均日干粪量、尿酸碱度、血清葡萄糖、Cl、碱性磷酸酶、总抗氧化能力、谷胱甘肽过氧化物酶及第3天尿素氮、肌酸激酶和第5天超氧化物歧化酶浓度降低,而血液红细胞数和血红蛋白、血清总蛋白、乳酸脱氢酶、丙二醛升高及第5天K、谷草转氨酶、肌酸激酶升高。
4.4 试验第5天血液白细胞数、红细胞数、血红蛋白、红细胞压积及血清总蛋白、白蛋白、球蛋白、尿素氮、葡萄糖、总胆固醇、甘油三酯、Ca、P、谷丙转氨酶、谷草转氨酶、碱性磷酸酶、乳酸脱氢酶和肌酸激酶大多组低于试验第3天,而血清抗氧化指标丙二醛高于试验第3天,总抗氧化能力、超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶在34℃和38℃时高于第3天。
总之,高温高湿环境不利于山羊的生长性能和机体抗氧化功能,其中,温度为38℃,相对湿度为80%时,山羊受到的影响最大。
DOI:10.3168/jds.S0022-0302(82)82484-3URLPMID:6759540 
Physiological state of dairy animals is a predisposing factor in environmental influences on animal health. Critical phases of life cycle include neonatal period, postpubertai reproduction, and lactation. Primary effect of environment in neonatal period is increased disease incidence associated with reduced immunoglobulin content in plasma of calves. Cold stress has little effect on reproduction; in contrast, heat stress reduces libido, fertility, and embryonic survival in cattle. Heat stress in late gestation reduces fetal growth and alters endocrine status of the dam. Carryover effects of heat stress during late gestation on postpartum lactation and reproduction also are detectable. Heat stress of lactating cattle results in dramatic reductions in roughage intake and rumination. Decreases in roughage intake contribute to decreased volatile fatty acid production and may contribute to alteration in ratio of acetate/propionate. Rumen pH also declines during thermal stress. Electrolyte concentrations, in particular sodium and potassium, also are reduced in rumen fluid of heat stressed cattle. The decrease in sodium and potassium are related to increases in loss of urinary sodium and loss of skin potassium as well as decline in plasma aldosterone and increase in plasma prolactin. Reduction in thyroxine, growth hormone, and glucocorticoid concentrations in chronically heat stressed cattle appear to be related to decreases in basal metabolism.
DOI:10.3168/jds.S0022-0302(00)75094-6URLPMID:11003246
Production data obtained from AIPL USDA included 119,337 first-parity, test-day records of 15,012 Holsteins from 134 Georgia farms collected in 1990 to 1997. Weather information was obtained from the Georgia Automated Environmental Monitoring Network and included daily minimum, average, and maximum temperatures and humidity for 21 stations throughout the state. Each test-day record was augmented with weather information from the closest weather station. Analyses were based on models that included effects of herd-year-season, age, test day, milking frequency, and several types of heat and humidity. The best model used a temperature-humidity index. With this model, the average test-day yield for milk was about 26.3kg for a temperature-humidity index <72 and decreased at about 0.2kg per unit increase in the temperature-humidity index for a temperature-humidity index 72. For fat and protein, the test yield was 0.92 and 0.85kg at a temperature-humidity index <72, respectively, and declined at a rate of 0.012 and 0.009kg per degree of the temperature-humidity index, respectively. The temperature-humidity index calculated with the available weather information can be used to account for the effect of heat stress on production.
DOI:10.3168/jds.2017-13676URLPMID:29153170
The objective of this study was to investigate the direct effects of feed supplements niacin and betaine on the heat shock responses of in vitro cultured cells derived from bovine mammary and uterine tissues. First, we determined the mRNA expression profiles of the niacin receptor (GPR109A) in bovine tissues (liver, skin, uterus, udder, and ovary) and in cells derived from bovine mammary… [Show full abstract]
DOI:10.3969/j.issn.1006-4907.2016.01.018URL
