Showing papers by "University of Veterinary Science published in 1996"

Sensitive ELISA Test for Determination of Ochratoxin A

Abstract: A direct, competitive enzyme-linked immunosorbent assay (ELISA) with monoclonal antibody has been developed for quantitative determination of ochratoxin A (OA) in different cereals. A dichloromethane/citric acid mixture was used for extraction of cereals. This cleanup procedure proved to be as effective for ochratoxin A extraction as protocols using strong acids. The mean within-assay and interassay coefficients of variation for the standard curve was <10%. The range of this test is 1−10 ng/g, with a detection limit of 0.5 ng/g OA. The toxin recovery from cereals infected with 5−100 ng/mL OA varied between 90 and 130%. Keywords: Ochratoxin A; ELISA; cereals

Complex study of the physiological role of cadmium. IV. Effects of prolonged dietary exposure of broiler chickens to cadmium.

Abstract: A 274-day long cadmium (Cd) feeding trial was carried out with broiler cockerel chickens. The diet of the control group (Cd-0, n = 6) contained no added Cd, whereas to the diet of group Cd-25 and group Cd-75 (n = 10 each) 25 ppm and 75 ppm Cd was added, respectively, in the form of CdSO4. The chickens were subjected to examinations described in detail earlier (Bokori et al., 1995b). In addition, the relative mass of five different organs (heart, liver, testis, spleen and brain), expressed as % of the body mass, was also determined. The clinical, gross and histopathological examinations and the assay of organs for mineral element content led to the following main findings. The feeding of diets containing 25 or 75 ppm Cd for more than 9 months did not cause signs indicative of acute Cd toxicosis or mortality in either group. The body mass gain of group Cd-75 chickens markedly decreased. Prolonged Cd exposure of the cockerels increased the relative mass of the liver and heart and markedly decreased that of the testes. The change in mass was proportional to the Cd load. The Cd-fed chickens developed focal pathological fatty infiltration of the liver, histiocytic infiltration of the jejunal mucosa and focal lympho-histiocytic interstitial infiltration and fibrosis of the kidney, which supports the view that prolonged Cd exposure leads to the development of subacute-chronic tissue changes in the kidney. The Cd content of the organs increased by one to three orders of magnitude, in direct proportion to the Cd load. The Cd content of most organs was 2 to 3 times as high as the value reported for broilers exposed to a similar Cd load lasting for 68 days (Bokori et al., 1995b). This indicates that the degree of Cd accumulation is markedly influenced by the duration of the Cd exposure. The highest Cd content was demonstrated in the kidney (724 mg/kg of dry matter). The Cd exposure markedly lowered the Zn, Mo and B content of the bones and the Ni content of the myocardium.

Characteristics of Malassezia pachydermatis strains isolated from canine otitis externa

Abstract: The morphological, cultural and biochemical characteristics of 80 M. pachydermatis strains isolated from cases of canine otitis externa were studied. Microscopically, the strains could be subdivided into two phenotypes. All M. pachydermatis strains grew well on Sabouraud glucose, yeast morphology and modified malt extract agar, but formed two distinct colony types. All strains were characterized by no fermentation. Assimilation of glucose, mannitol (42 strains), sorbitol (40 strains) and peptone was observed, but no ethanol assimilation. Urease and catalase tests were positive, while indole and acetoin production was not detected. All strains showed proteinase, caseinase, lecithinase and peroxidase positivity but to varying extents. Esterase activity was observed for all Malassezia strains when using Tween 20, 40 and 60, whereas Tween 80 was hydrolysed by only 42 strains. No coagulase or haemagglutinating activities were detected. When compared for satellite phenomenon and vitamin requirements, some Malassezia strains could not grow in the absence of nicotinic acid but grew well in the presence of staphylococci. In susceptibility tests, all strains showed the highest susceptibility to ketoconazole. On the basis of the biochemical differences, M. pachydermatis seems to be a heterogeneous species and can be divided into two groups.

