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

It has been over 50 years since vitamin E was originally described as a lipid-soluble dietary constituent required for normal reproduction in rats. Vitamin E is recognized as an essential vitamin required for all classes of animals functioning predominantly as an intracellular antioxidant in maintaining the integrity of biological cell membranes. Although a wealth of information has been gathered on clinical signs of vitamin E deficiency, establishing its requirements for animals has been exceedingly difficult because of interrelationships with other dietary constituents. Vitamin E requirements for animals cannot be defined in isolation. Requirements are influenced by the amount and type of fat (particularly with monogastrics) and degree of fat oxidation in the diet; the presence of antioxidants; dietary selenium (closely interrelated with vitamin E), iron, copper, and sulphur amino acids, as well as the physiological status of the animal. Other factors to be considered in assessing vitamin E needs of animals under commercial production conditions include: a) variability of vitamin E content in feedstuffs; b) poor stability of vitamin E during processing and storage of feeds; and c) management practices resulting in overstressed animals. Information on the function of or requirements for vitamin E in animals is very incomplete. Estimated dietary vitamin E requirements for most animal species are in the range of 10-40 IU/kg of diet. Of particular concern is the lack of vitamin E requirement information regarding young dairy and beef calves. Although good experimental evidence indicates a beneficial role of supplemental vitamin E above physiological levels on overall performance, enhanced immunocompetence and preservation of meat and milk products, levels of vitamin E required to produce these desired effects needs to be firmly established. Present estimated dietary requirements for vitamin E across species may need to be redefined as new information becomes available about the role this nutrient plays in growth, health and overall metabolism.

An indirect enzyme-linked immunosorbent assay (ELISA) has been developed for the rapid detection of antibodies to the porcine reproductive and respiratory syndrome (PRRS) virus in pig sera. Compared to the immunoperoxidase monolayer assay (IPMA) which was the only test available up till recently for serodiagnosis of the disease, the ELISA test proved to be more sensitive, particularly for early detection of antibodies. The test was also highly specific for the PRRS virus inasmuch as it scored negative all the hyperimmune sera directed to other swine viruses and the field sera sampled before the outbreak of the disease in Brittany (France). This easy test now provides further possibilities for epidemiological surveys and could also be a reliable tool for new sanitary prophylaxis of the disease.

Environmental pollution leads to increasing nitrate levels in dairy cattle's water supply. Possible repercussions regarding nitrate content in milk should therefore be considered. The results are presented of nitrate dosage in milk collected from cows provided with drinking water containing 0-180 mg/l nitrate. They show that drinking water has no significant effect on milk nitrate content which remains very low. It is concluded that this product does not constitute a health risk to consumers.

Porcine tracheae maintained in culture were used in order to study the colonization by Mycoplasma hyopneumoniae. Rings excised from tracheae of newborn piglets were infected with M hyopneumoniae strain BQ 14 and, after different incubation times, were examined by light and electron microscopy. Non-infected tracheal mucosae maintained a normal appearance for several days. Infected tracheal rings showed progressive colonization with concomitant progressive damage to the mucosal surface. Early on during the infection, few mycoplasmas occurred over a ciliated epithelium. As the infection progressed, there was gradual loss of cilia; mycoplasmas tended to form microcolonies and to accumulate over the remaining ciliated cells. Mycoplasmas, first seen at the apex of the cilia, were then seen deeper in the inter-ciliary space; some were even seen in contact with microvilli. In histological investigation, the final stage of the infection was characterized by a marked destruction of the epithelium with exfoliation of the epithelial cells. Infected mucosae showed typical damage caused by M hyopneumoniae, namely reduction of ciliary activity after 5 days, loss of cilia, and sloughing of ciliated cells. Our data indicate that porcine tracheal organ culture can be advantageously used to study colonization by M hyopneumoniae.

Pharmacokinetics and urinary excretion of sulfadiazine were determined in buffalo calves following single oral administration (150 mg/kg). Kinetic evaluation of plasma levels was performed using a 2-compartment model. The absorption half-life and elimination half-life were 3.41 +/- 0.63 and 13.75 +/- 1.94 h, respectively. Based on this study, an optimal dosage regimen of sulfadiazine in buffalo calves would be 165 mg/kg, followed by 75 mg/kg at 12-h intervals. Sulfadiazine was mainly excreted in the urine as free amine, while the percentage of acetylated sulfadiazine was comparatively low.

The aim of this study was to determine whether some muscular pathology existed in fighting bulls, in relation or not to the weakness shown in these animals during the bullfight (corrida for males and tienta for females). Creatinine kinase (CK), lactate dehydrogenase (LDH) and aspartate transaminase (AST) serum enzyme activities were increased after the corrida or the tienta. Most of the fighting bulls (78%) had some histological lesions in the skeletal or cardiac muscle, with predominance of chronic lesions. Clinical signs of these chronic lesions could only be seen after some trigger-effect, such as physical, exercise or stress, as shown after the corrida or tienta.