首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 797 毫秒
1.
Abstract. Up to 88-9% of five-bearded rocklings, Ciliata mustela L., from three localities in Wales harboured the coelozoic myxozoan parasite Zschokkella russelli Tripathi. Previously recorded only from the gall-bladder of British rocklings, Z. russelli was also found to produce proliferation, enlargement and thickening of hepatic ducts, lowering of the duct epithelium and pericholangitis. Histological, scanning and transmission electron microscopy techniques were used to examine the parasite, and comparisons were drawn between Z. russelli from Welsh fish and infections recorded elsewhere, particularly from Plymouth, Devon.  相似文献   

2.
Two new species of myxozoans from the Japanese anglerfish, Lophius litulon, are described using myxospore morphology and small subunit rDNA sequences. Ceratomyxa anko sp. n. is a parasite of the gall bladder and had a prevalence of 57%. Mature spores of C. anko sp. n. are arcuate to crescent shaped with valves tapering to rounded tips. A prominent sutural line runs centrally between the round adjacent polar capsules containing the polar filament coiled two to three times. Spore measurements: length 10.8 (9.7-11.9) microm, width 41.9 (36.9-47.2) microm, polar capsule diameter 4.6 (4.1-5.3) microm. Ceratomyxa anko sp. n. can be distinguished from other Ceratomyxa spp. due to its spore dimensions and shape. Zschokkella lophii sp. n. is a parasite of the urinary bladder and had a prevalence of 70%. Mature spores are ellipsoidal to semicircular with bluntly pointed ends. The sutural line is curved or sinuous and the valves have no discernable surface ornamentation. Two almost spherical polar capsules are located separately in the ends of the spore, opening in almost opposite directions and contain the polar filament with five coils. Spore measurements: length 20.1 (16.8-24.0) microm, width 14.9 (12.7-16.8) microm, polar capsule diameter 5.1 (3.6-5.8) microm. Zschokkella lophii sp. n. can be distinguished from other Zschokkella spp. due to the terminal opening of the polar capsules within the spores and the site of infection within the host fish. In the phylogenetic analyses, C. anko sp. n. grouped with other members of the same genus forming a monophyly. Zschokkella lophii sp. n. forms a discrete clade with another Zschokkella sp. that infects the urinary bladder of marine fish. This grouping forms a sister clade to one containing members of the genus Parvicapsula, all of which are parasites of the urinary system in marine fish.  相似文献   

3.
Zebrafish were exposed to the wood extractive betulinol (5 microg L(-1)) and to 17beta-oestradiol (E2, 0.27 microg L(-1)) for 8 weeks in an attempt to study the possible endocrine-disrupting activity of betulinol. Females exposed to betulinol showed increased spawning intensity, while males exposed to betulinol and E2 had increased incidences of structural alterations in the testes. However, histological examination of the fish revealed that they were infected by acid-fast bacteria suspected to be Mycobacterium sp. despite a careful examination of their health state prior to the onset of the experiment. Fish exposed to betulinol and E2 showed more serious consequences of the bacterial infection than control fish indicating that the test chemicals had weakened the immune defence of the fish. When the exposure was repeated with healthy fish, an increase in the proportion of spermatogonia was seen in the testes of betulinol-treated males. A similar alteration, although not statistically significant, was also seen in the first experiment. However, no increase in the incidences of structural alterations in the testes was seen in betulinol- and E2-treated fish in the second experiment. Our study indicates that betulinol might have an endocrine-disrupting effect in zebrafish, but the increase in incidences of structural alterations in the testes might have been caused by a synergistic action between the test compounds and the bacterial infection. Our study stresses the importance of carefully checking the health of experimental fish, not only prior to the onset of an experiment but also upon termination of the experiment, in order to avoid misinterpretation of the results.  相似文献   

