Spermatocrit and spermatozoa density in Atlantic cod (Gadus morhua): correlation and variation during the spawning season     

Ana Rakitin  Moira M. Ferguson  Edward A. Trippel 《Aquaculture (Amsterdam, Netherlands)》1999,170(3-4):349-358

The utility of spermatocrit (the proportion of solid packed material in semen after centrifugation) as an indicator of spermatozoa density and male spawning stage was tested in Atlantic cod (Gadus morhua). Semen was collected from captive male cod over three spawning seasons. Spermatocrit was positively and significantly correlated with spermatozoa density measured with a Coulter counter (Multisizer), but not with spermatozoa counts in a haemacytometer. Spermatocrit increased significantly as the spawning season progressed. However, day of season explained only 35% of the variation because spermatocrit varied among individual males. Spermatozoa size remained unchanged throughout the sampling period and was not correlated with spermatocrit, indicating that variation in spermatocrit was due to variation in spermatozoa number and not their size. Spermatocrit is a good estimator of sperm density but is not reliable as indicator of spawning stage because of the variation among individual males.  相似文献   

Atypical bacterial gill disease: a new form of bacterial gill disease affecting intensively reared salmonids     

V. E. Ostland  P. J. Byrne  J. S. Lumsden    D. D. MacPhee    J. A. Derksen    M. Haulena    K. Skar  E. Myhr  H. W. Ferguson 《Journal of fish diseases》1999,22(5):351-358

An unusual form of bacterial gill disease (BGD) was identified which affected five species of cultured salmonids from Canada (i.e. rainbow trout, chinook salmon and Atlantic salmon), Norway (i.e. brown trout) and Chile (i.e. coho salmon). All outbreaks occurred at low water temperatures (< 10 °C) and with clinical presentations distinct from classical BGD, which is caused by Flavobacterium branchiophilum. In contrast to classical BGD, fish did not show marked respiratory distress with flaring of the opercula, the animals did not orientate at the surface of the water column near inflow water or at the margins of the tanks, and the feed response of the fish was varied. While mortality was increased, it was not precipitous as in classical BGD. Eight outbreaks were examined in greater detail using histopathology, scanning electron microscopy, bacteriology and immunohistochemistry. Large numbers of small bacterial rods were seen adhering to the lamellar epithelium of affected gills from all outbreaks. Histologically, the lamellar epithelium appeared swollen, often with evidence of single cell degeneration and exfoliation. In more severe instances, the formation of lamellar synechiae was seen, usually associated with sequestration of bacteria between fused lamellae. By contrast with typical BGD, overt epithelial hyperplasia, lamellar fusion and filamental clubbing were not common sequelae to infection; instead, the end result was shortened and somewhat stubby lamellae covered with swollen epithelial cells. The predominant bacterium recovered from affected gills was a small, Gram-negative, motile, fluorescent pigment-producing rod that shared phenotypic characteristics with Pseudomonas fluorescens. Polyclonal antisera prepared against three representative isolates indicated a weak antigenic similarity among them. Immunohistochemistry corroborated this finding, in that the antisera reacted strongly with gill sections containing the homologous bacteria, but not against morphologically similar bacteria in heterologous sections. A Gram-negative, yellow pigmented bacterium (YPB), identified as Flavobacterium psychrophilum, was also recovered, but only from the gills in the Ontario outbreaks. Antiserum prepared against this YPB indicated an antigenic similarity among isolates recovered from the Ontario outbreaks, but immunohistochemistry failed to recognize antigenically related bacteria on the gills of fish from the other outbreaks. Based on the unusual clinical presentation and the histopathological appearance of the gills, in conjunction with the absence of filamentous bacteria associated with and recovered from affected gills, the present authors have called this condition ‘atypical bacterial gill disease’ or ABGD.  相似文献   

Influences of Aeromonas salmonicida lipopolysaccharide, prednisolone and water temperature on plasma protein composition in salmonids     

E. Simko  T. E. Kocal  B. A. Quinn  V. E. Ostland  H. W. Ferguson  M. A. Hayes 《Journal of fish diseases》1999,22(2):91-100

To further characterize the putative role of constitutive and inducible plasma proteins in innate resistance to furunculosis, the present authors compared the alterations in profiles of plasma proteins in resistant and susceptible salmonids, i.e. rainbow trout, Oncorhynchus mykiss (Walbaum), and brook trout, Salvelinus fontinalis (Mitchill), respectively. Rainbow trout were injected with prednisolone acetate and exposed to higher water temperature (18 °C versus 10 °C), or injected with purified lipopolysaccharide (LPS) from a virulent strain of Aeromonas salmonicida , and plasma components were examined by two-dimensional polyacrylamide electrophoresis . Two days after A. salmonicida LPS exposure, rainbow trout had a four- to five-fold increase in concentrations of plasma proteins composed of p48, p19 and p16 subunits, and a significant decrease in a 100-kDa protein group. Consistent elevation or depletion of proteins corresponding to previously reported rainbow trout A. salmonicida LPS-binding pentraxins and lectins in plasma were not observed. Brook trout exposed to A. salmonicida LPS did not have any consistent plasma protein changes. There were no significant alterations in major plasma proteins following temperature shock and prednisolone acetate administration in rainbow trout plasma. These studies demonstrate that rainbow trout with LPS-induced sterile inflammation have few alterations in major plasma proteins or LPS-binding proteins, and do not exhibit the spectrum of acute phase changes induced by inflammation in mammals.  相似文献   

