RESUMO
Genetic disorders in Holstein cattle are a health problem that has grown worldwide in recent years, compromising the sustainability of modern dairy production. In Uruguay, Holstein-based milk production is one of the most important sectors of the countrys economy, but high levels of inbreeding have decreased the breeds fertility in recent decades. This study investigated the presence and diffusion of lethal and semi-lethal alleles causing embryo death, abortions, fetal malformations, and neonatal diseases in Holstein calves. Using the GeneSeek® Genomic Profiler Bovine 50K BeadChip, we genotyped 383 calves (1-30 days-old) from 27 farms located in the main dairy region of Uruguay. Results showed a high prevalence of farms (85%) and carrier calves (21%), including one or more of the following semi-lethal or lethal alleles: Syndactylism (4.18%), brachyspina (3.39%), cholesterol deficiency haplotype (2.61%), complex vertebral malformation (2.09%), bovine leukocyte adhesion deficiency (1.04%s), and Holstein haplotypes HH1 (4.44%), HH3 (3.13%), HH4 (1.04%), and HH5 (0.26%). Most of these alleles had not been recognized previously in Uruguay. We concluded that lethal and semi-lethal mutations are widespread in the Holstein breed in Uruguay. More studies are required to determine their impact on dairy cattle fertility.(AU)
Os distúrbios genéticos nos bovinos da raça Holandesa são um problema de saúde que cresceu nos últimos anos a nível mundial, comprometendo a sustentabilidade da produção leiteira moderna. No Uruguai, a produção leiteira com base na raça Holstein é um dos setores mais importantes da economia do país, mas altos níveis de endogamia diminuíram a fertilidade da raça nas últimas décadas. O objetivo deste estudo foi investigar a presença e difusão de alelos letais e semi-letais causando morte de embriões, abortos, malformações fetais e doenças neonatais em bezerros da raça Holandesa. Usando o BeadChip Bovino 50K GeneSeek® Genomic Profiler, genotipamos 383 bezerros (menos de um mês) de 27 fazendas localizadas na principal região leiteira do Uruguai. Os resultados mostraram uma alta prevalência de fazendas (85%) e bezerros portadores (21%), incluindo um ou mais dos seguintes alelos letais ou semi-letais: sindactilismo (4,18%), braquipespina (3,39%), haplótipo de deficiência de colesterol (2,61%), malformação vertebral complexa (2,09%), deficiência de adesão de leucócitos bovinos (1,04% s) e haplótipos de Holstein HH1 (4,44%), HH3 (3,13%), HH4 (1,04%) e HH5 (0,26%). A maioria desses alelos não havia sido reconhecida anteriormente no país. Concluímos que as mutações letais e semi-letais são comuns na raça Holstein no Uruguai. Mais estudos são necessários para determinar seu impacto na fertilidade do gado leiteiro.(AU)
Assuntos
Animais , Bovinos , Doenças dos Bovinos/congênito , Doenças dos Bovinos/embriologia , Doenças dos Bovinos/genéticaRESUMO
Pathogen spillover from wildlife to humans or domestic animals requires a series of conditions to align with space and time. Comparing these conditions between times and locations where spillover does and does not occur presents opportunities to understand the factors that shape spillover risk. Bovine rabies transmitted by vampire bats was first confirmed in 1911 and has since been detected across the distribution of vampire bats. However, Uruguay is an exception. Uruguay was free of bovine rabies until 2007, despite high-cattle densities, the presence of vampire bats and a strong surveillance system. To explore why Uruguay was free of bovine rabies until recently, we review the historic literature and reconstruct the conditions that would allow rabies invasion into Uruguay. We used available historical records on the abundance of livestock and wildlife, the vampire bat distribution and occurrence of rabies outbreaks, as well as environmental modifications, to propose four alternative hypotheses to explain rabies virus emergence and spillover: bat movement, viral invasion, surveillance failure and environmental changes. While future statistical modelling efforts will be required to disentangle these hypotheses, we here show how a detailed historical analysis can be used to generate testable predictions for the conditions leading to pathogen spillover.
