Moya-Falcón C, Thomassen M S, Jakobsen J V, Ruyter B
AKVAFORSK, Institute of Aquaculture Research, NO-1432 As, Norway.
Lipids. 2005 Jul;40(7):709-17. doi: 10.1007/s11745-005-1434-9.
Atlantic salmon were fed fish meal-based diets supplemented with either 100% fish oil (FO) or 100% rapeseed oil (RO) from an initial weight of 85 g to a final average weight of 280 g. The effects of these diets on the capacity of Atlantic salmon hepatocytes to elongate, desaturate, and esterify [1-14C] 18:1n-9 and the immediate substrates for the delta5 desaturase, [1-14C] 20:3 n-6 and [1-14C] 20:4n-3, were investigated. Radiolabeled 18:1n-9 was mainly esterified into cellular TAG, whereas the more polyunsaturated FA, [1-14C] 20:3n-6 and [1-14C] 20:4n-3, were primarily esterified into cellular PL. More of the elongation product, [1-14C] 20:1n-9, was produced from 18:1n-9 and more of the desaturation and elongation products, 22:5n-6 and 22:6n-3, were produced from [1-14C]20:3n-6 and [1-14C] 20:4n-3, respectively, in RO hepatocytes than in FO hepatocytes. Further, we studied whether increased addition of [1-14C]18:1n-9 to the hepatocyte culture media would affect the capacity of hepatocytes to oxidize 18:1n-9 to acid-soluble products and CO2. An increase in exogenous concentration of 18:1 n-9 from 7 to 100 microM resulted in a nearly twofold increase in the amount of 18:1n-9 that was oxidized. The conversion of 20:4n-3 and 20:3n-6 to the longer-chain 22:6n-3 and 22:5n-6 was enhanced by RO feeding in Atlantic salmon hepatocytes. The increased capacity of RO hepatocytes to produce 22:6n-3 was, however, not enough to achieve the levels found in FO hepatocytes. Our data further showed that there were no differences in the hepatocyte FA oxidation capacity and the lipid deposition of carcass and liver between the two groups.
将初始体重85克的大西洋鲑鱼投喂以鱼粉为基础的日粮，日粮分别添加100%鱼油（FO）或100%菜籽油（RO），直至最终平均体重达到280克。研究了这些日粮对大西洋鲑鱼肝细胞延长、去饱和以及酯化[1-¹⁴C]18:1n-9的能力，以及对Δ5去饱和酶的直接底物[1-¹⁴C]20:3n-6和[1-¹⁴C]20:4n-3的影响。放射性标记的18:1n-9主要酯化为细胞内的甘油三酯（TAG），而多不饱和脂肪酸[1-¹⁴C]20:3n-6和[1-¹⁴C]20:4n-3主要酯化为细胞内的磷脂（PL）。与FO肝细胞相比，RO肝细胞中由18:1n-9产生的延长产物[1-¹⁴C]20:1n-9更多，由[1-¹⁴C]20:3n-6和[1-¹⁴C]20:4n-3分别产生的去饱和和延长产物22:5n-6和22:6n-3也更多。此外，我们研究了向肝细胞培养基中增加[1-¹⁴C]18:1n-9的添加量是否会影响肝细胞将18:1n-9氧化为酸溶性产物和二氧化碳的能力。18:1n-9的外源浓度从7微摩尔增加到100微摩尔，导致被氧化的18:1n-9量增加了近两倍。在大西洋鲑鱼肝细胞中，RO日粮喂养增强了20:4n-3和20:3n-6向更长链的22:6n-3和22:5n-6的转化。然而，RO肝细胞产生22:6n-3能力的增加并不足以达到FO肝细胞中的水平。我们的数据还表明，两组之间肝细胞脂肪酸氧化能力以及胴体和肝脏的脂质沉积没有差异。