4.
Sub-adults of silver pomfret (Pampus argenteus), produced and reared in the mariculture experimentation facilities of Mariculture and Fisheries Department of Kuwait Institute for Scientific Research (KISR), suffered 55–70% mortalities due to scuticociliatosis by Uronema sp. The parasitic infestation was noticed during April–May 2005. Affected fish showed varying levels of tissue damage including severe epidermal and dermal necrotic lesions. The disease occurred with the raise in water temperature from 20 to 22 °C during April. Loss of scales, appearance of bleached spots that coalesced to form brownish patches, haemorrhagic and severe dermal necrotic lesions were the major clinico-pathological manifestations. The parasite was found abundantly in the blood, peritoneal fluid and the cerebrospinal fluid, the skin and the gill wet mounts. Extensive fouling, necrotic degeneration of the gill epithelium and deep dermal necrosis resulted in mortality of the infected fish. The parasite was noticed in the lumen of the collecting ducts of the kidney and the alimentary canal. The parasite was also seen distributed extensively in the entire brain causing widespread nerve necrosis. Earliest separation of the clinically normal fish from the affected fish resulted in significantly higher survival. The investigations are of significant importance in view of the mariculture potentials of the fish especially after the success of captive spawning and larval rearing achieved by the KISR.  相似文献   

5.
利用组织切片、HE染色和显微观察的方法,研究了卵形鲳鲹患刺激隐核虫病组织病理变化。组织切片结果可见,感染鱼的鳃和体表受到直接机械损伤;鱼体在缺氧状态下,入侵的刺激隐核虫有可能对机体产生某种毒素,也可能因刺激隐核虫感染而引发细菌或病毒继发性感染,造成肝、脾和肾脏不同程度的间接性损伤。表现为鳃部机能严重受阻,肝脏脂肪肝变性严重,肝索紊乱,血窦缩小或消失;脾脏组织结构不清晰,有充血、出血和坏死等症状;肾脏结构不清晰,肾小管及肾小体缩小,肾小管细胞融合(黏连),组织间隙松散扩大,局部细胞坏死,存在脂肪粒。  相似文献   

6.
Abstract. A viral agent (13p2), isolated from clinically normal juvenile American oysters ( Crassostrea virginica ) and characterized as a new serotype of reovirus, was tested to determine if it could replicate and produce disease in experimental juvenile oysters. Because the virus replicated well in the bluegill fry (BF-2) fish cell line, fingerling bluegills Lepomis macrochirus were included in the pathogenicity experiments. Exposure of oysters to the 13p2 virus in ambient seawater resulted in no significant mortality and no increased virus titres or histological lesions. Virus particles were not observed in tissues of exposed oysters when examined with transmission electron microscopy (TEM). Intraperitoneal inoculation of the 13p2 virus into bluegills resulted in 44% mortality associated with a focal necrotic hepatitis. Evidence of virus replication, when evaluated histological or by virus titration, was observed in 94% of 32 inoculated fish. Samples of infected livers examined with TEM revealed typical cytoplasmic arrays of 13p2 virus particles in affected hepatocytes. Rising virus titres and hepatic lesions also occurred in bluegills exposed to water containing the 13p2 virus. These results indicated the natural host of the 13p2 virus was not the American oyster, but that it was a significant pathogen for at least one fish species.  相似文献   

7.
Arctic charr ( Salvelinus alpinus L.) were fed diets based on a commercial recipe supplemented with either linseed, soybean or marine oil prior to cohabitant challenge with Aeromonas salmonicida ssp. s almonicida . Mortality varied significantly between the three dietary groups. Highest mortality (48%) was observed in fish fed the marine oil and the lowest mortality (20%) was in the group fed soybean oil. Transmission electron microscopy (TEM) examination of the digestive tract of uninfected fish demonstrated substantial numbers of bacterial cells between microvilli. However, only a few bacteria were recovered that were associated with the microvilli of infected fish. Immunocytochemical staining/labelling investigations using TEM and an immunogold method were performed on mid-gut segments of fish fed the marine oil diet and showed augmentation of goblet cells and the presence of A. salmonicida ssp. salmonicida in the gastrointestinal tract of diseased fish after challenge with the pathogen. It is suggested that the gastrointestinal tract could be an infection route of A. salmonicida ssp. salmonicida. The greater prevalence of goblet cells supports the suggestion that sloughing off mucus is a protective response against bacterial infections. These results make an important contribution to our understanding of how nutrition can affect the disease resistance of fish.  相似文献   

