Polyclonal activation of B cells occurs in lymphoid organs from porcine reproductive and respiratory syndrome virus (PRRSV)-infected pigs

Porcine reproductive and respiratory syndrome virus (PRRSV) induces a persistent viral infection associated with an inefficient humoral immune response. A study of lymphoid B cells and specific humoral immune response was performed in blood and several lymphoid organs collected from PRRSV experimentally-infected pigs. Groups of specific pathogen-free (SPF) pigs were infected with the LHVA-93-3 isolate of PRRSV, and blood, tonsils, spleen and mediastinal lymph nodes (MLN) were collected at various times postinfection (p.i.) (3-60 days). Lymphoid cells were isolated, immunolabeled for cytofluorometric determination of B cell percentages, used for counting specific anti-PRRSV antibody secreting B cells by an ELISPOT assay, or cultured for metabolic activity. The presence of anti-PRRSV antibodies in the serum of infected pigs was determined using a commercial ELISA assay. Virus detection was performed in all tissues, including lungs, by virus isolation and RT-PCR. The results show that percentages of B cells increased in tonsils as soon as 3 days until 17 days p.i. in PRRSV-infected pigs while they increased in spleen at 3 days p.i. only, due to an increase of larger Ig(high)-producing B cells. Metabolic activity of lymphoid cells from blood and spleen increased at 3 days p.i. only while lymphoid cells from tonsils and MLN transiently decreased at that time and increased thereafter up to 60 days p.i. Anti-PRRSV antibody-secreting B cells occurred in tonsils after 10 days p.i. and strongly increased up to 60 days p.i. However, specific anti-PRRSV-secreting B cells were detected in blood and spleen after 17 days p.i and in MLN only after 45 days p.i. Specific antibodies were detectable in serum at 10 days p.i., reached the maximum level at 45 days and remained high up to 60 days p.i. Infectious virus was detected in lungs and MLN as soon as 3 days p.i., and remained detectable up to 45 days p.i. in tonsils of one pig while viral RNA was detected in most organs up to 60 days p.i. In vitro experiments revealed that inactivated virus induced a stimulation of lymphoid cells isolated from PRRSV-infected pigs while it was cytotoxic for lymphoid cells from control pigs. Taken together, these results indicate that viral infection induced simultaneously a polyclonal activation of B cells, mainly in tonsils, and an exaggerated and prolonged specific humoral immune response due to persistent viral infection in lymphoid organs.     

Pharmacokinetics and pharmacodynamics of butorphanol in llamas after intravenous and intramuscular administration.

OBJECTIVE: To evaluate disposition of butorphanol after i.v. and i.m. administration, effects on physiologic variables, and analgesic efficacy after i.m. administration in llamas. DESIGN: Nonrandomized crossover study. ANIMALS: 6 healthy adult male llamas. PROCEDURE: Butorphanol (0.1 mg/kg [0.045 mg/lb] of body weight) was administered i.m. first and i.v. 1 month later. Blood samples were collected intermittently for 24 hours after administration. Plasma butorphanol versus time curves were subjected to pharmacokinetic analysis. Two months later, butorphanol (0.1 mg/kg) was administered i.m., and physiologic variables and analgesia were assessed. RESULTS: Extrapolated peak plasma concentrations after i.v. and i.m. administration were 94.8 +/- 53.1 and 34.3 +/- 11.6 ng/ml, respectively. Volume of distribution at steady state after i.v. administration was 0.822 +/- 0.329 L/kg per minute and systemic clearance was 0.050 +/- 0.014 L/kg per minute. Slope of the elimination phase was significantly different, and elimination half-life was significantly shorter after i.v. (15.9 +/- 9.1 minutes) versus i.m. (66.8 +/- 13.5 minutes) administration. Bioavailability was 110 +/- 49% after i.m. administration. Heart rate decreased and rectal temperature increased. Somatic analgesia was increased for various periods. Two llamas became transiently sedated, and 2 became transiently excited after butorphanol administration. CONCLUSIONS AND CLINICAL RELEVANCE: Although i.v. administration of butorphanol results in a short half-life that may limit its analgesic usefulness, the elimination half-life of butorphanol administered i.m. is likely to be clinically useful. The relationship among plasma butorphanol concentration, time, and analgesia differed with the somatic analgesia model; clinically useful analgesia may occur at lower plasma concentrations than those reported here.     