本研究测定了湘西黄牛在热应激、无热应激状态下的18个常规血液生化指标,结果表明：在热应激（THI=82.06）状态下,试验牛血液的红细胞数（RBC）、平均血红蛋白（MCH）含量、红细胞压积（HCT）、红细胞平均血红蛋白（MCHC）含量、白细胞数（WBC）等5项血液生化指标与无热应激组差异显著（P〈0.05）,其余13个生化指标两组间差异不显著。说明湘西地区夏季高温高湿的自然气候会对舍饲湘西黄牛造成一定程度的热应激。本研究结果将为制定湘西黄牛科学防控热应激的饲养管理措施提供参考思路和基础数据。
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DOI:10.3969/j.issn.1006-4907.2016.01.018URL
本研究测定了湘西黄牛在热应激、无热应激状态下的18个常规血液生化指标,结果表明：在热应激（THI=82.06）状态下,试验牛血液的红细胞数（RBC）、平均血红蛋白（MCH）含量、红细胞压积（HCT）、红细胞平均血红蛋白（MCHC）含量、白细胞数（WBC）等5项血液生化指标与无热应激组差异显著（P〈0.05）,其余13个生化指标两组间差异不显著。说明湘西地区夏季高温高湿的自然气候会对舍饲湘西黄牛造成一定程度的热应激。本研究结果将为制定湘西黄牛科学防控热应激的饲养管理措施提供参考思路和基础数据。
DOI:10.3969/j.issn.1673-1182.2000.03.002URL
3只健康山羊置于人工热应激环境中 (环境温度 37.5～ 38.5℃ ) ,1小时后回到自然环境 ( 2 4 .5～ 2 6.5℃ )。试验前及试验开始后第 1 5、60、1 80分钟 ,分别测定心率、呼吸频率、体温、红细胞数 ( RBC)、白细胞数 ( WBC)、血糖、血清谷草转氨酶 ( GOT)、谷丙转氨酶( GPT)、肌酸激酶 ( CK)、总蛋白 ( TP)、清蛋白 ( Alb)、尿素氮 ( BUN)含量。结果表明 ,热应激时 ,山羊的心率、呼吸频率、血糖含量均有一定程度的上升 ;CK在热应激中有明显的上升 ;WBC略有下降 ;RBC和血清中 GOT、GPT、TP、BUN含量变化不显著。
DOI:10.3969/j.issn.1673-1182.2000.03.002URL
3只健康山羊置于人工热应激环境中 (环境温度 37.5～ 38.5℃ ) ,1小时后回到自然环境 ( 2 4 .5～ 2 6.5℃ )。试验前及试验开始后第 1 5、60、1 80分钟 ,分别测定心率、呼吸频率、体温、红细胞数 ( RBC)、白细胞数 ( WBC)、血糖、血清谷草转氨酶 ( GOT)、谷丙转氨酶( GPT)、肌酸激酶 ( CK)、总蛋白 ( TP)、清蛋白 ( Alb)、尿素氮 ( BUN)含量。结果表明 ,热应激时 ,山羊的心率、呼吸频率、血糖含量均有一定程度的上升 ;CK在热应激中有明显的上升 ;WBC略有下降 ;RBC和血清中 GOT、GPT、TP、BUN含量变化不显著。
DOI:10.2527/2005.83112590xURL
DOI:10.26667/2318-1265URL
DOI:10.3864/j.issn.0578-1752.2013.21.011URL
【Objective】Effect of heat stress on dairy goat production performance and rumen epithelial cell morphology were studied in order to provide a rational and experimental basis for animals in hot environments to maintain normal physiological function and to explore methods of resistance to heat stress. 【Method】 The animal modes were estabished when temperature and humidity index ＞72 (THI＞72) of early, medium and evening for a week. The effect of heat stress on rumen fermentation pattern, digestion and metabolism of nutritive materials, performance, morphology and structure of rumen epithelial cell were studied with mid- and late-lactation dairy goats by animal nutrition methods in this project. 【Result】 The results showed that THI of test sheep was between 72 and 87 during the tests, and in the mild and high heat stress, which showed dairy goat in continuous heat stress state during the whole experiment period. Heat stress significantly increased rectal temperature and respiration rate (P＜0.01), significantly reduced DM, CP, OM, NDF and ADF digestibility (P＜0.01), dry matter intake and milk yield of dairy goats (P＜0.01 ), and significantly reduced dairy goat milk protein and milk fat content (P＜0.05), but the effect on lactose content was not significant (P＞0.05). Heat stress significantly decreased pH value, NH3-N concentration and TVFAs concentration (P＜0.05) at each time point in a day. Compared with the control group, rumen fluid of dairy goat was found gruel shape and strongly sour flavor, and the rumen mucosa nipples showed a wide range of necrotic and fall off when in heat stress for 30 days, and the situations of mucosa papillary necrosis and fall off were more serious when in heat stress for 45 days. This showed that heat stress caused a certain degree injury to the animal rumen mucosa. In the heat stress for 30 days and 45 days, the length and width of rumen dorsal sac and ventral sacs villus were shorter than that of control group (P＜0.05), and with the prolonged heat stress, the length and width of rumen dorsal sac and ventral sac villus were shortened more short (P＜0.05). 【Conclusion】Heat stress can significantly improve rectal temperature and respiration rate, significantly reduce dietary nutrient digestibility, rumen fermentation parameters, dry matter intake, milk quality and performance of the dairy goat. Heat stress can damage morphology of rumen epithelial cell, make the mucosal villi atrophy, shed and even necrosis, which increase permeability of the rumen epithelial cell.
