Study On The Blood Physiological And Biochemical Indexes And Meat Relate Gene Expression Of Sheep Groups

The objective of this study was to evaluate blood parameters and carcass merit inLanzhou Fat-Tailed Sheep (n=30), Tibetan sheep (n=30) and hybrid German Merino(n=30) and to associate gene expression in H-FABP and CAPN2genes with the bloodparameters and carcass merit. Lambs were the same age (18months) and weight (45kg). Each breed group was divided into three groups and a ration treatment (70%maintenance, LOW; maintenance, MED;130%maintenance, HIGH) was assigned atrandom to each subgroup. After one month on feed, blood samples were taken on alllambs. Blood parameters measured included blood glucose (GLU), total protein (TP),albumin (ALB), globulin (GLO), triglyceride (TG), total cholesterol (CHO),high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Blood analyseswere performed by Automatic Chemistry Analyzer. Additionally, ten lambs from eachbreed group on the high ration were selected for harvest and carcass measurements.Lambs were harvested and aged on the rail24hr. After24hr, carcasses werefabricated into retail cuts and samples were vacuum packaged. Two samples fromeach lamb for longissimus dorsi and semitendinosus were retained for analyses. Onesample of each muscle was immediately frozen (aging day1), and the second samplewas allowed to age at4°C for48hr and then frozen until analyzed. Sample analysesincluded pH value，pressing loss, moist cooking loss and Warner-Bratzler shear forcefor each muscle. Additionally, samples of each muscle from each aging days weretaken to determine gene mRNA expression for CAPN2and H-FABP usingRT-qPCR.Results were as follows:(1) Increasing levels of dietary energy resulted in lesser percentages of, TP,ALB, GLO and greater percentages of TG,CHO and GLU for all breeds.(2) There were no ration difference in pH nor breed groups differences foreither aging days (P>0.05).Pressing loss of longissimus dorsi inLanzhou fat-tailedsheep was greater than German Merino sheep and Tibetan sheep (P<0.05) on agingday1.Pressing loss in Tibetan sheep was lesserthan the other two breed groups onaging day3(P<0.01).Moist cooking loss of Lanzhou fat-tailed sheep was greater thanGerman Merino and Tibetan sheep on aging day1（P<0.01）.(3) Inthe longissimusdorsi, H-FABP gene mRNA expression level of Tibetan sheep was greater than Lanzhou fat-tailed sheep and German Merino (P <0.01). In semitendinosus, H-FABPgene mRNA expression level of German Merino was greater than the other two breedgroups (P <0.01).In longissimus muscle, CAPN2gene mRNA expression level ofLanzhou fat-tailed sheep was greater than Tibetan sheep and German Merino(P<0.01). In semitendinosus, CAPN2gene mRNA expression level of Tibetan lesserthan German Merino and Lanzhou fat-tailed sheep (P<0.01)In Tibetan sheep,H-FABP gene mRNA expression level of longissimus dorsi was greater thansemitendinosus and CAPN2gene mRNA expression level of semitendinosus andlongissimus dorsi (P<0.01). In German Merino, H-FABP gene mRNA expressionlevel of semitendinosus and longissimus dorsi was greater than CAPN2gene mRNAexpression level of semitendinosus and longissimus dorsi (P<0.01), and H-FABP genemRNA expression levels between semitendinosus and longissimus dorsi weredifferent (P<0.01), but CAPN2gene mRNA expression level was notdifferentbetween longissimus dorsi and smitendinosus (P>0.05). In Lanzhou fat-tailed sheep,H-FABP and CAPN2gene mRNA expression level of the longissimus dorsi wasgreater than semitendinosus (P <0.01), but the two genes’ mRNA expression level ofeach musclewas similar.(4) For aging day1, in Tibetan sheep H-FABP gene mRNA expression leveland Warner-Bratzler shear force were negatively correlated (r=-0.92, p=0.012),CAPN2gene mRNA expression level and Warner-Bratzler shear force werenegatively correlated (r=-0.423, p=0.037), and CAPN2gene mRNA expressionlevel and pH were negatively correlated (r=-0.646, p=0.023). In German Merino,CAPN2gene mRNA expression level and moist cooking loss were positivelycorrelated (r=0.823, p=0.047), but CAPN2gene mRNA expression level andWarner-Bratzler shear force were negatively correlated (r=0.825, p=0.045). InLanzhou fat-tailed sheep CAPN2gene mRNA expression level and Warner-Bratzlershear force were negatively correlated (r=-0.865, p=0.026). The H-FABP genemRNA expression level and moist cooking loss were negatively correlated in Lanzhoufat-tailed sheep (r=-0.894, p=0.041).For aging day3, in Tibetan sheep, H-FABP gene mRNA expression level andpressing loss were negatively correlated (r=-0.807, p=0.039), and CAPN2genemRNA expression level and pH were negatively correlated(r=0.879, p=0.044).However, in Tibetan sheep, the ratio of H-FABP: CAPN2gene mRNA expression levels and pressing loss were positively correlated (r=0.854, p=0.025).In German Merino, the H-FABP gene mRNA expression level and pressing loss ratewere negatively correlated (r=-0.74, p=0.0279), and the ratio of H-FABP: CAPN2gene mRNA expression levels and pressing loss were negatively correlated (r=0.688,p=0.031). In Lanzhou fat-tailed sheep, CAPN2gene mRNA expression level andshear force were positively correlated (r=0.768, p=0.028).