Comparative study of different surface decontaminants on chicken quality

(1) A comparative study on the effect of different surface decontaminants: hot water at 70 degrees C for one minute; 2% lactic acid for 30 s; 1200 p.p.m. acidified sodium chlorite (ASC) solution for 5 s and 50 p.p.m. chlorine solution for 5 min in the form of dips and sprays on the surface of dressed broilers for 0, 24 and 48 h of storage was conducted. (2) The variables studied were, total plate count (TPC), presumptive coliform count (PCC), pH and extract release volume (ERV). All treatments reduced TPC and PCC. (3) Lactic acid dip and hot water dip were the most effective for reducing TPC (1.36 and 1.28 log/cm2, respectively) with no significant difference between them. (4) ASC and hot water in dip could diminish PCC (1.37 and 1.34 log/cm2, respectively) and did not vary significantly. (5) No treatment affected muscle pH, water holding capacity (WHC), ERV, appearance, smell, tenderness and overall acceptability of treated broilers significantly. (6) Hot water treatment is the cheapest, most convenient and simplest decontamination technique for hygienic and wholesome poultry production.     

Effect of dietary fumonisin B1 on laying Japanese quail

1. A 28-d experiment was conducted to evaluate the effects of fumonisin B1 (FB1) on egg production and egg quality of young laying Japanese quail fed on fumonisin-contaminated rations. 2. To this end, 128 7-week-old birds were randomly distributed into 4 experimental groups (32 birds per group) and given rations containing 0 (control), 10, 50 and 250mg FB1/kg feed. Each treatment consisted of 4 replicates of 8 quail. Egg production and egg weight were checked daily. Feed consumption and feed conversion were determined weekly. Eggs laid on the last day of each 7-d period were collected and subjected to individual analysis for specific gravity, Haugh units and percentage eggshell. 3. Compared with controls, quail given > or = 50 mg FB1/kg had reduced feed intake and lower body weight gain. Feed conversion was reduced only in birds given 250 mg FB1/kg. 4. Mean egg production and egg weight were lower in birds given 250mg FB1/kg. Eggshell weight was reduced in birds given > or =50mg FB1/kg. However, mean specific gravity, Haugh units and percentage eggshell were not affected by FB1. 5. No histopathological changes were observed in liver, kidney or heart samples from any treatment group. 6. The results indicated that exposure to FB1 at concentrations > or = 50 mg/kg could adversely affect quail performance, emphasising the importance of controlling fumonisin contamination of quail rations.     

Epidemiological, clinical, echo-doppler characteristics of mitral valve endocardiosis in Cavalier King Charles in France: a retrospective study of 451 cases (1995 to 2003)

A study performed on 451 Cavalier King Charles showed that 40.6% of dogs had a left apical systolic heart murmur, whose prevalence increased with age (> 11-year-old, 100%), but was not different between males and females. Mitral valve endocardiosis represented 93.3% of the ultrasonographic abnormalities.     

Association of markers in the bovine CAPN1 gene with meat tenderness in large crossbred populations that sample influential industry sires

Two previously identified single-nucleotide polymorphism markers located within the micromolar calcium-activated neutral protease gene (CAPN1) were evaluated for their association with variation in meat tenderness using one commercial sample of Simmental x Angus crossbred calves and one multibreed, crossbred research herd. The commercial sample included 362 animals sired by 23 registered Simmental bulls bred to unregistered Angus cows and represented current industry animals in which to test the predictive merit of the markers. The second sample was a research herd including 564 steers from the Germplasm Evaluation Cycle VII population at the U.S. Meat Animal Research Center, produced with semen from popular sires of the seven Bos taurus beef breeds with the most registrations in the United States (Angus, Charolais, Gelbvieh, Hereford, Limousin, Red Angus, and Simmental) on Angus, Hereford, and MARC III cows. These animals form a relatively outbred population that constituted a stringent test of the predictive merit of the genetic markers, although small groups were half-sibs. Warner-Bratzler shear force measurements were used to determine tenderness phenotypes for all animals. The populations were genotyped for two markers that predict variation at amino acid positions 316 and 530 of the mu-calpain polypeptide, produced by the CAPN1 gene. Minor allele frequencies for markers 316 and 530 in the commercial sample were 0.17 and 0.37, respectively, and in the Cycle VII animals, were 0.20 and 0.28, respectively. Both markers showed association with shear force in the commercial sample (P = 0.04) and the Cycle VII population (P = 0.02), supporting the hypothesis that they represent potential markers to aid selection for improved meat tenderness in commercial populations of beef cattle in the United States.     