8.
为探讨饲料中添加不同小麦淀粉和脂肪水平对大黄鱼幼鱼生长、饲料利用以及糖代谢关键酶活力的影响,进行了为期8周的生长实验。设计了3个小麦淀粉水平(5%、10%和30%)和2个脂肪水平(5%和10%)的3×2的两因子实验,配制了6种等氮的饲料,分别喂养平均体质量为(6.75±0.12)g的大黄鱼幼鱼。结果显示,饲料中小麦淀粉和脂肪水平对大黄鱼增重率(WG)、特定生长率(SGR)、饲料效率(FE)、成活率(SR)、肝体比(HSI)和肥满度(CF)无显著交互作用,对脏体比(VSI)有显著交互作用。在同一脂肪水平下,淀粉水平为30%组WG和SGR显著高于10%淀粉组。不同小麦淀粉和脂肪水平对肝糖原含量无显著交互作用,而对肌糖原含量有显著交互作用,在饲料脂肪水平为5%时,30%小麦淀粉水平下的肝糖原含量显著高于10%和20%淀粉水平,10%淀粉水平下的肌糖原含量显著高于20%和30%淀粉水平;在脂肪水平为10%时,10%淀粉水平下的肝糖原含量显著高于20%和30%淀粉水平,而30%小麦淀粉水平下的肌糖原含量显著高于10%和20%淀粉水平。小麦淀粉和脂肪水平对血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)、总胆固醇(TC)和葡萄糖(GLU)含量无显著交互作用,对总蛋白(TP)和甘油三酯(TG)交互作用显著。不同小麦淀粉和脂肪水平对肝脏脂肪酶活性有显著的交互作用,对淀粉酶活性无显著交互作用;同一脂肪水平下,脂肪酶的活性随着淀粉水平的升高而升高,同一饲料淀粉水平下,饲料脂肪水平为10%组的脂肪酶活性显著高于5%组。不同小麦淀粉和脂肪水平对肝脏丙酮酸激酶(PK)的活性有显著的交互作用,而对葡萄糖激酶(GK)、磷酸果糖激酶(PFK)、磷酸烯醇式丙酮酸羧激酶(PEPCK)、1,6-二磷酸果糖酶(FBPase)和6-磷酸葡萄糖酶(G6Pase)的活性均无显著交互作用。研究表明,当饲料脂肪水平为5%时,大黄鱼能够通过调节糖酵解关键酶活性及肝糖原含量来维持血糖平衡,改善对小麦淀粉的利用能力;而当脂肪水平为10%时,大黄鱼对小麦淀粉的利用能力降低。  相似文献   

9.
Abstract. Laboratory-raised Cryptobia -susceptible brook charr, Salvelinus fontinalis (Mitchill), and rainbow trout, Oncorhynchus mykiss (Walbaum), were vaccinated intraperitoneally with a live Cryptobia salmositica vaccine (250000 parasites per fish), and 4 weeks later were challenged with the pathogen (250000 parasites per fish). Unvaccinated and infected brook charr had high parasitaemias but no clinical signs of disease, while unvaccinated and infected rainbow trout had anaemia and general oedema. Vaccinated and challenged fish had very low parasitaemias compared to unvaccinated and infected brook charr and rainbow trout. Complement fixing antibodies were detected in vaccinated and challenged fish 2 weeks after challenge. Unvaccinated and infected brook charr had consistently higher litres of complement fixing antibody than unvaccinated and infected rainbow trout. Parasitaemias were lower in all fish in which titres of complement fixing antibody were high. In a second experiment, brook charr inoculated intraperitoneally or intramuscularly with 100000 C. salmositica per fish had high parasitaemias but no anaemia or other clinical signs. The results show that susceptible brook charr do not suffer from cryptobiosis and may serve as reservoir hosts for C. salmositica in areas where the disease is prevalent. Vaccination to reduce the parasitaemia when fish become infected may be a control strategy in these areas.  相似文献   

