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排序方式: 共有229条查询结果,搜索用时 15 毫秒
1.
Effect of age on absorption and immune responses to weaning or introduction of novel dietary antigens in pigs 总被引:14,自引:0,他引:14
Pigs weaned at three weeks old absorb food protein antigens from the intestine. The amount of antigen absorbed declines over the next three weeks, and this decline is associated with an increasing level of serum antibody to the fed proteins. There was no difference in the rate of immune elimination of intravenously injected antigen in fed and unfed controls. The reduction of serum antigen is thus likely to reflect reduced absorption, possibly mediated by locally produced antibody. Pigs weaned at 10 weeks old also absorbed antigens and produced an antibody response when introduced to soya; and after three weeks of feeding soya the absorption of antigen was substantially reduced. This latter exclusion was specific for soya as a second novel protein (ovalbumin) was absorbed when introduced to the diet at this time. At six months, pigs no longer absorbed soya proteins when they were introduced to the diet. Furthermore, pigs of this age had serum 'antibody' to soya and other proteins such as keyhole limpet haemocyanin to which they had never been exposed. 相似文献
2.
Newby TJ Stokes CR Huntley J Evans P Bourne FJ 《Veterinary immunology and immunopathology》1979,1(1):37-47
The immune response of pigs fed 200 mg per day of dinitrophenylated bovine gamma globulin has been evaluated in terms of the antibody and lymphocyte responses and of the induction of tolerance and immune exclusion. Although dosing for ten days resulted in a small IgA response as indicated by splenic plaque forming cells, serum antibody could only be detected when dosing was continued for 42 days. secretory antibody was detected at any time. Antigen feeding for two weeks rendered the animals hyporesponsive to subsequent parenteral antigenic challenge but had little effect upon their ability to exclude an oral dose of antigen from the circulation. 相似文献
3.
Jennifer E Stokes S Dru Forrester 《Veterinary Clinics of North America: Small Animal Practice》2004,34(4):909-22, vi
This article provides a source for easy reference, summarizing in one location newly recognized and unusual causes of acute renal failure (ARF) in dogs and cats. Several of the causes discussed in this article have been described previously. New or unusual causes of ARF in dogs and cats include infectious diseases (leptospirosis,borreliosis, and babesiosis), nephrotoxicants (aminoglycosides,vitamin D, and nonsteroidal anti-inflammatory drugs), and plant material (lilies and raisins/grapes). 相似文献
4.
Bissett SA Drobatz KJ McKnight A Degernes LA 《Journal of the American Veterinary Medical Association》2007,231(12):1843-1850
OBJECTIVE: To determine prevalence, clinical features, and causes of epistaxis in dogs. DESIGN: Retrospective case series. ANIMALS: 176 dogs with epistaxis. PROCEDURES: Medical records were reviewed for information related to signalment, clinical features, diagnosis, and outcome. RESULTS: 132 (75%) dogs were initially examined by the hospital's emergency service; prevalence of epistaxis was 0.3%. Dogs with epistaxis were more likely to be old (> or = 6 years), male, and large (> or = 26 kg [58.5 lb]) than were dogs in a reference population. In 109 (62%) dogs with epistaxis, an underlying cause was identified; 115 underlying disorders were identified, with 90 classified as local and 25 classified as systemic. Local causes of epistaxis included nasal neoplasia (n = 35), trauma (33), idiopathic rhinitis (20), and periapical abscess (2). Systemic causes included thrombocytopenia (12), thrombocytopathia (7), coagulopathy (3), hypertension (2), and vasculitis (1). Dogs with local causes were more likely to have unilateral than bilateral epistaxis, but 11 of 21 (52%) dogs with systemic disorders also had unilateral epistaxis. Dogs with systemic disorders were more likely to have clinical signs of systemic disease. Duration of epistaxis (acute vs chronic), severity, and duration of hospitalization were similar for dogs with local versus systemic disorders. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that epistaxis was a common disorder in dogs and frequently regarded as an emergency. Local causes of epistaxis were predominant, but clinical features traditionally thought to be helpful in distinguishing local versus systemic causes could not be reliably used for this purpose. 相似文献
5.
We examined the foraging behaviour and habitat use of two species of small Australian mammal (Antechinus flavipes and Sminthopsis murina) in response to predation risk in remnant eucalypt woodland. Predation risk was manipulated by providing refuge in the form of ground level wire netting to reduce risks from avian and mammalian predators. Giving-up-densities (GUD) using artificial food trays (20 mealworms in 1.5 l vermiculite) quantified the foraging behaviour in response to predation risk, by measuring the quitting harvest rate. Both A. flavipes and S. murina had lower GUDs (number of mealworms remaining) under the netting than in the open, most likely because these areas have lower predation risk. Animals also made greater visits to tracking tunnels under the netting compared to in the open. Tracking animal movements using fluorescent pigments also revealed preference for natural microhabitats that were structurally complex with animals moving most where logs and rock crevices were present. These results suggest that small mammals may use habitat structure to reduce their risks of predation. If future studies are able to demonstrate commensurate population-level responses, manipulation of habitat may be a useful management option to complement the direct control of exotic predators such as foxes and feral cats. 相似文献
6.
