Study On Correlation Between Tissue Expression Of Traits Of Peroxisome Proliferator Activated Receptors And Fatty Liver In Geese

The synthesis of triacylalycerol(TG) in poultry mainly occurs in liver.The synthesis and lipolysis of TG function in a balance under normal conditions,and TG content in hepatocytes should not increase to avoid depressed function of liver.Grown geese were overfeeded with corn to destroy lipid metabolism in vivo,so much TG deposit in hepatocytes to form fatty liver.Formation of fatty liver is very much complicated.Very little data is attained that what function of candidate gene correlating to lipid metabolism play in formation of fatty liver.Peroxisome Proliferator Activated Receptors(PPAR) almost regulate all presses of lipid metabolism,which include transportation,absorption and catabolism(βandγoxidation) of lipid,differentiation and formation of lipocytes,so PPAR play a key role in modulation of TG biosynthesis in liver and TG deposit in other tissues, and PPAR is considered as candidate gene correlating to lipid metabolism in medicine and stockbreeding.This research was study on the characterization of PPAR expression in tissues and association between expressed quantity and weight of fatty liver and abdominal fat,in order to find out regulative rules about lipid metabolism from molecular level,probe into importance of PPAR gene in formation of fatty liver,and provide reference for further research on association of PPAR and lipid metabolism in geese.In order to investigate the expression pattern of PPAR genes before and after overfeeding and examine the effect of expressed PPAR levels on weights of fatty liver and abdominal fat in geese,the RT-PCR products of PPAR genes in heart,liver,spleen,lung, kidney,stomach,small intestine,brain,breast muscle,let muscle and abdominal fat were determined in these two periods.RT-PCR was used to determine the expression levels of PPAR genes.The correlations between slaughter weight and blood indicatirx,expression of PPAR and blood indicatirx,among indicatirx were analyzed.Results showed that as follows.Expression levels of PPAR-αwere relatively high in most of detected tissues but undetectable in abdominal fat tissue before overfeeding,and the level was evidently increased in lung,appeared in abdominal fat tissue,and reduced in the other tissues after overfeeding.Expressed PPAR-γlevels were relatively high in liver,spleen,lung,small intestine and abdominal fat,and relatively low in the other tissues before overfeeding. Expressed PPAR-γlevels were enhanced in liver,spleen,lung,stomach and kidney,but decreased in abdominal,and without obvious changes in the other tissues.Expression patterns of PPAR genes show specific-tissue manner.In addition,expression patterns of PPAR-αare different from PPAR-γafter overfeeding.It may suggest that different functions of PPAR subtypes are involved responsive to overfeeding.Expressed PPAR-αlevels appeared individual differences in fatty lives and abdominal fats,and expressed PPAR-αwere presented two bands in abdominal fat,which may implied different structural mRNAs were transcribed by PPAR-α.The pattern of expressed PPAR-γin livers were the same as that of expressed PPAR-α,and it impossibly associated with suffered degree in individual liver,and suffered more,expressed less.That Expressed PPAR-γlevel were high in individual abdominal fat demonstrated importance of PPAR-γfor accumulating fatNo significant differences presented between expression level of PPAR and weight of fatty liver and abdominal fat,also and blood indicatirx.Living weight before overfeeding positively correlated carcass weight and eviscerated weight after overfeeding(r=0.45 and 0.41),and more carcass weight with higher eviscerated weight(r=0.84).TCHO is the total CHO in lipoprotein and most of TCHO is biosynthesized in liver,and our results just showed that TCHO level have positive correlation with weight of fatty liver.VLDL biosynthesized in liver is a leading lipoprotein that transports triglyceride from liver to fat tissues for accumulating,so VLDL level is very positively correlated to TG level(r=0.86), and VLDL level is also correlated to weight of abdominal fat(r=0.41).Most of TCHO is used for biosynthesis of lipoprotein,mainly for VLDL(r=0.45),and TCHO level has positive correlation with TG level(r=0.66).TG was transported by lipoprotein from liver to other tissues for lightening metabolized burthen in liver and reducing suffered degree in hepatocytes.Redundant HDL was transported back to liver for metabolism,so negatively correlated with VLDL and TG level(r=—0.65 and—0.43).The results from this study indicated that the expression patterns of PPAR-αand PPAR-γin geese are almost consistent with that of rodent and human.These two genes play a pivotal role in formation of fatty liver.The expression patterns of PPAR before and after overfeeding indicated different subtype of PPAR genes have different function in different tissues,and changes of expressed PPAR levers are consistent with physiological situation.