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1.
D. J. SPEARE H. W. FERGUSON F. W. M. BEAMISH J. A. YAGER S. YAMASHIRO 《Journal of fish diseases》1991,14(1):1-20
Abstract. The range of branchial lesions associated with bacterial gill disease (BGD) in rainbow trout, Oncorhynchus mykiss (Richardson), was investigated through the ultrastructural examination of 23 separate outbreaks of the disease condition within commercially reared stocks. Diseased branchial tissues had a large and diffusely distributed monomorphic population of filamentous bacteria which were strictly epicellular. Although bacterial colonization was restricted to the branchial cavity, it was neither site nor cell specific: epithelial and chloride cells of the lamellae, filaments and lining tissues of the branchial cavity were all uniformly affected. The bacteria possessed an extensive glycocalyx which appeared to facilitate adhesion to the apices of the microridged sub-unit modifications of the cell surface. Sites of colonization were accompanied by a diffuse pattern of cellular degeneration and necrosis that was generally restricted to the outer layers of epithelium. The polarity and nature of these changes suggest that the mechanism of interaction between the bacteria and host cells includes progressive hydropic change as a sequel to primary membrane damage and consequent increased cell permeability. These cellular changes were accompanied by the range of stereotypical responses of the gill to damage frequently reported for BGD including lamellar fusion, epithelial hyperplasia, and squamous and mucous cell metaplasia, in addition to lamellar spongiosis. 相似文献
2.
Abstract. An outbreak of proliferative gill disease occurred in a group of rainbow trout fingerlings. kept for experimental purposes. Lesions were multifocal among filaments and uniquely severe in the distal region of affected filaments, forming nodules; this contrasted with the more common forms of proliferative gill disease in Ontario, such as bacterial gill disease, in which lesions are diffuse along and among filaments. The cause of the condition is unknown, although cells with a very distinctive morphology were closely associated with the lesions. 相似文献
3.
Gills of Atlantic salmon, Salmo salar L., with amoebic gill disease (AGD), were analysed by routine histology to identify lesion morphology and distribution patterns. Numbers of lesions occurring dorsally, medially and ventrally in the gill filaments were recorded as was lesion size, proximity to the gill arch and the degree of pathological severity involved. The mean number of lesions and pathological severity in the dorsal region of the second left gill arch were significantly higher than that found ventrally ( P < 0.01). There were no significant differences between gill regions in lesion size or proximity of lesions to the gill arch. Serially sectioned lesions revealed interlamellar cysts to be spherical to ovate in shape and fully enclosed within a wall of epithelium. Small to medium size cysts sometimes contained necrotic amoebae. Inflammatory cells, morphologically identified as neutrophils and macrophages, were occasionally seen infiltrating medium sized cysts. Larger cysts were mostly clear of any cellular debris. 相似文献
4.
Generation of Paramoeba perurans clonal cultures using flow cytometry and confirmation of virulence 
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下载免费PDF全文 C Collins M Hall D Bruno J Sokolowska L Duncan R Yuecel U McCarthy M J Fordyce C C Pert R McIntosh Z MacKay 《Journal of fish diseases》2017,40(3):351-365
Amoebic gill disease (AGD) in farmed Atlantic salmon is caused by the amoeba Paramoeba perurans. The recent establishment of in vitro culture techniques for P. perurans has provided a valuable tool for studying the parasite in detail. In this study, flow cytometry was used to generate clonal cultures from single‐sorted amoeba, and these were used to successfully establish AGD in experimental Atlantic salmon. The clonal cultures displayed differences in virulence, based on gill scores. The P. perurans load on gills, determined by qPCR analysis, showed a positive relationship with gill score, and with clonal virulence, indicating that the ability of amoebae to proliferate and/or remain attached on gills may play a role in virulence. Gill scores based on gross signs and histopathological analysis were in agreement. No association between level of gill score and specific gill arch was observed. It was found that for fish with lower gill scores based on histopathological examination, gross examination and qPCR analysis of gills from the same fish were less successful in detecting lesions and amoebae, respectively. 相似文献
5.
