摘要:

AbstractSympatric populations of the hermaphroditic scallop,Pecten fumatusReeve, and of the dioecious scallop,Chlamys (Mimachlamys) asperrima(Lamarck), from Jervis Bay, New South Wales, Australia, were sampled between October 1991 and December 1994. Over the first 2 years, 5.1% of adultP. fumatusand 4.5% of adultC. asperrimawere infected with a trematode,Bucephalussp., that causes parasitic castration. A significant increase in the numbers of infected scallops occurred in spring 1993, teaching 63% inP. fumatusand 24% inC asperrimain May and March 1994, respectively. The prevalence of infection increased with scallop size, reaching 66% inP. fumatusgreater than 80 mm in shell height and 40% inC. asperrimagreater than 75 mm in 1994. Seasonal and interannual variations in parasitism for theP. fumatusrecorded over a continuous period of 5 years in Jervis Bay are discussed, as are interspecies differences and the potential impact of the parasitic castration on reproductive potential and marketability ofP. fumatusandC. asperrima.

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1996.tb00371.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractProblems of temporary immunosuppression following vaccination againstAeromonas salmonicidainfection had to be overcome in the development of a furunculosis vaccine. Empirical observations have indicated that immunosuppression persists for some time after vaccination, rendering fish, especially subclinical carriers ofA. salmonicida, highly vulnerable to bacterial invasion. The efficacy of simultaneous application of furunculosis vaccine and a long‐lasting amoxycillin preparation to a population of Atlantic salmon smolts was evaluated. Control groups were treated with either vaccine alone, amoxycillin alone or were untreated. Moderate stress, simulating smolt transfer with a 5°C temperature rise, resulted in a rapid outbreak in mortalities reaching 100% in the vaccinates. Losses among the untreated controls were more gradual and rose to about 50%. Both amoxycillin‐treated groups survived well. Further severe stress resulted in total mortalities among the untreated fish but no further losses in the amoxycillin groups. Four months after vaccination, evidence of a specific immune response was confirmed by ELISA, demonstrating circulating antibodies in the blood of vaccinates. In a severe and in a moderate challenge withA. salmonicida., the relative specific protection was 63 and 86%, respectively. Thus, effective protection against furunculosis was achieved without jeopardizing the stock during the vaccination process and with elimination of the carrier s

ISSN:0140-7775    

DOI:10.1046/j.1365-2761.1996.d01-86.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe distribution of lysozyme in the intestine of Atlantic salmon,Salmo salarL., was studied by light‐ and electron‐microscopic immunocytochemistry. Eosinophilic granule cells (EGCs) in the subepithelial region of the lamina propria showed strong immunoreactivity to lysozyme, while epithelial cells were only occasionally stained. At the ultrastructural level, lysozyme was localized to secretary granules of EGCs, demonstrating features in common with the Paneth cell of the mammalian small intestine, previously shown to produce antibacterial substances such as lysozyme. Furthermore, EGCs stained positive with phloxine‐tartrazine, a histochemical stain that is used for identification of Paneth cells. This study reveals that EGCs show close resemblance to mammalian intestinal Paneth cells, and thus, may be important for the intestinal defense system in salmonid

ISSN:0140-7775    

DOI:10.1046/j.1365-2761.1996.d01-87.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe morphogenesis of a highly organized cellular membrane structure, a membranous labyrinth (ML), in the cells of penaeid shrimp infected withPenaeus monodonbaculovirus (MBV) is described. The ML possibly originates from dilated Golgi apparatus, endoplasmic reticulum (ER) or the outer nuclear membrane. The ML apparently grows by proliferation of the cellular membranes of these systems. In addition, its degree of development was correlated with stages of MBV reproduction.

ISSN:0140-7775    

DOI:10.1046/j.1365-2761.1996.d01-89.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThere has been an increasing number of reports on cataracts in Norwegian and international salmon farming. The present study was undertaken to examine physiological and nutritional conditions during an outbreak of cataracts observed in rapidly growing Atlantic salmon,Salmo salarL., smolt with emphasis on zinc status. During this study, the cataracts were classified as irreversible. The outbreak of cataracts was positively related to fish growth and negatively related to the condition factor of the fish. Zinc concentrations in liver, eye and plasma were recorded in fish with cataract and in healthy fish from December to May. Lower zinc status (around 20%) was found in fish with cataracts compared to healthy fish, both over time and with regard to severity of the cataract. The decline in organ zinc concentrations seems to be explained by increased relative liver size, lower dry matters in liver and eye, and lower plasma protein. From the present data, the incidence of cataracts could not be directly related to zinc or any of the other nutrients (vitamin A, iron) examined, although relative deficiencies caused by other unknown rearing factors cannot be excluded. The lower condition factor and differences in organ water composition in fish with cataracts indicate that the cataracts may be related to the smoltification processes. Smoltification in the fish population was most probably accelerated by elevated water temperatures.

ISSN:0140-7775    

DOI:10.1046/j.1365-2761.1996.00259.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe development of a pathological condition in the distal intestine of Atlantic salmon,Salmo salarL., induced by dietary soybean meal, was studied in a 6‐week feeding experiment. The fully developed condition, as observed after 3 weeks on the experimental diets, was characterized by: (1) a shortening of heights of the mucosal foldings; (2) a loss of the normal supranuclear vacuolization of the absorptive cells in the intestinal epithelium; (3) a widening of the central stroma within the mucosal foldings, with increased amounts of connective tissue; and (4) a profound infiltration of inflammatory cells in the lamina propria. The first signs of morphological changes were observed after 2 days on a diet containing a solvent extracted soybean meal, and within 7 days, all the above mentioned signs were observed. When the fish were subsequently transferred to a control diet, the mucosal folds were rebuilt from the base, resulting in an apparently functional epithelium after 3 weeks. Starved fish also exhibited characteristic changes of the mucosa, including a finely granular cytoplasm replacing the supranuclear vacuoles seen in the epithelial cells of normal fish. In addition, a pattern of irregularly spaced indentations developed in the epithelium of the simple folds. The condition induced by dietary soybean meal was classified as a no n‐infectious subacute enteritis, and a pathogenesis involving immunological mechanisms is sugges

ISSN:0140-7775    

DOI:10.1046/j.1365-2761.1996.d01-92.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1046/j.1365-2761.1996.d01-88.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1046/j.1365-2761.1996.d01-90.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1996.tb00379.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY