摘要:

Abstract.This paper describes the histopathological changes observed in the Mexican native cichlidCichlasoma urophthalmus(Günther) when try with an initial weight of between 160 and 170 mg were fed with diets deficient in vitamin C for 90 days. The epidermis showed an extensive inflammatory response, with spongiosis and also degenerative changes in the basal cells. Muscle showed a range of pathological changes including inflammation, changes in the number and position of the nuclei, vacuolation and necrosis, granular degeneration, and fibre loss. Gills showed thickening of the primary lamellae, oedema, hyperplasia, telangiectasis and atrophy of the bony supporting structures. Ganglia and neurones of nervous tissue were abnormal with changes which ranged from slight inflammation to central chromatolysis. The hepalopanereas was also affected and focal necrosis of the hepatocytes was frequently observed. The pancreas showed major changes with shrinkage of the acinar cells and reduction of zymogen granule content. Fish fed diets containing 0 and 40 mg vitamin C kg‐1of diet were infected withMycobacteriumsp. and miliary tuberculosis was found affecting kidney, spleen, choroid gland, stomach, heart and muscle. The association between fish tuberculosis and vitamin C deficiency is discuss

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00606.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.This study reports the histopathogical observations made upon the livers and gills of rainbow trout exposed to a continuing series of exposures to l·6ppm 40 min baths of malachite green at weekly intervals. After the third week of exposure, sinusoidal congestion and focal necroses were evident on the livers. At the ultrastructural level, consistent mito‐chondrial damage was evident with swelling and disruption of the cristac, together with dilation of the rough endoplasmic reticulum. Nuclear alterations increased in severity in the later periods of exposure. However, these hepatic changes were not severe enough to be reflected in scrum protein changes. In the gills of treated fish, separation of the epithelial lining from both lamellar and interlamellar regions was noted and lamellar cell necrosis and leucocyte infiltration became more frequent with increased exposu

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00607.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.Cyprinid herpesvirus 1 (CHV) orHerpesvirus cypriniwas virulent for carp,Cyprinus carpioL., fry following 1 h immersion in water at 20 °C. Cumulative mortality for carp fry was 86–97% in 2‐week‐old common carp, 20% in 4‐week‐old fancy carp, and 0% in both 8‐week‐old common and fancy carp. The virus did not produce mortality in fry of crucian carp, grass carp or other cyprinids. It was also oncogenic in carp, inducing papillomas to the extent of 55% among both common and fancy carp fry. The neoplasms appeared 5–6 months after carp had been exposed to the virus by immersion and recurred at an incidence of 83% in carp 7·5 months post‐desquamation of the tumour. The CHV was reisolated from all moribund fish and from all survivors. It also induced papillomas at an incidence of 13% in adult mirror carp and at 10% in adult fancy carp 5 months after intraperitoneal inoculation of 105TCID50ml‐1fish. The virus was rcisolated only from the ncoplastic tissue and not from internal organs. The neoplasms were normally located on fin, skin or mandible, at the intraperitoneal inoculation site. Specific fluorescence for CHV antigen was frequently detected in the gills, liver, kidneys and intestine of 2‐week‐old fry from 3 to 21 days following challenge with CHV. It was found in greater concentrations in experimentally induced papillomata on 2‐week‐old carp fry survivors examined 24 weeks after challenge than in

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00608.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.A non‐lethal study of the disease status of adult rainbow trout,Oncorhynchus mykiss(Walbaum), suspected of being carriers of infectious pancreatic necrosis virus (IPNV) was carried out using purified leucocytes from pooled blood samples. Leucocytes were stained by indirect immunofluorcscence to detect IPN viral antigen and analysed by flow cytometry. Leucocytes from an IPN free source were also used as controls. Three populations of leucocytes were analysed: (1) leucocytes examined immediately following purification from blood, which gave positive results with 30–58% of fluorescent cells: (2) purified leucocytes cultured for 7 days in medium at 15 °C. which gave a higher number of fluorescent cells, suggesting multiplication of IPNV; and (3) leucocytes co‐cultured on CHSE‐214 cell monolayers for 7 days at 15 °C, which amplified the number of infected leucocytes to more than 90% but delayed the result 7 days. Isolation and serological identification of the pathogen was carried out on CHSE‐214 cells, which confirmed the positive results obtained by flow cytometry analysis. Further experiments are in progress to complete the applications of flow cytometry to salmonid vi

