Study On Relationship Between TIGAR Transcript Level And Postmortem Glycolysis In Swine

Pork was the first consumption meat of China and leaner pork was in higher demand.While leanerpork was sensitive to stress and the slaughtering enterprises were lack of attention to animal welfare,causing the incidence of PSE meat. The incidence of PSE meat each year caused huge economic lossesto the enterprises.We have known that the incidence of PSE was closely related with glycolysis, the faster the rate ofglycolysis, the more prone to PSE meat.The newly discovered TIGAR gene expression in living cellshad inhibitory effect on glycolysis. However there were no researches in postmortem glycolysis ofanimals. Therefore this research studied the relationship between TIGAR gene and postmortemglycolysis, exploring TIGAR gene inhibition of PSE meat from molecular level, to provide theoreticalbasis for the pork quality control.The main contents and results are as follows:(1) The correlation between relative transcript level of TIGAR mRNA and metabolic indices atdifferent postmortem time. The relative transcript level of TIGAR mRNA in longissimus muscle ofTaihu pig and Duroc×(Yorkshire×Landrace) at different postmortem time(45min,2h,4h,8h,24h)were measured, and the metabolic indices, including lactic content, ATP content, AMP content, fructose2,6-diphosphate content, AMPK activity and PK activity were also measured.Then correlation betweenthe relative transcript level of TIGAR mRNA and metabolic indices were analyzed. The results showedthat changes in TIGAR mRNA transcript level were negatively correlated with lactic content, and hadpositive correlation with ATP content, AMP content, fructose2,6-diphosphate content, AMPK activityand PK activity（P<0.01）.(2) The correlation between relative transcript level of TIGAR mRNA and metabolic indices ofdifferent breeds.The relative transcript level of TIGAR mRNA in longissimus muscle of Taihu pig,Yimeng Black, Duroc, Duroc×landrace×(Yorkshire) and Duroc×(Yorkshire×Landrace) at45minand2h postmortem were measured, and the metabolic indices, including lactic content, ATP content,AMP content, fructose2,6-diphosphate content, AMPK activity and PK activity were also measured.Then correlation between the relative transcript level of TIGAR mRNA and metabolic indices at45minand2h postmortem were analyzed. The results showed that changes in TIGAR mRNA transcript levelwere negatively correlated with lactic content, AMP content, fructose2,6-diphosphate content, AMPKactivity and PK activity and had positive correlation with ATP content（P<0.01）at45min postmortem.The correlation between TIGAR mRNA transcript level and metabolic indices was not significant. Thissuggested that the pig breeds (Duroc×(Yorkshire×Landrace), Duroc×landrace×(Yorkshire)) whichhad a higher metabolism level had a lower TIGAR mRNA transcript level, the pig breeds(Taihu,YimengBlack) had a lower metabolism level had a higher TIGAR mRNA transcript level,which suggested thatTIGAR gene had inhibitory effect on postmortem glycolysis.(3) The effect of stress before slaughter on TIGAR mRNA transcript level,meat quality and metabolic indices. The transcript levels of TIGAR mRNA, meat quality indicators and glycolysismetabolic indices of Taihu and Duroc×landrace×(Yorkshire) at different slaughter time with differentstress treatment were determinated. The results showed that the two breeds without stress treatment hadhigher transcript level, better meat quality and lower energy status (P<0.05). Taihu had higher transcriptlevel of TIGAR and better meat quality with stress or not before slaughter (P<0.05), which suggestedthat stress can reduce TIGAR mRNA transcript level.