Implications of hypoxia tolerance for wetland refugia use in Lake Nabugabo,Uganda     

Andrea J. Reid  Maxwell J. Farrell  Max N. Luke  Lauren J. Chapman 《Ecology of Freshwater Fish》2013,22(3):421-429

Aquatic hypoxia can affect predator‐prey interactions by altering the success rate of the predator and/or the vulnerability of prey. For example, in the Lake Victoria basin of East Africa, native prey exploit hypoxic wetlands as refugia from predation by introduced Nile perch (Lates niloticus). Here, it is predicted that species exploitation of wetlands depends on their hypoxia tolerance relative to the heterogeneity of wetland hypoxia. In this study, we compared the hypoxia tolerance of four fish taxa that differ in their use of hypoxic wetlands in Lake Nabugabo, Uganda: the cichlid Pseudocrenilabrus multicolor victoriae that inhabits the dense swamp interior; and three taxa that inhabit wetland ecotones including Nile tilapia (Oreochromis niloticus), L. niloticus and juvenile endemic haplochromine cichlids. We characterised hypoxia tolerance by exposing fish to progressive hypoxia and quantifying variation in aquatic surface respiration (ASR). The effect of body size on tolerance was explored in L. niloticus by quantifying ASR behaviour across a range of size classes. ASR behaviour was also compared between O. niloticus groups from wetland versus open‐water habitats to detect habitat‐associated intraspecific variation. The most tolerant taxon was the swamp specialist P. multicolor, indicated by its low ASR thresholds and small percentage of fish using ASR during the final sample interval. The other three taxa did not differ in ASR behaviour, and no differences were detected between O. niloticus groups. Body size effects were present for L. niloticus suggesting a lower tolerance to hypoxia in larger‐bodied individuals, thus limiting their ability to penetrate wetlands.  相似文献   

Fathead minnow reproduction: Implications for commercial culture     

Nathan M. Stone  Luke A. Roy  Eric D. Park 《Journal of the World Aquaculture Society》2019,50(2):267-298

The fathead minnow, Pimephales promelas, is widely used as a bait, forage, and research fish in the United States. A hardy and fecund fish, this species has many attributes that are excellent for culture. Unfortunately, despite the widespread use of fathead minnows in toxicity testing and thousands of resulting publications, relatively little aquaculture‐related research has been conducted in support of commercial production. On the surface, current commercial fathead minnow production practices appear much the same as those of a decade ago. However, producers continue to refine culture methods, balancing broodfish stocking rates, spawning substrate quantity, and feeding rates in an attempt to meet both losses to predators and market demand. This review examines relevant reproduction‐related studies in the fields of ecology, behavior, toxicology, and aquaculture with the goal of advancing fathead minnow culture. In fathead minnow production, relative to the culture of food fish species, reproduction is vital, more so than rapid growth or a low feed conversion ratio. Fish numbers may exceed 1 million fish/ha, while feeding rates are relatively low and in feeder fish production, growth is deliberately restrained in order to maintain fish within market sizes year‐round. Underappreciated factors identified as affecting reproduction and with implications for commercial culture include: (a) poor egg adhesion to commonly used spawning substrates, (b) egg and fry cannibalism at high fish densities, and (c) the relatively short breeding period of individual males. Results highlight the importance of selecting an appropriate broodfish stocking rate based on fish size, anticipated pond fertility, and feeding program. New methods to improve reproductive performance will likely increase costs and will need to be accompanied by thorough economic analyses.  相似文献   

Results of a US and Canada community garden survey: shared challenges in garden management amid diverse geographical and organizational contexts     

Luke Drake  Laura J. Lawson 《Agriculture and Human Values》2015,32(2):241-254

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Diagnosis and management of Wegener's granulomatosis in a dog     

Krug W  Marretta SM  de Lorimier LP  White DK  Borst L 《Journal of veterinary dentistry》2006,23(4):231-236

A four-year-old maele/neutered mixed-breed dog was prsented for severe, multifocal, proliferative gingivitis. Histopathologic examination of incisional biopsies supported a diagnosis of Wegener's granulomatosis, an autoimmune vasculitis previously unreported in the veterinary literature. Diagnostic investigations for infectious, neoplastic, or other inflammatory conditions all provided negative results. Management with a combination of immunosuppressive agents resulted in complete resolution and remission of the presenting lesions and associated clinical signs.  相似文献   

The clinical presentation and surgical treatment of verrucous dermatitis lesions in a draught horse     