DOI:10.3864/j.issn.0578-1752.2013.21.011URL
【Objective】Effect of heat stress on dairy goat production performance and rumen epithelial cell morphology were studied in order to provide a rational and experimental basis for animals in hot environments to maintain normal physiological function and to explore methods of resistance to heat stress. 【Method】 The animal modes were estabished when temperature and humidity index ＞72 (THI＞72) of early, medium and evening for a week. The effect of heat stress on rumen fermentation pattern, digestion and metabolism of nutritive materials, performance, morphology and structure of rumen epithelial cell were studied with mid- and late-lactation dairy goats by animal nutrition methods in this project. 【Result】 The results showed that THI of test sheep was between 72 and 87 during the tests, and in the mild and high heat stress, which showed dairy goat in continuous heat stress state during the whole experiment period. Heat stress significantly increased rectal temperature and respiration rate (P＜0.01), significantly reduced DM, CP, OM, NDF and ADF digestibility (P＜0.01), dry matter intake and milk yield of dairy goats (P＜0.01 ), and significantly reduced dairy goat milk protein and milk fat content (P＜0.05), but the effect on lactose content was not significant (P＞0.05). Heat stress significantly decreased pH value, NH3-N concentration and TVFAs concentration (P＜0.05) at each time point in a day. Compared with the control group, rumen fluid of dairy goat was found gruel shape and strongly sour flavor, and the rumen mucosa nipples showed a wide range of necrotic and fall off when in heat stress for 30 days, and the situations of mucosa papillary necrosis and fall off were more serious when in heat stress for 45 days. This showed that heat stress caused a certain degree injury to the animal rumen mucosa. In the heat stress for 30 days and 45 days, the length and width of rumen dorsal sac and ventral sacs villus were shorter than that of control group (P＜0.05), and with the prolonged heat stress, the length and width of rumen dorsal sac and ventral sac villus were shortened more short (P＜0.05). 【Conclusion】Heat stress can significantly improve rectal temperature and respiration rate, significantly reduce dietary nutrient digestibility, rumen fermentation parameters, dry matter intake, milk quality and performance of the dairy goat. Heat stress can damage morphology of rumen epithelial cell, make the mucosal villi atrophy, shed and even necrosis, which increase permeability of the rumen epithelial cell.
DOI:10.1016/j.smallrumres.2006.10.003URL
The exposure of sheep to elevated ambient temperatures induces an increase in the dissipation of excess body heat, in order to negate the excessive heat load. Dissipation of excess body heat is excluded by evaporation of water from the respiratory tract and skin surface via panting and sweating, respectively. Sweating in woolled sheep is much less effective due to the presence of the wool cover. With the elevation in environmental temperature to 36 C, a high proportion of heat is dissipated via the ears and legs. When the physiological mechanisms of the animal fail to negate the excessive heat load, the rectal temperature increases. At the same time, such exposure of sheep to heat stress evokes a series of drastic changes in the biological functions, which include a decrease in feed intake efficiency and utilization, disturbances in water, protein, energy and mineral balances, enzymatic reactions, hormonal secretions and blood metabolites. Recent studies indicate that the suprachiasmatic nucleus (SCN) regulates the circadian and seasonal rhythms of most biological functions, particularly the reproductive functions and behaviour in mammals. The regulation includes the phasic and tonic release of hormones, oestrus and in some cases, gonadal size. This is due to the fact that there is evidence suggesting that the SCN is sensitive to changes in ambient temperature ith some cells being more responsive to cold and others more responsive to heat, although photoperiodic changes may also have a strong influence. In conclusion, it can be said that exposure of sheep to elevated ambient temperature negatively affects the biological functions which are reflected in the impairment of their production and reproduction traits.
DOI:10.1071/AN16472URL
DOI:10.1111/jpn.12379URLPMID:26250521
Summary Elevated ambient temperatures affect animal production and welfare. Animal’s reduced production performances during heat stress were traditionally thought to result from the decreased feed intake. However, it has recently been shown that heat stress disturbs the steady state concentrations of free radicals, resulting in both cellular and mitochondrial oxidative damage. Indeed, heat stress reorganizes the use of the body resources including fat, protein and energy. Heat stress reduces the metabolic rates and alters post-absorptive metabolism, regardless of the decreased feed intake. Consequently, growth, production, reproduction and health are not priorities any more in the metabolism of heat-stressed animals. The drastic effects of heat stress depend on its duration and severity. This review clearly describes about biochemical, cellular and metabolic changes that occur during thermal stress in farm animals.
DOI:10.3969/j.issn.1004-4264.2013.01.003URL
本研究测定了中国荷斯坦牛分别 在中度热应激、无热应激状态下的23个血液生化指标,结果表明:在中度热应激(THI=82.06)状态下,试验牛血液的总蛋白(TP)含量、红细胞数 (RBC)、平均血红蛋白(MCH)含量、红细胞压积(HCT)与无热应激组差异显著(P0.05);血清肌酐(CRE)含量、胆固醇(CHO)含量、淀 粉酶(AMY)含量、红细胞平均血红蛋白(MCHC)含量、白细胞数(WBC)、碱性磷酸酶(ALP)6项血液生化指标与无热应激组差异极显著 (P0.01),其余13个生化指标两组间差异不显著。同时对结果进行了分析讨论,希望能为科学防控奶牛热应激提供参考思路和基础数据。
