摘要:

Abstract.In a parasitic survey of gilthead sea bream,Sparus aurataL., cultured in different systems in Spain, eight protozoan species were found. Ectoparasites included two ciliates (Trichodinasp. and aCryptocaryon‐like species), one dinoflagellate (Amyloodiniumsp.) and the zooflagellateIchthyobodosp. Endoparasites were represented by members of the Apicomplexa (Eimeriasp.) and Myxosporea (Polysporoplasma sparis. Ceratomyxasp. andLeptothecasp.).Ichthyobodosp.,Eimeriasp.,Ceratomyxasp. andLeptothecasp. are reported for the first time inS. aurata. Amyloodiniumsp. andIchthyobodosp. were associated with outbreaks of disease in larval and juvenile fish. Data on prevalence and intensity of infection and the location in the host are provided. The potential importance of these protozoan parasites for gilthead sea bream culture is discusse

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00268.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.During a study of the gametogenesis of the swamp eel.Synbranchus marmoratusBloch, conspicuous structures were found randomly distributed among the germinal cells and gonadal stroma. At low magnification, these structures appeared as yellowish to dark spherical bodies. Histological and histochemical examination showed clusters of cells with generally pyknotic nuclei and cytoplasm containing lipofusein‐like substances. A comparison of these structures with the melano‐macrophage centres (MMCs) present in the liver and spleen, showed the same structure and features. Their presence and function in the gonads ofS. marmoratusmight be related not only with the basic functions of the MMCs, but also with the degradation of atretic and/or non‐ovulated follicules, principally during the post‐spawning

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00269.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.A series of experiments were carried out to assess the reproducibility of a bath challenge model to induce experimental furunculosis. The challenge method was shown to reliably induce a control mortality of 78.9 ± 3.8%. Although the method was shown to be robust, some tanks failed to achieve an acceptable control mortality. The reasons for this are unclear; however, the failure of a tank to induce a satisfactory control mortality is related to a rapid disappearance of the initial inoculum. The reason for the disappearance of the inoculum appears to be related to the presence of hydrophobic regions in the challenge tank

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00270.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.Infectious salmon anaemia (ISA) is a viral disease of farmed Atlantic salmon,Salmo salarL., in Norway. The enveloped virus particles (100nm) believed to be the causative agent of the disease have been observed budding from endothelial cells in heart blood vessels. However, it is not known if the virus propagates in endothelial cells in all tissues/organs, if other target cells exist or if material collected from different salmon farms with natural outbreaks of ISA contain the same virus particles. Salmon smolts from three hatcheries with no history of disease were taken into the laboratory and experimentally challenged with ISA collected from Atlantic salmon during natural outbreaks of the disease in three different fish farms outside Bergen. Norway. Tissues for TEM studies were Collected from: (1) organs that showed clinical signs of ISA (i.e. used in the diagnosis of the disease); (2) tissues believed to be important in transmission of the virus (integument, kidney, urinary bladder, gut and somatic muscle); and (3) hormone‐producing tissues (pituitary gland, saccus vasculosus, thymus, thyroid, ultimobranehial gland, gonad, head kidney, heart and ventral aorta). The same virus as that believed to be the causative agent of ISA was found in all tissues examined from the challenged fish, i.e. a multiorgan infection with the same virus present in salmon from all three fish farms. The virus particles are about 100 nm in diameter, consisting of a slightly pleomorphic unit membrane envelope within which are a number of granules about 10–12nm in diameter. The granules seemed to be arranged in two concentric circles (spheres). The virus was seen budding from the surface of endothelial cells in blood vessels/sinus only. However, the virus was found intracellularly in both endothelial cells and in leucocy

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00271.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.Blood and head kidney (HK) leucocytes were isolated from Atlantic salmon,Salmo salarL., carrying infectious pancreatic necrosis virus (IPNV), and the cells were separated into adherent and non‐adherent populations. Significant increases in both intra‐ and extracellular IPNV titres, and in the number of IPNV‐positive fluorescent cells were detected in adherent HK leucocytes during 7 days in culture, and demonstrated that IPNV multiplied in these cells. Infectious virus was not detected in culture medium collected from blood leucoeytes, and only occasionally, in very low titres, from non‐adherent HK leucocytes. No IPNV‐positive fluorescent cells were detected in these cell populations. IPNV infection of adherent leucocytes isolated from non‐carrier fish indicated that adherent blood leucocytes (mainly monocytes) could become productively infectedin vitro, but to a lesser degree than adherent HK leucocytes (mainly macrophages). The present results suggest a major role for adherent HK leucocytes in maintaining the IPNV carder state in Atla

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00272.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.Intracytoplasmic organisms resembling rickettsia were observed in tissues of two blue‐eyed plecostoitius,Panaqae suttoni(Eigenmann&Eigenmann), a tropical freshwater fish. Gross lesions were limited to renomegaly and splenomegaly. Cytopathological and histopathological examination of the various tissues revealed numerous small, discrete, coccoid organisms in the cytoplasm of monocytes as well as tissue macrophages of the spleen, heart, kidney and sometimes liver. Transmission electron microscopy confirmed that these organisms were within membrane‐bound vacuoles and had a morphology resembling rickett

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00273.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.Changes in plasma cortisol concentrations and inter‐renal and chromaffin tissues of rainbow trout,Oncorhynchus mykiss(Walbaum), exposed to harmful concentrations of the diatomChaetoceros concavicorniswere investigated. The plasma cortisol level of trout exposed toC. concavicorniswas over 10‐fold greater than that of untreated trout. Computer‐assisted feulgen‐microspectrophotometry was employed in order to assess the activity of inter‐renal and chromaffin cells. The total areas of inter‐renal and chromaffin nuclei in trout treated withC. concavicornissignificantly increased compared to those of untreated fish. In contrast, the chromatin density of inter‐renal and chromaffin nuclei in treated trout decreased significantly. This decrease of chromatin density in treated fish was caused by an increase in the low‐density components, and a decrease in the middle‐density and high‐density components. Although the hypertrophic changes to the inter‐renal and chromaffin nuclei of treated fish exhibited the same general trend, the extents to which the changes took place were different, occurring more rapidly within inter‐renal tissues. The rainbow trout exposed to harmful concentrations ofC. concavicorniswere experiencing a severe physiological disturbance to wh

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00274.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Abstract.The stimulatory effect of LPS (Vibrio anguillarum), laminaran and sulphated laminaran, aqueous soluble β(1,6)‐branched β(l,3)‐D‐glucan obtained fromLaminaria hyperborea, on head kidney macrophages of Atlantic salmon,Salmo salarL., is reported. The macrophages, after stimulation with LPS or laminaran, showed pronounced spreading, membrane ruffling and increased organellc content when examined by light microscopy. LPS stimulation induced enhanced phagocytic and pinocytic activity, higher intraccllular production of superoxide anion, and higher activity of acid phosphatase compared to control cells. Native laminaran stimulated the cells to pinocytose more fluid phase, increase the intracellular production of superoxide anion and to elevate the activity of acid phosphatase. Sulphated laminaran induced higher production of superoxide anion and higher activity of acid phosphatase by macrophages than in contro

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00275.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00276.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1995.tb00277.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY