Duck lymphocytes. VI. Requirement for phagocytic and adherent cells in lymphocyte transformation.

Preparations of duck (Anas platyrhynchos) spleen and blood lymphocytes depleted of cells capable of phagocytosing carbonyl iron gave lower transformation responses to the mitogens phytohaemagglutinin (PHA), concanavalin A (Con A), Bandeiraea simplicifolia seed lectin (BSS), wheat germ agglutinin (WGA), lentil lectin (LL) and phorbol ester (PMA) than intact cell preparations. When cell populations were fractionated on the basis of their adherence to plastic, it was found that the adherent cells were responsive to PHA, Con A, BSS, WGA and PMA, while the non-adherent cells responded to LL. These observations confirm the expected requirement for phagocytic accessory cells in the induction of in vitro mitogen-driven duck lymphocyte responses. The responses of plastic-adherent populations of cells to most mitogens are believed to reflect the generally close physical relationship between the adherent accessory cells and the lymphocytes, although it remains possible that duck monocytes respond to some of the mitogens employed. The data also suggest that LL stimulates a population of cells different to those responding to other mitogens.     

Detection and characterization of leptospiral antigens using a biotin/avidin double-antibody sandwich enzyme-linked immunosorbent assay and immunoblot.

A biotin/avidin double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) for the detection of antigens of Leptospira interrogans serovars in experimentally inoculated bovine urine samples was evaluated. Immunoglobulin G (IgG) from rabbits immunized with L. interrogans serovar hardjo type hardjobovis sonicated, whole cell, and formalinized-heated antigen preparations were purified by a protein A-superose column coupled to fast protein liquid chromatography, and evaluated for species specificity in the ELISA. The ELISA using each specific IgG detected as few as 10(4) leptospires of the homologous serovar hardjo diluted in phosphate-buffered saline solution with Tween 20 (PBSS-Tween 20). On immunoblot analysis of proteinase-K-digested whole cell leptospiral preparations, each IgG revealed the presence of bands specific to serovar hardjo, suggesting the presence of serovar-specific epitopes on the lipopolysaccharide molecules. The minimum number of cells of heterologous serovars pomona, grippotyphosa, bratislava, icterohaemorrhagiae and copenhageni detected by each ELISA was greater, ranging from 10(6) to 10(7). The common antigenic determinants observed on immunoblot analysis were different for each specific IgG, except for a major cross-reacting, possibly flagellar, protein doublet at approximately 36-36.5 kDa. Leptospires were equally well detected by the ELISA in both bovine urine and PBSS-Tween 20.     

Nutrient intake of horses in Thoroughbred and Standardbred stables

SUMMARY Twenty-five Thoroughbred (TB) and 25 Standardbred (SB) stables were visited to determine their feeding practices. The ingredients of the main feed of the day for a mature gelding of average size in full training were weighed at each stable. Nutrient content of diets was calculated using published data for the individual ingredients. Results are expressed as mean±sd. The estimated body weight of TB horses was 493±34 kg and 437±32 kg for SB horses. There was considerable variation in diet composition and nutrient intake between stables. The TB trainers fed 11.0±2.4 kg and SB trainers 11.8±2.5 kg per day. The concentrate component of the diet weighed 7.8±1.6 and 7.7±2.3 kg for TB and SB stables, respectively, and the roughage component for TB horses 3.3±1.4 and SB horses 4.1±1.4 kg per day. The digestible energy intake of horses at TB stables was 129±29 MJ per day and at SB stables 132±31 MJ per day. Crude protein intake of TB horses was 1452±363 g and SB horses 1442±338 g per day. There were differences in some feeding practices at TB and SB stables. Standardbred trainers fed more roughage than TB trainers. Standardbred trainers fed chaffed lucerne (alfalfa) and cereal hays as the major roughage, whereas TB trainers fed more hay. The major hay type fed by TB trainers was lucerne, whereas many SB trainers preferred clover hay. Both trainers fed oats as the major grain, but TB trainers fed slightly more maize (corn) than SB trainers. The SB trainers fed barley as part of the concentrate component of the diet, whereas TB trainers usually fed boiled barley and linseed oil in winter only. Although many trainers used vitamin and mineral supplements, this appeared unnecessary in many Instances, especially with respect to Iron. Calcium and NaCI supplementation was necessary for some diets. We concluded that while there was a wide range in feed intake and diet composition for both TB and SB horses, average nutrient intakes were similar to National Research Council (1989) recommendations for horses performing intense work.     