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DOI:10.3969/j.issn.1004-4264.2013.01.003URL
本研究测定了中国荷斯坦牛分别 在中度热应激、无热应激状态下的23个血液生化指标,结果表明:在中度热应激(THI=82.06)状态下,试验牛血液的总蛋白(TP)含量、红细胞数 (RBC)、平均血红蛋白(MCH)含量、红细胞压积(HCT)与无热应激组差异显著(P0.05);血清肌酐(CRE)含量、胆固醇(CHO)含量、淀 粉酶(AMY)含量、红细胞平均血红蛋白(MCHC)含量、白细胞数(WBC)、碱性磷酸酶(ALP)6项血液生化指标与无热应激组差异极显著 (P0.01),其余13个生化指标两组间差异不显著。同时对结果进行了分析讨论,希望能为科学防控奶牛热应激提供参考思路和基础数据。
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为研究夏季热应激对长毛兔生产性能、血清生化指标及血浆细胞数的影响,在夏季不同温度阶段选用16只长毛兔进行试验,试验期85 d。结果表明:热应激对长毛兔产毛量影响显著;对血糖、甘油三酯、超氧化物歧化酶(SOD)、谷丙转氨酶、谷草转氨酶、胆固醇、嗜中性粒细胞数目、总抗氧化能力(T-AOC)等生理生化指标影响显著(P0.05);对丙二醛(MDA)、白细胞数目、红细胞数目、中值细胞数目、高密度脂蛋白等影响不显著(P0.05)。
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为研究夏季热应激对长毛兔生产性能、血清生化指标及血浆细胞数的影响,在夏季不同温度阶段选用16只长毛兔进行试验,试验期85 d。结果表明:热应激对长毛兔产毛量影响显著;对血糖、甘油三酯、超氧化物歧化酶(SOD)、谷丙转氨酶、谷草转氨酶、胆固醇、嗜中性粒细胞数目、总抗氧化能力(T-AOC)等生理生化指标影响显著(P0.05);对丙二醛(MDA)、白细胞数目、红细胞数目、中值细胞数目、高密度脂蛋白等影响不显著(P0.05)。
DOI:10.3969/j.issn.1006-267x.2012.12.024URL
This study was conducted to investigate the effects of heat stress on endocrine hormone content, antioxidant enzyme activity and physiological and serum biochemical indices of beef cattle. Nine eight-month-old ＜0.05); in heat stress period the rectal temperature of beef cattle was significantly increased on 20th day (＜0.05), and then gradually recovered to normal. 2)Compared with normal period, triiodothyronine (T) content in serum was lower significantly (＜0.05), but thyroxine (T) content was not changed (＞0.05); cortisol (COR) content was significantly increased on 20th day (＜0.05), and then gradually recovered to normal; the glucose (GLU) content in serum was decreased by 41.55% on 60th day (＜0.05); the activities of superoxide dismutase (SOD) and alkaline phosphatase (ALP) in serum were significantly lower on 40th day (＜0.05), but the content of malondialdehyde (MDA) and the activity of lactate dehydrogenase (LDH) were significantly increased (＜0.05). These results indicate that high temperature and high humidity induce heat stress of beef cattle, and heat stress can enhance the rectal temperature and increase the content of cortisol, and decrease the contents of T and glucose. However, the rectal temperature and endocrine hormone content of beef cattle would gradually recover to normal with the extension of heat stress time.
DOI:10.3969/j.issn.1006-267x.2012.12.024URL
This study was conducted to investigate the effects of heat stress on endocrine hormone content, antioxidant enzyme activity and physiological and serum biochemical indices of beef cattle. Nine eight-month-old ＜0.05); in heat stress period the rectal temperature of beef cattle was significantly increased on 20th day (＜0.05), and then gradually recovered to normal. 2)Compared with normal period, triiodothyronine (T) content in serum was lower significantly (＜0.05), but thyroxine (T) content was not changed (＞0.05); cortisol (COR) content was significantly increased on 20th day (＜0.05), and then gradually recovered to normal; the glucose (GLU) content in serum was decreased by 41.55% on 60th day (＜0.05); the activities of superoxide dismutase (SOD) and alkaline phosphatase (ALP) in serum were significantly lower on 40th day (＜0.05), but the content of malondialdehyde (MDA) and the activity of lactate dehydrogenase (LDH) were significantly increased (＜0.05). These results indicate that high temperature and high humidity induce heat stress of beef cattle, and heat stress can enhance the rectal temperature and increase the content of cortisol, and decrease the contents of T and glucose. However, the rectal temperature and endocrine hormone content of beef cattle would gradually recover to normal with the extension of heat stress time.
DOI:10.2527/jas.2009-2551URLPMID:20190161
Abstract A study was performed to evaluate differences in thermoregulatory ability of 2 Bos taurus breeds with known differences in heat tolerance. Nine Angus (AG; 304 +/- 7 kg of BW) and 9 Romosinuano (RO; 285 +/- 7.5 kg of BW) steers were transported to the Brody Environmental Center at the University of Missouri. Steers were housed for 18 d at thermoneutrality (TN; 21 degrees C) before initiation of heat stress (HS), which consisted of daily cyclic air temperature (26 degrees C, night; 36 degrees C, day) for 14 d. Rectal temperature and respiration rate were measured 6 times daily throughout the study. Sweat rates at shaved skin sites were recorded on specific days. Blood samples were taken once per week. Angus steers maintained rectal temperature 0.5 degrees C greater than RO at TN (P < 0.001). Likewise, respiration and sweat rates were greater (P < 0.001) in AG than RO at TN (P < 0.05). Rectal temperature increased during HS for both breeds with AG maintaining greater temperatures (P < 0.001). Both breeds increased respiration rate during HS, with AG steers exhibiting the greater rate (P < 0.001). Sweat rate increased more than 4-fold during HS (P < 0.001), followed by reduction after 7 d. Even after HS acclimation, AG exhibited the greater sweat rate (P < 0.001). Breed differences for serum leptin, creatinine, and cholesterol were found throughout the study with AG being greater than RO. Although there were no breed differences (P = 0.21) at TN, only AG steers exhibited a HS-induced increase (P < 0.05) in prolactin, creatinine, and cholesterol concentrations to suggest that an increase in rectal temperature is required for this effect. Use of rectal temperature along with endocrine markers, such as prolactin, may aid in the identification of B. taurus sensitivity to heat.