SciQuest and the complete archive of the NZVJ launched online

The complete archive of the New Zealand Veterinary Journal went online on 1 January 2003 on SciQuest (www.sciquest.org.nz), an innovative new e-publishing website developed by the New Zealand Veterinary Association (NZVA). This follows hot on the heels of the CD-Rom version released from the same platform in June last year. Subscribers in 2003 will be able to search and retrieve, online, the full text of any article published in the journal since its inception in 1952. To date, few veterinary science journals are able to offer such a complete and comprehensive resource. SciQuest's mission is to provide high-speed access to science and continuing education articles to scientists and veterinarians in a fully indexed and searchable format, both online (via the internet) and offline (via CD-Rom). Searching and browsing the archive online is free and abstracts are available for all articles published from 1972 onwards. Access to full text, which is presented in PDF format exactly as published, is restricted to journal subscribers. The site will be updated with each issue of the journal as it is published. The online format will largely suit institutional users and casual enquiries, whereas the offline version is designed to be loaded onto computer hard drives for immediate access, any-time, and is better suited to frequent users and veterinary practitioners. A major advantage of the offline resource is its speed and immediacy, returning search results and full text much faster than the online version, without the need for internet access. The search engine has been designed to suit specific problem-oriented enquiries, and great effort has been expended to ensure the archive is both complete and accurate. The same search engine and interface has been provided on both versions, which allows for fast and highly specific searching of titles and full text of all articles for the occurrence of any word or combinations of words, as well as indexes of author, volume, year, article type, animal type and subject. Search results can be instantly sorted by author and date of publication, and powerful secondary search features such as 'by the same author', 'in the same issue' and 'same subject' links add power and flexibility. The offline version will be updated with annual releases and is available for purchase to subscribers and members of the NZVA.     

Attempt to control the day of ovulation in cycling pony mares by associating a GnRH antagonist with hCG

With the objective of controlling the day of ovulation, 40 mares were assigned to a control or three treated groups: A3d, A4d, and A5d. The treated groups received antarelix (Teverelix 0.01 mg/kg, i.v., twice a day) for 3, 4, or 5 days from the day the dominant follicle (F1) reached 28 mm (=D0), and one injection of hCG (1600 IU, i.v.) on D1, D2, or D3, respectively. Control mares received one injection of hCG when F1 reached 35 mm. Plasma LH, FSH, progesterone, and total estrogens were assayed. In the A3d, A4d, and A5d groups, 9 (90%), 6 (60%), and 5 (50%) out of 10 mares, respectively, ovulated on the expected day (i.e. between 24 and 48 h after hCG injection). In the control group, 7/10 (70%) presented the typical response to hCG. For 3 mares in both the A4d and A5d groups, the dominant follicle at the time the treatment was started did not ovulate and ovulation was postponed for between 11 and 15 days after the end of treatment. In the treated mares, the LH surge was abolished, and total estrogens were depressed during the preovulatory peak but the concentrations of FSH were not modified. Endocrine parameters were not altered in postponed cycles. Fertility did not differ in treated and control cycles. These results demonstrate that in mares: (1) ovulation can be programmed on a specific day of a 3-day period, with a success rate of 67%, by a treatment associating antarelix and one injection of hCG; (2) nevertheless in 20% of cases the dominant follicle regresses and does not ovulate; (3) for these mares ovulation is postponed by approximately 2 weeks; (4) terminal growth of the preovulatory follicle only requires low circulating concentrations of LH but atresia induced by a GnRH antagonist is significant when this treatment is administrated for more than 18 h.     

Genotypic prevalence of the adhesin involved in diffuse adherence in Escherichia coli isolates in pre-weaned pigs with diarrhoea in Korea

A total of 1002 Escherichia coli strains isolated from pre-weaned pigs with diarrhoea on 1114 swine farms were screened for the presence of the adhesin involved in diffuse adherence (AIDA) gene by polymerase chain reaction (PCR). Escherichia coli isolates that carried AIDA genes were also tested by PCR for the detection of five fimbriae (F4, F5, F6, F18 and F41), heat-stable (STa, STb) and heat-labile (LT) enterotoxin, enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1), and Shiga toxin 2 oedema disease (Stx2e) genes. Twenty-three (2.3%) of the 1002 E. coli isolates carried the gene for AIDA. Among 23 isolates shown to carry genes for AIDA, three carried the AIDA gene as the only shown virulence factor. Other isolates carried other virulence factor genes in addition to AIDA. Four isolates carried genes for at least one of the fimbrial adhesins and enterotoxins. Sixteen isolates carried genes for enterotoxins only. The AIDA may represent an additional virulence determinant in pre-weaned pigs with diarrhoea.