da Silva Filipa F G, Støttrup Josianne G, Kjørsvik Elin, Tveiten Helge, Tomkiewicz Jonna
National Institute of Aquatic Resources, Technical University of Denmark, Charlottenlund, Denmark.
National Institute of Aquatic Resources, Technical University of Denmark, Charlottenlund, Denmark.
Anim Reprod Sci. 2016 Aug;171:17-26. doi: 10.1016/j.anireprosci.2016.05.007. Epub 2016 May 21.
Farmed female eels were fed two experimental diets with similar proximate composition but different n-3 polyunsaturated fatty acid (PUFA) levels. Both diets had similar levels of arachidonic acid (ARA), while levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in one diet were approximately 4.5 and 2.6 times higher compared to the other diet, respectively. After the feeding period, each diet group was divided into two and each half received one of two hormonal treatments using salmon pituitary extract (SPE) for 13 weeks: i) a constant hormone dose of 18.75mg SPE/kg initial body weight (BW) and ii) a variable hormone dosage that increased from 12.5mg SPE/kg initial BW to 25mg SPE/kg initial BW. Results showed a significant interaction between diets and hormonal treatments on gonadosomatic index (GSI), indicating that the effect of broodstock diets on ovarian development depends on both nutritional status and hormonal regime. Females fed with higher levels of n-3 series PUFAs and stimulated with the constant hormonal treatment reached higher GSIs than those receiving the variable hormonal treatment. However, when females were fed lower levels of n-3 series PUFAs there was no difference in the effect of hormonal treatments on GSI. We also found that, independent of hormonal treatment, the diet with higher levels of n-3 series PUFAs led to the most advanced stages of oocyte development, such as germinal vesicle migration. Concentration of sex steroids (E2, T, and 11-KT) in the plasma did not differ between diets and hormonal treatments, but was significantly correlated with ovarian developmental stage. In conclusion, increasing dietary levels of n-3 PUFAs seemed to promote oocyte growth, leading to a more rapid progression of ovarian development in European eel subjected to hormonal treatment.
养殖的雌性鳗鱼被投喂两种实验饲料，这两种饲料的近似成分相似，但n-3多不饱和脂肪酸（PUFA）水平不同。两种饲料的花生四烯酸（ARA）水平相似，而其中一种饲料中的二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）水平分别比另一种饲料高约4.5倍和2.6倍。投喂期结束后，每个饲料组被分成两组，每组一半接受两种激素处理之一，使用鲑鱼垂体提取物（SPE）处理13周：i）每千克初始体重（BW）18.75mg SPE的恒定激素剂量，ii）从每千克初始BW 12.5mg SPE增加到每千克初始BW 25mg SPE的可变激素剂量。结果表明，饲料和激素处理对性腺指数（GSI）有显著的交互作用，表明亲鱼饲料对卵巢发育的影响取决于营养状况和激素调节。投喂较高水平n-3系列PUFA并接受恒定激素处理的雌性鳗鱼的GSI高于接受可变激素处理的雌性鳗鱼。然而，当雌性鳗鱼投喂较低水平的n-3系列PUFA时，激素处理对GSI的影响没有差异。我们还发现，与激素处理无关，n-3系列PUFA水平较高的饲料导致卵母细胞发育到最先进阶段，如生发泡迁移。血浆中性类固醇（E2、T和11-KT）的浓度在饲料和激素处理之间没有差异，但与卵巢发育阶段显著相关。总之，增加饲料中n-3 PUFA的水平似乎能促进卵母细胞生长，使接受激素处理的欧洲鳗鱼卵巢发育更快。
