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本试验旨在研究饲料中不同亚麻酸(C18:3n-3)/亚油酸(C18:2n-6)比对凡纳滨对虾(Litopenaeus van-namei)幼虾生长性能和脂肪酸组成的影响。采用鱼油、亚麻油和豆油作为脂肪源,以不同的比例配制4种粗脂肪水平约为7.2%的等氮饲料,饲料中C18:3n-3/C18:2n-6比值为0.17、0.30、0.56和0.68。选用平均体重为(0.573±0.002)g的凡纳滨对虾幼虾480尾,随机分为4组(每组3个重复,每个重复40尾虾),分别记为L0.17、L0.30、L0.56和L0.68。试验期为8周。结果显示,随着饲料中C18:3n-3/C18:2n-6比的升高,凡纳滨对虾幼虾增重率呈现先升高后降低的趋势,而饲料系数则呈现先下降后上升的趋势,但组间的差异均不显著(P>0.05)。通过二元回归分析得出增重率(y)与C18:3n-3/C18:2n-6比(x)的关系为y=-1333.2x2+1175.5x+785.66(R2=0.7238),并得出当C18:3n-3/C18:2n-6比为0.44时,增重率最高。全虾粗蛋白质含量以L0.68组为最高,显著高于其他3组(P<0.05)。全虾水分和粗脂肪含量以及肝胰指数组间差异均不显著(P>0.05)。各组对虾肌肉中C18:2n-6和C18:3n-3含量低于它们在肝胰腺中的含量,而C20:4n-6、C20:5n-3(EPA)、C22:6n-3(DHA)在肌肉中的含量高于其在肝胰腺中的含量。L0.68组肝胰腺EPA含量显著高于L0.30组(P<0.05),DHA含量显著高于其他3组(P<0.05)。肌肉EPA、DHA含量以L0.30组最高,但组间差异不显著(P>0.05)。由此得出,饲料中C18:3n-3/C18:2n-6比一定程度地影响凡纳滨对虾幼虾的生长性能,显著影响肝胰腺和肌肉中C18:3n-3和C18:2n-6系列脂肪酸的含量。以增重率作为判定指标,建议饲料中C18:3n-3/C18:2n-6比值为0.44。
The purpose of this study was to investigate the effects of dietary linolenic acid (C18: 3n-3) / linoleic acid (C18: 2n-6) on juvenile shrimp Litopenaeus vannamei juvenile growth performance and fatty acid composition. Using fish oil, linseed oil and soybean oil as fat sources, four kinds of isonitrogenous feed with a crude fat level of 7.2% were prepared in different proportions. The ratios of C18: 3n-3 / C18: 2n-6 in the feed were 0.17, 0.30 and 0.56 And 0.68. A total of 480 juveniles of Litopenaeus vannamei with a mean body weight of (0.573 ± 0.002) g were randomly divided into 4 groups (3 replicates per group and 40 shrimp per replicate), which were recorded as L0.17 and L0.30 , L0.56 and L0.68. The test period is 8 weeks. The results showed that with the increase of C18: 3n-3 / C18: 2n-6 ratio in feed, the weight gain rate of juvenile Litopenaeus vannamei firstly increased and then decreased, while the feed coefficient decreased firstly and then increased But there was no significant difference between groups (P> 0.05). The binary regression analysis showed that the relationship between weight gain (y) and C18: 3n-3 / C18: 2n-6 ratio (x) was y = -1333.2x2 + 1175.5x + 785.66 (R2 = 0.7238) When the C18: 3n-3 / C18: 2n-6 ratio is 0.44, the weight gain rate is the highest. The crude protein content of whole shrimp was the highest in L0.68 group, significantly higher than the other three groups (P <0.05). There was no significant difference between the whole shrimp water and crude fat content and the index of hepatopancreas (P> 0.05). The levels of C18: 2n-6 and C18: 3n-3 in shrimp muscle of each group were lower than those in hepatopancreas, whereas C20: 4n-6, C20: 5n-3 ) Is higher in muscle than it does in hepatopancreas. The content of EPA in liver and pancreas in L0.68 group was significantly higher than that in L0.30 group (P <0.05), and the DHA content was significantly higher than the other three groups (P <0.05). Muscle EPA, DHA content in the L0.30 group was the highest, but the difference between the groups was not significant (P> 0.05). It was concluded that the C18: 3n-3 / C18: 2n-6 ratio in feeds affected the growth performance of juvenile Litopenaeus vannamei to a certain extent and significantly affected the C18: 3n-3 and C18: 2n- 6 series of fatty acid content. To weight gain rate as a judge, the proposed feed C18: 3n-3 / C18: 2n-6 ratio of 0.44.