Assuntos
Migração Animal , Doenças dos Bovinos/embriologia , Quirópteros , Monitoramento Epidemiológico/veterinária , Vírus da Raiva/fisiologia , Raiva/veterinária , Animais , Bovinos , Vigilância da População , Raiva/epidemiologia , UruguaiRESUMO
Bovine neosporosis has become a disease of international concern as it is among the main causes of abortion in cattle. Viable N. caninum has been isolated from brains of fetuses and neonatal calves, and there is no report of isolation of tachyzoites from kidney. Also, detailed information about the genetic diversity of N. caninum is scarce. N. caninum tachyzoites were isolated from the kidney and the brain of an aborted 4-month-old bovine foetus. The parasite was confirmed to be N. caninum by PCR. The tachyzoites of the new isolate, named BNC-PR4, were propagated in Vero cell cultures. Pathogenicity of the parasite was examined in BALB/c mice. Mice inoculated intraperitoneally with BNC-PR4 failed to yield clinical signs of disease and did not induce severe brain lesions, suggesting a bovine isolate with low virulence. The N. caninum-positive DNA sample was further analyzed by multilocus microsatellite (MS) genotyping for MS4, MS5, MS6A, MS6B, MS7, MS8, MS10, MS12, and MS21. Multilocus-microsatellite genotyping revealed a unique genetic profile that differed from previously reported isolates.
Assuntos
Feto Abortado/parasitologia , Encéfalo/parasitologia , Doenças dos Bovinos/parasitologia , Coccidiose/veterinária , Rim/parasitologia , Neospora/isolamento & purificação , Aborto Animal/parasitologia , Animais , Encéfalo/embriologia , Brasil , Bovinos , Doenças dos Bovinos/embriologia , Chlorocebus aethiops , Coccidiose/embriologia , Coccidiose/parasitologia , DNA de Protozoário/química , DNA de Protozoário/isolamento & purificação , Indústria de Laticínios , Feminino , Rim/embriologia , Camundongos , Camundongos Endogâmicos BALB C , Neospora/genética , Neospora/patogenicidade , Células Vero , VirulênciaRESUMO
In vitro-produced bovine embryos become infected after exposure to bovine Herpesvirus type 5 (BoHV-5), yet no changes in developmental rates, mitochondrial activity and inhibition of apoptosis are detected in comparison to unexposed embryos. Thus, the aim of the present study was to assess the transcription of mitochondria-mediated apoptosis genes using TaqMan real-time polymerase chain reaction. Transcripts of mcl-1, caspase-2, -3, Apaf-1 and Bax genes were measured after exposure to BoHV-5 in vitro. Mitochondrial dehydrogenase activity was evaluated by MTT test and compared between groups of exposed and unexposed embryos, at day 7 of development. The rate of oocyte maturation was assessed by the extrusion of the first polar body. In summary, BoHV-5 exposed embryos retained their viability, mitochondrial dehydrogenase activity and displayed up-regulation of transcription of survival mcl-1 gene and down-regulation of Bax transcription in relation to mitochondria-mediated pathway which might improve embryo viability. These findings demonstrate that BoHV-5 exposed embryos maintain their viability and mitochondrial dehydrogenase activity with no compromise of embryos produced in vitro.
