Department of Morphology, Veterinary Faculty, University of Las Palmas de Gran Canaria, 35413 Arucas (Las Palmas), Spain.
Dis Aquat Organ. 2022 Sep 1;151:23-27. doi: 10.3354/dao03686.
Intensive breeding of the Siamese fighting fish Betta splendens, a species that inhabits marshlands in Thailand and other countries in south-east Asia, was traditionally focused on game fighting because the males are very territorial, but has evolved to become mainly devoted to ornamental purposes. Recently, a preliminarily named 'skin nodule syndrome' (SNS) has been described affecting this fish species in Thailand, with multiple bacterial infections suggested, including 4 species of Mycobacterium spp., although the etiology remains elusive. Here we describe the histopathological and immunohistochemical characteristics of 2 iridophoromas in 2 male Siamese fighting fish that strongly resemble the lesions described for SNS. Immunohistochemical analysis yielded negative results for Melan-A, PNL-2, and S-100, likely due to species-specific reasons. The results for molecular detection of mycobacterial DNA were also negative in both cases. The published histological lesions of SNS are very similar to the 4 chromatophoromas that have been reported affecting this species since 2015. Taken together with the present cases, we hypothesize that the preliminarily named SNS in fighting fish may be characterized as invasive chromatophoromas, although the true etiology remains to be elucidated and could include infectious and non-infectious causes. Further studies are necessary to examine whether commercial breeding of Siamese fighting fish has resulted in a possible genetic origin.
暹罗斗鱼（Betta splendens）的集约化养殖传统上侧重于游戏性打斗，因为雄性斗鱼具有很强的领地意识，但现已演变为主要用于观赏目的。最近，在泰国描述了一种初步命名为“皮肤结节综合征（SNS）”的疾病，该疾病影响到这种鱼类，提示存在多种细菌感染，包括 4 种分枝杆菌属（Mycobacterium spp.），尽管病因仍不清楚。在这里，我们描述了 2 条雄性暹罗斗鱼的 2 个虹彩瘤的组织病理学和免疫组织化学特征，这些特征与描述的 SNS 病变非常相似。免疫组织化学分析对黑色素瘤-A（Melan-A）、PNL-2 和 S-100 的结果为阴性，这可能是由于物种特异性的原因。在这两种情况下，对分枝杆菌 DNA 的分子检测结果也为阴性。已发表的 SNS 的组织学病变与自 2015 年以来报道的影响该物种的 4 个色素细胞瘤非常相似。综合这两种情况，我们假设暂定命名为 SNS 的暹罗斗鱼可能具有侵袭性色素细胞瘤的特征，尽管真正的病因仍有待阐明，可能包括传染性和非传染性病因。需要进一步的研究来检查暹罗斗鱼的商业养殖是否导致了可能的遗传起源。