10.
Atlantic salmon fingerlings were fed a vitamin C deficient diet for four months. The fish were then provided a dry, practical fishmeal based diet supplemented with 0, 500 or 5000 mg vitamin C/kg as L-ascorbic acid or equivalent amounts of ascorbate-2-sulfate. After six weeks on these diets ten fish in each group were injected with a soluble antigen (NIP11-LPH). Six weeks thereafter blood, liver, kidney, spleen and vertebrae were examined for trace elements. The livers were also analysed for metallothionein. The vitamin C deficient fish were anemic despite the significantly elevated iron concentrations in the liver. Vitamin C had no positive effect in lowering tissue levels of cadmium. The highest level of dietary vitamin C given as ascorbic acid reduced the liver selenium concentrations. In response to antigen injection, the fish in all groups showed increased levels of hepatic metallothionein, copper, zinc and cadmium, while hepatic selenium and iron levels were less affected. The elemental composition in other organs was affected by the antigen injection to a minor extent.  相似文献   

11.
方卫东  鲁康乐  张春晓  王玲  冯伟  骆源 《水产学报》2016,40(11):1742-1752
为减少牛蛙饲料鱼粉使用量以降低养殖成本,研究了豆粕替代饲料中不同比例的鱼粉对牛蛙的生长性能、体组成、肠道消化酶活力和肝脏生化指标的影响。用豆粕分别替代0%、20%、40%、60%、80%和100%的鱼粉配制出6种等氮等能的实验饲料,每组饲料设3重复,养殖牛蛙60 d。结果显示,豆粕替代鱼粉对牛蛙摄食率、成活率、肝体指数、脏体指数、蛙体水分和灰分含量、蛙腿肌肉组成以及肝脏丙二醛含量的影响不显著;豆粕100%替代鱼粉显著降低牛蛙增重率、特定生长率、饲料系数、蛋白质效率、蛋白质累积率;随豆粕替代鱼粉比例的提高,牛蛙的肥满度和后腿指数呈下降趋势,替代100%鱼粉显著降低牛蛙肥满度,替代60%鱼粉显著降低牛蛙后腿指数;替代80%鱼粉显著降低牛蛙全体粗蛋白的含量;牛蛙全体粗脂肪含量随替代鱼粉比例的提高呈上升的趋势,替代100%鱼粉组粗脂肪含量最高;随着替代比例的提高,牛蛙肠道蛋白酶的活力显著降低,而肠道淀粉酶和脂肪酶活力显著提高。豆粕替代鱼粉显著影响肝脏超氧化物歧化酶和过氧化氢酶活力,其中超氧化物歧化酶活力最低值出现在替代80%鱼粉组,过氧化氢酶活力最低值出现在替代100%鱼粉组。基于以上实验结果,建议牛蛙饲料中豆粕可替代鱼粉的比例为60%~80%。  相似文献   

12.
The purpose of this study was to investigate the nature of variably sized pigmented foci encountered in fillets of farmed Atlantic salmon, Salmo salar L. The material was sampled on the fillet production line and on salmon farms from fish with an average size of 3 kg from various producers. The fish had been routinely vaccinated by injection. Gross pathology, histology, immunohistochemistry using antisera against major histocompatibility complex (MHC) class II beta chain and transmission electron microscopy (TEM) were used to characterize the changes. Macroscopically, melanized foci were seen penetrating from the peritoneum deep into the abdominal wall, sometimes right through to the skin, and also embedded in the caudal musculature. Histological investigation revealed muscle degeneration and necrosis, fibrosis and granulomatous inflammation containing varying numbers of melano-macrophages. Vacuoles, either empty or containing heterogeneous material, were frequently seen. The presence of abundant MHC class II+ cells indicated an active inflammatory condition. TEM showed large extracellular vacuoles and leucocytes containing homogeneous material of lipid-like appearance. The results showed that the melanized foci in Atlantic salmon fillet resulted from an inflammatory condition probably induced by vaccination. The described condition is not known in wild salmon and in farmed salmon where injection vaccination is not applied.  相似文献   

