380 resultados para Ovine Paratuberculosis


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The mechanisms that regulate the gradual exit of ovarian follicles from the non-growing, primordial pool are very poorly understood. The objective of this study was to evaluate the effects of adding indole acetic acid (IAA), epidermal growth factor (EGF) and follicle stimulating hormone (FSH) to the media for in vitro culture of ovine ovarian fragments and determine their effects on growth activation and viability of preantral follicles. The ovarian cortex was divided into small fragments; one fragment was immediately fixed in Bouin (control). The other fragments were cultured for 2 or 6 days in culture plates with: minimum essential medium (MEM) supplemented with insulin-transferrin-selenium (ITS), pyruvate, glutamine, hypoxantine, bovine serum albumine and antibiotics (MEM+); MEM+ plus IAA (40 ng/mL); MEM+ plus EGF (100 ng/mL); MEM+ plus FSH (100 ng/mL); MEM+ plus IAA + EGF; MEM+ plus IAA + FSH; MEM+ plus EGF + FSH; or MEM+ plus IAA + EGF + FSH. After 2 or 6 days of culture in each treatment, the pieces of ovarian cortex were fixed in Bonin for histological examination. Follicles were classified as primordial or developing (primary and secondary) follicles. Compared to the control, in all media tested, the percentages of primordial follicles were reduced (P < 0.05) and the percentages of developing follicles were increased (P < 0.05) after 2 or 6 days of culture. Furthermore, culture of ovarian cortex for 6 days reduced the percentages of healthy, viable follicles when compared with the control (P < 0.05), except for cultures supplemented with IAA + EGF and EGF + FSH. In conclusion, the addition of IAA and EGF or EGF and FSH to the culture media were the most effective treatments to sustain the health and viability of activated ovine primordial follicles during in vitro culture. (c) 2005 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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In this study we optimized an enzyme-linked immunosorbent assay (ELISA) to evaluate bothropic venom levels in biological samples. These samples were obtained by two distinct protocols. In the first one, Swiss mice were injected with 1 LD 50 of Bothrops jararaca (B. jararaca) venom and 15 minutes later, animals were treated with ovine antibothropic serum. Blood and spleen homogenate samples were obtained 6 hours after antiserum therapy. Ovine antibothropic serum significantly neutralized venom levels in serum and spleen. In the second protocol, BALB/c mice were injected with 1 LD 50 of bothropic venom by either intraperitoneal (IP) or intradermal (ID) route and venom levels were evaluated 1, 3 and 6 hours after, in blood, spleen homogenates and urine. Serum and splenic venom levels were significantly higher in animals envenomed by IP route comparing with animals envenomed by ID route. Higher venom levels were also detected in urine samples from animals envenomed by IP route. However, these differences were not statistically significant. These results demonstrated that the optimized ELISA was adequate to quantify venom levels in different biological samples. This assay could, therefore, substitute the in vivo neutralizing assay and also be useful to evaluate the severity of human and experimental envenomations.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Molecular findings that confirmed the participation of ovine herpesvirus 2 (OVH-2) in the lesions that were consistent with those observed in malignant catarrhal fever of cattle are described. Three mixed-breed cattle from Rio Grande do Norte state demonstrated clinical manifestations that included mucopurulent nasal discharge, corneal opacity and motor incoordination. Routine necropsy examination demonstrated ulcerations and hemorrhage of the oral cavity, corneal opacity, and lymph node enlargement. Significant histopathological findings included widespread necrotizing vasculitis, non-suppurative meningoencephalitis, lymphocytic interstitial nephritis and hepatitis, and thrombosis. PCR assay performed on DNA extracted from kidney and mesenteric lymph node of one animal amplified a product of 423 base pairs corresponding to a target sequence within the ovine herpesvirus 2 (OVH-2) tegument protein gene. Direct sequencing of the PCR products, from extracted DNA of the kidney and mesenteric lymph node of one cow, amplified the partial nucleotide sequences (423 base pairs) of OVH-2 tegument protein gene. Blast analysis confirmed that these sequences have 98-100% identity with similar OVH-2 sequences deposited in GenBank. Phylogenetic analyses, based on the deduced amino acid sequences, demonstrated that the strain of OVH-2 circulating in ruminants from the Brazilian states of Rio Grande do Norte and Minas Gerais are similar to that identified in other geographical locations. These findings confirmed the active participation of OVH-2 in the classical manifestations of sheep associated malignant catarrhal fever.