Eumycetoma and disseminated phaeohyphomycosis in a Sumatran tiger     

Amanda R. Schaff  Sylvia Ferguson  Kristen Phair  Rachel Ferris  Alexandra Goe 《Journal of veterinary diagnostic investigation》2021,33(6):1197

A 16-y-old female Sumatran tiger (Panthera tigris sumatrae) was evaluated for hyporexia. Examination revealed chronic kidney disease and a large subcutaneous axillary mass with draining tracts that contained numerous small black grains. Histologic examination revealed the presence of intralesional fungal hyphae. Persistent hyporexia and pyogranulomatous disease, as well as progressive cachexia and azotemia occurred despite treatment, and euthanasia was performed. Disseminated phaeohyphomycosis was diagnosed on postmortem examination, additionally affecting various lymph nodes, the nasal cavity, mesenteric adipose tissue, abdominal aorta, pericardium, and kidney. Fungal culture from a deep-tissue sample isolated a pure growth of Curvularia sp., a dematiaceous opportunistic fungus able to cause eumycetomas and/or phaeohyphomycosis. Phaeohyphomycosis is a rare but emerging condition, not previously reported as disseminated disease in an exotic carnivore, to our knowledge. Aggressive systemic antifungal treatment was unsuccessful, likely complicated by diagnostic challenges and concurrent renal disease. The presence of a swelling with abundant grains exiting draining tracts should direct clinicians to the diagnosis of a mycetoma, warranting early and aggressive treatment.  相似文献   

Genomic comparison of virulent and non‐virulent Streptococcus agalactiae in fish          下载免费PDF全文

C M J Delannoy  R N Zadoks  M Crumlish  D Rodgers  F A Lainson  H W Ferguson  J Turnbull  M C Fontaine 《Journal of fish diseases》2016,39(1):13-29

Streptococcus agalactiae infections in fish are predominantly caused by beta‐haemolytic strains of clonal complex (CC) 7, notably its namesake sequence type (ST) 7, or by non‐haemolytic strains of CC552, including the globally distributed ST260. In contrast, CC23, including its namesake ST23, has been associated with a wide homeothermic and poikilothermic host range, but never with fish. The aim of this study was to determine whether ST23 is virulent in fish and to identify genomic markers of fish adaptation of S. agalactiae. Intraperitoneal challenge of Nile tilapia, Oreochromis niloticus (Linnaeus), showed that ST260 is lethal at doses down to 10² cfu per fish, whereas ST23 does not cause disease at 10⁷ cfu per fish. Comparison of the genome sequence of ST260 and ST23 with those of strains derived from fish, cattle and humans revealed the presence of genomic elements that are unique to subpopulations of S. agalactiae that have the ability to infect fish (CC7 and CC552). These loci occurred in clusters exhibiting typical signatures of mobile genetic elements. PCR‐based screening of a collection of isolates from multiple host species confirmed the association of selected genes with fish‐derived strains. Several fish‐associated genes encode proteins that potentially provide fitness in the aquatic environment.  相似文献   

Long‐term survival and colony growth of Acropora palmata fragments transplanted by volunteers for restoration          下载免费PDF全文

Graham E. Forrester  Megan A. Ferguson  Caitlin E. O'Connell‐Rodwell  Lianna L. Jarecki 《水产资源保护:海洋与淡水生态系统》2014,24(1):81-91

Evaluation of sunlight‐exposed pyrethroid‐treated netting for the control of face fly and housefly (Diptera: Muscidae)     

George W Peck  Holly J Ferguson  Jane T LePage  Vincent R Hebert  Sally D O'Neal  Douglas B Walsh 《Pest management science》2014,70(1):123-129

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Nuclear Configuration, Spindle Morphology and Cytoskeletal Organization of In Vivo Maturing Horse Oocytes     

MAR Siddiqui  EL Gastal  JC Ju  MO Gastal  MA Beg  OJ Ginther 《Reproduction in domestic animals》2009,44(3):435-440

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Book Review or Diatribe?     

Bruce Ferguson 《Australian veterinary journal》2009,87(6):213-213

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Syncytial hepatitis of farmed tilapia,Oreochromis niloticus (L.): a case report   总被引：1，自引：0，他引：1  

H W Ferguson  R Kabuusu  S Beltran  E Reyes  J A Lince  J del Pozo 《Journal of fish diseases》2014,37(6):583-589

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