Maciel Patricia Oliveira, Muniz Celli Rodrigues, Alves Rosiana Rodrigues
Empresa Brasileira de Pesquisa Agropecuária, Embrapa Pesca e Aquicultura, Postal Box 90, 77008-900, Palmas, TO, Brazil.
Empresa Brasileira de Pesquisa Agropecuária, Embrapa Agroindústria Tropical, Rodovia CE 253, Km 42, s/n - Zona Rural, Pacajus - CE, Brazil.
Vet Parasitol. 2017 Nov 30;247:57-63. doi: 10.1016/j.vetpar.2017.09.022. Epub 2017 Sep 28.
Within the production chain of the Arapaima gigas (pirarucu), sanitary issues are still faced at the fingerling phase regarding infestations by the monogenean Dawestrema cycloancistrium. The present study had the objectives of describing the morphology and development phases of this parasite's eggs and oncomiracidia and determining the hatching time and lifespan of the oncomiracidia at different temperatures. D. cycloancistrium eggs were oval and elongated and had a single long appendage at one pole. The egg development was divided into four phases: embryonated egg, developing egg, larva appearance and ecloded egg. They were found in four forms: isolated in gill filaments; grouped in clusters that were anchored in a gill filament; grouped in clusters and entangled in part of a dead adult monogenean; and grouped in clusters in the environment, fixed to a substrate. Eclosion occurred after 72-96h, with faster development at 29°C and 32°C than at 24°C. The morphology of the oncomiracidia were rounded and elongated. They had two pairs of pigmented eye-spots as well as two ciliated areas located on each lateral part of the body and another on the anterior part of the body. The lifespan of the D. cycloancistrium oncomiracidia were 50 and 58h at 24°C and 27°C, respectively. Larvae were found in the mucus, indicating that the oncomiracidia penetrated the host integument. Understanding reproductive aspects of the D. cycloancistrium monogenean is important for developing specific prophylactic management strategies in aquaculture and providing valuable data for further studies.
在巨骨舌鱼（巨滑舌鱼）的生产链中，在鱼种阶段仍面临卫生问题，即受到单殖吸虫环锚道氏吸虫的侵扰。本研究的目的是描述这种寄生虫的卵和纤毛幼虫的形态及发育阶段，并确定不同温度下纤毛幼虫的孵化时间和寿命。环锚道氏吸虫的卵呈椭圆形且细长，在一端有一个单一的长附属物。卵的发育分为四个阶段：胚胎卵、发育卵、幼虫出现和孵化卵。它们以四种形式被发现：孤立于鳃丝中；成簇聚集并锚定在一根鳃丝上；成簇聚集并缠绕在一只死亡的成年单殖吸虫的一部分上；以及在环境中聚集成簇并附着在基质上。孵化在72 - 96小时后发生，在29°C和32°C下的发育比在24°C下更快。纤毛幼虫的形态呈圆形且细长。它们有两对色素沉着的眼点，以及位于身体每一侧部分和身体前部的另外两个纤毛区域。环锚道氏吸虫纤毛幼虫在24°C和27°C下的寿命分别为50小时和58小时。在黏液中发现了幼虫，这表明纤毛幼虫穿透了宿主的体表。了解环锚道氏单殖吸虫的生殖方面对于制定水产养殖中的特定预防管理策略以及为进一步研究提供有价值的数据非常重要。