DOI:10.1017/S1751731115001652URL
Among domestic ruminants, goats are renowned for their ability to tolerate water deprivation, water restriction and energy restriction. However, some basic questions regarding their ability to endure water restriction under heat stress are still open. Three levels of water restriction (56%, 73% and 87% of thead libitum) were imposed on 20 cross-bred 3-year-old female goats (75% German Fawn and 25% Hair Goat) distributed into four groups, with five animals per treatment. The experiment was conducted from the beginning of July to the end of August in a farm located in the Eastern Mediterranean region of Turkey (40 m in altitude; 36 59′ N, 35 18’E), in which subtropical weather conditions prevail. The average daily temperature during the experiment was 34.2 C, whereas the highest and lowest temperatures were 42 C and 23.1 C, respectively. The average relative humidity was 68.2% and wind speed was 1.2 km/h. Weekly average thermal heat indexes during the experiment were 78.3 (week 1), 79.1 (week 2), 80.1 (weak 3), 79.8 (weak 4), 81.3 (weak 5) and on average 79.7. Feed intake, heart rate, thermoregulatory responses (rectal temperature, respiration rate), blood plasma concentrations of ions (Na, K), antidiuretic hormone (ADH), metabolites (glucose, cholesterol, creatinine and urea) and behavioral aspects (standing, walking, lying) were studied over 30 days. The responses to water restriction were proportional to the level of restriction. The reductions in feed intake (up to 13%), BW (up to 4.6%) and the increases in rectal temperature (0.5 C) and breath rate (10 respirations/min) were moderate and also were far from responses encountered under severe heat and water stresses. The increase in plasma Na (from 119 to 140 mM) and ADH concentrations (from 12.6 to 17.4 pg/ml) indicates that the physiological response to water restriction was in response to mild dehydration, which also explains the increase in blood plasma concentrations of glucose, cholesterol, creatinine and urea. Behavioral responses (reduction in walking from 226 to 209 min/day and increase in lying from 417 to 457 min/day) were associated with conservation of energy or thermoregulation (reducing the exposure to direct radiation).
DOI:10.3969/j.issn.1000-6850.2005.05.004URL
Between 2002 to 2003，we made a test of cow’s physiological and performance in part of Chongqing. We also examine the cow’s blood. The result showed that：(1) From June to September，the cow’s temperature of rectum and rate of respiration are higher than that in March to May or October to February (P<0.05)；(2) The daily lactation between March to May and October to February are （23.5±4.2）kg/d（n=31）、（22.1±5.3）kg/d（n=43），also higher than (17.6±5.1) kg/d（n=52）（P<0.05）which in June to September. (3)In heat stress, the density of K+、Cl-、iCa 2+ in serum of cows are higher than other times. (P<0.05) .But the proteins in serum of cows are lower, the activity of alkaline phosphatase drop 38.96 percent and the activity of α-anylase drop 8.52 percent, the activity of GTP raise 3.74 percent.(4) In heat stress, the fecundation insemination of cow slower than the other times, but the diseases in heat stress are more .
DOI:10.3969/j.issn.1000-6850.2005.05.004URL
Between 2002 to 2003，we made a test of cow’s physiological and performance in part of Chongqing. We also examine the cow’s blood. The result showed that：(1) From June to September，the cow’s temperature of rectum and rate of respiration are higher than that in March to May or October to February (P<0.05)；(2) The daily lactation between March to May and October to February are （23.5±4.2）kg/d（n=31）、（22.1±5.3）kg/d（n=43），also higher than (17.6±5.1) kg/d（n=52）（P<0.05）which in June to September. (3)In heat stress, the density of K+、Cl-、iCa 2+ in serum of cows are higher than other times. (P<0.05) .But the proteins in serum of cows are lower, the activity of alkaline phosphatase drop 38.96 percent and the activity of α-anylase drop 8.52 percent, the activity of GTP raise 3.74 percent.(4) In heat stress, the fecundation insemination of cow slower than the other times, but the diseases in heat stress are more .