Effects of bursectomy and thymectomy on the development of resistance to Cryptosporidium baileyi in chickens

Abstract: Comparisons were made between the course of infection with Cryptosporidium baileyi in normal chickens and in chickens with functional deficiencies in either B-lymphocytes (bursectomized) or T-lymphocytes (thymectomized). Bursectomy did not influence the acquired immune response to C. baileyi infection as measured by the oocyst excretion. However, the total oocyst output of bursectomized birds was less than a quarter of that of the controls due to the reduced site for multiplication of the parasite. The total oocyst output of thymectomized chickens was more than 2 times higher and the patency was 2 times longer as compared with control animals. Moreover, thymectomized birds failed to acquire resistance to the challenge infection. These findings attest to the primary role of cell-mediated immunity in the expression of resistance to C. baileyi as opposed to the antibody-mediated mechanisms.

Coagglutination test for serotyping Pasteurella haemolytica.

Abstract: A coagglutination test was described for simple, fast, and reliable detection of Pasteurella haemolytica type-specific antigens in lung lesions even in the absence of viable P. haemolytica. The coagglutinating reagents were prepared by coating protein A-producing Staphylococcus aureus cells with hyperimmune sera raised against P. haemolytica type strains. Bacterial suspensions, saline extracts, and boiled saline extracts of the bacteria were used as antigens. Homologous reactions with all types of antigens were precise. Some cross-reactions were similar to those obtained by the indirect hemagglutination test, and some additional one-way cross-reactions were identified. The coagglutination test was used for serotyping 65 P. haemolytica field strains and for the detection of P. haemolytica type-specific antigens in the lung specimens of 62 calves and 78 sheep. Ninety-four percent of the field strains could be serotyped by the coagglutination test. P. haemolytica type-specific antigens were detected in the lung specimens of 3 calves and 5 sheep that had succumbed to naturally occurring P. haemolytica pneumonia and in the lungs of 20 calves experimentally infected with P. haemolytica A1. The coagglutination test detected type-specific antigens in 36% of the lung specimens of slaughtered field sheep but not in the lungs of slaughtered field cattle with small chronic lung lesions. No reaction occurred in the case of nonpneumonic calves and sheep or when pneumonic lesions were caused by other bacteria. No P. haemolytica strains could be isolated from lung samples that were coagglutination test negative. This test is recommended as an additional method for fast and reliable serotyping of P. haemolytica.

Antioxidant Parameters and Ageing in Some Animal Species

Abstract: Connection between ageing and some tissue antioxidant parameters have been studied in four experiments on different animal species. Prenatal studies on the developing chick embryos showed discrepancies between the lipid-rich liver and brain antioxidant defence. In the liver, high levels of reduced glutathione (GSH), vitamins A and E and high activities of the antioxidant enzymes glutathione peroxidase (GPX) and superoxide dismutase (SOD) were found whereas brain expressed a high vitamin C concentration. In newborn healthy calves during the first two days of life, atmospheric oxygen tension did not cause either increased lipid peroxidation as reflected in a high malondialdehyde (MDA) level or any changes in GSII, GPX, SOD and catalase (CAT) activities in red blood cells (RBC). Plasma vitamin E and carotene concentrations also did not change. In growing healthy calves during two months after birth increasing MDA, decreasing GSH, GPX and CAT are leading features, whereas plasma vitamin E and carotene concentrations significantly increased. In young (1-year-old) and old (9-year-old) dogs RBC results showed significant differences with the highest MDA and lowest GSH levels in the old males. Activity of GPX and SOD was higher in old dogs than in the young ones, especially in the females.

Efficacy of ivermectin and moxidectin injection against larvae of wohlfahrtia magnifica (Diptera: Sarcophagidae) in sheep