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Scrapie and bovine spongiform encephalopathy (BSE) are both prion diseases affecting ruminants, and these diseases do not share the same public health concerns. Surveillance of the BSE agent in small ruminants has been a great challenge, and the recent identification of diverse prion diseases in ruminants has led to the development of new methods for strain typing. In our study, using immunohistochemistry (IHC), we assessed the distribution of PrP(d) in the brains of 2 experimentally BSE-infected sheep with the ARQ/ARQ genotype. Distribution of PrP(d) in the brain, from the spinal cord to the frontal cortex, was remarkably similar in the 2 sheep despite different inoculation routes and incubation periods. Comparatively, overall PrP(d) brain distribution, evaluated by IHC, in 19 scrapie cases with the ARQ/ARQ, ARQ/VRQ, and VRQ/VRQ genotypes, in some cases showed similarities to the experimentally BSE-infected sheep. There was no exclusive neuroanatomical site with a characteristic and specific PrP(d) type of accumulation induced by the BSE agent. However, a detailed analysis of the topography, types, and intensity of PrP(d) deposits in the frontal cortex, striatum, piriform cortex, hippocampus, mesencephalon, and cerebellum allowed the BSE-affected sheep group to be distinguished from the 19 scrapie cases analyzed in our study. These results strengthen and emphasize the potential interest of PrP(d) brain mapping to help in identifying prion strains in small ruminants.

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The progress in molecular genetics in animal breeding is moderately effective as compared to traditional animal breeding using quantitative genetic approaches. There is an extensive disparity between the number of reported quantitative trait loci (QTLs) and their linked genetic variations in cattle, pig, and chicken. The identification of causative mutations affecting quantitative traits is still very challenging and hampered by the cloudy relationship between genotype and phenotype. There are relatively few reports in which a successful identification of a causative mutation for an animal production trait was demonstrated. The examples that have attracted considerable attention from the animal breeding community are briefly summarized and presented in a table. In this mini-review, the recent progress in mapping quantitative trait nucleotides (QTNs) are reviewed, including the ABCG2 gene mutation that underlies a QTL for fat and protein content and the ovine MSTN gene mutation that causes muscular hypertrophy in Texel sheep. It is concluded that the progress in molecular genetics might facilitate the elucidation of the genetic architecture of QTLs, so that also the high-hanging fruits can be harvested in order to contribute to efficient and sustainable animal production.

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Limitations in the use of autologous bone graft, which is the gold standard therapy in bone defect healing, drive the search for alternative treatments. In this study the influence of rhTGFbeta-3 on mechanical and radiological parameters of a healing bone defect in the sheep tibia was assessed. In the sheep, an 18-mm long osteoperiosteal defect in the tibia was treated by rhTGFbeta-3 seeded on a poly(L/DL-lactide) carrier (n = 4). In a second group (n = 4), the defect was treated by the carrier only, in a third group (n = 4) by autologous cancellous bone graft, and in a fourth group (n = 2) the defect remained blank. The healing process of the defect was assessed by weekly in vivo stiffness measurements and radiology as well as by quantitative computed tomographic assessment of bone mineral density (BMD) every 4 weeks. The duration of the experiment was 12 weeks under loading conditions. In the bone graft group, a marginally significant higher increase in stiffness was observed than in the PLA/rhTGFbeta-3 group (p = 0.06) and a significantly higher increase than in the PLA-only group (p = 0.03). The radiographic as well as the computed tomographic evaluation yielded significant differences between the groups (p = 0.03), indicating the bone graft treatment (bone/per area, 83%; BMD, 0.57 g/cm(3)) performing better than the PLA/rhTGFbeta-3 (38%; 0.23 g/cm(3)) and the PLA-only treatment (2.5%; 0.09 g/cm(3)), respectively. Regarding the mechanical and radiological parameters assessed in this study, we conclude that rhTGFbeta-3 has a promoting effect on bone regeneration. However, under the conditions of this study, this effect does not reach the potential of autologous cancellous bone graft transplantation.