Assuntos
Embrião de Mamíferos/citologia , Embrião de Mamíferos/virologia , Genes Mitocondriais , Infecções por Herpesviridae/patologia , Herpesvirus Bovino 5/fisiologia , Animais , Apoptose , Bovinos , Doenças dos Bovinos/embriologia , Doenças dos Bovinos/virologia , Regulação da Expressão Gênica no Desenvolvimento , Infecções por Herpesviridae/embriologia , Infecções por Herpesviridae/veterinária , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Oócitos/fisiologia , Oócitos/virologia , Reação em Cadeia da Polimerase em Tempo RealRESUMO
BACKGROUND: Bovine Herpesvirus type-5 (BoHV-5) is a neurovirulent α-Herpesvirus which is potentially pathogenic for cows and suspected to be associated with reproductive disorders. Interestingly, natural transmission of BoHV-5 by contaminated semen was recently described in Australia. Additionally, BoHV-5 was also isolated from the semen of a healthy bull in the same country and incriminated in a natural outbreak of reproductive disease after artificial insemination. In contrast with BoHV-1, experimental exposure of in vitro produced bovine embryos to BoHV-5 does not affect embryo viability and seems to inhibit some pathways of apoptosis. However, the mechanisms responsible for these phenomena are poorly understood. In this study, we examined mitochondrial activity, antioxidant protection, stress response and developmental rates of in vitro produced bovine embryos that were exposed and unexposed to BoHV-5. METHODS: For this purpose, bovine embryos produced in vitro were assayed for cell markers after experimental infection of oocytes (n = 30; five repetitions), in vitro fertilization and development. The indirect immunofluorescence was employed to measure the expression of superoxide dismutase 1 (SOD1), anti-oxidant like protein 1 (AOP-1), heat shock protein 70.1 (Hsp 70.1) and also viral antigens in embryos derived from BoHV-5 exposed and unexposed oocytes. The determination of gene transcripts of mitochondrial activity (SOD1), antioxidant protection (AOP-1) and stress response (Hsp70.1) were evaluated using the reverse transcriptase polymerase chain reaction (RT-PCR). MitoTracker Green FM, JC-1 and Hoechst 33342-staining were used to evaluate mitochondrial distribution, segregation patterns and embryos morphology. The intensity of labeling was graded semi-quantitatively and embryos considered intensively marked were used for statistical analysis. RESULTS: The quality of the produced embryos was not affected by exposure to BoHV-5. Of the 357 collected oocytes, 313 (+/- 6.5; 87.7%) were cleaved and 195 (+/- 3.2; 54.6%) blastocysts were produced without virus exposure. After exposure, 388 oocytes were cleaved into 328 (+/- 8.9, 84.5%), and these embryos produced 193 (+/- 3.2, 49.7%) blastocysts. Viral DNA corresponding to the US9 gene was only detected in embryos at day 7 after in vitro culture, and confirmed by indirect immunofluorescence assay (IFA). These results revealed significant differences (p < 0.05) between exposed and unexposed oocytes fertilized, as MitoTracker Green FM staining Fluorescence intensity of Jc-1 staining was significantly higher (p < 0.005) among exposed embryos (143 +/- 8.2). There was no significant difference between the ratios of Hoechst 33342-stained nuclei and total cells in good-quality blastocysts (in both the exposed and unexposed groups). Using IFA and reverse transcriptase polymerase chain reaction (RT-PCR) for the set of target transcripts (SOD1, AOP-1 and Hsp 70.1), there were differences in the mRNA and respective proteins between the control and exposed embryos. Only the exposed embryos produced anti-oxidant protein-like 1 (AOP-1). However, neither the control nor the exposed embryos produced the heat shock protein Hsp 70.1. Interestingly, both the control and the exposed embryos produced superoxide dismutase (SOD1), revealing intense mitochondrial activity. CONCLUSION: This is the first demonstration of SOD1 and AOP-1 production in bovine embryos exposed to BoHV-5. Intense mitochondrial activity was also observed during infection, and this occurred without interfering with the quality or number of produced embryos. These findings further our understanding on the ability of α-Herpesviruses to prevent apoptosis by modulating mitochondrial pathways.
