| Environmental high temperature and high humidity affect the production and lives of animals,threaten their health,and reduce economic benefits.At present,many studies focus on the effects of temperature on goats,but there are few reports about the combined effects of temperature and humidity on goats.Environmental controlled chambers were used to accurately control the environmental factors(temperature and relative humidity)in this experiment.This study was aimed to investigate the effects of temperature and relative humidity on physiological,endocrine,immune index and expression of related heat shock proteins of goat.It would provide reference to understand the mechanism of the effects of temperature and relative humidity on the production performance and health of goat,and to reveal appropriate temperature and relative humidity for goat.Exp.1 Effects of temperature and relative humidity on physiological,endocrine and immune index of goatEight goat(Boer Goat × GuanZhong Dairy Goat),aged 18 months old,with similar weight(36.3 ± 3.2 kg)were randomly divided into 2 groups,and placed in a separated,environmentally controlled chamber,respectively.It was carried out with two factors layout(temperature and relative humidity).Among them,4 levels of temperature(26 °C,30 °C,34 °C,38 °C)and 4 levels of relative humidity(35%,50%,65%,80%)were set.The experiment lasted for 5 days,including 30 days for adaptation.The results showed that:(1)The respiration rate and skin temperature at 5 sites(head,back,abdomen,left thorax,right thorax)were 38 °C> 34 °C> 30 °C> 26 °C(P < 0.05).The heart rate of the 34 °C group was significantly lower than that of the 30 °C group(P<0.05).The heart rate of the 38 °C group was significantly lower than that of the other temperature treatment groups(P<0.05).The heart rate and rectal temperature of the 26 °C and 30 °C groups were significantly lower than the 34 °C.38 °C group(P <0.05).The rectal temperature in the 80% RH group was significantly higher than that in the 30% RH group(P<0.05).(2)At 48 h,the level of serum T3 of 30 °C group was significantly higher than that of 38 °C group(P<0.05),and the level of T4 of 38 °C group was significantly higher than that of 30 and 34 °C groups(P<0.05),and the level of serum COR of 30 °C group was significantly higher than that of 26 °C and 38 °C groups(P<0.05).The serum levels of T4 in 96 h,26 °C and 30 °C were significantly higher than those of 34 °C and 38 °C groups(P<0.05),and the serum levels of COR were not significantly changed under different temperatures(P>0.05).The level of COR in the 80%RH group was significantly higher than that in the 30%RH and 50%RH groups(P<0.05).At 96 h,COR and T3 levels at 30 °C and 34 °C,T4 at 34 °C,were significantly lower than those of 48 h(P<0.05).(3)At 48 h,level of serum IL-4 of the 26 °C group was significantly higher than 34 °C group(P<0.05),and the IL-6 level of the 34 °C group was significantly higher than the 30 °C group(P<0.05).At 48 h,levels of serum IgA in the 65% RH group were significantly higher than in the 35% RH group(P<0.05).Serum IgM and IgG levels in the 65% RH group were significantly higher than in the 50% RH and 35% RH groups(P<0.05).The IL-2 level of the 35%RH was significantly higher than other humidity groups and 80%RH group was the lowest(P<0.05).The IL-4 of the 65%RH and 80%RH was significantly higher than that in the 35%RH group(P<0.05).The IL-6 level in the 35% RH was significantly higher than that in the 65% RH and 80% RH groups(P<0.05).At 96 h,IL-4 in the 35% RH was significantly higher than that in the 80% RH group(P<0.05).At 96 h,the IgA and IgM in the 30 °C and 38 °C groups,the IgG in the 30 °C group,and the IL-6 in the 34 °C group were significantly lower than 48 h.At 96 h,IL-4 was significantly higher in the 34 °C and 38 °C groups than 48 h.At 48 h the effects of temperature and relative humidity on IgA,IgM,and IgG were all higher than 96 h.At 96 h,serum C3 level in the 30 °C group were significantly higher than at 38 °C group,and serum C4 level