13.
Mycobacteria are significant pathogens of laboratory zebrafish, Danio rerio (Hamilton). Stress is often implicated in clinical disease and morbidity associated with mycobacterial infections but has yet to be examined with zebrafish. The aim of this study was to examine the effects of husbandry stressors on zebrafish infected with mycobacteria. Adult zebrafish were exposed to Mycobacterium marinum or Mycobacterium chelonae , two species that have been associated with disease in zebrafish. Infected fish and controls were then subjected to chronic crowding and handling stressors and examined over an 8-week period. Whole-body cortisol was significantly elevated in stressed fish compared to non-stressed fish. Fish infected with M. marinum ATCC 927 and subjected to husbandry stressors had 14% cumulative mortality while no mortality occurred among infected fish not subjected to husbandry stressors. Stressed fish, infected with M. chelonae H1E2 from zebrafish, were 15-fold more likely to be infected than non-stressed fish at week 8 post-injection. Sub-acute, diffuse infections were more common among stressed fish infected with M. marinum or M. chelonae than non-stressed fish. This is the first study to demonstrate an effect of stress and elevated cortisol on the morbidity, prevalence, clinical disease and histological presentation associated with mycobacterial infections in zebrafish. Minimizing husbandry stress may be effective at reducing the severity of outbreaks of clinical mycobacteriosis in zebrafish facilities.  相似文献   

14.
Infectious Lepeophtheirus salmonis (Krøyer) cause localized inflammation at the site of attachment on the host fish, while the greatest physiological impact occurs with the development of the subadult and adult stages. We exposed Oncorhynchus mykiss (Walbaum) to infectious copepods at 30, 25 and 14 days prior to a net confinement procedure, while a second group were sham infected. Fish were sampled at time zero, 2, 4, and 6 h of continuous net confinement, and at 24 h after 2 h confinement. Plasma Na+, Cl–, gill Na+/K+‐ATPase activity and skin mucous cell numbers were measured, and skin and gill condition assessed microscopically. Exposure to copepods resulted in lower numbers of acidophilic mucous cells and poor condition of the skin and gill epithelia. Total numbers of mucous cells were decreased in net confined infected fish only. Plasma Na+ was elevated in all samples from non‐infected netted fish, without altered gill Na+/K+‐ATPase activity, while infected fish had higher plasma Na+ only at 2 h and increased gill ATPase activity at 4 h. The epithelia of infected fish were more severely affected by the confinement procedure. Exposure to juvenile lice can induce effects that become apparent only when a stressor is applied.  相似文献   

15.
Abstract. A histopathological study was carried out on rainbow trout suffering from acute and chronic diplostomiasis. Clinical signs were few in acutely infected fish but in chronic cases fish were blind, exophthalmic and emaciated. Acute infections resulted in subcapsular cataract formation with varying capsular change. Chronically infected fish frequently showed lens dislocation, capsular rupture or duplication and the formation of Elschnig's pearls and Wedl cells. Phacogenic uveitis was seen in many fish with capsular rupture and retinal detachment frequently occurred as a sequal to vitreous detachment.  相似文献   

16.
Fish which survive a sublethal ichthyophthiriasis acquire protective immunity against Ichthyophthirius multifiliis Fouquet (Ich). This study evaluated the protective effect of cutaneous antibody secreted by channel catfish, Ictalurus punctatus (Rafinesque), immune to Ich on cohabited non-immune catfish. Non-immune and immune fish controls were separately maintained and infected with theronts. The Ich infection was assessed by scoring 0, < 50, 50-100, and > 100 trophonts fish(-1) at 5 days post-infection. The results of infection showed that cohabited fish at the ratio of 15 non-immune to two immune fish had < 50 trophonts fish(-1). Eighty per cent of the cohabited fish at the ratio of 10 non-immune to two immune fish showed 0 or < 50 trophonts fish(-1). The 76% of control non-immune fish had more than 100 trophonts fish(-1). The control immune fish had 0 trophonts fish(-1). Anti-Ich antibody was detected using enzyme-linked immunosorbent assay in water samples taken from tanks containing immune fish after the water samples were concentrated 40-fold. The study suggests that immune fish cohabited with non-immune fish may protect non-immune fish against Ich infection.  相似文献   