对苏氏Mang鲶鳃结构进行扫描和透射电镜观察。Mang鲶鳃丝末端膨大呈杓状结构，每一鳃丝两侧具有许多呈褶状的鳃小片，相邻两鳃丝上的鳃小片紧密镶嵌排列。鳃弓和鳃耙表面分布众多味蕾。鳃丝呼吸面上皮细胞薄，高度血管化，形成呼吸面隆起，非呼吸面由微脊细胞彼此相连，间缝具分泌细胞开口。鳃小片由单层或数层外上皮细胞和由基膜相隔的柱状细胞及其围在血管腔的凸缘构成，氯细胞多分布在鳃小片基部，并有开口通外，还探讨了Mang鲶鳃丝和鳃小片特殊的结构与功能。 相似文献
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A study of microfauna, associated with pathological changes in the gills of Atlantic salmon, Salmo salar L., was conducted over 2001-2002. Monthly samples of 1(+) salmon smolts were taken, protozoan populations were quantified and gill health was assessed histologically. Protozoan densities were correlated with pathological changes, in order to determine their possible role in lesions in the gills. The most severe gill tissue changes were observed in summer/autumn and the least in spring. A diverse polyphyletic protozoan community was observed colonizing the gills, including Neoparamoeba sp., other amoebae, scuticociliates, Ichthyobodo-like flagellates, trichodinid ciliates and prostomatean ciliates. The earlier gill tissue changes in the gill were not always associated with the presence of these microorganisms, whereas amoebae (other than Neoparamoeba sp.), Ichthyobodo-like flagellates and trichodinid ciliates correlated with augmenting gill lesions. Neoparamoeba sp. was present, but its abundance did not correlate with the disease. This study suggests that a diversity of protozoans including Ichthyobodo-like flagellates, trichodinid ciliates and amoebae other than Neoparamoeba sp. are involved in the aetiology of amoebic gill disease in the Irish situation. 相似文献
8.
N.Harold Richman III Susan Tai de Diaz Richard S. Nishioka Patrick Prunet Howard A. Bern 《Aquaculture (Amsterdam, Netherlands)》1987,60(3-4):265-285
Chloride cell morphology and density in the gill and opercular membrane of coho salmon (Oncorhynehus kisutch) were examined during the 1982 and 1983 smolt-seasons for structural correlates to smoltification-associated changes in hypoosmoregulatory ability and plasma hormone levels. Although not synchronous in the two years, plasma thyroxine levels displayed two peaks each year. In 1982, changes in gill Na+,K+-ATPase activity were preceded by elevations in plasma thyroxine. In 1983, the increase in enzyme activity corresponded with the April increases in plasma thyroxine and prolactin. Seawater (SW) acclimation experiments showed discrete increases in SW tolerance which coincided with changes in gill enzyme activity. Although these data suggest a relationship between SW tolerance and plasma thyroxine levels, the patterns in the two years were different. A significant peak in plasma prolactin levels in April suggests possible involvement in the parr-smolt transformation.
Chloride cells were studied in the opercular membrane, a chloride cell-containing epithelium lining the branchial side of the operculum, and the gill epithelium. Opercular membrane chloride cells (1982), marked with a mitochondrion-specific fluorescent stain, increased nearly two-fold in late May, concurrent with the second increase in gill Na+,K+-ATPase activity and SW tolerance. Gill morphology was examined (1983) with scanning and transmission electron microscopy and light microscopy. Initially, the gill filament surface appeared rough but became smoother during smoltification and rough again toward the end of smoltification. Two mitochondrion-rich (chloride) cell types were present in the gill epithelium during smoltification. The electron-lucent type I cell contained large, circular mitochondria while the electron-dense type II cell contained thin, elongate mitochondria. Ultrastructurally, many type I cells appeared disrupted which may indicate cellular degeneration or a special response of type I cells to fixation. However, it was unusual to find either intact or disrupted type I cells after March. Chloride cell density (type I plus type II) remained constant during smoltification. The inability to distinguish between these cell types with the light microscope may have obscured changes in their individual densities. The data from both the opercular membrane and the gill epithelium and their relationship with gill Na+,K+-ATPase activity suggest that the development of SW tolerance during smoltification is partially due to changes in chloride cell enzyme activity and density. The presence of two mitochondrion-rich cell types is discussed with regard to their possible role in the hypoosmoregulatory changes which occur during smoltification. 相似文献
9.
D. J. SPEARE H. W. FERGUSON F. W. M. BEAMISH J. A. YAGER S. YAMASHIRO 《Journal of fish diseases》1991,14(1):21-32
Abstract. This study examines the sequential pattern of bacterial colonization and the sequential development of branchial lesions during typical outbreaks of bacterial gill disease (BGD) among four groups of commercially reared rainbow trout fingerlings, Oncorhynchus mykiss (Richardson). During a 5-month monitoring regime, prior to the onset of natural outbreaks of BGD, gill morphology of examined fish remained unaltered. Bacterial colonization of the gills was immediately preceded by several gill changes which were widely present in fish from all groups under study. These changes, which were detectable at the ultrastructural level only, included cytoplasmic blistering and degeneration of the microridges of the superficial filament epithelium, in addition to slight topographical irregularity of the filament tips suggestive of mild hyperplasia. Bacterial colonization began at these altered filament tips before spreading to more proximal regions of the filament and adjacent lamellar surfaces. Explosive increases in proportional morbidity and mortality coincided with the development of the following gill lesions: extensive bacterial colonization of lamellar surfaces, lamellar epithelial hydropic degeneration and necrosis, and lamellar oedema. In contrast, gill lesions such as lamellar fusion, epithelial hyperplasia and various metaplastic responses were detected later either as subacute (3–5 days) or chronic (7–14 days) changes. The role of epithelial necrosis as an important event during BGD is discussed as a possible mechanism leading to the development of sub-acute and chronic gill lesions. 相似文献
10.
