饥饿对太平洋鲑(Oncorhynchus spp.)鱼体脂肪与脂肪酸的影响

THE EFFECTS OF STARVATION ON FAT AND FATTY ACIDS COMPOSITION IN PACIFIC SALMON(ONCORHYNCHUS spp.)

采用禁食试验方法进行了太平洋鲑生长鱼经8—32d饥饿后对其鱼体脂肪与脂肪酸变化的影响研究。结果表明,饥饿期间脂肪是太平洋鲑主要的能量来源,饥饿初期太平洋鲑主要消耗肝脏脂肪作为能量维持生命活动,能耗较低;饥饿中后期主要以消耗肠系膜脂肪和肌肉脂肪作为能量维持生命活动,能耗逐步增加(P<0.05)。饥饿后,鱼体肝脏、背肌和肠系膜脂肪中大多数饱和脂肪酸(SFA)和单不饱和脂肪酸(MUFA)比例显著性下降(P<0.05),大多数多不饱和脂肪酸(PUFA)(P<0.05)比例显著性上升,表明太平洋鲑饥饿期间主要消耗SFA和MUFA供能,而PUFA多予以保留,较少消耗供能;二十二碳六烯酸(DHA)和二十碳五烯酸(EPA)比例和DHA/EPA比值均升高显著性上升(P<0.05),表明太平洋鲑在饥饿条件对脂肪中的DHA和EPA,特别是DHA有较强选择性保留能力。鱼体对肝脏、背肌和肠系膜脂肪利用差异性的主要原因是其组织器官中脂肪酸比例不同。鱼体主要利用体内不同组织脂肪中的SFA和MUFA供能,从而节约了机体蛋白质与脂肪中的PUFA以维持重要的生命活动。

This experiment was conducted to determine the effects of starvation on fat and fatty acids composition in grower fish of Pacific Salmon （Oncorhynchus spp.） by fasting test. The results indicated that fat in fish body was main energy resource for Pacific Salmon during the starvation. Pacific salmon consumed liver fat on early starvation stage mainly and the consumption of energy was relatively low. On middle and later starvation stages, fish consumed mesentery fat and muscle fat for energy resource mainly and the consumption of energy rose obviously （P〈0.05）. After starvation, the proportion of saturated fatty acids （SFA） and Monounsaturated fatty acids （MUFA） reduced significantly, Polyunsaturated fatty acids （PUFA） proportion as well as the rates of docosahexaenoic Acid （DHA）/Eicosapentaenoic Acid （EPA） and to 6PUFA/w 3PUFA elevated significantly （P〈0.05）. The grower fish of Pacific salmon under starvation could utilize fatty acids in tissue fat selectively. On starvation stage, the fish got energy by oxidation of SFA and MUFA mainly, while PUFA, especially DHA was seldom utilized for energy. The proportion of fatty acids in fat of liver, muscle and mesentery were different, so that the consumption degree of fat in above tissues also showed difference on starvation stage. The test con- siders that the fish utilized SFA and MUFA in fat of different tissues mainly, and therefore it saved body protein and PUFA in fat for keeping important life activities.