17.
An 8-week feeding trial was conducted to evaluate the effect of dietary carbohydrate sources on the growth performance and hepatic carbohydrate metabolic enzyme activities of juvenile cobia. Six experimental diets were formulated to contain 20% glucose, sucrose, maltose, dextrin, corn starch and wheat starch respectively. The results indicated that fish fed the wheat starch and dextrin diets showed significantly better weight gain, specific growth rate and protein efficiency ratio compared with those fed the other diets. However, fish fed the glucose diet had a significantly lower survival and condition factor than those fed the other diets. There were significant differences in the total plasma glucose and triglyceride concentration in fish fed diets with different dietary carbohydrate sources. Haematocrit, haemoglobin, red blood cell and leucocytes were significantly affected by the dietary carbohydrate sources. The activities of glucose-6-phosphate dehydrogenase (G6PD), 6-phosphofructokinase (PFK) and fructose-1,6-bisphosphatase (FBPase) were significantly affected by the dietary carbohydrate sources, while fish fed the glucose diet showed higher G6PD, PFK and FBPase activities than those fed the other diets. These data indicated that dextrin and wheat starch were the most optimal carbohydrate sources for juvenile cobia.  相似文献   

18.
驼背鲈肝脏结构的光镜和透射电镜观察   总被引：1，自引：0，他引：1  
采用HE、Mallory氏三色法、Heidenhain氏Azan染色,PAS反应,组织块银浸染方法,对组织切片染色处理,应用光学显微镜和透射电镜对驼背鲈肝脏的显微和超微结构进行了观察,结果表明驼背鲈肝组织中肝细胞界限不明显,不存在双核现象,有暗细胞和亮细胞之分,胞质中细胞器丰富,有大量的线粒体、内质网和溶酶体,高尔基体很难观察到,仅在胆小管和狄氏间隙的附近发现。此外,在肝血窦的附近观察到成纤维细胞、枯否氏细胞和贮脂细胞。肝组织中胆管数量众多包括肝叶中央胆管、支胆管、小叶间胆管和小叶内胆管,并且在中央静脉附近偶见辐射状排列的肝细胞索。  相似文献   

19.
Atlantic Salmon, Salmo salar L., experimentally infected with marine Eubothrium sp. were kept together with uninfected salmon in the laboratory for 11 months in two tanks, 80 infected and 80 uninfected in each tank. The infected fish had a reduced growth rate compared with the uninfected fish. Significant differences in growth between infected and uninfected fish were not observed until several months post-infection. There was no correlation between the number of Eubothrium sp. and fish weight, indicating that even low intensity alters the growth rate of the salmon. The cestode had the same effect on both sexes of salmon. Haematocrit level was found to be significantly lower in infected compared with uninfected salmon in one of the samples during the experiment.  相似文献   

20.
4-Nonylphenol (NP) toxicity in fish attracts much attention due to its ability in targeting several organs; however, the researches regarding its potential hepatotoxicity are conflicting and still require further investigation. Therefore, the objective of this study is to focus on this issue from the histophysiological point of view using NP intoxicated African catfish (Clarias gariepinus) as a model of hepatotoxicity. Twelve adult fish (6 per group) were divided into two groups; the first was considered as a control and the second was exposed to NP dissolved in water at a dose of 0.1 mg/kg BW for 3 weeks. A significant reduction in the hepatic alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase levels was observed in NP-exposed fish. Concerning the oxidant/antioxidant balance, a significant depletion in superoxide dismutase, catalase, and glutathione peroxidase was found along with a significant elevation in total peroxide and malondialdhyde. The histopathological examination of the hepatic tissues revealed that NP had marked hepatotoxic effects including hepatitis, centrilobular and focal hydropic and fatty degeneration, fatty change (steatosis), hepatic coagulative necrosis, and nuclear alterations in addition to apoptosis of hepatocytes and necrosis of endothelial cells. Depletion of the glycogen and increased in pigments (lipofuscin and hemosiderin) content in the hepatocytes were also recorded. Hemosiderosis and proliferation of the connective tissue around the blood vessels and branches of bile ducts and in the portal areas were also observed. In light of these findings, it was concluded that NP has a well-defined hepatotoxic impact paving the road towards other studies to investigate other detrimental cyto-physiological influences of this aquatic pollutant.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号