Bianchi Virginia A, Castro Juan M, Rocchetta Iara, Nahabedian Daniel E, Conforti Visitación, Luquet Carlos M
Laboratorio de Ecotoxicología Acuática, INIBIOMA (CONICET-UNCo) - CEAN, Ruta Provincial N° 61, Km 3, CCP 7, Junín de los Andes, 8371 Neuquén, Argentina.
Laboratorio de Ecotoxicología Acuática, INIBIOMA (CONICET-UNCo) - CEAN, Ruta Provincial N° 61, Km 3, CCP 7, Junín de los Andes, 8371 Neuquén, Argentina.
Fish Shellfish Immunol. 2015 Feb;42(2):367-78. doi: 10.1016/j.fsi.2014.11.022. Epub 2014 Nov 24.
We evaluated the modulating effect of long-term feeding with lyophilized Euglena gracilis cells on immune response, oxidative balance and metabolic condition of the freshwater mussel Diplodon chilensis. Mussels, previously fed with Scenedesmus vacuolatus (SV) or E. gracilis (EG) for 90 days, were challenged with an environmentally relevant concentration of Escherichia coli in water for 5 days, under feeding or starvation conditions. EG diet increased overall phagocytic activity and tissue hemocyte accumulation (gill and mantle), and favored hemocyte viability upon E. coli challenge. Tissular hemocyte accumulation, and humoral bacteriolytic activity and protein content were similarly stimulated by EG and E. coli, with no further effect when both stimuli were combined. Both, E. coli challenge and EG diet reduced gill bacteriolytic activity with respect to nonchallenged SV mussels, while no effect was observed in challenged EG mussels. Gill and digestive gland protein contents, along with digestive gland bacteriolytic activity were higher in EG than in SV mussels. Both SV and EG mussels showed increased gill mass upon E. coli challenge, while digestive gland mass was increased by bacterial challenge only in SV mussels. Bacterial challenge produced no effect on humoral reactive oxygen species levels of both groups. Total oxyradical scavenging capacity levels was reduced in challenged SV mussels but remained unaffected in EG ones. In general, EG diet decreased glutathione S-transferase and catalase activities in gill and digestive gland, compared with SV diet; but increased enzyme activity was evident in challenged mussels of both groups. Gill and digestive gland lipid peroxidation levels were higher in EG than in SV mussels but E. coli challenge had stronger effect on SV mussels. Adductor muscle RNA:DNA ratio was higher in EG mussels than in SV ones, and increased upon E. coli challenge in mussels of both groups. E. gracilis can be suggested as a nutritional and protective diet complement suitable for filtering bivalves. However, our results obtained from starved mussels show that starvation periods after supplying this diet should be avoided, since these could revert part of the acquired benefits and/or exacerbate detrimental effects.
我们评估了长期投喂冻干的纤细裸藻细胞对淡水贻贝智利双齿蚌免疫反应、氧化平衡和代谢状况的调节作用。此前分别用空球藻（SV）或纤细裸藻（EG）投喂90天的贻贝，在投喂或饥饿条件下，于水中用与环境相关浓度的大肠杆菌攻击5天。EG饮食增加了总体吞噬活性和组织血细胞积累（鳃和外套膜），并在大肠杆菌攻击时有利于血细胞活力。EG和大肠杆菌同样刺激了组织血细胞积累、体液溶菌活性和蛋白质含量，当两种刺激同时存在时没有进一步影响。与未受攻击的SV贻贝相比，大肠杆菌攻击和EG饮食均降低了鳃的溶菌活性，而在受攻击的EG贻贝中未观察到影响。EG贻贝的鳃和消化腺蛋白质含量以及消化腺溶菌活性高于SV贻贝。大肠杆菌攻击后，SV和EG贻贝的鳃质量均增加，而仅SV贻贝的消化腺质量因细菌攻击而增加。细菌攻击对两组的体液活性氧水平均无影响。受攻击的SV贻贝的总氧自由基清除能力水平降低，但EG贻贝不受影响。总体而言，与SV饮食相比，EG饮食降低了鳃和消化腺中的谷胱甘肽S -转移酶和过氧化氢酶活性；但两组受攻击的贻贝中酶活性均明显增加。EG贻贝的鳃和消化腺脂质过氧化水平高于SV贻贝，但大肠杆菌攻击对SV贻贝的影响更强。EG贻贝的闭壳肌RNA:DNA比值高于SV贻贝，两组贻贝在大肠杆菌攻击后该比值均增加。可以认为纤细裸藻是适合滤食性双壳贝类的营养和保护性饮食补充剂。然而，我们从饥饿贻贝获得的结果表明，提供这种饮食后应避免饥饿期，因为这些可能会逆转部分获得的益处和/或加剧有害影响。
