Morphologic changes in chicken cells after in vitro exposure to Mycoplasma gallisepticum     

Lam KM 《Avian diseases》2004,48(3):488-493

Mycoplasma gallisepticum (MG) was used to expose chicken peripheral blood lymphocytes (PBLs), red blood cells (RBCs), heterophils, and chicken tumor cells (MSB-1 and HD-11 cells). Incubation of PBLs with MG for 3 hr resulted in extensive clumping of lymphocytes. Incubation of the MSB-1 cells with MG also caused clumping of the cells, with many of the cells showing perforations and others showing capping of the surface projections. Incubation of RBCs with MG resulted in an altered cell surface morphology, a decrease in cell size, and perforation. There were no discernible changes on the surface of the heterophils and the HD-11 cells. However, the HD-11 cells appeared to have a decreased ability to attach to the surface of the plastic and to have a decreased ability to respond to chemoattractant fMLP after 24 hr of incubation. These results suggest that, under the conditions used, MG caused certain damage to peripheral blood cells and a significant decrease in chemotactic response in the HD-11 cells.  相似文献   

The immunostimulatory activity and stability of grass carp (Ctenopharyngodon idellus) roe lectin     

Ng TB  Lam YW  Woo NY 《Veterinary immunology and immunopathology》2003,94(3-4):105-112

A hexameric rhamnose-specific lectin with a molecular mass of 205kDa and exhibiting some N-terminal sequence similarity to other fish lectins was isolated from roe of the grass carp (Ctenopharyngodon idellus) by affinity chromatography on rhamnose-Sepharose and ion exchange chromatography by fast protein liquid chromatography on a Mono S column. The lectin exhibited mitogenic activity toward murine splenocytes with a potency lower than that of the plant lectin ConA. It exerted a stimulatory effect at a concentration of 10 micro g/ml on the phagocytic activity of seabream (Sparus sarba) macrophages. It was unstable toward heat (temperature > or =40 degrees C), acid (0.1M HCl), alkali (0.1M NaOH), trypsin and succinylation.  相似文献   

Mycoplasma mastitis in dairy cattle     

Tolboom RK  Snoep JJ  Sampimon OC  Sol J  Lam TJ 《Tijdschrift voor diergeneeskunde》2008,133(3):96-101

The most important characteristics of Mycoplasma mastitis on dairy farms are described, based on two case studies. Clinical symptoms, diagnostics, epidemiology, and a plan of action are presented. In the herds investigated, Mycoplasma mastitis was characterized by multiple affected quarters unresponsive to treatment with antibiotic and/or anti-inflammatory agents. Most striking were a sandy sediment, brown colouring, and rice-like structure of the milk of affected animals. Clinical symptoms differed in the two affected herds. Diagnosis was based on bacteriological investigation of samples of milk and synovial fluid taken from infected cows. Affected animals were culled immediately, and the herds were monitored by repeated testing of bulk milk samples. It was concluded that a consequence of the increasing size of cattle herds in the Netherlands is that subclinical/clinical Mycoplasma mastitis may be diagnosed more frequently than in the past. In the case of Mycoplasma mastitis, farmers and veterinary practitioners are advised to draw up a plan of action together, incorporating aspects such as diagnostics at cow level, direct culling of affected animals, hygiene during milking, including post-milking teat disinfection, and routine monitoring of bulk milk. Unpasteurized milk should not be given to calves.  相似文献   

Shear behaviour of laminated Douglas fir veneer     

L. P. Norlin  C. M. Norlin  F. Lam 《Wood Science and Technology》1999,33(3):199-208

The rolling shear and longitudinal shear behaviour of laminated Douglas fir veneers was studied using specimens with 15 layers of 2.5 mm veneers. The rolling shear specimens were constructed such that the 3 central veneers were cross-plies with grain angle oriented perpendicular to the long axis of the specimen. The other layers were orthogonal to the cross-plies. The longitudinal shear specimens had a LVL lay-up with the exception of a reinforcement layer of fiber-glass attached to the bottom face veneer. The fiber-glass layer prevented specimens from failing in bending/tension mode and ensured longitudinal shear failures. Specimens were subjected to static and cyclic loads in a “flatwise” three point bending configuration. It was found that the rolling shear failure mode exhibited a higher fatigue resistance than the longitudinal shear failure mode. A damage model that took the stress history into account was calibrated to the experimental data of each specimen type. Good agreement between model predictions and experimental results were obtained for both failure modes. Received 5 November 1997  相似文献   

Effect of Particle Size and Moisture Content on Viscosity of Fish Feed     

C. Desmond Lam  Rolando A. Flores 《Cereal Chemistry》2003,80(1):20-24

A model was developed for the influence of particle size on the extrusion of a fish feed and the physical characteristics of the extrudates evaluated. The study was conducted using factorial experiments in a fractional replication design for four variables with three levels, and one‐third of the replicates (3⁴ factorial in 27 units) were examined in a laboratory extruder. The torque‐screw speed measurement was used to develop a viscosity model equation that considered different shear rates, product temperature, initial moisture content, and particle size. When particle size decreased, the apparent viscosity became smaller. The barrel pressure was important in producing extrudate with a uniform volume over the range of processing conditions tested because it had a strong correlation with the volumetric expansion. The material with lower moisture and larger particles caused the specific mechanical energy to increase. The viscosity model developed in this study can be applied to the development of large‐scale extrusion models that determine the effect of particle size on the feed material extrudates.  相似文献   

Effects of cortisol on growth and development in tilapia larvae,Oreochromis mossambicus   总被引：1，自引：0，他引：1  

A. Mathiyalagan  P. K. Reddy  Professor T. J. Lam 《Fish physiology and biochemistry》1996,15(6):453-458

Treatment of one-day-old yolksac larvae of tilapia (Oreochromis mossambicus), by immersion in cortisol solution for two weeks, significantly enhanced growth. The standard length, tail length, head width and wet weight showed dose-dependent increases at concentrations of cortisol (hydrocortisone) from 0.05 ppm to 0.5 ppm, with no further increase at 1.0 ppm. However, cortisol at 5.0 ppm retarded the growth of the larvae without causing any morphological abnormality. Yolk absorption and the onset of free-swimming activity in the larvae were also accelerated by cortisol treatment.  相似文献   

Differential incorporation of conjugated linoleic acid isomers into egg yolk lipids   总被引：1，自引：0，他引：1  

Yang L  Huang Y  James AE  Lam LW  Chen ZY 《Journal of agricultural and food chemistry》2002,50(17):4941-4946

The incorporation pattern of conjugated linoleic acids (CLA) isomers into the egg yolk of hens in relation to that in the diet was studied. Silver-ion high-performance liquid chromatography (Ag-HPLC) was used to separate individual CLA isomers. It was found that the isomeric distribution pattern in the egg yolk lipids was different from that in the dietary fat. Total cis/trans isomers accounted for 81.2% of total CLA incorporated into the egg yolk, which was in contrast to the value of 92.0% of total CLA in the diet. Total cis/cis isomers accounted for 3.8% total CLA in the diet but they were 6.6% of the total CLA in the egg yolk lipids. In contrast, total trans/trans isomers were 12.2% of the total CLA isomers in the egg yolk lipids, whereas they were only 4.2% of total CLA in the diet. The results showed that total trans/trans-CLA was preferentially incorporated into the egg yolk, whereas the incorporation of total cis/trans-CLA isomers was partially discriminated. Within each group, the incorporation of individual isomers into the egg yolk lipids was also selective. cis-9,trans-11/trans-9,cis-11 and cis-10,trans-12/trans-10,cis-12 were the two major isomers in the diet. Ag-HPLC analysis showed that the former was preferentially transferred into the egg yolk compared with the latter. It was observed that supplementation of CLA in the diet of laying hens decreased the concentration of oleic acid (18:1n-9), arachidonic acid (20:4n-6), and docosahexaenoic acid (22:6n-3) but increased that of linolenic acid (18:3n-3), stearic acid (18:0), and palmitic acid (16:0) in the egg yolk, suggesting that CLA may inhibit Delta6 and Delta9 desaturases.  相似文献   

Fetus delivery as a useful method     

Lam TJ 《Tijdschrift voor diergeneeskunde》2000,125(13):429

  相似文献   

Managing animal wellbeing: a preliminary survey of pig farmers     

RL Wilson  PK Holyoake  GM Cronin  RE Doyle 《Australian veterinary journal》2014,92(6):206-212

  相似文献   

Streptomyces cyaneus dermatitis in a dog     

PK Nicholls  G Allen  PJ Irwin 《Australian veterinary journal》2014,92(1-2):38-40

  相似文献