Hajji Tarek, Telahigue Khaoula, Rabeh Imen, Ben Ammar Rym, Mdaini Zied, El Cafsi M'hamed, Ghali Ridha
Laboratory of Biotechnology and Valorization of Bio-Geo-Resources LR11ES31, Higher Institute of Biotechnology - Sidi Thabet, University Manouba, 2020, Ariana, Tunisia.
Laboratory of Ecology, Biology and Physiology of Aquatic Organisms LR 18ES41, Faculty of Sciences of Tunis, University Tunis El Manar, 2092, Tunis, Tunisia.
Parasitol Res. 2021 Jun;120(6):1979-1991. doi: 10.1007/s00436-021-07182-z. Epub 2021 May 14.
Parasitic copepod Lernaeocera lusci is a common mesoparasite of the hake Merluccius merluccius. Although widely distributed throughout the Mediterranean, little is known about this pathogen. The current study was designed to assess the impact of different L. lusci infection loads on lipid classes and their fatty acid (FA) composition in both parasite and the host organs (gills, liver, and muscle). Results showed a significant decrease in total lipid, neutral lipid (NL), and polar lipid (PL) contents in all analyzed host's organs in relationship with parasite intensity. Gills appeared to be the most impacted organ under the lowest parasite intensity (loss of 50% of NL and PL amounts). At the highest parasitic infection, a loss of about 80% of lipid moieties was recorded in all analyzed organs. Simultaneously, no significant differences were found for the parasite reflecting its ability to sustain an appropriate lipid amount required for its survival and development. Significant changes in the FA composition were recorded in both host and parasite. Particularly, we have noticed that for L. lusci, the intraspecific competition has resulted in an increased level of some essential FA such as C22:6n-3 (docosahexaenoic acid, DHA), C20:5n-3 (eicosapentaenoic acid, EPA), and C20:4n-6 (arachidonic acid, ARA). This probably reflects that in addition to a direct host FA diversion, L. Lusci can modulate its FA composition by increasing the activity of desaturation. Within the host, liver PL appeared to be the less impacted fraction which may mirror an adaptive strategy adopted by the host to preserve the structural and functional integrity of this vital organ.
寄生桡足类动物卢氏鱼虱是无须鳕的一种常见中寄生虫。尽管它在地中海广泛分布，但对这种病原体的了解却很少。当前的研究旨在评估不同感染负荷的卢氏鱼虱对寄生虫和宿主器官（鳃、肝脏和肌肉）中脂质类别及其脂肪酸（FA）组成的影响。结果表明，所有分析的宿主器官中的总脂质、中性脂质（NL）和极性脂质（PL）含量均与寄生虫强度呈显著下降关系。在最低寄生虫强度下，鳃似乎是受影响最大的器官（NL和PL含量损失达50%）。在最高寄生虫感染时，所有分析器官中脂质部分损失约80%。同时，在寄生虫中未发现显著差异，这反映了其维持生存和发育所需适当脂质含量的能力。宿主和寄生虫的FA组成均有显著变化。特别是，我们注意到对于卢氏鱼虱，种内竞争导致一些必需FA如C22:6n-3（二十二碳六烯酸，DHA）、C20:5n-3（二十碳五烯酸，EPA）和C20:4n-6（花生四烯酸，ARA）的水平升高。这可能反映出除了直接从宿主转移FA外，卢氏鱼虱还可以通过增加去饱和活性来调节其FA组成。在宿主体内，肝脏PL似乎是受影响较小的部分，这可能反映了宿主为维持这个重要器官的结构和功能完整性而采取的一种适应性策略。
