Study On The Meat Qualities And The Sedimentary Mechanism Of Intramuscular Fat In YL F1Pigs

Changbai boars were used as male parent and Laiwu pigs which were the finenes localvariety in Shandong Province were uesd as female parent. The F1hybrid pigs (called YL F1pigs) have became the favourite and green health food of people because of its delicious pulp,dense wild taste, unique flavor, high cutability, low fat and eutrophy. In order to research theformation mechanism of unique qualitative in YL F1pigs, and to reveal the sedimentationlaw and control mechanism of intramuscular fat, YL F1pigs and Length×Yarkshire wereselected each40(male, female in the same evenly). Longest musclen in back and lumbar part,backfat and liver were harvested respective when the body weight got20,35,50,70and90kglevels. Carcass quality, meat character and histology character, developmental patterns ofcontent of intramuscular fat, composition of fatty acids and fatty emzymatic activities inmuscle, fat and liver were determined by using biochemistry approach in those two pigs, andthe developmental patterns of the MDH and LPL mRNA expression in muscle weredetermined by using fluorescent quantitation RT-PCR approach. We undertook statisticalanalysis on the results by biology statistical methods, and researched the correlativity of fattyemzymatic activities, gene expression, content of intramuscular fat and composition of fattyacids. The results showed as follows:Carcass quality, meat character and histology character：The results indicated that thecarcass quality, meat character and histology character had no law in those two pigs; On90kg body weight, the carcass length, lean percentage and ham percentage in YL F1pigs werehigher than that in L×DB, and the shear force in YL F1pigs was lower than that in L×DB; InYL F1pigs, the meat color score, marbling score were better than that in L×DB, and thewater loss, drip loss and shear force were lower than that in L×DB, which indicates that thecolor, sappiness and tenderness of muscle in YL F1pigs were better than that in L×DB.Intramuscular fat content and fatty acids composition: The results indicated that thedevelopmental patterns of intramuscular fat content in YL F1pigs and Length×Yarkshirewere similar; Both rised from20kg to50kg and descended from50kg to70kg, and rised from 70kg to90kg at last; The content of intramuscular fat inYL F1pigs was higher than that inLength×Yarkshire at every body weight stage; As gaining of body weight, the satisfied fattyacid and monounsaturated fatty acid of YL F1pigs rised at first and descended next and risedat last, and that got the higtest level at50kg and showed notable difference compared to otherlevel(P＜0.05); The polyunsaturated fatty acid rised first and descended next with the gain ofbody weight, and it got the higtest level at50kg and showed not notable difference comparedto other level(P＞0.05); The PUFA:SFA descended first and rised next and descended at lastwith the gain of body weight; Correlation analysis showed that the rate of polyunsaturatedfatty acid to saturated fatty acid had significant inverse correlation with the content ofintramuscular fat for both kinds of pigs(r=-0.91, P＜0.05). The results suggest that there is avery compacted relationship between the content of intramuscular fat and the content ofPUFA in fatty acids, and high content of PUFA can inhibit the sdimentation of intramuscularfat.Fatty enzymatic activities: The results indicated that the FAS activities of three tissuesin YL F1pigs were higher than that in Length×Yarkshire, and the FAS activities of adiposetissue were significantly higher than that in muscle and liver(P＜0.05); The MDH activitiesin YL F1pigs were higher than that in Length×Yarkshire in the whole, and the MDHactivities of adipose tissue were significantly higher than that in muscle and liver(P＜0.05);The ICDH activities were equivalency in those two pigs, but the ICDH activities of muscleand liver were higher than that of adipose; The developmental patterns of HSL activities weresimilar in those two pigs, and the HSL activities of adipose tissue were significantly higherthan that in muscle and liver(P＜0.05); The LPL activities rised from begin to last in thosetwo pigs and that were higher in YL F1pigs than that in Length×Yarkshire, and the LPLactivities of adipose tissue were significantly higher than that in muscle and liver(P＜0.05);Correlation analysis showed that in YL F1pigs, the FAS and LPL activities had extremesignificant direct correlation and significant direct correlation with content of intramuscularfat respectively (P<0.01and P<0.05); The ICDH and LPL of adipose tissue showedsignificant direct correlation(P＜0.05); The MDH and LPL of liver showed significantdirect correlation(P＜0.05), and the FAS and ICDH showed extreme significant directcorrelation(P<0.01). The results suggest that the sedimentation of intramuscular fat is coregulated by the fatty enzymatic activities of muscle、fat and liver; We can adjust thesedimentation of intramuscular fat by controlling the activities of fatty emzymatic.MDH and LPL mRNA expression: The results indicated that as gaining of body weight,the MDH gene expression of muscle in F1hybrids with boar and Laiwu pigs and white pigsof Landrace and Yorkshire increased from20kg to70kg, and decreased from70kg to90kg.The developmen tal tendencies of muscle LPL gene in F1hybrids with boar and Laiwu pigsand white pigs of Landrace and Yorkshire were similar. With gaining of body weight, theexpression of LPL gene increased from begin to last. On the whole, the expression level ofboth genes in muscle of F1hybrid with boar and Laiwu pigs tended to be higher than that ofwhite pigs of Landrace and Yorkshire. Correlation analysis showed that in F1hybrids withboar and Laiwu pigs, the expression of MDH mRNA and LPL mRNA had significant directcorrelation with content of intramuscular fat(P<0.05), but had no correlation with rate ofpolyunsaturated fatty acid to saturated fatty acid (P>0.05). In white pigs of Landrace andYorkshire, the expression of MDH mRNA and LPL mRNA had no correlation and significantdirect correlation with content of intramuscular fat respectively(P>0.05and P<0.05), and hadextreme significant inverse correlation and significant inverse correlation with rate ofpolyunsaturated fatty acid to saturated fatty acid respectively (P<0.01and P<0.05). Theresults suggest that with gaining of body weight, the expression of both MDH gene and LPLgene in muscle of pigs have apparent developmental characteristic. We can adjust the contentof PUFA in muscle by controlling the content of PUFA in pigs’ diet, which can affect theexpression of MDH gene and LPL gene, and get the goal of adjusting the content ofintramuscular fat.