Haemonchus contortus is a constraint to sheep production. Seeking to reduce the use of hosts and ... more Haemonchus contortus is a constraint to sheep production. Seeking to reduce the use of hosts and produce parasitic stages in large-scale, a 42-day in vitro culture protocol of H. contortus third-stage larvae was optimized using Dulbecco’s modified Eagle’s medium (DMEM). In cell-free culture, larvae were maintained at 39.6°C, in acidic media (pH 6.1) for 3 or 6 days with Δ4-dafachronic acid followed by DMEM pH 7.4 supplemented or not with Fildes’ reagent. In DMEM pH 7.4 at 37°C, supplementation with Caco-2 cells was compared to Fildes. On Day 14, fourth-stage larvae (L4) development rates in acidic media supplemented (86.8-88.4%) or not (74.4-77.8%) with Fildes and in Caco-2 cell co-culture (92.6%) were similar, and superior to DMEM pH 7.4 with Fildes (0.0%). On Day 21, Caco-2 cell co-culture resulted in higher larvae differentiation (25.0%) and lower degeneration (13.9%) compared to acidic media (1.5-8.1% and 48.6-69.9%, respectively). This is the first report of prolonged in vitro ...
Gastrointestinal nematodes (GIN) are a major constraint for sheep production. Selection of animal... more Gastrointestinal nematodes (GIN) are a major constraint for sheep production. Selection of animals resistant to GIN infection is an effective and sustainable control strategy. In this study, the possibility of selection for resistance and resilience, as well as potential correlated responses, were evaluated. A total of 256 lambs and 123 ewes were submitted to two consecutive independent artificial infections with 4,000 infective larvae (L3) of Haemonchus contortus. Records of faecal egg count (FEC), packed cell volume (PCV), and body weight (BW) were taken serially until day 42 after infection in both challenges. Estimates of genetic parameters were obtained for individual records (in lambs) and for overall traits (in lambs and ewes) using mixed models. Phenotypic and genetic correlations were estimated between traits in lambs, with genetic correlations being based on estimated breeding values (EBVs). In addition, correlations between FEC in lambs and FEC in ewes, as well as PCV in lambs and ewes, were calculated. Heritability estimates for FEC in the first and second parasite challenge were, respectively, 0.25 ± 0.18 and 0.46 ± 0.19 for lambs, and 0.00 ± 0.09 and 0.20 ± 0.16 for ewes. For PCV, heritability estimates were 0.23 ± 0.14 and 0.32 ± 0.16 for lambs and 0.13 ± 0.11 and 0.37 ± 0.18 for ewes. For the overall daily weight gain (DWG), the heritability estimate was 0.70 ± 0.21. No significant genetic correlation was found between DWG and the other traits, while there was a negative genetic correlation between FEC and PCV (-0.70 ± 0.03). Genetic correlations of FEC and PCV between lambs and ewes were 0.36 ± 0.08 and 0.42 ± 0.08, respectively. The results of the present study suggest that selection for low FEC, high PCV and high BW/DWG is possible in Morada Nova lambs. Furthermore, selection for low FEC should have a correlated response on PCV (leading to higher PCV), while no correlated response is expected on DWG. Selection for low FEC in lambs would, in future generations, lead to higher resistance of lambs and also of ewes. Simultaneous selection for all three traits is possible in Morada Nova lambs, which would increase performance, decrease losses due to parasite infection and reduce the need for anthelmintic treatments, with beneficial consequences regarding selection pressure on parasite populations and productivity.bitstream/item/223811/1/Selection-Resistance-Resilience.pd
Additional file 2: Table S2. Significant variants detected by X-QTL mapping of monepantel resista... more Additional file 2: Table S2. Significant variants detected by X-QTL mapping of monepantel resistance in Haemonchus contortus from the RS population.
Additional file 1: Table S1. Significant variants detected by X-QTL mapping of monepantel resista... more Additional file 1: Table S1. Significant variants detected by X-QTL mapping of monepantel resistance in Haemonchus contortus from the SR population.
Gastrointestinal nematodes (GIN) are a major constraint in small ruminant production, in particul... more Gastrointestinal nematodes (GIN) are a major constraint in small ruminant production, in particular Haemonchus contortus, due to parasitic resistance spread worldwide.
