Xu Youqing, Ding Zhaokun, Zhang Haizhu, Liu Liang, Wang Shuqi, Gorge John
Institute for Fisheries Sciences, Guangxi University, 100 University Road, 530004 Nanning, Guangxi, China.
Lipids. 2009 Dec;44(12):1091-104. doi: 10.1007/s11745-009-3340-4. Epub 2009 Sep 17.
An experiment was performed to study the effect of different ratios of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on the growth, nucleic acid and fatty acids of cobia (Rachycentron canadum) juveniles. The juveniles were fed for 8 weeks using seven treatment diets (D-1-D-7) with the same amount of DHA and EPA (1.50 +/- 0.1% of dried diet), but varying ratios of DHA to EPA (0.90, 1.10, 1.30, 1.50, 1.70, 1.90, 2.10, respectively) and a control diet (D-0, DHA + EPA = 0.8% of dried diet, DHA/EPA = 1.30). At the end of the experiment, the mean body weight (BW) of juveniles fed D-0-D-7 increased significantly (from 6.86 +/- 1.64 in the week 0 to 58.52 +/- 16.45 g at the end of week 8, P < 0.05). The mean RNA amount and RNA/DNA ratio in the muscle (from 39.62 +/- 1.30 microg mg(-1) and 2.29 +/- 0.11 in the week 0 to 272.55 +/- 10.70 microg mg(-1) and 14.54 +/- 1.75 at the end of week 8, respectively) and the mean weight in the liver (from 117.70 +/- 11.15 microg mg(-1) and 3.14 +/- 0.25 in the week 0 to 793.07 +/- 13.38 microg mg(-1) and 13.16 +/- 0.76 at the end of week 8, respectively) of cobia juveniles fed D-0-D-7 were significantly higher at the end of 8-week experiment than initially (P < 0.05). The RNA/DNA ratio in the muscle and liver of cobia juveniles increased with their growth and appeared an obvious positive relationship, especially in the muscle, based on regression analysis. The mean lipid content increased significantly in the liver (from 29.82 +/- 0.99 to 37.47 +/- 3.25% totally) and muscle (from 6.74 +/- 0.25 to 10.63 +/- 0.23% totally) of cobia juveniles (P < 0.05). However, no significant difference was found on the lipid contents of juveniles fed different diets for 8 weeks (P > 0.05). In the muscle and liver of juveniles, EPA decreased with its reduction in the diet; DHA, DHA/EPA ratio and poly unsaturated fatty acids (PUFAs) generally increased with their increment in the diet. The conclusion was drawn that the growth, nucleic acid and fatty acids of cobia juveniles were not significantly affected by different DHA/EPA ratios in our experiments.
进行了一项实验，以研究不同比例的二十二碳六烯酸（DHA）和二十碳五烯酸（EPA）对军曹鱼幼鱼生长、核酸和脂肪酸的影响。使用七种处理饲料（D-1 - D-7）喂养幼鱼8周，这些饲料中DHA和EPA的总量相同（占干饲料的1.50±0.1%），但DHA与EPA的比例不同（分别为0.90、1.10、1.30、1.50、1.70、1.90、2.10），还有一种对照饲料（D-0，DHA + EPA = 干饲料的0.8%，DHA/EPA = 1.30）。实验结束时，投喂D-0 - D-7饲料的幼鱼平均体重（BW）显著增加（从第0周的6.86±1.64克增加到第8周结束时的58.52±16.45克，P < 0.05）。军曹鱼幼鱼投喂D-0 - D-7饲料后，肌肉中的平均RNA含量和RNA/DNA比值（分别从第0周的39.62±1.30微克/毫克和2.29±0.11增加到第8周结束时的272.55±10.70微克/毫克和14.54±1.75）以及肝脏中的平均重量（分别从第0周的117.70±11.15微克/毫克和3.14±0.25增加到第8周结束时的793.07±13.38微克/毫克和13.16±0.76）在8周实验结束时显著高于初始水平（P < 0.05）。基于回归分析，军曹鱼幼鱼肌肉和肝脏中的RNA/DNA比值随其生长而增加，呈现出明显的正相关关系，尤其是在肌肉中。军曹鱼幼鱼肝脏（总量从29.82±0.99%增加到37.47±3.25%）和肌肉（总量从6.74±0.25%增加到10.63±0.23%）中的平均脂质含量显著增加（P < 0.05）。然而，喂养不同饲料8周的幼鱼脂质含量未发现显著差异（P > 0.05）。在幼鱼的肌肉和肝脏中，EPA随着饲料中其含量的减少而降低；DHA、DHA/EPA比值和多不饱和脂肪酸（PUFAs）通常随着饲料中其含量的增加而增加。得出的结论是，在我们的实验中，不同的DHA/EPA比例对军曹鱼幼鱼的生长、核酸和脂肪酸没有显著影响。
