不同碳链长度n-3脂肪酸及脂肪水平对罗非鱼生长、肝功能和餐后血液指标的影响

Effects of n-3 Fatty Acids with Different Carbon Chain Lengths and Lipid Levels on Growth,Liver Function and Postprandial Blood Indices of Tilapia( Oreochromis niloticus)

在实用饲料配方的基础上分别添加5%鱼油(低水平鱼油)、10%鱼油(高水平鱼油)、5%亚麻籽油(低水平亚麻籽油)和10%亚麻籽油(高水平亚麻籽油),配制4种试验饲料,在室内淡水循环水族缸内饲喂罗非鱼8周,比较研究不同碳链长度n-3脂肪酸及脂肪水平对罗非鱼生长、肝功能以及餐后血液指标的影响。将360尾初重为(43.70±1.06)g的罗非鱼随机分成4组,每组设3个重复,每个重复30尾鱼,每组试验鱼随机饲喂1种试验饲料。结果表明:各组罗非鱼末重、特定生长率、饲料系数、蛋白质效率均无显著差异(P>0.05),但高水平亚麻籽油组的摄食量显著低于低水平亚麻籽油组(P<0.05)。鱼油组罗非鱼血清总胆固醇(TCHO)、高密度脂蛋白胆固醇(HDL-C)以及低密度脂蛋白胆固醇(LDL-C)含量均高于亚麻籽油组,且同一脂肪源的高水平组高于低水平组。鱼油组血清TCHO含量峰值出现在餐后6 h,而亚麻籽油组出现在餐后9 h。各组血清HDL-C含量均在餐后6 h回落到最低值。亚麻籽油组血清甘油三酯(TG)和极低密度脂蛋白胆固醇(VLDL-C)含量高于鱼油组。各组血清TG与VLDL-C含量峰值均出现在餐后6 h。随餐后时间的延长,罗非鱼血糖含量基本呈降低趋势。鱼油组肝胰脏谷丙转氨酶(ALT)活性极显著低于亚麻籽油组(P<0.01),而各组间肝胰脏谷草转氨酶(AST)活性差异不显著(P>0.05)。肝胰脏丙二醛(MDA)含量表现为高水平鱼油组>高水平亚麻籽油组>低水平鱼油组>低水平亚麻籽油组,且组间差异极显著(P<0.01)。同一水平下,鱼油组肝胰脏超氧化物歧化酶(SOD)活性与亚麻籽油组没有显著差异(P>0.05),而低水平鱼油组肝胰脏SOD活性显著高于高水平鱼油组(P<0.05)。由此可见,不同碳链长度n-3脂肪酸及脂肪水平不会影响罗非鱼的生长,但会影响其肝功能以及餐后血液指标。

An 8-week feeding trial was conducted to evaluate the effects of n-3 fatty acids with different carbon chain lengths and lipid levels on growth, liver function and postprandial blood indices of tilapia （ Oreochromis niloticus） . Four experimental diets were formulated containing either 5% fish oil （ low level of fish oil） , 10%fish oil （ high level of fish oil） , 5% linseed oil （ low level of linseed oil） or 10% linseed oil （ high level of lin-seed oil ） on the basis of practical diet formulation. A total of 360 tilapia with the initial body weight of （43.70±1.06） g were randomly distributed into 4 groups with 3 replicates per group and 30 fish per replicate, and the fish in each group were randomly fed one of four experimental diets. The results showed that no signifi-cant differences were found in finial body weight （ FBW） , specific growth rate （ SGR） , feed conversion ratio （FCR） and protein efficiency ratio （PER） of fish among all groups （P〉0.05）, but the feed intake （FI） in low level of linseed oil group was significantly lower than that in high level of linseed oil group （ P〈0.05） . Se-rum total cholesterol （ TCHO） , high density lipoprotein-cholesterol （ HDL-C） and low density lipoprotein-cho-lesterol （ LDL-C） contents in fish oil groups were higher than those in linseed oil groups; besides, the above indices in high level group were higher than those in low level group of the same lipid source. The peak of ser-um TCHO content in fish oil groups was observed at 6 h after meal, but that in linseed oil groups was observed at 9 h after meal. The bottom of serum HDL-C content appeared at 6 h after meal in 4 groups. Linseed oil groups had higher serum triglyceride （ TG） and very low density lipoprotein-cholesterol （ VLDL-C） contents compared with fish oil groups. With the postprandial time going on, blood glucose content showed a basic de-creasing tendency. The hepatopancreas alanine transaminase （ ALT） activity in fish oil groups was significantly lower than that in linseed oil groups （ P〈0.01） , but there were no differences in hepatopancreas aspartate ami-notransferase （ AST） activity among all groups （ P〉0.05） . Hepatopancreas malondialdehyde （ MDA） content showed a trend of high level of fish oil group〉high level of linseed oil group〉low level of fish oil group〉low level of linseed oil group, and the difference among all groups was significant （P〈0.01）. No difference was found in hepatopancreas superoxide dismutase （ SOD ） activity between fish oil and linseed oil groups in the same level （P〉0.05）, but the hepatopancreas SOD activity in low level of fish oil group was significantly higher than that in high level of fish oil group （ P〈0.05） . In conclusion, n-3 fatty acids with different carbon chain lengths and lipid levels have little effects on growth of tilapia, but can affect their liver function and post-prandial blood indices.