Aerobic bacterial isolates in horses in a university hospital, 1986-1988

Bacterial isolations were reviewed from equine trachea, guttural pouch, uterus, wounds, abscesses, blood, synovial fluid, and abdominal fluid submitted to the Clinical Bacteriology Laboratory of the School of Veterinary Medicine at the University of Montreal for aerobic bacterial culture from 1986 to 1988. Of the 733 samples submitted, 324 (44%) were positive for bacterial growth, and 233 antimicrobial sensitivity tests were performed. Seventy-six percent of all positive samples yielded one bacterial species and two were isolated from 22% of positive samples. Streptococcus zooepidemicus, Escherichia coli, and Actinobacillus spp. were isolated from 39%, 18%, and 15% of the samples, respectively.

Bacterial growth was most common from guttural pouches, wounds and abscesses, and transtracheal washes (TTW), but was less common from uterus, blood, abdominal fluid, and synovial fluids. Streptococcus zooepidemicus was the most common bacterium recovered from guttural pouches, TTW, uterus, and wounds and abscesses. Escherichia coli predominated in abdominal fluids, blood, and synovia. Bacterial sensitivities to common antimicrobials are presented.

     

Evaluation of a Killed Vaccine Against Porcine Pleuropneumonia Due to Haemophilus pleuropneumoniae

A bacterin containing serotypes 1 and 5 of Haemophilus pleuropneumoniae was developed for the prevention and the control of porcine pleuropneumonia. It was injected intramuscularly into three groups of ten piglets, the first group with one dose, the second one with two doses and the third one with three doses at two-week intervals. Another group of ten piglets did not receive the vaccine. All the piglets were then challenged by an aerosol of mixed suspensions of H. pleuropneumoniae serotypes 1 and 5. Two and three injections of vaccine completely prevented mortality, whereas half of the control piglets and of those receiving only one dose of vaccine died. All surviving piglets, both control and vaccinated, had severe signs of respiratory disease for at least 36 hours after exposure to challenge. Moreover, vaccination did not induce the production of antibodies at high titers. Local reactions were not noted after vaccination and at postmortem; ten weeks after the challenge, there were no signs of abscess formation or induration.     

Experimental transmission of intestinal coccidiosis to piglets: clinical, parasitological and pathological findings.

Twenty-eight piglets coming from a "specific pathogen free" herd were inoculated at three days of age with 50 000 or 100 000 sporulated oocysts of Isospora suis. Fecal samples were examined for oocyst shedding daily and several clinical parameters were recorded. Ten piglets were used as normal controls. Groups of piglets were euthanized from three days to 12 days postinoculation and routine necropsies were performed. Bacteriological, virological, parasitological and histopathological examinations were made on the intestinal tracts. The incubation period was four to five days. Clinical signs and microscopic intestinal lesions observed in the experimentally infected animals were similar to those reported in spontaneous cases of porcine neonatal coccidiosis. Lesions of villous atrophy in the small intestine seemed to result from the destruction of villous epithelial cells mainly during the peak of asexual reproduction which occurred around four to five days postinoculation. Intracellular coccidial organisms were difficult to find during the late atrophic and villous regrowth stages of the intestinal lesions. The prepatent period varied from four to seven days and the most common was five days. Eighty percent of the piglets kept alive more than four days postinoculation have shed oocysts. Piglets dosed with old sporulated oocysts (ten months old) shed many more oocysts than those infected with a fresh inoculum (less than two months old). The patent period was not determined precisely with the design of the experiment but some of the infected piglets shed oocysts for at least five days.     

Detection and genetic diversity of porcine rotavirus A,B and C in eastern Australian piggeries

Rotaviruses (RV) have a high prevalence in piggeries worldwide and are one of the major pathogens causing severe diarrhoea in young pigs. RV species A, B, and C have been linked to piglet diarrhoea in Australian pig herds, but their genetic diversity has not been studied in detail. Based on sequencing of the structural viral protein 7 (VP7) RVA G genotypes G3, G4 and G5, and RVC types G1, G3, G5, and G6 have been identified in Australian piggeries in previous studies. Although occurrence of RVB was reported in Australia in 1988, no further genetic analysis has been conducted. To improve health management decisions in Australian pig herds, more information on RV prevalence and genetic diversity is needed. Here, 243 enteric samples collected from 20 pig farms within Eastern Australia were analysed for the presence of RV in different age groups using a novel PCR-based multiplex assay (Pork MultiPath™ enteric panel). RVA, RVB, and RVC were detected in 10, 14, and 14 farms, respectively. Further sequencing of VP7 in selected RV-positive samples revealed G genotypes G2, G5, G9 (RVA), G6, G8, G14, G16, G20 (RVB), and G1, G3, G5, G6 (RVC) present. RVA was only detected in young (<10 weeks old) pigs whereas RVB and RVC were also detected in older animals (>11 weeks old). Interestingly, RVB and RVC G-type occurrence differed between age groups. In conclusion, this study provides new insights on the prevalence and diversity of different RV species in pig herds of Eastern Australia whilst demonstrating the ability of the Pork MultiPath™ technology to accurately differentiate between these RV species.