Assuntos
Apoptose , Blastocisto/virologia , Ectogênese , Herpesvirus Bovino 5/metabolismo , Mitocôndrias/metabolismo , Peroxirredoxina III/metabolismo , Superóxido Dismutase/metabolismo , Animais , Blastocisto/metabolismo , Blastocisto/patologia , Bovinos , Doenças dos Bovinos/embriologia , Doenças dos Bovinos/metabolismo , Doenças dos Bovinos/patologia , Doenças dos Bovinos/virologia , Fase de Clivagem do Zigoto/metabolismo , Fase de Clivagem do Zigoto/patologia , Fase de Clivagem do Zigoto/virologia , Feminino , Fertilização in vitro/efeitos adversos , Fertilização in vitro/veterinária , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Infecções por Herpesviridae/embriologia , Infecções por Herpesviridae/patologia , Infecções por Herpesviridae/veterinária , Infecções por Herpesviridae/virologia , Herpesvirus Bovino 5/isolamento & purificação , Técnicas de Maturação in Vitro de Oócitos , Masculino , Mitocôndrias/enzimologia , Mitocôndrias/virologia , Oócitos/fisiologia , Oócitos/virologia , Peroxirredoxina III/genética , RNA Mensageiro/metabolismo , Superóxido Dismutase/genética , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismoRESUMO
Bovine Herpesvirus type-5 (BoHV-5), which is potentially neuropathogenic, was recently described to be related with reproductive disorders in cows. The objective was to elucidate mechanisms involved in propagation of BoHV-5 in embryonic cells. For this purpose, bovine embryos produced in vitro were assayed for apoptotic markers after experimental infection of oocytes, in vitro fertilization, and development. Host DNA fragmentation was detected with a TUNEL assay, expression of annexin-V was measured with indirect immunofluorescence, and viral DNA was detected with in situ hybridization. Infective BoHV-5 virus was recovered from embryos derived from exposed oocytes after two consecutive passages on Madin-Darby bovine kidney (MDBK) cells. The viral DNA corresponding to US9 gene, localized between nucleotides 126243 to 126493, was detected in situ and amplified. There was no significant difference between the ratio of TUNEL stained nuclei and total cells in good quality blastocysts (0.87 ± 0.05, mean ± SD), but there were differences (P < 0.05) between infected (0.18 ± 0.05) and uninfected blastocysts (0.73 ± 0.07). The Annexin-V label was more intense in uninfected embryos (0.79 ± 0.04; P < 0.05). The quality of infected and uninfected embryos was considered equal, with no significant effect on embryonic development. In conclusion, we inferred that BoHV-5 infected bovine oocytes, replicated, and suppressed some apoptotic pathways, without significantly affecting embryonic development.
Assuntos
Apoptose/fisiologia , Embrião de Mamíferos/virologia , Desenvolvimento Embrionário/fisiologia , Infecções por Herpesviridae/veterinária , Herpesvirus Bovino 5/fisiologia , Animais , Anexina A5/genética , Anexina A5/metabolismo , Bovinos , Doenças dos Bovinos/embriologia , Doenças dos Bovinos/transmissão , Doenças dos Bovinos/virologia , Fertilização in vitro , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Marcação In Situ das Extremidades Cortadas , Transmissão Vertical de Doenças Infecciosas/veterináriaRESUMO
The purpose of this study was to characterize the exposure of bovine aborted fetuses from beef and dairy herds of the humid pampas of Argentina to different infectious agents by the evaluation of fetal fluid antibodies. Presence of fetal antibodies to bovine viral diarrhea virus genotype 1 (BVDV-1), bovine herpes virus type 1 (BHV-1), Leptospira interrogans, Brucella abortus, and Neospora caninum was determined. Of the 95 fetuses processed, 66 came from 49 beef herds and 29 from 12 dairy herds. The average gestational age of the aborted fetuses was 7.1 months. Antibodies to the mentioned agents were detected in 65 of the 95 fetal fluids (68.4%). In addition, antibodies to more than one infectious agent were detected in 32 fetuses (33.7%), suggesting fetal exposure to multiple antigens during gestation. There were antibodies to BVDV-1, BHV-1, N. caninum and Leptospira interrogans in 43 (45.2%), 29 (30.5%), 26 (27.4%) and 5 (5.2%) specimens, respectively. Antibodies to B. abortus were not detected in any of the fetal fluids. The results of this study provide information on the determination of antibodies in fluids from bovine aborted fetuses exposed to different infectious agents in the region.
Assuntos
Aborto Animal/imunologia , Doenças dos Bovinos/imunologia , Doenças Fetais/veterinária , Feto/imunologia , Complicações Infecciosas na Gravidez/veterinária , Aborto Animal/embriologia , Aborto Animal/epidemiologia , Líquido Amniótico/imunologia , Animais , Argentina/epidemiologia , Bovinos , Doenças dos Bovinos/embriologia , Doenças dos Bovinos/epidemiologia , Feminino , Doenças Fetais/epidemiologia , Doenças Fetais/imunologia , Idade Gestacional , Herpesvirus Bovino 1/imunologia , Leptospira interrogans/imunologia , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Complicações Infecciosas na Gravidez/imunologiaRESUMO
A retrospective study was conducted on two farms in Trinidad to determine the impact of retained foetal membranes (RFM) on reproductive efficiency in dairy cattle. The measures of reproductive efficiency examined were days open, services per conception, calving interval, and first-service conception rate.(AU)