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00609.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The effects of infection with salmonid viruses on mitogen‐stimulated cells and colonies from rainbow trout,Oncorhynchus imkiss(Richardson), kidney cell cultures have been studied using culture in clots of fibrin. Phytohaemaglutinin, concanavalin A and lypo‐polysaccharides fromEscherichia colihave been used as mitogens. The viral haemorrhagic septicaemia (VHS) virus destroyed any mitogen‐induced trout kidney colonies or cells, but the infectious pancreatic necrosis (IPN) virus caused no cell or colony death, and even increased their count in the cultures. The results suggested that the target for IPN virus replication is not any trout leucocyte but that among the possible targets of VHS virus are the different types of leucocytes found in the trout kidney and in theirin vitromitogen‐stimulated c

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00610.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The expression of iron‐regulated outer membrane proteins (OMPs) was examined in 36 isolates ofYersinia ruckeriselected to represent a range of biotypes, serotypes and OMP‐types. Iron‐restricted growth was achieved in tryptone soya broth by chelation with 200 μm α,α'‐dipyridyl, although similar results could be achieved with 25 μm transferrin or 280 μM ethylenediaminedihydroxyphenylacetic acid (EDDA). During growth under iron‐restricted conditions, all 36 isolates produced four additional outer membrane proteins of molecular weights 72, 69·5, 68 and 66 kDa. Expression of these proteins was repressed by the addition of 100 μm FeCl3to the growth medium, confirming that the proteins were iron‐regulated. The facts that all of the isolates examined possessed the same four iron‐regulated OMPs, and that the plasmid content of different serotypes is known to vary indicated that production of these proteins is probably chromosomally mediated and not plasmid‐mediated. Production of siderophores was not detected in low iron media and suggested a direct iron‐uptake mec

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00611.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.On the basis of previous observations,in vivoexperiments were conducted in rainbow trout,Oncorhynchus mykiss(Walbaum), to detect possible competition between strains ofAeromonas salmonicidadiffering in their pattern of resistance to antimicrobial drugs. Serial infections, or reinfection of naturally‐infected trout, were induced by intramuscular injection. Surviving fish were artificially stressed, and all dying fish were examined using selective media to assess the type of latent infection. Secondary infections with virulent strains always resulted in mortality and reisolation of the secondary strain in pure culture. However, when trout having undergone the two successive infections were stressed, the primary strain was always reisolated. Primary strains seem to be able to survive in unknown locations within cells or tissues, regardless of their virulence or growth potency. Although a protective effect conferred by latent infection to secondary challenge could not be clearly proven, such mechanisms resemble what occurs in premunition and could be of epidemiological interes

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00612.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The efficacy of 10 polysaccharides (curdlan, inulin, krestin, laminaran, lentinan, levan, schizophylian, selerogiucan, yeast glucan and zymosan) to enhance protection of carp,Cyprinus carpioL., against bacterial infection was investigated. Carp were intraperitoneally injected with the polysaceharides (2–l0 mgkg‐1) on days 1 and 4, and challenged withEdwardsiella tardaon day 7. Among the polysaccharides tested, lentinan, schizophyllan and scleroglucan, which are l,6‐branchcd‐β‐l,3‐glucans, significantly increased the survival rate. They also induced a protective effect againstAeromonas hydrophilaat a dose of 5 mg kg‐1. The ability of the polysaccharides to activate the alternative complement pathway (ACP) was examined by incubating the polysaccharides with carp serum and measuring the residual ACP activity. At a final concentration of 0.l mgml‐1, l,6‐branched‐β‐1,3‐glucans greatly reduced (76–77%) the ACP activity. Therefore, it is suggested that the protective effect of the l,6‐branched‐β‐1,3‐glucans may be a

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00613.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.In an investigation of the occurrence of proliferative kidney disease (PKD) in freshwater fish other than rainbow trout, 18 species of wild fish and seven species of fish raised in cultivation wore sampled from waters where the disease occurred annually in rainbow trout,Oncorhynchus mykiss(Richardson). Results revealed that certain wild stocks of brown trout.Salmo truttaL., grayling,Thymallus thymallusL., and pike,Esox luciusL., were infected with PKD, as were cultivated Atlantic salmon,Salmo salarL., parr, brown trout and char,Salvelinus alpinus(L.). Microscopical examination revealed the presence of the PKX cell in these species and also intraluminal protozoa possibly related to the PKX cell, which were not found in the rainbow trout. Other species of freshwater fish had myxosporidan infections but, unlike PKD infection, there was little host/parasite tissue response. The PKX cell as a myxosporidan stage is discussed and the presence of the disease in wild fish is reported.

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00614.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1991.tb00615.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY