Annales de recherches veterinaires. Annals of veterinary research最新文献

The illegal use of anabolics in 1989-1990 and its control in Belgium are reviewed. After a short presentation of the Belgian legislation and EEC directives, a recent hormone scandal published by a consumer magazine is related and the composition of 17 hormone cocktails found on the black market is given. The strategy of control involves screening of the main artificial anabolics in urine by radioimmunoassay (RIA) and confirmation by thin-layer chromatography (TLC). Samples of fat and injection sites are also examined by TLC. In the future, RIA will probably be replaced by enzyme immunoassay and TLC by mass spectrometry.

Carbohydrate metabolism of 62 glucidolytic strains of mycoplasma belonging to 4 species (M ovipneumoniae, M putrefaciens, M mycoides, M capricolum) has been studied using the API 50 Ch system for bacterial identification. This microtechnique and colony aspect were relevant in distinguishing M ovipneumoniae and M putrefaciens from the group M mycoides and M capricolum isolated from goats, but still presented a lack of specificity in distinguishing M mycoides from M capricolum. Similar results were obtained when the mycoplasma strains were tested by electrophoresis.

A new means of access to the encephalic ventricles in the cow has been proposed, consisting of the catheterization of the olfactory recess, situated approximately 25 mm under the skin in the frontal region, vertically from a point situated 15 mm laterally from the median plane at the level of a line drawn between the lateral angles of the eyes. Radiographs show that a radioopaque medium can be diffused throughout the cavities on both sides.

Three monoclonal antibody (anti-HN Mab 3115) resistant variants of the Newcastle disease virus (NDV) La Sota strain, were selected (a25, b23, a16); once cloned and shown by haemagglutination inhibition, ELISA and Western blot, not to bind to Mab 3115 they were used as experimental vaccines for chicken. The intracerebral pathogenicity index (ICPI) of a25 and b23 variants was low (0.2 and 0.0 respectively). Three to 4 weeks post-administration of alive variants or inactivated b23, respectively administered via eye drop and subcutaneously, the protection against a challenge was not different from that following La Sota vaccination. Antibody titers induced by a25 and b23, as measured by 2 ELISA blocking tests (the first employing a NDV specific Mab 2114, the second employing Mab 3115), were significantly lower (P less than 0.001) than post-challenge antibody titers. On the contrary, the difference between post-La Sota vaccination antibodies and post challenge antibodies was weak (P less than 0.02). Following 3 successive exposures by contact of chickens to live b23 variant, no variation in antibody titers was observed as measured by ELISA employing Mab 3115. This constituted a necessary criterion, but insufficient to test the stability of the b23 variant. At the same time, the latter exhibited poor ability to diffuse. Vaccination with these variants should be considered in differentiating post-vaccinal from post-infectious antibodies.

The aim of the experiment was to evaluate in pregnant ewes the clinical, bacteriological and serological effects of conjunctival instillation of S abortusovis. An individual dose of 1 x 10(10) viable S abortusovis were administered to 20 ewes 92 d after mating. Among 18 pregnant ewes, 8 aborted 110 +/- 13 d after mating, 4 had stillborn lambs and 6 a clinically normal lambing (114 +/- 1.3 d). S abortusovis was isolated from placentas, swabs and foetuses of the 12 lambings. Evolution of "H" agglutination titers measured by means of a microtechnique using a coloured antigen was found to be independent of the clinical results. Instillation by conjunctival route could constitute an experimental model closer to a natural mode of infection than the subcutaneous route.

The sensitivity of 701 Gram negative strains, representing 16 species or bacterial genera, towards 4 antiseptics (cetrimide, chlorhexidine, hexachlorophene, mercuric chloride) and 6 antibiotics (ampicillin, streptomycin, erythromycin, chloramphenicol, kanamycin, tetracycline) was analysed. For 3 antiseptics (cetrimide, chlorhexidine, mercuric chloride) minimal inhibitory concentration distribution showed strains to be heterogeneous, particularly in the group Pseudomonas. Most strains were resistant to antibiotics. The statistical analysis of correlation showed positive resistance links between antiseptics (cetrimide, chlorhexidine, hexachlorophene) or between these antiseptics and antibiotics for S marcescens and Alcaligenes. Many strains proved resistant, at the same time, to mercuric chloride and to several antibiotics. These associations of resistance suggest either a common mechanism of action or a crossed resistance.

The toxicity of benzamido-2-nitro-5-thiazole (BNT) and 3 derivatives was studied on Lymnaea peregra ovata and Gammarus pulex pulex. These results were compared with the toxicity obtained by application of a basic product, niclosamide. The evaluation of LC50 (50% lethality concentration) was studied to evaluate the toxicity of each product after 4 different assay periods: 24, 48, 72 and 96 h. The compounds had a high toxicity against snails. Molluscicidal effect was higher than the lethal activity against Crustacea. The ortho substitution decreased the toxicity of products compared with BNT.

The prevalence and level of infection with Fasciola hepatica were assessed monthly over a 12-month period in goats slaughtered in the Haouz area, in correlation with the dynamics of Lymnaea truncatula populations. The infection rate was high in winter (23.8%) in January), and summer (17.1% in August), and relatively low in spring and at the beginning of autumn. The infected animals had a fluke burden range of 1-48; a mean of 13 was recorded in July. Lymnaeid snails were observed in their habitat throughout the year, but were more abundant during the hot months (July and August). Snails infected with F hepatica were found in February, June, July and August; their infection rate did not exceed 3%. These data enabled us to hypothesize that the main periods for transmission of fascioliasis were spring and fall; however, potential infections during other periods of the year were possible. The susceptibility of goats to infection with F hepatica appears to be similar to that reported in sheep.

In vivo covalent binding of trenbolone and estradiol was assayed using either radiolabeled compounds or 32P-post labeling. The covalent binding index, as measured with tritiated molecules, was 2.4 for the alpha isomer of trenbolone, 5.4 for its beta isomer and 5.4 for 17-beta estradiol. Using 32P-post labeling at repeated medium doses or a single high dose did not allow any of the 3 compounds to reveal specific adducts in the background of adducts spontaneously formed in control animals. It can therefore be concluded that these steroids most probably do not have a direct genotoxic action.

The EEC policy (prohibition on the use of anabolics in cattle breeding) has released a succession of negative effects, and in particular the breaking off of the commercial relationship with regard to meat exchange and the appearance of an intensive black market. It has involved strong reactions from the USA as well as from other countries.