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DOI:10.1515/aoas-2016-0064URL
DOI:10.14202/vetworld.2017.650-654URLPMID:5499082
This study was conducted to evaluate the impact of summer and winter season on physiological, biochemical, hormonal, and antioxidant parameters in Indigenous sheep. The research was carried out during summer and winter season. 8 adult apparently healthy female sheep (aged 2-4 years) of similar physiological status were selected. Daily ambient temperature and relative humidity were recorded to calculate the temperature-humidity index (THI). The THI value of summer and winter season were 82.55 and 59.36, respectively, which indicate extreme hot condition during summer season and extreme cold condition during winter season. Physiological parameters were recorded daily during the experimental periods. Blood samples were collected at weekly interval and analyzed for biochemical, hormonal, and antioxidant parameters. The results were analyzed using completely randomized design. From data obtained in this study, we found that higher THI during summer have significant effect over various physiological, biochemical, hormonal, and enzymatic indices of indigenous sheep. The physiological response such as rectal temperature, respiration rate (RR), pulse rate (PR), and skin temperature (ST) was increased significantly. We also found a significant increase in some biochemical parameters such as blood urea nitrogen (BUN), uric acid, creatinine (Cr), alanine transaminase (ALT), aspartate transaminase (AST), sodium (Na), and potassium (K). The level of cortisol hormone and superoxide dismutase (SOD), glutathione peroxidase (GPx), and lipid peroxidase (LPO) antioxidants increased significantly during summer. Whereas, some parameters such as glucose, cholesterol, calcium (Ca), inorganic phosphorus (IP), triiodothyronine (T3), and thyroxine (T4) were decreased significantly during summer season. It was concluded that the THI is a sensitive indicator of heat stress and is impacted by ambient temperature more than the relative humidity in Indigenous sheep. Higher THI is associated with significant increase in RT, RR, PR, ST, BUN, uric acid, Cr, ALT, AST, Na, K, cortisol, SOD, GPx, and LPO and with a significant decrease in glucose, cholesterol, Ca, IP, T3and T4.
DOI:10.1007/s12192-017-0803-zURLPMID:5573694
No Abstract available for this article.
DOI:10.11843/j.issn.0366-6964.2016.09.012URL
本研究旨在探索热应激对牛miRNA表达量和血清生化指标的影响及其相互关系,筛选牛血清中与热应激相关的调控因子。选择20头体况相近、饲养管理一致的红安格斯公牛,分别于热应激期和非热应激期采集血样,进行血清生化指标及miRNA表达量的测定。结果表明,与非热应激期相比,热应激下血清Cl-浓度、LDH活性显著升高(P0.05),MDA含量极显著升高(P0.01);T-AOC活性、GSH-Px活性、IgA含量、IgG含量显著降低(P0.05),SOD活性、IL-2含量极显著降低(P0.01)。对血清miRNA定量分析发现,miR-181a、miR-486表达量显著下调(P0.05),分别与IgA、IL-2含量均呈显著正相关(P0.05),分别与IgG含量呈极显著正相关(P0.01)。而miR-1246表达量极显著上调(P0.01),与MDA含量呈极显著正相关(P0.01)。综上表明,miR-1246、miR-181a、miR-486在机体热应激状态下参与了调控免疫应答及抗氧化等方面的作用,可作为肉牛抗热应激的分子标记。
DOI:10.11843/j.issn.0366-6964.2016.09.012URL
本研究旨在探索热应激对牛miRNA表达量和血清生化指标的影响及其相互关系,筛选牛血清中与热应激相关的调控因子。选择20头体况相近、饲养管理一致的红安格斯公牛,分别于热应激期和非热应激期采集血样,进行血清生化指标及miRNA表达量的测定。结果表明,与非热应激期相比,热应激下血清Cl-浓度、LDH活性显著升高(P0.05),MDA含量极显著升高(P0.01);T-AOC活性、GSH-Px活性、IgA含量、IgG含量显著降低(P0.05),SOD活性、IL-2含量极显著降低(P0.01)。对血清miRNA定量分析发现,miR-181a、miR-486表达量显著下调(P0.05),分别与IgA、IL-2含量均呈显著正相关(P0.05),分别与IgG含量呈极显著正相关(P0.01)。而miR-1246表达量极显著上调(P0.01),与MDA含量呈极显著正相关(P0.01)。综上表明,miR-1246、miR-181a、miR-486在机体热应激状态下参与了调控免疫应答及抗氧化等方面的作用,可作为肉牛抗热应激的分子标记。
DOI:10.5958/0973-9718.2017.00060.5URL
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This study was conducted to evaluate the effects of short- and long-term exposure to solar radiation during the summer season on coat characteristics, some plasma biochemical constituents and thyroid activity in two breeds of goat (Baladi, as an indigenous adapted breed and Damascus, as an exotic breed). The study was a part of project entitled “effect of acclimatization on energy requirements …
DOI:10.3906/vet-0708-3URL
This study was conducted to determine the effects of different physical modifications (sprinkler and fan) related to heat stress during summer on relevant blood biochemical measures and physiological responses, such as rectal temperature (RT), respiration rate (RR), heart rate (HR), testis temperature (TT), and head temperature (HT), in kids. In total, 32 male German Fawn Hair kids at 6 month…
DOI:10.1038/sj.bjp.0705776URLPMID:15155533
Free radicals and other reactive species (RS) are thought to play an important role in many human diseases. Establishing their precise role requires the ability to measure them and the oxidative damage that they cause. This article first reviews what is meant by the terms free radical, RS, antioxidant, oxidative damage and oxidative stress. It then critically examines methods used to trap RS, including spin trapping and aromatic hydroxylation, with a particular emphasis on those methods applicable to human studies. Methods used to measure oxidative damage to DNA, lipids and proteins and methods used to detect RS in cell culture, especially the various fluorescent ‘probes’ of RS, are also critically reviewed. The emphasis throughout is on the caution that is needed in applying these methods in view of possible errors and artifacts in interpreting the results. British Journal of Pharmacology (2004) 142 , 231 255. doi: [DOI link]
DOI:10.3969/j.issn.1006-267x.2017.09.005URL
热应激是指机体在高温条件下对热暴露所做出的非特异性生理反应的总和.有研究 表明热应激会引起机体氧化还原平衡紊乱,发生氧化应激,损伤细胞和组织,从而影响机体的生 长发育及健康状况.热应激一直都是国内外研究的热点,随着全球气温的上升,热应激问题将 会更加突出,本文就热应激条件下氧化应激发生的机制作一综述,以期为后续的相关研究提供 参考.
