Ractopamine对大约克猪蛋白质和脂肪代谢的影响

用添加２０ｍｇ／ｋｇＲａｃｔｏｐａｍｉｎｅ的饲粮饲喂纯种大约克肥育猪，发现半腱肌ＤＮＡ含量降低１４％（Ｐ＜０．０１），ＲＮＡ含量升高７．７％（Ｐ＜０．０１），背最长肌ＤＮＡ含量下降７％（Ｐ＜０．０１），ＲＮＡ上升５．５％（Ｐ＜０．０１），且两种肌肉中的ＲＮＡ／ＤＮＡ均呈升高趋势；背最长肌中酪氨酸、苏氨酸和蛋氨酸含量分别降低２５％（Ｐ＜０．０５）、９％（Ｐ＜０．０１）和１７％（Ｐ＜０．０５），而甘氨酸和丙氨酸含量分别上升１５％（Ｐ＜０．０５）和８％（Ｐ＜０．０５），肝组织中天冬氨酸和异亮氨酸分别提高１１．６％（Ｐ＜０．０１）和１２％（Ｐ＜０．０１）；此外背最长肌肌原纤维的降解系数（ＭＦＩ）明显降低，血清尿素氮下降１６．６％（Ｐ＜０．０５）。同时还发现Ｒａｃｔｏｐａｍｉｎｅ使皮下脂肪中异柠檬酸脱氢酶活力降低２７％（Ｐ＜０．０１），血清脂肪酶活力升高１２．２％（Ｐ＜０．０５），血清胆固醇降低２３．５％（Ｐ＜０．０５）。上述结果显示：Ｒａｃｔｏｐａｍｉｎｅ可促进体内蛋白质的合成和脂肪的分解，而抑制蛋白质的降解和脂肪的合成

Effects of Ractopamine on Adipose and Protein Metabolism in Finishing Yorkshire Swine

Effects of Ractopamine(20mg/kg)on adipose and protein metabolism in finishing yorkshire pigs were studied.The results showed that the content of DNA in semitendinosus(ST)was decreased by 14%( P <0.01).RNA in ST was increased by 7.7%( P <0.01)while DNA in longis simus dorsi(LD)was decreased by 7%( P <0.01)and RNA in LD was increased by 5.5%( P <0 01).Furthermore,the content of Tyr,Thr,and Met of LD in treated pigs were decreased by 25% ( P <0.05),9%( P <0.01)and 17%( P <0.05)respectively,while the content of Gly and Ala were increased by 15%( P <0.05)and 8%( P <0.05),the content of Asp and Ile in livers were increased by 11.6%( P <0.01)and 12%( P <0.01).Ractopamine decreased myofibril fragmentation index(MFI)significantly.The concentration of SUN was decreased by 16.6%( P <0.01 )in treated pigs.Compared to the control,Ractopamine decreased the activity of isocitric dehydrogenase in subcutaneous fat by 27%( P <0.01),increased serum fattase activity by 12.2%( P <0.05).In addition,the concentration of serum cholesterol was decreased by 23.5%( P <0.05).These results suggested that Ractopamine could promote protein synthesis and lipolysis whereas inhibit lipogenesis and protein degradation.