Cold Stress Influenced Expression Of Energy Metabolism Related Genes In Broilers

In order to investigate the expression patterns of lipid metabolism and energy metabolism related genes under the condition of cold stress,and observe the regulation effects of green tea power on these expression patterns,140 Huainan partridge chickens with 21 days of age were used in this study.After 2 weeks’(34 days old)preparatory feeding at 24-26℃,the temperature of rearing house was down to 10±2℃.On the time point of 0h、6h、12h、18h、30h、78h and 150 h of cold stress,we determined partial serum biochemical indices(SBI)which include: TC、LDL、HDL、VLDL and FFA contents,and the mRNA expression levels of L-FABP、PPARα、LPL genes in liver PPAR pathway and LKB1、AMPKα1、TSC2、mTOR genes in heart mTOR pathway of broiler.We also performed the green tea power addition experiments with all 7 time points of cold stress at the same time,and observed the change of the expression patterns in those related genes.Correlation analysis between the expression of L-FABP、PPARα、LPL genes and the 5 serum biochemical indices(SBI)was conducted later.1.There were no significant differences in serum HDL and LDL contents,but significant increase in TC、VLDL、FFA contents were found with 34 days Huainan partridge chickens under the condition of 10±2℃ cold exposure.2.Compared with cold stress of 0h,the mRNA expression level of L-FABP in 6h(9.72±8.85)and the other time points was significantly decreased(P<0.01).The mRNA expression level of PPARα in 6h and the other time points was also significantly decreased(P<0.01),and showed a declining trend generally,but with no statistically significant.The mRNA expression level of LPL in 6h(0.67±0.20)、12h(0.60±0.29)and 150h(1.32±0.28)revealed significant difference(P<0.05).3.Compared with cold stress of 0h,the mRNA expression level of LKB1 in 6h was significantly decreased(P<0.05),reached the minimum of 0.48±0.07,and showed significant difference in 78h(reached the maximum of 1.25±0.14)which is distinct from gene expression in 6h-30 h,the mRNA expression pattern of LKB1 showed a trend of increase first and then decrease later in general.The mRNA expression level of AMPKα1 in 78 h reached the maximum of 1.34±0.21,and significantly different with the time points of 6h an 12 h.The expression level of TSC2 mRNA in 78 h reached the maximum of 1.33±0.12,and showed significant difference from 4 time points within 6h-30 h,the expression pattern of TSC2 mRNA presented a trend of decrease first and then increase later in general.The expression of mTOR mRNA in 78 h reached the maximum of 1.22±0.10,and showed significant difference from 4 time points within 6h-30 h,the expression pattern of mTOR mRNA presented a trend of decrease first and increase later.4.In PPAR pathway,under the interaction effects of cold stress and green tea power addition,only LPL mRNA expression displayed a significant increase in addition group compared with cold stress group,the mRNA expression of L-FABP,PPARα had no statistically significant dirrerence between groups.In mTOR pathway,under the interaction effects of cold stress and green tea power addition,no significant difference was found in AMPKα1,while the mRNA expression of LKB1、TSC2 and mTOR showed a significant increase.When compared the addition group(1.79±0.06)with cold stress group(0.98±0.10),only LKB1 mRNA expression had an obvious increase.5.According to the correlation analysis between genes in PPAR pathway and 5 SBI,the correlation coefficient between the relative expression level of L-FABP mRNA in liver and TC、LDL、VLDL and FFA contents in serum were-0.590(P<0.01)、0.931(P<0.01)、0.929(P<0.01)and-0.916(P<0.01),respectively.The correlation coefficient between the relative expression level of L-FABP mRNA in liver and serum HDL was-0.264(P>0.05).The mRNA relative expression levels of PPARα,LPL and 5 serum biochemical indices(SBI)did not show any significant correlation.The correlations between L-FABP mRNA relative expression level in liver and TC、FFA contents in serum were negative,while the correlations between L-FABP mRNA relative expression level and serum LDL、VLDL contents were positive.In conclusion,under the condition of 10±2℃ cold exposure,the serum TC、VLDL、FFA contents in broiler were elevated.Long time continuous cold stress increased the mRNA expression levels of LKB1、TSC2 and AMPKα1 in mTOR pathway compared with the early stage of cold stress.And feeding with 0.5% green tea power improved partial key genes expression related to cold stress,obviously.