不同水平亚麻籽油对罗非鱼肝功能和脂质代谢的影响

在基础饲料中分别添加0%、1.5%、3.0%、4.5%的亚麻籽油(LO)配制4种等氮(粗蛋白质33%)试验饲料,在淡水循环养殖系统中,分别饲喂初均重为(9.15±0.03)g的吉富罗非鱼(Oreochromis niloticus)8周,研究饲料中添加亚麻籽油对罗非鱼肝功能和脂质代谢的影响。结果显示:4.5%LO组鱼体肝胰脏脂肪和丙二醛(MDA)含量显著高于其他组,而各组间比肝重(HSI)无显著差异。随饲料中LO水平的增加,鱼体肝胰脏EPA、DHA、n-3 PUFA、n-3 HUFA含量及n-3/n-6比例显著升高,而3.0%LO水平后无显著变化。鱼体肝胰脏亚油酸和n-6多不饱和脂肪酸(n-6 PUFA)含量以对照组最高,4.5%LO组最低。各试验组鱼体肝胰脏中油酸、花生四烯酸(ARA)、饱和脂肪酸(SFA)和单不饱和脂肪酸(MUFA)含量无显著差异。随LO添加水平的增加,鱼体血液中胆固醇(CHOL)、甘油三酯(TG)及低密度脂蛋白胆固醇(LDL-C)含量也显著升高。而4.5%LO组血液中高密度脂蛋白胆固醇(HDL-C)含量显著低于其他组。4.5%LO组鱼体肝胰脏苹果酸脱氢酶(MDH)活性显著高于其他组,而脂蛋白脂酶(LPL)活性以1.5%和3.0%LO组最高。3.0%LO组鱼体肝胰脏超氧化歧化酶(SOD)和过氧化氢酶(CAT)活性显著高于其他组。而肝胰脏谷丙转氨酶(GPT)和谷草转氨酶(GOT)活性以4.5%LO组最低。结果表明,饲料中添加3.0%的亚麻籽油有利于罗非鱼肝胰脏和机体健康。

Effects of different linseed oil level on liver function and lipid metabolism of Oreochromis niloticus

Four practical diets were formulated to contain 4 levels of linseed oil ( LO, 0%, 1.5%, 3.0%and 4.5%) on an equal nitrogen basis (CP=33%).Tilapia (Oreochromis niloticus, initial weight (9.15 ±0.03) g) were fed in a re-circulating freshwater system for 8 weeks to investigate the effects of different levels of LO in diets on liver function and lipid metabolism of tilapia.The results showed as follows: 4.5%LO group showed the highest content of hepatopancreas lipid and malonaldehyde ( MDA) than the other groups, whereas all groups showed no significant differences in hepatosomatic index (HSI).With dietary LO level increasing, the hepatopancreas fatty acid content (EPA, DHA, n-3 PUFA, n-3 HUFA) and the ratio of n-3/n-6 increased significantly until dietary LO level was 3.0%.The highest content of hepato-pancreas C18∶2n-6 and n-6 PUFA occurred in the control group, and the lowest in 4.5%LO group.No significant differ-ences were observed in hepatopancreas C18∶1n-9, C20∶4n-6, SFA and MUFA among any of the groups.Blood levels of cholesterol (CHOL), triglyceride (TG) and low density lipoprotein cholesterin (LDL-C) had a significant increase with increasing dietary LO level.Nevertheless, high density lipoprotein cholesterin ( HDL-C) in 4.5% LO group was signifi-cantly lower than the other groups.The highest level of malate dehydrogenase ( MDH) activities was found in 4.5% LO group, and the lowest level of lipoprotein lipase ( LPL) activities in both 1.5% and 3.0% LO groups.The activities of superoxide dismutase (SOD) and catalase (CAT) were significantly higher in 3.0% LO group than the other groups, whereas both glutamic-pyruvic transaminase ( GPT) and glutamic oxalacetic transaminase ( GOT) activities were the lowest in 4.5%LO group.Thus it suggested that diets with 3.0%level of LO was beneficial for hepatopancreas and body of tila-pia.