Amoebic gill disease (AGD) is a significant disease of Atlantic salmon farmed in South East Tasmania. The commercial treatment for the disease is a freshwater bath for up to 4 h. Previous studies have shown that the chemical composition of the freshwater, in particular total water hardness, affects the efficacy of the treatment. The aim of this study was to determine if other water chemistry parameters, such as dissolved organic carbon (DOC), interact with total water hardness to affect treatment success. Firstly, the relative survival of isolated gill amoebae incubated for up to 3 h with hard or soft water (346.0 and 34.6 mg L?1 CaCO3 respectively) with low or high concentrations of humic or tannic acid (5 and 50 mg L?1 respectively) was determined. Secondly, fish with AGD were bathed for 2.5 h in hard or soft water (249.3 and 35.3 mg L?1 CaCO3) containing either 5 or 20 mg L?1 humic acid. The number of viable amoebae surviving on the gills and number of gill lesions were determined. It was found that the concentration of DOC used in this study that represents the levels commonly found around SE Tasmania is unlikely to have any commercial significance in the reduction in amoebae on the gills of Atlantic salmon. However, this study provided further support that freshwater selected for bathing AGD‐affected salmonids should be chosen primarily on its total water hardness. 相似文献
11.
Steinum T Kvellestad A Rønneberg LB Nilsen H Asheim A Fjell K Nygård SM Olsen AB Dale OB 《Journal of fish diseases》2008,31(3):205-214
12.
B K Diggles 《Journal of fish diseases》2001,24(2):99-110
Mortalities of puerulus and juvenile rock lobsters, Jasus edwardsii (Hutton, 1875), held in shore-based ongrowing facilities at water temperatures between 10 and 18 °C were associated with infection by an invasive oomycete identified as Haliphthoros sp. Gross signs of disease included loss of appetite, lethargy and 1–3 brown/black focal necrotic lesions in the gills near insertion of the walking legs. Hyphae were observed in wet preparations of gill filaments excised from lesions. Histology of gill lesions showed hyphae inside the gill cuticle, invasion and lysis of the skeletal muscle and massive haemocyte infiltration and melanization at the base of walking legs adjacent to infected gill filaments. Lobsters over approximately 30 mm carapace length appeared resistant to infection. Death of affected lobsters usually occurred prior to or during the moult and in some cases may have been associated with secondary bacterial infection. Haliphthoros sp. was isolated in pure culture and marine agar 2216 was the medium that produced best growth in vitro . Two isolates were exposed in vitro to five chemicals to determine if an effective treatment could be found. Chemicals that interrupted the life cycle by killing zoospores or preventing sporulation included malachite green, trifuralin, formalin and copper sulphate. The appearance of the disease was associated with poor hygiene and its elimination may be achievable by improving husbandry practices. 相似文献
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Lumsden JS Russell S Huber P Wybourne BA Ostland VE Minamikawa M Ferguson HW 《Journal of fish diseases》2008,31(12):889-898
Chinook salmon from New Zealand were shown to have a generalized membranous glomerulonephritis that was most severe in large fish. Marked thickening of the glomerular basement membrane was the most consistent lesion, with the presence of an electron-dense deposit beneath the capillary endothelium.Severely affected glomeruli also had expansion of the mesangium and loss of capillaries,synechiae of the visceral and parietal epithelium and mild fibrosis of Bowmans capsule. Chinook salmon from British Columbia, Canada with bacterial kidney disease caused by Renibacterium salmoninarum had similar histological lesions. They also had thickened glomerular basement membranes that were recognized by rabbit antiserum to rainbow trout immunoglobulin. This was true only when frozen sections of kidney were used and not formalin-fixed tissue. An attempt to experimentally produce a glomerulopathy in rainbow trout by repeated immunization with killed R. salmoninarum was not successful. Case records from the Fish Pathology Laboratory at the University of Guelph over a 10-year period revealed that a range of species were diagnosed with glomerulopathies similar to those seen in Chinook salmon. The majority of these cases were determined to have chronic inflammatory disease. This report has identified the presence of immunoglobulin within thickened basement membranes of Chinook salmon with glomerulonephritis and supports the existence of type III hypersensitivity in fish. 相似文献
15.