Na ovinocultura, sao grandes os prejuizos causados tanto por Haemonchus contortus quanto pela res... more Na ovinocultura, sao grandes os prejuizos causados tanto por Haemonchus contortus quanto pela resistencia desse parasita aos anti-helminticos. Assim, no presente trabalho, foram investigados polimorfismos associados a resistencia ao monepantel em H. contortus apos sequenciamento genomico. Com taxas de mapeamento de 79,12% a 79,43% e cobertura de 64,54 a 71,22X, foram detectados Single Nucleotide Polymorphisms (SNPs) em exons e variantes de alto impacto nos genes codificantes para: subunidade de receptor nicotinico de acetilcolina, transportadores ABC, glicoproteina-P, proteinas afetadas por outros anti-helminticos, proteinas de canal de ions, peptidases, kinases e genes da maquinaria epigenetica de modificacao de histonas. Em analises de enriquecimento, destacaram-se genes envolvidos em locomocao, atividade de peptidase, canal de ions, transportador e receptor acoplado a proteina-G. Ainda, por investigacao in silico, foram encontradas evidencias da ausencia de metilacao do DNA em H....
E possivel selecionar ovinos mais resistentes as parasitoses dentro do proprio rebanho; Fenotipos... more E possivel selecionar ovinos mais resistentes as parasitoses dentro do proprio rebanho; Fenotipos; A selecao por OPG permite respostas favoraveis a obtencao de ovinos mais resistentes aos parasitos gastrintestinais; Tipos de desafio; Correlacao da selecao por OPG com caracteristicas produtivas; Programas de selecao; Desafio de campo.
A contaminacao de larvas de Tricostrongilideos em pastagem de capim-massai (Panicum maximum Jacq.... more A contaminacao de larvas de Tricostrongilideos em pastagem de capim-massai (Panicum maximum Jacq.) com tres niveis de irrigacao correspondentes a 0-50-100% de evapotranspiracao foi avaliada apos ser pastejada com ovinos durante o periodo de agosto 2015 e agosto 2016. O experimento foi realizado no municipio de Lageado, Tocantins, uma regiao com altas temperaturas e duas estacoes no ano: seca e chuvas. A hipotese foi de que haveria uma alta infeccao dos ovinos por parasitos em areas irrigadas de pasto, em funcao da melhor sobrevivencia dos parasitos em locais mais umidos. Os resultados mostraram que a pastagem nao ficou altamente infestada de parasitos, uma vez que os ovinos experimentais apresentaram baixa infestacao parasitaria. O fato de que a area foi mantida sem ruminantes nos ultimos 10 anos teve um efeito positivo, sem o aporte de carga residual de parasitos de outros animais.
Gastrointestinal nematodes significantly affect the ovine industry, andHaemonchus contortusis con... more Gastrointestinal nematodes significantly affect the ovine industry, andHaemonchus contortusis considered the most pathogenic parasite in tropical regions. This situation is aggravated when the main strategy to control worms fails because of the genetic resistance that parasites acquire against anthelmintics. Aiming to anticipate the events involved in anthelmintic resistance, we induced monepantel resistance inH. contortusbyin vivosubdosing of sheep hosts. Four successive passages of a monepantel-susceptibleH. contortusisolate in Santa Ines or Ile de France sheep hosts resulted in three monepantel-resistant (efficacy varying from 0 to 58.5%)H. contortusisolates. Sheep hosts were treated from 0.075 mg/kg to the therapeutic dose of 2.5 mg/kg of monepantel in 19–26 rounds of selection for 112–133 weeks. Success in inducingH. contortusresistance to monepantel may have been affected by worm burden and by host–parasite interactions, including a possible effect of the breed of sheep hosts....
Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 2019
RESUMO Este trabalho teve como objetivo avaliar a fauna parasitária de tambaquis na região do Bai... more RESUMO Este trabalho teve como objetivo avaliar a fauna parasitária de tambaquis na região do Baixo São Francisco-AL/SE-Brasil e correlacionar os índices de prevalência e intensidade média com fatores bióticos e abióticos. Foram coletados 252 espécimes para análise parasitológica de 10 pisciculturas. Os parasitos foram contabilizados, identificados, e determinaram-se os índices de prevalência e intensidade média, que foram correlacionados com fatores bióticos e abióticos. Dos peixes coletados, 65,5% estavam parasitados por pelo menos um táxon. Foram encontrados 10 táxons: Monogeneas, Ichthyophthirius multifiliis, tricodinídeos, Piscinoodinium pillulare, Ichthyobodo sp., Dolops carvalhoi, Lernaea cyprinacea, Procamallanus (Spirocamallanus) inopinatus, Henneguya sp. e Myxobolus sp. As maiores prevalências foram encontradas para Monogeneas (49,2%) e Myxobolus sp. (31,5%). Correlações negativas entre prevalência e fatores bióticos (peso e comprimento) foram observadas para Monogeneas (r...
