Characteristics of LC‐PUFA biosynthesis in marine herbivorous teleost Siganus canaliculatus under different ambient salinities
Characteristics of LC‐PUFA biosynthesis in marine herbivorous teleost Siganus canaliculatus under different ambient salinities
复制标题
DOI：
10.1111/anu.12178
复制
发表时间：
2015-10
影响因子：
3.5
通讯作者：
Dizhi Xie;Shuqi Wang;C. You;Fang Chen;D. Tocher;Yuanyou Li
中科院分区：
文献类型：
--
作者：
Dizhi Xie;Shuqi Wang;C. You;Fang Chen;D. Tocher;Yuanyou Li
本研究旨在研究盐度对长链多不饱和脂肪酸(LC-PUFA)生物合成的影响。用含鱼油(FO)或混合植物油(紫苏油和菜籽油，VO)两种盐度(32ppt和10ppt)的饲料对兔鱼幼鱼进行了为期8周的饲养试验。用全身脂肪酸质量平衡法测定体内LC-PUFA的生物合成活性，用实时荧光定量聚合酶链式反应检测肝脏Δ4和Δ6/Δ5脂肪酰基去饱和酶(FAD)和超长链脂肪酸伸长酶(ELOV15)基因的表达水平。结果表明，在两种盐度下，摄食VO饲料的鱼的体外LC-PUFA产量均显著高于摄食FO饲料的鱼。此外，VO饲料组在盐度为10ppt时的LC-PUFA产量显著高于盐度为32ppt时的产量，而在FO饲料组中没有发现盐度对LC-PUFA产量的影响。与此一致的是，计算出的体内表观去饱和度和伸长活性在VO和低盐度处理中也更高。此外，在低盐度条件下，Δ-4和Δ-6/Δ-5 FADS基因表达水平较高，这与计算的酶活性一致。相反，elov15的表达低于FADS，且表达水平与伸长酶活性不一致。这些结果表明，环境盐度可能通过调节脂肪酰基去饱和酶和延伸酶的活性来影响兔鱼LC-PUFA生物合成途径的活性，部分是通过对去饱和酶的转录控制机制来实现的。
The present study aimed to characterize the influence of salinity on the biosynthesis of long-chain polyunsaturated fatty acid (LC-PUFA) in rabbitfish Siganus canaliculatus. An eight-week feeding trial was performed in rabbitfish juveniles with diets containing fish oil (FO) or a blend of vegetable oils (perilla and Canola oils, VO) at two salinities, 32 and 10 ppt. The whole-body fatty acid mass balance (FAMB) method was used to evaluate the in vivo LC-PUFA biosynthetic activities, and the hepatic mRNA levels of Δ4 and Δ6/Δ5 fatty acyl desaturases (Fad) and elongase of very long-chain fatty acids (Elovl5) genes were determined by real-time quantitative PCR. The results showed that the ex novo production of LC-PUFA in fish receiving the VO diet was significantly higher than fish fed the FO diet at both salinities. Furthermore, LC-PUFA production at 10 ppt salinity was significantly higher than that at 32 ppt salinity in the VO dietary groups, whereas no effect of salinity was found in the FO dietary groups. Consistent with this, the calculated apparent in vivo desaturation and elongation activities were also higher in VO and low-salinity treatments. In addition, higher levels of Δ4 and Δ6/Δ5 fads mRNA expression were obtained at low salinity, which was consistent with the calculated enzyme activities. In contrast, the expression of elovl5 was lower than that of fads, and the levels were not consistent with the elongase activity. The results suggest that ambient salinity may affect the activity of the LC-PUFA biosynthetic pathway in rabbitfish through regulating fatty acyl desaturase and elongase activities, partly through a transcriptional control mechanism in the case of desaturases.