Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627 412, India.
Environ Sci Pollut Res Int. 2020 Jul;27(19):23420-23436. doi: 10.1007/s11356-019-05957-7. Epub 2019 Jul 30.
Aeromonas hydrophila, an opportunistic fish pathogen, which causes several major diseases including skin ulcer and haemorrhagic septicemia, contributes considerably to the lethality in aquaculture. Chemical and antibiotic treatment employed against A. hydrophila for disease management are expensive and consequently prompted the advent of drug resistance among the pathogens. To overcome these draw backs, alternative aquatic disease control methods using conventional plant-based medicines are focussed. Our present study aimed to augment the fish non-specific immune system with the implementation of methanolic crude extracts of Andrographis paniculata to Labeo rohita, for evaluating their efficacy against A. hydrophila. Histology of major organs of A. hydrophila-infected fish such as the gills and liver displayed severe tissue damage. A. paniculata extracts exhibited the strong antibacterial activity against A. hydrophila even at lower concentrations (50 μl). The extracts also altered the haematological profile of treated infected fishes by increasing the levels of haemoglobin and total erythrocyte-leucocyte counts, along with the phagocytic index. The extracts also had a significant impact on modifying the anatomy and swimming pattern of infected fish, post treatment with the extracts. Also, A. paniculata treated infected fishes in all the plant extract administration methods, viz. injection, oral feeding and diffusion, and reduced the cumulative mortality rate to less than 30%. Even lower concentrations of A. paniculata extracts (50 μl) resulted in maximum relative percentage survival of treated fishes. Therefore, our findings suggest that A. paniculata was effective against A. hydrophila infection in aquaculture, thereby maintaining a healthy status of these fishes in aquaculture.
嗜水气单胞菌是一种机会性鱼类病原体，可引起多种主要疾病，包括皮肤溃疡和出血性败血症，对水产养殖的致死率有很大影响。用于治疗嗜水气单胞菌疾病的化学和抗生素治疗既昂贵又导致病原体产生耐药性。为了克服这些缺点，人们关注使用传统植物药来替代水产疾病控制方法。我们目前的研究旨在通过向罗非鱼施用穿心莲的甲醇粗提取物来增强鱼类的非特异性免疫系统，以评估其对嗜水气单胞菌的疗效。感染嗜水气单胞菌的鱼类的主要器官（如鳃和肝脏）的组织学显示出严重的组织损伤。穿心莲提取物即使在较低浓度（50 μl）下也表现出对嗜水气单胞菌的强抗菌活性。提取物还通过增加血红蛋白和总红细胞白细胞计数以及吞噬指数来改变受感染鱼类的血液学特征。提取物还对受感染鱼类的解剖结构和游泳模式产生了重大影响，在处理后。此外，穿心莲处理的受感染鱼类在所有植物提取物给药方法（注射、口服和扩散）中，cumulative mortality rate 都降低到 30%以下。即使是穿心莲提取物的较低浓度（50 μl）也导致了受处理鱼类的最大相对百分比存活率。因此，我们的研究结果表明，穿心莲对水产养殖中的嗜水气单胞菌感染有效，从而保持了这些鱼类在水产养殖中的健康状态。