DOI:10.3969/j.issn.1006-267x.2017.09.005URL
热应激是指机体在高温条件下对热暴露所做出的非特异性生理反应的总和.有研究 表明热应激会引起机体氧化还原平衡紊乱,发生氧化应激,损伤细胞和组织,从而影响机体的生 长发育及健康状况.热应激一直都是国内外研究的热点,随着全球气温的上升,热应激问题将 会更加突出,本文就热应激条件下氧化应激发生的机制作一综述,以期为后续的相关研究提供 参考.
DOI:10.5455/ijlr.URL
DOI:10.1016/j.theriogenology.2016.09.033URLPMID:27771118
Puerarin, a bioactive isoflavone glucoside extracted from radixPuerariae, has been proven to possess many biological activities. However, the role of puerarin in protecting bovine Sertoli cells (bSCs) under heat stress conditions remains to be clarified. The present study aimed to explore the possible protective mechanism of puerarin for primary cultured bSCs subjected to heat stress. Bovine Sertoli cells were treated with 1502μM of puerarin before they were exposed to 4202°C for 102hour. The dose of puerarin (1502μM) was determined on the basis of cell viability. The results showed that puerarin treatment suppressed the production of reactive oxygen species and decreased the oxidative damage of the bSCs subjected to heat stress, as indicated by changes in superoxide dismutase, catalase, and glutathione peroxidase activities and malondialdehyde content. Moreover, puerarin treatment also suppressed the initiation of mitochondria-dependent apoptotic pathway, as revealed by changes in Bax to Bcl-2 ratio, mitochondrial membrane potential, cytochrome C release, caspase-3 activation, and apoptotic rate compared with the heat stress group. In addition, puerarin treatment increased Hsp72 expression in the bSCs with no apparent cellular cytotoxicity compared with the control group. Furthermore, increased Hsp72 was detected in the heat stress plus puerarin group compared with the heat stress group. In conclusion, puerarin attenuates heat stress–induced oxidative damage and apoptosis of bSCs by suppressing reactive oxygen species production and upregulating Hsp72 expression.
DOI:10.3969/j.issn.1006-267x.2011.04.022URL
The experiment was conducted to study the effects of glutamine (Gln) on antioxidant function of broilers under heat stress. Two hundred and forty 1 day-old Kebao-500 broilers were randomly selected and divided into 6 groups with 4 replicates, and 10 chicks in each replicate. Six groups were consisted of group Ⅰ (control group) to Ⅵ, which was supplemented with Gln at the level of 0, 0.4%, 0.8%, 1.2%, 1.6% and 2.0% in 6 basal diets, respectively. The experiment lasted for 28 days (from 15-day-old to 42-day-old) During the experimental period, the temperature maintained at (35±2) ℃ for 8 h from 09:00 to 17:00 and maintained at (30±2) ℃ from 17:00 to 09:00 of the next day. The relative humidity of the chicken house was controlled from 70% to 80%. The effects of Gln on the activities of GSH-Px, SOD and CAT, the ability of inhibiting hydroxyl radical (·OH) and resisting superoxide anion free radical (O-2·), and the content of MDA, T-AOC in serum and intestine of broilers under heat stress were studied. The results showed that, at 28 days of age, supplemental Gln could significantly enhance the activities of GSH-Px, SOD and T-AOC (P
DOI:10.3969/j.issn.1006-267x.2011.04.022URL
