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排序方式: 共有358条查询结果,搜索用时 15 毫秒
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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
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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
4.
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
5.
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
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.
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
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K. Haverson F. Zuckermann A. Saalmüller J. Lipp B. Aasted C. R. Stokes 《Veterinary immunology and immunopathology》1998,60(3-4):351-365
Fifty-nine monoclonal antibodies (mAb) were assigned to the adhesion section of the Second International Swine CD Workshop. They were analysed for their reactivity to selected lymphoid cell populations, as well as to non-lymphoid cell lines. Cell lysate ELISAS and Western Blot analyses were also carried out. As a result, thirteen separate cluster groups emerged (p>0.95). Workshop assignments for adhesion molecules were made: wCD29/49 for mAbs UCP1D2 (#133) and FW4-101 (#165), and PNK-I (#194) and MUC76A (#025) could be assigned to wCD18. For one cluster (FQ1D7, #161 and 2F4, #069) the cellular distribution and MW were characteristic for MHC Class II, and another cluster comprising several antibodies which appeared to recognise MHC Class I. Other clusters could not be assigned to cell surface structures known to be linked to cellular adhesion, however, two further antibodies, 335-2 (#112) and FG1F6 (#156), could be added to SWC1, and the new SWC8 was defined by MIL3 (#077) and MUC20A (#029), binding a ligand of 29–32 kDa. Clustering for these two antibodies was confirmed by blocking studies. The cellular distribution is known for MIL3, recognising an epitope present on granulocytes, B cells, and a subset of T cells expressing CD8 at high intensity. 相似文献