Abstract: The therapeutic efficacies of ivermectin (Ivomec injection, Merck Sharp & Dohme B.V.) and moxidectin (Cydectin 1% injection, American Cyanamid Company) were evaluated in sheep naturally infested with larvae of Wohlfahrtia magnified. Sheep were randomly allocated to one of the 2 groups, each consisting of 19 animals. Sheep in one group received ivermectin and those in the other, moxidectin by subcutaneous injection at a dose of 0.2 mg/kg body weight. Evaluation was performed at 19, 24, 28, 39, 43, 48, 52, 63, 67, 72, 87, 96, 120, 144 and 168 h after treatment. At 144 and 168 h post-treatment, late third-instar larvae were collected from wounds of four sheep in both groups and from untreated, infested sheep. These larvae were reared in the laboratory to assess adult emergence. Neither ivermectin nor moxidectin was effective as a rapid acting treatment or as a long-term, or even short-term, prophylactic. Despite the treatment, 30–40% of sheep had live larvae at every evaluation. Although larvae disappeared from the wounds of some sheep in both groups after the treatment, the wounds in these animals failed to recover and were reinfested by larvae of W. magnified. On day 7 post-treatment the trial had to be finished because the majority of treated sheep were severely infested by Wohlfahrtia maggots. The average number of infested sheep in the two groups and the number of adults that were produced from larvae collected from treated sheep indicate that ivermectin and moxidectin did not differ significantly in efficacy.

Attempts to immunize chickens with Cryptosporidium baileyi oocyst extract.

Abstract: In order to study the possibility of immunization against Cryptosporidium baileyi with extracted crude antigen, Arbor Acres chickens were injected intramuscularly with 80 micrograms of C. baileyi oocyst-derived proteins (uninfected immunized, UI) or inoculated orally with 8 x 10(5) viable C. baileyi oocysts (infected control, IC) at 1 wk of age. The immunization was repeated in the UI group at 2 wk of age. Uninfected (UC) birds served as controls. All animals in UI, IC, and UC groups were challenged orally with 8 x 10(5) C. baileyi oocysts at the age of 4 wk. Blood samples were collected when birds were 4 and 6 wk of age, and sera were examined by enzyme-linked immunosorbent assay for the presence of antibodies against C. baileyi. Total oocyst output of UI chickens was about 60% of that of UC birds after challenge, and the prepatent and patent periods were nearly identical in the latter 2 groups. In contrast, IC birds developed complete resistance to challenge infections. These results suggest that immunization with the oocyst extract of C. baileyi may confer some degree of protection against oral challenge; however, the protection is less effective than that induced by primary oral infection. The lack of significant difference between the antibody responses of IC and UI animals to C. baileyi at 2 wk of age suggests that serum antibodies play little role in acquired resistance to challenge infection.

Comparison of characteristic components from chickens of different genotype kept in intensive and extensive farming systems

Abstract: Male and female Broiler chickens and male of Transylvanian naked-neck chickens kept in extensive and intensive farming systems were investigated. The leg and chest muscle of these chickens were used for the analysis. Muscle weight and muscle to bone ratio were significantly higher but protein content had a lower tendence in the muscle of Broiler chickens kept intensively as compared to the extensive way. There was no difference in the level of cholesterol between the animals from the two farming systems although the fat contents were much higher in the chickens kept intensively. The level of conjugated dienes and thiobarbituric acid reactive substances (TBARS) were found significantly less in the muscles of Broiler chickens kept extensively than those raised intensively which may be related to the lower fat content. Extensive farming system proved to be superior for Broiler (mainly in legs) and Transylvanian naked-neck chickens in the aspect of lowered lipid peroxidation and significant higher iron, zinc and thiamin levels. The higher protein and zinc levels showed a relationship with the better water binding capacity (WBC) in the legs of Broiler chickens kept extensively. Myristic and palmitic acid concentration in the fatty acid composition were higher in intensive Broilers as compared to the chickens kept extensively.

Body composition of mice of different body condition score and sex

Abstract: After a critical review ·of recent research on the whole body chemical composition of laboratory animals, especially that of the mouse, the authors pres­ ent data on the body composition of a mouse line of diflerent body condition score, varying from nonnal to double-muscled ("culard", "compact") type. One hundred male and 100 female mice of different compact categories were meas­ ured in vivo, using total body electrical conductivity (TOBEC method), then by direct chemical analysis perfonned on day 77 of life. In male mice, body weight and protein content were found to increase while fat content decreased parallel to the incn,ase in phenotypic condition score. Female mice showed a rather con­ stant fat, protein and ash content in the dry matter of the body. The precision and validity ofTOBEC data under 40 grams of body weight proved to be insufficient.

