摘要:

AbstractThis study involved 34 960 specimens of deepwater redfish,Sebastes mentella(Travin), from the North Atlantic, 21 460 of them from the Irminger Sea. One hundred and three specimens of this species, 96 with pigmented lesions, were examined histologically. The black patches on the redfish skin proved to be superficial melanosis (48 cases) and deep melanosis (24 cases). Skin pterinophorosis was noted in 20 cases. Pigment tissue neoplasms were observed in 26 fish; all were benign chromatoblastomas. Fourteen tumours were diagnosed as melanomas originating from melanophores, seven as pterinophoromas originating from pterinophores, and five as pterino‐melanophoromas or melano‐pterinophoromas of mixed origin of both chromatophore types. The tumours on the trunk of redfish occurred only in pigmented areas larger than 20 cm2. Fish with such areas constitute no more than 2.4% of the total Irminger Sea redfish population. Most (76.2%) of pigmented lesions in this redfish population did not exceed 5 cm2in area. The arrangement of pigmented areas differed in males and females. In females, 97% of patches were found between the pectoral and the first dorsal fins, whilst in males, 84% of patches were situated on the head and caudal fin. Pigmented lesions occurred 2–5 times more often in females than males. The causes of pigment tissue neoplasms and pigmented lesions in deepwater redfish are un

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01234.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA new myxosporean,Myxobolus jirovecisp. nov. has been found to infect the brain of bullhead,Cottus gobioL., in several localities in Czechoslovakia and England. Trophozoites, up to about 200 μm in size, were encountered in various regions of the brain where they occupied the space within the distended myelin sheath of the axons. Trophozoites provoke local compression and atrophy of the neighbouring nervous tissue. Host reaction — mostly glial cell proliferation, less often perivascular lymphocytic infiltration — can be associated with heavy infections. The sporoplasmosomes, spherical, double membrane‐bound dense bodies in the sporoplasm of mature spores, are described and compared with similar bodies of other myxosporeans and with the haplosporosomes found in representatives of the phylum Haplo

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01235.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Oxolinic acid (OA), oxytetracyline (OTC) and trimetoprim (TMP) were investigated in whole gutted rainbow trout,Salmo gairdneriRichardson, and in their skin, muscle and blood, at 6, 12 and 18°C. Concentrations of drugs were measured by high‐pressure liquid chromatography. It is recommended that withdrawal times for rainbow trout be based on whole gutted rainbow trout and not, as in earlier investigations, from residual concentrations in muscle. Any concentrations in rainbow trout feed were found to be stable during the pelleting process used and up to 81 days after pelleting. The absorption of the drugs in rainbow trout show different temperature dependencies. A quantitative comparison of our overall data from this work with individual results from earlier investigations was undertaken. Suggested withdrawal times for freshwater rainbow trout treated with these drugs are: for OTC, 90 days below 6°C, 70 days between 6 and 12°C and 60 days above 12°C; for TMP, 60 days below 8°C and 40 days above 8°C; for OA, 20 days at approximate

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01287.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Blindness developed in Atlantic menhaden,Brevoortia tyrannus(L.), within 4 weeks of captivity in an indoor open culture system. Ophthalmoscopic changes indicative of retinal degeneration were substantiated by the absence of retinal electrical activity as measured by conventional electroretinography. Results of histological evaluation suggest that photo‐receptor degeneration, occurring initially in the rods of the central retina, was the primary abnormality. With chronicity, all retinal layers degenerated, and marked pigment proliferation developed. Other pathological changes included uveal vascular engorgement, vitreal and anterior chamber haemorrhage, and cataracts. With the exception of dermal hyperpigmentation, no systemic abnormalities were consistently observed. Phototoxicity is the suspected cause of this degenerative retinopath

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01288.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.The role of the caseinase extracellular enzyme in the pathogenesis of furunculosis was investigated. Natural and mutant strains ofAeromonas salmonicidawhich were unable, or limited, in their ability to produce this enzyme were studied. The virulence of the mutant strains ofA. salmonicidawas not significantly reduced by the lack of extracellular caseinase production. Furthermore, there was no difference in the toxicity of extracellular products produced by these mutant strains and the wild‐typeA. salmonicidastrain studied. It is reasonable to assume from these results that the caseinase enzyme has no major role in the pathogenesis ofA. salmonicidainfection

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01289.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Five isolates of a rhabdovirus associated with a severe ulcerative disease of striped snakehead,Ophicephalus striatus, and other freshwater fish in S.E. Asia were examined for growth in a range of cold and warm water fish cell lines and for serological relationships to other pathogenic fish rhabdoviruses. All five isolates grew in AS, BF‐2, snakehead,O. striatusandO. micropeltis, and climbing perch,Anabas testudineus, cell lines. CHSE‐214, RTG‐2, EPC, Nile tilapia,Oreochromis niloticus, and grass carpCtenopharyngodon idella, cell lines were all refractory to infection. Cross neutralization tests showed the ulcerative disease rhabdovirus (UDRV) to be serologically distinct from VHSV, IHNV, EVA, EVX, SVCV, PFRV and perch rhabdovirus. UDRV appears to be a new distinct pathogen of freshwater fish in S.E.

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01290.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01291.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01292.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01293.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1989.tb01294.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY