Alterations in the epidermis of the carp,Labeo rohita (Cyprinidae: Cypriniformes), infected by the bacteria,Aeromonas hydrophila: A scanning electron microscopic,histopathological and immunohistochemical investigation

This study was carried out to comprehend the pathogenicity of the bacteria in the epidermis of Labeo rohita inoculated with Aeromonas hydrophila. Alterations in the histopathology of the epidermis were examined using scanning electron microscopy, light microscopy and the localization of iNOS and caspase 3 + ve cells by means of immunohistochemical methods. Skin samples obtained from infected fish at different intervals 2, 4, 6, 8 and 10 days showed significant changes in the cellular components of the epidermis. Epithelial cells often appeared hypertrophied with fragmented and loosely arranged microridges, and in the process of exfoliation. Mucous goblet cells increased significantly in density. Club cells showed degenerative changes, often with simultaneous confluence of adjacent cells and release of their contents. Increase in density of iNOS and caspase 3 + ve cells indicates inflammatory response and apoptosis. This study could provide valuable information on the pathogenesis of the disease, and disease outbreaks in farmed fish. Further, it could provide useful guidelines for fish farmers to take preventive measures for the control of the disease.     

四川地区养殖鲫鲤疱疹病毒Ⅱ型的鉴定及病理学研究

为探究疾病病因和流行特点,对患病鲫进行剖检、病理学观察、分子生物学检测及人工感染实验。结果显示,患病鲫临床表现为离群独游、浮头、全身发黑及体表出血等。剖检发现鳃、肝脏、肾脏等器官出血、肿胀和坏死,鳔点状出血。组织病理观察显示,鳃呼吸上皮细胞肿胀、坏死及脱落;肾脏局灶性坏死;脾脏组织广泛变性坏死,造血系统崩解;肝脏发生空泡变性和坏死。透射电镜观察到脾脏和肾脏中存在4种大小不同的病毒颗粒,分别为DNA病毒内核、空衣壳、实心衣壳和有包膜的成熟病毒粒子。未成熟的病毒粒子存在于细胞核,成熟的病毒粒子存在于细胞质。电镜下可见鲤疱疹病毒Ⅱ型(CyHV-2)在细胞核内完成核酸复制和核衣壳装配,囊膜蛋白在出核后获得。细胞核萎缩、核染色质边缘化,线粒体肿胀、坏死、嵴断裂,细胞质空泡化。取患病鲫组织匀浆滤菌后接种到鲤上皮瘤细胞系(epithelioma papulosum cyprinid cell line,EPC)和胖头鲤肌肉细胞系(fathead minnow cell line, FHM),盲传3代后未见细胞病变。通过腹腔注射患病鲫组织匀浆进行人工感染实验,实验组鲫表现出与自然感染鲫相同的临床症状,对照组鲫正常,实验组累积死亡率为80%。用PCR方法检测CyHV-2的解旋酶基因片段,扩增出预期大小相符的目的条带。利用邻近法对该病毒的解旋酶基因进行系统发育分析,结果显示与CyHV-2(YZ-01)的同源性为99%。以上实验结果证实了CyHV-2是导致这次疾病暴发的原因。     

Gyrodactylus salmonis infection impairs the olfactory system of rainbow trout

Monogenean worms are ectoparasites that are known to be infectious to a wide variety of fish. Few species of monogenean parasites have been reported in the olfactory chamber of fish in current peer‐reviewed literature. However, the impacts of these parasites on the olfactory system are not well understood. In this study, the effects of Gyrodactylus salmonis on the olfactory system structure and performance were investigated in rainbow trout (Oncorhynchus mykiss). The olfactory performance of the infected fish was examined using an electro‐olfactography (EOG) technique, while the ultrastructure of the olfactory rosette was studied using scanning electron microscopy (SEM) and light microscopy (LM). The infected rainbow trout displayed reduced responses to two standard olfactory cues (L‐alanine and TCA). The SEM micrographs revealed that many regions of the olfactory epithelium in the infected fish were heavily pitted and the LM examination of the olfactory epithelium showed local proliferation of mucous cells in the sensory regions as compared to the control group. The results of this study demonstrated that G. salmonis causes physical damage to the olfactory system of fish that lead to olfactory impairment.     