Brian N. Hogg Keith Stokes Min B. Rayamajhi John Geiger Paul D. Pratt 《Weed Research》2020,60(3):212-220
Schinus terebinthifolia is a dioecious tree native to South America that has become an invasive weed in Florida, southern California, southern Arizona, Texas and Hawaii and has been naturalised in over 20 countries. Biological control is considered a viable long-term control option for S. terebinthifolia because release from natural enemies appears to be at least partly responsible for its success in Florida. We examined leaf phenology of S. terebinthifolia over a period of 15 months at five sites in central and southern Florida to provide information that may help in predicting the impacts of potential biocontrol agents for this weed. We documented leaf lifespan, the seasonality of leaf development and abscission and the survivorship of leaves that emerged during either spring, summer or autumn. Average leaf lifespan was >4.5 months at all sites, and leaf phenology followed the seasons closely. Although S. terebinthifolia possesses leaves throughout the year, leaf production was greatest from April to September, and most leaves were abscised in February and March. Spring- and summer-emerging leaves were also longer-lived than leaves produced during autumn. These results suggest that leaves of S. terebinthifolia would be most vulnerable to herbivory during the spring and summer months when newly growing leaf tissue is most plentiful. Biocontrol agents capable of damaging these tissues during spring/summer might be an effective means of controlling this invasive weed. 相似文献
7.
8.
Domitilla Pulcini Tommaso Russo Paola Reale Alexia Massa‐Gallucci Grace Brennan Stefano Cataudella 《Aquaculture Research》2014,45(3):397-409
Prolonged exposure to captive conditions has led to the development of a rainbow trout ‘farmed’ phenotype, which is different from that of wild trout. Selection for desirable productive traits in hatcheries has resulted in the development of some morphological traits that are maladaptive in nature. The recent development of organic aquaculture, guided by the well‐being of the fish, could potentially produce a new farmed phenotype that would be more adaptive in nature. In this study, rainbow trout reared in intensive and organic farms were compared by means of shape analysis, to detect patterns of shape variation associated with rearing environment. The results of this study highlight a significant effect of the rearing method on rainbow trout shape: organically reared trout showed a higher body profile, in particular in the head and trunk regions, shorter median fins and a deeper caudal peduncle. A combined effect of density and habitat complexity could have contributed to the observed shape differences: in organic rearing systems, lower densities and steady water could increase territoriality and aggressive interactions, promoting body designs more functional in rapid attacks and escapes. 相似文献
9.
Valérie Sauvé DMV Kenneth J. Drobatz DVM MSCE DACVIM DACVECC Amy B. Shokek VMD Alexia L. McKnight DVM DACVR Lesley G. King MVB DACVIM DACVECC 《Journal of Veterinary Emergency and Critical Care》2005,15(1):38-47
Objective: Correlate the necropsy diagnosis with the history, diagnostic findings, and clinical course of dyspneic cats with primary lung parenchymal disease. Design: Retrospective study. Setting: Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania. Animals: Client‐owned cats over 6 months of age hospitalized in the Intensive Care Unit (ICU) with a primary problem of respiratory distress that had pulmonary parenchymal disease on thoracic radiographs, and a complete necropsy. Interventions: None. Measurements and main results: Cats included were assigned into 2 groups based on the pulmonary histopathology: inflammatory (n=8) and neoplastic (n=7) disease. No statistical difference was found between the groups with regard to age, body weight, clinical signs, duration of clinical signs, physical examination findings, thoracic radiography, duration of hospitalization, treatment, and outcome. Cats with neoplasia had a statistically higher mean total white blood cell count (26.60 k/μL±10.41) than those with inflammatory lung disease (11.59 k/μL±4.49; P=0.026). Cats with bacterial or viral pulmonary disease had a significantly shorter median duration of illness (5 days, range 1–7 days) than all other cats (30 days, range 7–365 days; P=0.0042). Ultrasound guided pulmonary fine‐needle aspiration (FNA) provided an accurate diagnosis in 5/5 cases. Conclusions: Forty‐seven percent of cats with pulmonary parenchymal disease had neoplasia. The clinical diagnosis was difficult to obtain ante‐mortem; lung FNA appeared to be the most helpful diagnostic tool in these cases. 相似文献
10.
Lavage techniques were used to obtain secretions from the nasal cavity, trachea and bronchi of conscious horses. The techniques, which utilised fibreoptic endoscopy for recovery of tracheal and bronchial secretions, were well tolerated by the horses. The recovery rates of the lavaged fluids were acceptable, but were lowest for bronchial secretions, and there was minimal contamination by blood. The fluids were analysed for IgG and IgM by single radial immunodiffusion, and for IgA and albumin by rocket immunoelectrophoresis. Relative to albumin there was significantly more IgA and IgM, and significantly less IgG, in the nasal cavity than the trachea. IgA and IgM levels were greatest in the nasal cavity and decreased progressively to the bronchi, whereas IgG levels showed the reverse trend. The immunoglobulin: albumin ratios of secretions taken from many levels of the tract were significantly higher than those of serum, suggesting local production of immunoglobulin in the respiratory tract. 相似文献