Atlantic salmon, S almo salar L., were exposed to different concentrations of Paramoeba sp. The lowest concentration which induced amoebic gill disease (AGD) was 230 Paramoeba sp. L–1 and the severity of infection increased with increasing concentration. The concentration of Paramoeba sp. positively correlated with the number of gill lesions ( R 2 > 0.7). This study provides evidence that Paramoeba sp. is the causative agent of AGD and describes an experimental model that enables the severity of the induced disease to be controlled. 相似文献
16.
Atlantic salmon were exposed to amoebic gill disease (AGD) immediately following their acclimatization to sea water (group 1), or following a 2 week period of maintenance in sea water (group 2). Three fish from each group were sampled on days 0, 1, 2, 4, 7, 14 and 28 post-infection. Characteristic gill lesions began to occur between days 2 and 4, and dramatically increased by day 7. The number of gill lesions on fish from group 2 was significantly higher than on fish from group 1 on days 7 and 14 ( P <0.001), but the two groups did not differ in any other parameter. Histologically, Paramoeba sp., the aetiological agent of AGD, could be seen on the gills of fish as soon as 1 day post-exposure, attached to healthy-appearing gills. Gill pathology in the form of hyperplasia and lamellar fusion followed shortly. AGD infection was accompanied by a significant increase in the number of gill mucous cells ( P =0.002). Different methods for the diagnosis of AGD are discussed. 相似文献
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Fusarium incarnatum isolated from black tiger shrimp, Penaeus monodon Fabricius, with black gill disease cultured in Vietnam 总被引：1，自引：0，他引：1
Fusarium incarnatum was isolated from gill lesions of cultured black tiger shrimp, Penaeus monodon, in every crop during 2000-2002 in Nghe An province, Vietnam. Infected shrimps showed typical signs of black gill disease and mortalities about a month prior to harvest. Detailed morphological examinations, as well as molecular phylogenic analyses based on partial nucleotide sequences of ribosomal DNA, were made on the isolates. An artificial infection of kuruma prawn, Penaeus japonicus, using two selected isolates was also conducted and their pathogenicity determined. 相似文献
19.
Brian G Bosworth David J. Wise Jeffery S. Terhune & William R. Wolters 《Aquaculture Research》2003,34(7):569-573
The severity of gill damage (percentage of gill lamellae with lytic lesions) was determined in juveniles from 10 USDA 103 line channel catfish Ictalurus punctatus full‐sib families, 10 channel catfish×blue catfish I. furcatus backcross hybrid (7/8 channel catfish, 1/8 blue catfish) full‐sib families and a mixed‐family group of blue catfish placed in a commercial catfish pond experiencing proliferative gill disease (PGD)‐related fish mortalities. An initial challenge was conducted with all families, and a second challenge was conducted using the two most susceptible (most gill damage) channel catfish and backcross hybrid families and the two most resistant (least gill damage) channel catfish and backcross hybrid families. In the initial challenge, percentage gill damage was not different between channel catfish (12.3%) and backcross hybrids (11.6%), but was lower in blue catfish (0.2%). Mean percentage gill damage in the second challenge was not different among resistant backcross hybrid families (6.9%), resistant channel catfish families (7.6%) and blue catfish (4.8%), but was higher in susceptible backcross hybrid and channel catfish families (19.0% and 11.9% respectively). The correlation among family means for gill damage from challenge 1 and challenge 2 was r=0.87. Consistent differences between channel catfish and blue catfish and between resistant and susceptible families within genetic groups for gill damage after PGD challenge suggest that there is a genetic component for resistance to PGD and that improving PGD resistance through selection may be possible. 相似文献
20.
Susan O. Mitchell Emily J. Baxter Celia Holland Hamish D. Rodger 《Aquaculture International》2012,20(5):813-825
Gill health and disease in farmed Atlantic salmon (Salmo salar) were studied at a marine site on the west coast of Ireland. Fish were sampled on a regular basis during the summer and autumn of 2009. A novel histopathological scoring system was devised to give a semi-quantitative measure of gill pathology. The index criteria for gill histopathology were lamellar hyperplasia, lamellar fusion, circular anomalies (necrosis or sloughing) and lamellar oedema, a score from 0 to 3 being assigned for each parameter. Ancillary criteria, such as hypertrophy, haemorrhage and the presence of specific pathogens, were assigned a score of 0 or 1. Environmental monitoring undertaken included zooplankton and phytoplankton sampling, as well as temperature and oxygen recordings for the site. Epitheliocystis was frequently observed at low levels but was not associated with any significant gill pathology. Clinically significant gill pathology was observed on one occasion during the sampling period, coinciding with the occurrence of Pelagia noctiluca, Muggiaea atlantica and Solmaris corona. Throughout the longitudinal study, the scoring system provided an accurate and effective means of assessing gill health, demonstrating the ability of this practical tool to be used in future studies of gill health and disease. 相似文献