Poore LA  Else RW  Licka TL 《Veterinary dermatology》2012,23(1):71-5, e17

Verrucous pastern dermatitis is a progressive inflammatory skin disease commonly involving the palmar or plantar aspects of the pasterns of horses. There are no reports of successful surgical treatment for multifocal circumscribed verrucous masses in the chronic stages of verrucous pastern dermatitis. A combination of sharp dissection and electrocautery was used to resect numerous multifocal circumscribed verrucous masses from the distal hindlimb of an 11-year-old gelding draught horse. There was no evidence of significant regrowth or complications at a 24 month postoperative examination.  相似文献   

Congenital Aneurysmal Bone Cyst in a Foal     

Uneeda Bryant  Luke Fallon  Matilda Lee  Roy Pool 《Journal of Equine Veterinary Science》2012

A 2-week-old female Thoroughbred foal was born with a firm, expansile, progressively enlarging mass involving the left hemimandible. Grossly, the mass was composed of variably sized cavernous spaces containing clotted blood and serofibrinous exudate, separated by fibrous and fibroosseous septa. Histologically, the spaces were lined by flattened to plump spindle cells and contained hemorrhage, fibrin, and multinucleated osteoclast-like cells. The septa separating adjacent cavernous spaces contained interlacing bundles and streams of spindle cells, multinucleated giant cells, hemosiderophages, mineral deposits, and spicules and trabeculae of reactive and poorly mineralized bone. A diagnosis of congenital aneurysmal bone cyst was made based on histologic features. The pathogenesis for the development of aneurysmal bone cysts is still undetermined, although spindle cells lining cavernous spaces in the foal exhibited negative immunolabeling for factor-VIII (F8) and positive immunolabeling for smooth muscle actin, suggesting vascular smooth muscle origin and possible blood flow disturbance.  相似文献   

Focus on bovine mastitis: knowledge into practice   总被引：1，自引：0，他引：1  

O'Grady L  Doherty M 《Irish veterinary journal》2009,62(Z4):258

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Processing and storage effects on the ellagitannin composition of processed blackberry products     

Hager TJ  Howard LR  Prior RL 《Journal of agricultural and food chemistry》2010,58(22):11749-11754

Changes in blackberry ellagitannin composition in response to juicing (clarified and nonclarified), pureeing, canning (in water or syrup), and freezing as well as changes in processed products during 6 months of storage were investigated. Canning, pureeing, and freezing had little effect on ellagitannins, but processing berries into nonclarified and clarified juices resulted in total ellagitannin losses of 70 and 82%, respectively, due to removal of ellagitannin-rich seeds in the presscake. Minimal changes in total ellagitannin content were observed during storage of thermally processed products, but compositional changes indicative of ellagitannin depolymerization were apparent. The ellagitannin content and composition of frozen berries remained stable over 6 months of storage. Ellagitannins are well retained in canned, pureed, and frozen blackberries, but methods are needed to prevent losses during juice processing and/or exploit the ellagitannin-rich coproducts.  相似文献   

Discrimination of isolates of Mycobacterium bovis in Northern Ireland on the basis of variable numbers of tandem repeats (VNTRs)     

Skuce RA  McDowell SW  Mallon TR  Luke B  Breadon EL  Lagan PL  McCormick CM  McBride SH  Pollock JM 《The Veterinary record》2005,157(17):501-504

The ability to reproducibly discriminate Mycobacterium bovis isolates and trace their transmission has the potential to clarify sources of infection and major routes of transmission for bovine tuberculosis (TB). A PCR-based genotyping assay has been developed to discriminate between strains of M bovis by examining multiple sites in its genome that consist of variable numbers of tandem repeats (VNTRS). The discriminatory power and reproducibility of this VNTR typing has been compared with that of the established PCR-based spoligotyping technique by using a panel of 461 isolates of M bovis prevalent in Northern Ireland. The VNTR assay discriminated 40 different profiles, the most prevalent of which constituted 21 per cent of the total, compared with 14 profiles discriminated by spoligotyping, the most prevalent of which constituted 65 per cent. No significant differences were observed between the prevalences of the VNTR profiles in the years from 1999 to 2003. A preliminary evaluation indicated that most genotypes predominated in particular areas of the country. This VTNR typing assay was found to be highly discriminating, with the performance characteristics to support its systematic application to the molecular epidemiology of bovine TB.  相似文献   

Antibody responses of mares to prepartum vaccination with Clostridium perfringens bacterin and beta2 toxin     

Timoney JF  Hartmann M  Fallon L  Fallon E  Walker J 《The Veterinary record》2005,157(25):810-812

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