舟山地区大棚凡纳滨对虾生长缓慢病因的调查分析

2013年以来,浙江省舟山地区大棚养殖的凡纳滨对虾(Penaeus vannamei)普遍出现生长缓慢、养殖成功率低的现象。为了查明该原因,本研究采用分子生物学和组织病理学等方法对引起对虾生长缓慢的病因开展了调查分析。结果显示,采集的270份病虾样本中,对虾肝肠胞虫(Enterocytozoon hepatopenaei,EHP)PCR阳性检出率高达85.19%,传染性皮下及造血器官坏死病毒(infectious hypodermal and hematopoietic necrosis virus,IHHNV)检出率为0;所有采集的病虾样本中也未分离到常见的致病菌;54份正常的对虾样本中EHP和IHHNV均未检出。将病虾PCR扩增产物进行序列测定和比对分析,结果获得的序列片段与Gen Bank中已有EHP相关序列相似性高达99.55%;病虾的肝胰腺组织病理切片观察显示,在虾肝胰腺组织中可观察到处于各个生长发育阶段的EHP。通过上述研究,初步认为EHP是引起舟山地区大棚养殖对虾生长缓慢的一个重要病原。     

The effect of dietary taurine on growth performance and liver histopathology in Persian sturgeon,Acipenser persicus (Borodin, 1897) fed plant‐based diet

This experiment was conducted to illustrate the effect of dietary taurine levels on Persian sturgeon, Acipenser persicus (mean weight of ~35 g) fed plant‐based diet. A basal diet containing low level of fishmeal (19%) was formulated containing 0.05% endogenous taurine (control diet). To this diet were added five levels of exogenous taurine: 0.25 (0.25T), 0.5 (0.5T), 0.8 (0.8T), 1.2 (1.2T) and 1.6% (1.6T). These diets were fed to the experimental fish for 42 days. Results showed that growth performance decreased and food conversion ratio increased as dietary taurine increased, although no significant difference was observed between the control and 0.25T treatments. Increased dietary taurine led to increased carcass moisture and decreased carcass lipid percentages. Feed intake was significantly and negatively correlated with dietary taurine. Carcass taurine content significantly increased with dietary taurine elevation up to 1.2% and then decreased. Hepatic taurine content showed a significant increase in 0.25T treatment and then decreased along with dietary taurine elevation and reached the control values at 1.6% taurine level. Dietary taurine elevation led to more hepatic damages compared to the control. In conclusion, although within the range reported for other studied fish, the tested taurine levels in this study might be supra‐optimal causing adverse effects in Persian sturgeon and further study with lower taurine levels is encouraged.     

Plasma proteins,hepatic enzymes,thyroid hormones and liver histopathology of Cyprinus carpio (Linnaeus, 1758) exposed to an oxadiazin pesticide,indoxacarb

Indoxacarb is a relatively new pesticide from oxadiazin class, which is used near carp ponds for agricultural purposes. Thus, the aim of this study was to determine indoxacarb effects on common carp (Cyprinus carpio). The fish were exposed to 0 (control), 0.75, 1.5 and 3 ppm of indoxacarb over 21 days and plasma biochemical characteristics and liver histopathology were examined. Exposure to indoxacarb induced fall in total protein after 21 days. Globulin increased after 7 days and then decreased after 14‐ and 21‐day exposure. Plasma alanine transaminase and aspartate transaminase activities increased in 1.5 and 3 ppm treatments after 7‐day exposure. Indoxacarb exposure significantly decreased plasma alkaline phosphatase after 7 days with no change at the second and third samplings. After 7 days, plasma T₃ levels had no significant change; however, it decreased after 14 days in the 1.5 and 3 ppm treatments and also reduced after 21‐day exposure to the 3 ppm treatment compared to the control group. Plasma T₄ level only decreased significantly in the 3 ppm treatment compared to the control group after 21 days. Different histopathological symptoms such as necrosis, hyperaemia, sinusoidal space extension, pyknotic nuclei, leucocyte infiltration and melanomacrophage aggregates were observed after 21‐day exposure to indoxacarb. The symptoms intensity was dependent on indoxacarb concentration. In conclusion, the present results show that indoxacarb exposure adversely affects common carp health and welfare, which consequently may induce serious problems in this species aquaculture.     