Bootstrap tests in correspondence analysis

Abstract: A bootstrap test is developed for testing models specified by Goodman in 1985 and 1986 for the correspondence analysis of two-way contingency tables. It enables testing goodness-of-fit in relation with the usual matrix decomposition method. An approximate table of critical values for the proposed test statistic is presented. Bootstrap confidence interval construction is also included. The behaviour of the test statistic and the confidence intervals is studied using Monte Carlo simulation.

The role of feed protein quality in reducing environmental pollution by lowering nitrogen excretion. III. Strategies of feeding: a review.

Abstract: To meet the requirements of pigs a better supply of amino acids can be achieved by using ileal digestibility data of feed ingredients in least-cost feed formulation. Digestibility of amino acids can be improved by addition of multienzyme products, antimicrobial additives and probiotics. Protein accretion may be positively influenced by beta-adrenergic agonists. An adequate ratio of protein to dietary energy is essential to achieve optimal protein utilization. Nitrogen output can be minimized by improving feed efficiency and by eliminating antinutritional substances with adequate processing. The use of the ideal protein concept helps to minimize nitrogen excretion. Management and animal hygiene also have a significant impact on the overall nitrogen balance in animal production.

Efficacy of a monensin-duokvin combination against Eimeria acervulina in chickens

Abstract: Anticoccidial efficacy of a drug combination monensin at 8 ppm plus the new antioxidant duokvin at 120 ppm in the feed was compared with that of monensin alone at the recommended level of 100 ppm against a field isolate of the coccidium Eimeria acervulina Tyzzer, 1929 in a battery study Both monensin and monensin duokvin combination were effective against E acervulina when judged by weight gain, feed conversion and faecal scores There was no significant difference in the chemoprophylactic activity of either treatments Neither monensin at 100 ppm nor the combination proved effective in terms of oocyst production In accordance with the earlier findings with E tenella, the combination seems appropriate for field trials

Influence of a deficient intake of high and low degradable protein on body composition, metabolic adaptation, production and reproductive performance in early lactation dairy cows.

Abstract: High-yielding dairy cows (n = 34) were divided into high (HD) and low (LD) protein degradability groups after delivery, and used for a feeding trial which lasted up to day 80 +/- 10 of lactation. The cows were regularly weighed, their body condition was scored (BCS), and their reproductive status assessed. Blood samples were taken simultaneously, and ruminal fluid was collected on the last day of the trial. On postpartum day 45 +/- 6 and 11 days thereafter two prostaglandin F2 alpha (PGF2 alpha) injections were administered. The ammonia and urea concentrations of the ruminal fluid were higher in cows of group HD. The C2:C3 ratio was 2.7:1 vs. 2.3:1 in HD and LD cows, respectively. The amino acid and lipid composition of blood reflected the dietary treatments. The BCS and blood urea concentration were slightly higher in HD animals. The average daily milk production of LD cows was 1.5 kg higher than that of HD cows. The pregnancy rates of the two groups at day 200 after calving did not differ, but LD cows showed their first visible oestrus and reconceived significantly (p < 0.05) later. It can be concluded that--at a marginal energy supply-a moderate (13%) deficiency of rumen-degradable protein during the first 10 weeks after calving can be more detrimental to reproductive performance than a severe (27%) deficiency of undegradable protein.

Susceptibility of Hydrotaea aenescens (Wiedemann) (Diptera: Muscidae) to selected insecticides and its importance in integrated fly management

Abstract: The doses lethal to 50% of the insects (LD50 values) obtained for a strain of Hydrotaea aenescens (Wiedemann) adults from a layer farm revealed higher sensitivity to 16 insecticides than those recorded for the susceptible WHO/SRS strain of the housefly. Because H. aenescens adults are about half the size of the housefly, the chemical compounds used for adult control may jeopardize the survival of Hydrotaea populations released in animal confinement houses. An efficient and economical combined application of biological and chemical control methods is possible only if the local management conditions and the dissimilar behavior of the adults of the two species are taken into consideration during the use of insecticides. Other suggestions and implications are further discussed.