The experiment was conducted to study the effects of glutamine (Gln) on antioxidant function of broilers under heat stress. Two hundred and forty 1 day-old Kebao-500 broilers were randomly selected and divided into 6 groups with 4 replicates, and 10 chicks in each replicate. Six groups were consisted of group Ⅰ (control group) to Ⅵ, which was supplemented with Gln at the level of 0, 0.4%, 0.8%, 1.2%, 1.6% and 2.0% in 6 basal diets, respectively. The experiment lasted for 28 days (from 15-day-old to 42-day-old) During the experimental period, the temperature maintained at (35±2) ℃ for 8 h from 09:00 to 17:00 and maintained at (30±2) ℃ from 17:00 to 09:00 of the next day. The relative humidity of the chicken house was controlled from 70% to 80%. The effects of Gln on the activities of GSH-Px, SOD and CAT, the ability of inhibiting hydroxyl radical (·OH) and resisting superoxide anion free radical (O-2·), and the content of MDA, T-AOC in serum and intestine of broilers under heat stress were studied. The results showed that, at 28 days of age, supplemental Gln could significantly enhance the activities of GSH-Px, SOD and T-AOC (P
DOI:10.11843/j.issn.0366-6964.2017.06.009URL
本试验旨在模拟夏季规模化蛋鸡舍内温度变化,研究不同日循环高温对蛋鸡抗氧化能力及机体免疫机能的影响,以期引起生产及研究人员对夏季高温的重视。选取28周龄海兰褐蛋鸡288只,随机分为适温组(21℃,自由采食)、低循环温度组(27~30℃,自由采食)、高循环温度组(29~35℃,自由采食)及采食配对组(21℃,饲喂量同高循环温度组)4个处理组,每个处理6个重复,每个重复12只鸡,分别饲养于4个人工环境控制舱内,试验持续4周。从试验第25天开始,使用微型温度记录仪测定连续3天蛋鸡的体核温度。试验第29天,每重复随机选取1只鸡翅静脉采血,而后屠宰,分离脾和肝,计算脾脏指数,测定蛋鸡血清和肝中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)、总抗氧化能力(T-AOC)及血清中免疫球蛋白A(IgA)、G(IgG)、M(IgM)、溶菌酶。结果表明,与适温组相比,低循环温度组蛋鸡体核温度(TC)无显著差异,除血清T-AOC降低外,肝和血清中MDA含量及抗氧化酶活性均无显著差异,血清IgA、IgM含量显著降低(P0.05);而高循环温度组蛋鸡TC显著升高(P0.05),血清和肝中MDA含量显著升高(P0.05),T-AOC显著下降(P0.05),血清GSH-Px活性有降低趋势(0.05P0.1),血清IgA、IgM含量以及脾脏指数显著降低(P0.05);与采食配对组相比,高循环温度组蛋鸡TC显著升高(P0.05),血清和肝中MDA含量同样显著升高(P0.05),T-AOC显著下降(P0.05),血清GSH-Px活性显著降低(P0.05),血清中仅IgA含量显著降低(P0.05),IgM、IgG含量以及脾脏指数无显著差异。结果表明,夏季蛋鸡舍温度在27~30℃波动时,蛋鸡血液和肝中抗氧化能力变化不明显,但血液中IgA和IgM含量显著降低;在29~35℃波动时,蛋鸡的体核温度显著升高,血液和肝中抗氧化能力显著降低,脾脏指数及血液中IgA和IgM含量显著降低。高温对蛋鸡抗氧化能力的影响可能与升高体温有关,对免疫机能的影响可能与降低采食量有关。
DOI:10.11843/j.issn.0366-6964.2017.06.009URL
本试验旨在模拟夏季规模化蛋鸡舍内温度变化,研究不同日循环高温对蛋鸡抗氧化能力及机体免疫机能的影响,以期引起生产及研究人员对夏季高温的重视。选取28周龄海兰褐蛋鸡288只,随机分为适温组(21℃,自由采食)、低循环温度组(27~30℃,自由采食)、高循环温度组(29~35℃,自由采食)及采食配对组(21℃,饲喂量同高循环温度组)4个处理组,每个处理6个重复,每个重复12只鸡,分别饲养于4个人工环境控制舱内,试验持续4周。从试验第25天开始,使用微型温度记录仪测定连续3天蛋鸡的体核温度。试验第29天,每重复随机选取1只鸡翅静脉采血,而后屠宰,分离脾和肝,计算脾脏指数,测定蛋鸡血清和肝中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)、总抗氧化能力(T-AOC)及血清中免疫球蛋白A(IgA)、G(IgG)、M(IgM)、溶菌酶。结果表明,与适温组相比,低循环温度组蛋鸡体核温度(TC)无显著差异,除血清T-AOC降低外,肝和血清中MDA含量及抗氧化酶活性均无显著差异,血清IgA、IgM含量显著降低(P0.05);而高循环温度组蛋鸡TC显著升高(P0.05),血清和肝中MDA含量显著升高(P0.05),T-AOC显著下降(P0.05),血清GSH-Px活性有降低趋势(0.05P0.1),血清IgA、IgM含量以及脾脏指数显著降低(P0.05);与采食配对组相比,高循环温度组蛋鸡TC显著升高(P0.05),血清和肝中MDA含量同样显著升高(P0.05),T-AOC显著下降(P0.05),血清GSH-Px活性显著降低(P0.05),血清中仅IgA含量显著降低(P0.05),IgM、IgG含量以及脾脏指数无显著差异。结果表明,夏季蛋鸡舍温度在27~30℃波动时,蛋鸡血液和肝中抗氧化能力变化不明显,但血液中IgA和IgM含量显著降低;在29~35℃波动时,蛋鸡的体核温度显著升高,血液和肝中抗氧化能力显著降低,脾脏指数及血液中IgA和IgM含量显著降低。高温对蛋鸡抗氧化能力的影响可能与升高体温有关,对免疫机能的影响可能与降低采食量有关。
DOI:10.2307/2484398URL
The effect of summer heat stress on physiological responses and some of the biochemical constituents (lipid peroxidation, superoxide dismutase and glucose-6-phosphte dehydrogenase) of blood was studied during pre-summer and summer months in Beetal goats. A significant rise was observed in the heart rate, respiration rate and rectal temperature of the goats during summer compared to pre-summer months. Similar rise was observed in blood biochemical parameters viz lipid peroxidation, superoxide dismutase and glucose-6-phosphte dehydrogenase during summer as compared to the pre-summer period.
