| The purpose of this study was to investigate the effects of postnatal heat stress on maternal behavior,components of colostrum and reproductive performance and metabolic indicators and hippocampal neurogenesis development.The experiments included three parts,the first part detected the maternal behavior and the reproductive performance of the sow.the the second part detected the influence of heat stress on blood biochemical indexes of piglets and components of colostrum.the third part,to study the effects of heat stress on the hippocampus and hypothalamus of male pigs.1.The effect of sows behavior and reproductive performance in pregnancy with heat stressIn our study,12 the first farrowing sows were randomly divided into two groups including heat stress group with 6 sows and control group with 6 sows,each stall equipped with cameras,recording the sows behavior data during the experiment,and statistics sow after giving birth to number born alive,and newborn birth weight and weaning weightThe results showed that the heat stress caused by the sow standing,Non-feeding oral activities and Sham chewing behavior significantly reduced(P<0.05),the sow Sitting behavior,Overall ingestion behavior increased significantly(P<0.05),and the sows of heat stress group Lying behavior has not been changed;Compared with the control group,the number born alive was significantly increased(P<0.05),compared with the control group,There was no difference in the birth weight of newborn males and females in the heat stress group,the weight of the weaned pigs in the heat stress group was significantly lower(P<0.05),among which,the weight of the weaning males of the heat stress group(P=0.01)were decreased;and the weaning weight of female pigs was decreased when compared to the control group(P<0.05).All the data elucidate that heat stress not only changes the control behavior of pregnant sows and the weight of the weaned pigs,which is especially significant for the weaning males.2 The effects of the heat stress on the blood biochemical and hormone levels of the offspring.this study was aim to study the effects of the heat stress on the blood biochemical indexes,hormone levels in the offspring and components of colostrum.The results showed that heat stress affects components of colostrum compared with control group,heat stress group sows colostrum milk proteins have an obviously decreased(P<0.05),and triglycerides and INF-y has a significantly increased(P<0.05),the levels of tumor necrosis factor(TNF-?)has a tendency to rise;The levels of the cortisol(COR)in the milk were significantly increased(P<0.05),and the levels of PRL was significantly decreased(P<0.05)compared to the control group.heat stress on sows affect piglet blood biochemical and hormone levels,compared with control group,the heat stress group newborn piglets blood cholesterol has a tendency to rise(P=0.08),when compared to control group,the level of glucose and triglycerides were not difference?Therefore,Compared with the control group,the level of transaminase(AST)in the heat stress group was significantly decreased(P<0.05),and the levels of ALT was not changed,newborn female piglets had lower cholesterol.There was no change in the levels of T3,T4,Cortisol and Insulin in newborn piglets.Compared with the control group of weaning pigs,there was no difference in plasma glucose,AST,ALT,cholesterol and total triglyceride in the blood of male pigs.Compared with control group,the levels of hormones T3,Cortisol and Insulin in weaning pigs were no different,but the levels of T4 in the blood were significantly increased.3 On offspring behavior and the effect of related gene expression of mechanism.Within 3?10 days of age,the control group piglets backtests(BS)focused on between 0 to 6,the backtests BS of heat stress group distribution at 0 to 4,in the age of 17,heat stress group backtests BS scope 0 to 6.compared to 3 days old the 10?17 days of age BS has the trend of decreased(P<0.05).In the age of 3,when compared with control group,the experimental group has a tendency to reduce(P<0.05),but in the age of 10,17,there is no difference;the male piglets within 10,17 d,compared with 3 days old the BS has a tendency to reduce(P<0.05),and the female piglets in the age of 10,17,compared with group within 3 days of age the BS has a tendency to reduce(P<0.05);Compared with the control group,there was a significantly decrease in the male offspring(P<0.05),and the female piglets were not difference.The results showed that there was no difference in the gene expression of IGF 1,IGF2,BDNF,Trkb and IGF1R in the hippocampal of newborn piglets,when compared to control group.Compared with the control group,there was no difference in the expression of hippocampal GR,MR gene and GR/MR in the female offspring of sow under the condition of heat stress,and there was no difference in the expression of hippocampal GR and MR protein.Compared to the control group,there was no changed of the expression level of GR gene in the hypothalamus of female pigs under the condition of heat stress,but there was an increase in MR gene and GR/MR.The levels of 5-HT in the hippocampus of newborn male piglets were significantly increased(P<0.05),and there was no difference in the level of dopamine(DA);the gene expression of 5-HT1A receptor was significantly increased(P<0.05),but there is no difference 5-HT2A receptor gene expression,therefore,the protein expression of 5-HT1A receptor has no difference.In addition,the level of 5-HT in the hypothalamus of newborn piglets was increased significantly(P<0.05),but there was no difference in the level of dopamine(DA).The gene expression of 5-HT2A receptor in hypothalamus was significantly changed(P<0.05),and the gene expression of 5-HT1A receptor was not difference.Under heat stress condition the newborn piglets hippocampal apoptosis gene Bax expression level was significantly increased(P<0.05),the gene expression of inhibit apoptosis(Bcl-2)was significantly decreased(P<0.05),and the protein expression of hippocampus apoptosis gene Bax and inhibiting apoptosis gene Bcl-2 were not different.The above results indicated that the heat stress had limited effect on the development and function of the hippocampus of piglets,which often occurred at the gene level and had no effect on protein expression. |
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