四种抗脂肪肝物质降低草鱼肝胰脏脂质积累的替代关系

SUBSTITUTIONAL EFFECTS OF FOUR LIPOTROPIC AGENTS ON LIPID ACCUMULATION IN GRASS CARP LIVER

采用11种添加不同水平的蛋氨酸（Met）、胆碱（Ch）、甜菜碱（Bet）和大豆卵磷脂（Lec）的饲料饲养初始体重约15g的草鱼，研究了它们降低草鱼肝胰脏脂质积累的相互替代关系。11种饲料中这四种物质的含量分别为（％）：（1）1．1Met0．08Ch，（2）1．1Met0．33Ch，（3）1．3Met0．23Ch，（4）1．5Met0．13Ch，（5）1．3Met0．13Ch，（6）1．3Met0．13Ch0．08Bet，（7）1．3Met0．13Ch0．1Bet，（8）1．3Met0．13Ch0．12Bet，（9）1．3Met0．13Ch4．0Lec，（10）1．3Met0．13Ch6．0Lec和（11）1．3Met0．13Ch8．0Lec。52d后测定草鱼的相对生长率、饲料转化率和蛋白质效率，分析肝胰脏的脂质含量、组成和脂肪酸构成，测定血清脂蛋白和脂质含量以及全鱼和肌肉的营养成份组成。实验结果表明，（1）与摄食合1．1％蛋氨酸和0．08％胆碱饲料的第1组草鱼相比，第2组—第11组这10组草鱼的相对生长率升高17—73％，并且第10组显著高于第1组。（2）草鱼肝胰脏的脂质含量以第1组最高，增加蛋氨酸含量和添加胆碱、甜菜碱或大豆卵磷脂使肝胰脏脂质含量下降26—74％。在摄食蛋氨酸、胆碱、甜菜碱和大豆卵磷脂组合不同的一些饲料组草鱼之间，肝胰脏脂质含量存在显著差异，表现出四种物质间存在相互加强和替代关系。（3）?

A feeding experiment was conducted to determine the substitutional effects of dietary methionine (Met), choline (Ch), betaine (Bet) and soy beau lecithen (Lec) on lipid accumulation in liver of grass carp, Ctenopharyngodon idellus (C. et V.), weighing about 15g, which were fed separatedly 11 diets containing different levels of these four substances. The dietary levels of these sunbstances were (%): (1) 1.1Met 0.08Ch, (2) 1.1Met 0.33Ch, (3) 1.3Met 0.23Ch, (4) 1.5Met 0.13Ch,(5) 1.3Met 0.13Ch, (6) 1.3Met 0.13Ch 0.08Bet (7) 1.3Met 0.13Ch 0.1Bet (8)1.3Met 0.13Ch 0.12Bet (9) 1.3Met 0.13Ch 4.0Lec, (10) 1.3Met 0.13Ch 6.0Lec and (11) 1.3Met 0.13Ch 8.0Lec. After a 52-day feeding period, the diet supplemented with 1.1% methionine and 0.08% choline resulted in the lowest growth rate and the highest liver lipid content and the addition of different levels of choline, betaine or soy beau lecithin to the diets increased the relative growth rate by 17- 73% and decreased the liver lipid content by 26-74%. Some significant differences in the liver lipid content were observed among the groups of fish fed different diets, showing a coordinated action and a substitional relationship among these four substances. When analyzing the lipid content of serum and liver as well as the serum lipoprotein components, it was found that the lipid content in serum increased with the decrease of that in liver, the coefficient of correlation (r) being - 0.7804, and the same was true for the level of serum pre-β plus β-lipoproteins (r = - 0.6897). So, it may be deduced that the decreased accumulation of lipids in grass carp liver by dietary methionine, choline, betaine and soy beau lecithin was accomplished, to some extent,by increasing the biosynthesis of serum lipoproteins responsible for the transport of lipids from liver to extra-hepatic tissues.