in the 26 °C and 30 °C groups were significantly higher than the 34 °C and 38 °C groups(P<0.05).At 48 h,the content of serum LZM in the 80%RH group was significantly higher than that in the 50%RH group(P<0.05),and the C4 content in the 80%RH group was significantly higher than that in the 35%RH group(P<0.05).At 96 h,LZM at 26 °C,30 °C,38 °C and in the 50% RH,C4 contents at 38 °C and in the 80% RH were significantly lower than 48 h.At 96 h,the C4 in the 26 °C group was significantly higher than 48 h.Exp.2 Effects of temperature and relative humidity on the expression of heat shock protein of(HSP)goatThe experimental design was the same as that of Exp.1.Venous blood was collected respectively at 48 h and 96 h to measure the expression of heat shock protein in the blood.The results showed that:(1)The relative mRNA expression of heat shock protein: compared the relative mRNA expression of HSP of the four temperature levels at 48 h and 96 h,the HSP60 expression levels were the lowest in the 26 °C and 34 °C groups respectively,and the highest were in the 30 °C group.Compared four relative humidity levels at 48 h and 96 h,the expression levels were the highest in the 35%RH and 65%RH groups respectively,and the lowest were in the 50%RH and 80%RH groups.The expression level of HSP70 mRNA at 48 h and 96 h was the lowest in the 26 °C group and the highest in the 38 °C and 34 °C groups,respectively.Compared four relative humidity levels at 48 h and 96 h,the expression level was the highest in the 80%RH,and the lowest was in the 65%RH group.The minimum expression of HSP90 mRNA expression at 48 h and 96 h was in the 34 °C and 30 °C groups,respectively,and the highest was at 38 °C.Compared the four relative humidity levels at 48 h and 96 h,the expression level was highest in the 80% RH group and lowest in the 50% RH and 65% RH groups.The expression level of HSP110 mRNA at 48 h and 96 h was lowest at 26 °C and highest at 30 °C.48 h and 96 h were highest in the 35% RH and 80% RH groups respectively,and the lowest were in the 65% RH group.(2)The relative protein expression of heat shock protein: the lowest expression level of HSP60 of 48 h and 96 h was at 26 °C,the highest was at 38 °C group.Under humidity,the lowest expression level of HSP60 of 48 h and 96 h was the highest in 35%RH and 80%RH groups,respectively,and lowest in 50%RH and 65%RH groups.The expression level of HSP70 protein,the lowest expression level of 48 h and 96 h were at 26 °C,and the highest were at 30 °C and 34 °C,respectively.Under humidity,48 h and 96 h were the highest in 35%RH and 50%RH groups,respectively,the lowest in 80%RH and 35%RH groups.The expression level of HSP90 protein,the lowest expression level of 48 h and 96 h were all at 26 °C,and the highest was at 38 °C and 30 °C,respectively.Under humidity,48 h and 96 h were the highest in 35%RH and 50%RH groups,the lowest in 65%RH group.The expression level of HSP110 protein,the lowest expression level of 48 h and 96 h were all at 26 °C,and the highest was at 34 °C and 38 °C,respectively.Under humidity,48 h and 96 h were the highest in 50%RH and 80%RH groups,the lowest in 65%RH group.Conclusions:(1)With the increase of temperature(26-38 °C)and humidity(35-80%RH),the physiological index and the level of endocrine hormones changed significantly,and the immune function decreased,negatively affected the goat's health.(2)Expression levels of different heat shock protein had different trends of change which played an important role in maintaining the stability of the intracellular environment.According to the regularity of heat shock protein expression,it suggested that the expression level of HSP70 mRNA should be considered as an objective index for evaluating heat stress.Based on the expression levels of heat shock protein,it was evaluated that goat were more appropriate at 26 °C under different temperature conditions,and 65%RH was more appropriate under different relative humidity conditions in this study. |
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