Among the gastrointestinal nematodes affecting sheep, Haemonchus contortus is the most prevalent ... more Among the gastrointestinal nematodes affecting sheep, Haemonchus contortus is the most prevalent and virulent, resulting in health problems and production losses. Therefore, selecting sheep resistant to H. contortus is a suitable and sustainable strategy for controlling endoparasites in flocks. Here, 287 lambs of the native Brazilian Morada Nova hair sheep breed were subjected to two consecutive artificial infections with H. contortus and assessed for fecal egg count (FEC), packed cell volume (PCV), and live weight (LW). Forty-four animals ranked as having extreme resistance phenotypes were genotyped using the Illumina OvineSNP50v3 chip. A case–control genome-wide association study (GWAS) detected 37 significant (p < 0.001) markers in 12 ovine chromosomes in regions harboring quantitative trait loci (QTL) for FEC, Trichostrongylus spp. adults and larvae, weight, and fat; and candidate genes for immune responses, mucins, hematological parameters, homeostasis, and growth. Four sing...
Additional file 4: Table S4. Sample sequencing data available at the European Nucleotide Archive ... more Additional file 4: Table S4. Sample sequencing data available at the European Nucleotide Archive repository (study accession PRJEB33301).
Additional file 3: Table S3. Significant variants detected by X-QTL mapping of monepantel resista... more Additional file 3: Table S3. Significant variants detected by X-QTL mapping of monepantel resistance in Haemonchus contortus from both the SR and RS populations.
A verminose e um dos principais entraves na producao ovina da regiao Sul do Brasil. Tratamentos q... more A verminose e um dos principais entraves na producao ovina da regiao Sul do Brasil. Tratamentos quimioterapicos tem solucionado o problema, no entanto a crescente resistencia dos parasitas aos antihelminticos utilizados exige novas alternativas de controle.
Vantagens e desvantagens dos testes de campo e laboratoriais serao, portanto, abordados neste Com... more Vantagens e desvantagens dos testes de campo e laboratoriais serao, portanto, abordados neste Comunicado Tecnico, que tem por objetivo mostrar a tecnicos e ovinocultores (a) os fundamentos dos atuais testes de campo para a avaliacao dos isolados de parasitos de animais de campo como resistentes (ou nao) a principios ativos, e (b) os avancos obtidos com os testes laboratoriais de antiparasitarios na esperanca de facilitar a identificacao do antihelmintico mais recomendado, sem a necessidade de testes a campo.
Haemonchus contortus is a constraint to sheep production. Seeking to reduce the use of hosts and ... more Haemonchus contortus is a constraint to sheep production. Seeking to reduce the use of hosts and produce parasitic stages in large-scale, a 42-day in vitro culture protocol of H. contortus third-stage larvae was optimized using Dulbecco’s modified Eagle’s medium (DMEM). In cell-free culture, larvae were maintained at 39.6°C, in acidic media (pH 6.1) for 3 or 6 days with Δ4-dafachronic acid followed by DMEM pH 7.4 supplemented or not with Fildes’ reagent. In DMEM pH 7.4 at 37°C, supplementation with Caco-2 cells was compared to Fildes. On Day 14, fourth-stage larvae (L4) development rates in acidic media supplemented (86.8-88.4%) or not (74.4-77.8%) with Fildes and in Caco-2 cell co-culture (92.6%) were similar, and superior to DMEM pH 7.4 with Fildes (0.0%). On Day 21, Caco-2 cell co-culture resulted in higher larvae differentiation (25.0%) and lower degeneration (13.9%) compared to acidic media (1.5-8.1% and 48.6-69.9%, respectively). This is the first report of prolonged in vitro ...
