Gomes Aline D, Tolussi Carlos E, Boëchat Iola G, Pompêo Marcelo L M, Cortez Maíra P T, Honji Renato M, Moreira Renata G
Departamento de Fisiologia do Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Trav. 14, 321, São Paulo, SP, 05508-090, Brazil.
Departamento de Geociências, Universidade Federal de São João Del Rei, São João Del Rei, MG, Brazil.
Lipids. 2016 Oct;51(10):1193-1206. doi: 10.1007/s11745-016-4196-z. Epub 2016 Sep 8.
Eutrophication results in a deficiency of n-3 LC-PUFA (long-chain polyunsaturated fatty acids) in aquatic food chains, affecting fish nutrition and physiology. The trophic transfer of FA (fatty acids) to fish species of different feeding habits was investigated in two reservoirs in southeast Brazil-the mesotrophic Ponte Nova Reservoir (PN) and the hypereutrophic Billings Reservoir (Bil). Total FA profile of stomach contents and adipose tissue, triacylglycerols (TAG), and phospholipids (PL) from liver and muscle of the omnivorous Astyanax fasciatus and the carnivorous Hoplias malabaricus were analyzed by gas chromatography. A prevalence of n-6PUFA, as 18:2n-6 (linoleic acid) and 20:4n-6 (arachidonic acid, ARA) was observed in the stomach contents and in the tissues of A. fasciatus from the PN reservoir. In contrast, n-3 LC-PUFA, as 20:5n-3 (eicosapentaenoic acid, EPA) was accumulated in fish tissues from Bil, resulting in higher n3/n6 and EPA/ARA ratios, compared to fish from PN. This differential FA accumulation was also observed for H. malabaricus, but differences were slightly minor, and no changes were observed in the EPA/ARA ratios between fish from both reservoirs. Regardless reservoir, FA profiles of TAG resembled that of their diet, whereas FA profiles of PL were more conservative and mainly comprised by LC-PUFA. We conclude that reservoir trophic status affected the FA composition of food resources available to these fish species, resulting in differential allocation of n-3 and n-6 FA. As expected, FA profile of the investigated fish species also reflected their feeding habit and physiological demands.
富营养化导致水生食物链中n-3长链多不饱和脂肪酸（LC-PUFA）缺乏，影响鱼类营养和生理。在巴西东南部的两个水库——中营养的新蓬特水库（PN）和超富营养的比林斯水库（Bil），研究了脂肪酸（FA）向不同食性鱼类的营养传递。通过气相色谱分析了杂食性的条纹鲮脂鲤和肉食性的马拉巴锯脂鲤胃内容物、脂肪组织、肝脏和肌肉中的三酰甘油（TAG）和磷脂（PL）的总脂肪酸谱。在PN水库条纹鲮脂鲤的胃内容物和组织中，观察到n-6多不饱和脂肪酸（如18:2n-6（亚油酸）和20:4n-6（花生四烯酸，ARA））占优势。相比之下，Bil水库鱼类组织中积累了n-3长链多不饱和脂肪酸，如20:5n-3（二十碳五烯酸，EPA），与PN水库的鱼类相比，其n3/n6和EPA/ARA比值更高。在马拉巴锯脂鲤中也观察到了这种不同的脂肪酸积累，但差异略小，两个水库的鱼类之间EPA/ARA比值没有变化。无论哪个水库，TAG的脂肪酸谱都与其饮食相似，而PL的脂肪酸谱更保守，主要由长链多不饱和脂肪酸组成。我们得出结论，水库的营养状态影响了这些鱼类可获得的食物资源的脂肪酸组成，导致n-3和n-6脂肪酸的分配不同。正如预期的那样，所研究鱼类的脂肪酸谱也反映了它们的食性和生理需求。
