ABSTRACT: Isopodiosis in cultured meagre Argyrosomus regius was investigated at 3 farms in the northern lakes of Egypt throughout 2018, based upon prevalence rate, parasitological examination, and molecular identification by PCR targeting the large ribosomal subunit 16S of the rRNA gene. Further, the susceptibility of A. regius to isopod infection was experimentally evaluated under hyposalination of 25, 15, and 8 ppt for 1 wk. The isolated isopod stages were morphologically identified as Livoneca redmanii Leach, 1818 with prevalence rates of 77.05 and 77.9% in Al-Madiyyah and Sidi Krir, respectively. The highest prevalence and salinity of 78.85% and 30-34 ppt were reported in El Matareya. DNA sequencing and molecular analysis confirmed the identification of L. redmanii. A. regius experimentally infected with L. redmanii under a hyposalination protocol at 15 and 8 ppt showed marked reduction in mortality (20 and 50%, respectively), and infection prevalence (40 and 63.33%, respectively). The serum lysozyme concentration and nitric oxide of treated fish at 15 and 8 ppt were significantly increased compared to those held at 25 and 33 ppt, whereas serum osmolality levels were higher at 25 and 33 ppt. To our knowledge, this is the first molecular characterization of L. redmanii in cultured A. regius in Egypt.

中文翻译：

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极少的Argyrosomus regius地区的Livoneca redmanii（等足目，蛾科）：寄生虫学和分子诊断及建议的控制措施。

摘要：根据流行率，寄生虫学检查以及通​​过针对rRNA基因16S核糖体亚基的PCR分子鉴定，整个2018年在埃及北部湖泊的3个农场中，对养殖的少量Argyrosomus regius的等生线虫进行了调查。此外，的易感性A. REGIUS到等足感染下的25，15 hyposalination进行了实验评价，和8个百分点为1周。形态学上鉴定为孤立的等足动物阶段，称为利沃尼卡·雷德曼尼·利奇（Livoneca redmanii Leach），1818年，在Al-Madiyyah和Sidi Krir中的患病率分别为77.05和77.9％。El Matareya的患病率和盐度最高，分别为78.85％和30-34 ppt。DNA测序和分子分析证实了L. redmanii。A. REGIUS实验感染L. redmanii一个hyposalination协议下，在15和8个百分点显示（分别为20和50％）的死亡率显着降低，和感染流行（分别为40和63.33％）。与保持在25和33 ppt时相比，处理过的鱼的血清溶菌酶浓度和一氧化氮浓度显着增加，分别为25和33 ppt，而血清渗透压浓度则更高，分别为25和33 ppt。据我们所知，这是第一个分子特征L. redmanii培养A. REGIUS在埃及。