Effects of azithromycin on tilapia (Oreochromis niloticus): health status evaluation using biochemical,physiological and morphological biomarkers

Bacterial diseases cause tilapia's high‐mortality outbreak. This study investigated the toxicity of azithromycin (AZT), a macrolide antibiotic that has been considered a possible therapeutic drug for tilapia aquacultural use. The 48‐h acute toxicity (50% lethal concentration, LC50; 48 h) of AZT was determined for Oreochromis niloticus. Thereafter, fish were exposed to 0, 1, 50 and 100 mg L^?1 AZT during 14 days (chronic exposure) and measured the haematological variables, the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione‐S‐transferase (GST) and the concentration of glutathione (GSH), protein carbonyl and lipid peroxidation in the liver; histopathology was analysed the liver, gills and kidneys. The LC50; 48 h was >100 mg L^?1. No fish died during chronic exposure. Haematocrit and haemoglobin concentration increased in fish exposed to 50 and 100 mg L^?1, and the total number of leucocyte and thrombocyte increased after exposure to 100 mg L^?1 AZT, suggesting a stimulation of defence cell production. In the liver, the antioxidant enzyme activities did not change, but GST activity and the GSH level increased in fish exposed to 100 mg L^?1 AZT. Oxidative stress did not occur. Histopathological index (HI_L) indicates moderate liver damage; minor histological changes in the gill and no change in the kidneys. AZT was considered non‐toxic for O. niloticus after acute exposure and, although it causes moderated histopathology in the liver after chronic exposure, this antibiotic may be an alternative against bacterial infections, depending on its efficacy to control bacterial disease in fish.     

Cutaneous papilloma and multicentric squamous cell carcinoma in four-toed hedgehogs (Atelerix albiventris)

Skin lesions possibly caused by Papillomavirus infections in two four-toed hedgehogs are described. In case 1, there was a papillary mass on the right hind limb. Histologically, the mass was consistent with a viral papilloma. In the other case, multifocal papillary masses with erosions and ulcers were found throughout the body, mainly on the extremities. Histology showed continuative lesions composed of acanthosis, Bowenoid in situ carcinoma, and squamous cell carcinoma, with abrupt transitions between the lesions. In both cases, keratinocytes in the granular layer infrequently had features of koilocytes and intranuclear inclusion bodies, and immunohistochemical staining was positive for anti-human papillomavirus antibody. To the best of the authors’ knowledge, this is the first pathological documentation of possibly papillomavirus-associated skin lesions in four-toed hedgehogs.     

鸡IL-2重组杆状病毒的构建及其病理组织学研究

以鸡白细胞介素2(IL-2)为免疫刺激因子,探讨鸡IL-2重组杆状病毒(BV-LMI-IL-2)对鸡脏器的影响,为IL-2促进疫苗免疫的研究提供理论依据。以IL-2为目的基因,以p LMI为杆状病毒转移载体,构建BV-LMI-IL-2。最终使用BV-LMI-IL-2与新城疫(NDV)抗原疫苗BV-LMI-F进行单独免疫和联合免疫,观察鸡腺胃、肝脏、心脏、十二指肠等器官病理变化情况。免疫和攻毒试验结果显示:BV-LMI-F与BV-LMI-IL-2联合免疫时,保护率提高了12.5%,说明BV-LMI-IL-2对疫苗起到了免疫增强作用,可以作为免疫增强剂使用。对攻毒后的对照组死亡鸡只和免疫组死亡的鸡只剖检,观察病变器官和病理组织切片结果显示,联合免疫组器官无明显病理变化,证明鸡IL-2重组杆状病毒提高了对鸡脏器器官的免疫保护作用。     

关于阿维菌素对异育银鲫的急性毒性和组织病理研究

采用每24h换液式毒性试验法研究了不同浓度（0,01～2．56mg／L）的阿维菌素对异育银鲫Allogynogenetic cruciancarp的急性毒性,并对暴露在0（对照）、0．01、0．04mg／L阿维菌素溶液中养殖21d后异育银鲫的鳃、肾、肝、脾和脑组织器官的病理切片进行了观察。结果表明：阿维菌素对异育银鲫24、48、72h和96h LC50分别为0．21、0．14、0．08、0．06mg／L,安全浓度为0．019mg／L;对照组鱼元组织病理变化。0．01mg／L浓度组鱼只在鳃、肝脏和脾脏的部分细胞中出现颗粒变性或空泡变性轻度病理变化。0．04mg／L浓度组鱼出现严重的病理损伤：1）鳃小片尖端膨胀,基部上皮细胞脱落,部分鳃小片发生融合等;2）肾脏中肾小球充血,肾小管透明变性,部分肾小管上皮细胞核溶解消失;3）肝脏中肝细胞空泡变性,细胞核膜破裂、核仁溶解消失,病变严重的肝细胞坏死;4）脾脏中出现网状组织增生和铁血黄素沉淀;5）脑组织中神经细胞空泡变性,部分细胞核移位到边缘。