Gastrointestinal nematodes (GIN) are a major constraint for sheep production. Selection of animal... more Gastrointestinal nematodes (GIN) are a major constraint for sheep production. Selection of animals resistant to GIN infection is an effective and sustainable control strategy. In this study, the possibility of selection for resistance and resilience, as well as potential correlated responses, were evaluated. A total of 256 lambs and 123 ewes were submitted to two consecutive independent artificial infections with 4,000 infective larvae (L3) of Haemonchus contortus. Records of faecal egg count (FEC), packed cell volume (PCV), and body weight (BW) were taken serially until day 42 after infection in both challenges. Estimates of genetic parameters were obtained for individual records (in lambs) and for overall traits (in lambs and ewes) using mixed models. Phenotypic and genetic correlations were estimated between traits in lambs, with genetic correlations being based on estimated breeding values (EBVs). In addition, correlations between FEC in lambs and FEC in ewes, as well as PCV in lambs and ewes, were calculated. Heritability estimates for FEC in the first and second parasite challenge were, respectively, 0.25 ± 0.18 and 0.46 ± 0.19 for lambs, and 0.00 ± 0.09 and 0.20 ± 0.16 for ewes. For PCV, heritability estimates were 0.23 ± 0.14 and 0.32 ± 0.16 for lambs and 0.13 ± 0.11 and 0.37 ± 0.18 for ewes. For the overall daily weight gain (DWG), the heritability estimate was 0.70 ± 0.21. No significant genetic correlation was found between DWG and the other traits, while there was a negative genetic correlation between FEC and PCV (-0.70 ± 0.03). Genetic correlations of FEC and PCV between lambs and ewes were 0.36 ± 0.08 and 0.42 ± 0.08, respectively. The results of the present study suggest that selection for low FEC, high PCV and high BW/DWG is possible in Morada Nova lambs. Furthermore, selection for low FEC should have a correlated response on PCV (leading to higher PCV), while no correlated response is expected on DWG. Selection for low FEC in lambs would, in future generations, lead to higher resistance of lambs and also of ewes. Simultaneous selection for all three traits is possible in Morada Nova lambs, which would increase performance, decrease losses due to parasite infection and reduce the need for anthelmintic treatments, with beneficial consequences regarding selection pressure on parasite populations and productivity.bitstream/item/223811/1/Selection-Resistance-Resilience.pd
Additional file 2: Table S2. Significant variants detected by X-QTL mapping of monepantel resista... more Additional file 2: Table S2. Significant variants detected by X-QTL mapping of monepantel resistance in Haemonchus contortus from the RS population.
Additional file 1: Table S1. Significant variants detected by X-QTL mapping of monepantel resista... more Additional file 1: Table S1. Significant variants detected by X-QTL mapping of monepantel resistance in Haemonchus contortus from the SR population.
Gastrointestinal nematodes (GIN) are a major constraint in small ruminant production, in particul... more Gastrointestinal nematodes (GIN) are a major constraint in small ruminant production, in particular Haemonchus contortus, due to parasitic resistance spread worldwide.
Na ovinocultura, sao grandes os prejuizos causados tanto por Haemonchus contortus quanto pela res... more Na ovinocultura, sao grandes os prejuizos causados tanto por Haemonchus contortus quanto pela resistencia desse parasita aos anti-helminticos. Assim, no presente trabalho, foram investigados polimorfismos associados a resistencia ao monepantel em H. contortus apos sequenciamento genomico. Com taxas de mapeamento de 79,12% a 79,43% e cobertura de 64,54 a 71,22X, foram detectados Single Nucleotide Polymorphisms (SNPs) em exons e variantes de alto impacto nos genes codificantes para: subunidade de receptor nicotinico de acetilcolina, transportadores ABC, glicoproteina-P, proteinas afetadas por outros anti-helminticos, proteinas de canal de ions, peptidases, kinases e genes da maquinaria epigenetica de modificacao de histonas. Em analises de enriquecimento, destacaram-se genes envolvidos em locomocao, atividade de peptidase, canal de ions, transportador e receptor acoplado a proteina-G. Ainda, por investigacao in silico, foram encontradas evidencias da ausencia de metilacao do DNA em H....
E possivel selecionar ovinos mais resistentes as parasitoses dentro do proprio rebanho; Fenotipos... more E possivel selecionar ovinos mais resistentes as parasitoses dentro do proprio rebanho; Fenotipos; A selecao por OPG permite respostas favoraveis a obtencao de ovinos mais resistentes aos parasitos gastrintestinais; Tipos de desafio; Correlacao da selecao por OPG com caracteristicas produtivas; Programas de selecao; Desafio de campo.
A contaminacao de larvas de Tricostrongilideos em pastagem de capim-massai (Panicum maximum Jacq.... more A contaminacao de larvas de Tricostrongilideos em pastagem de capim-massai (Panicum maximum Jacq.) com tres niveis de irrigacao correspondentes a 0-50-100% de evapotranspiracao foi avaliada apos ser pastejada com ovinos durante o periodo de agosto 2015 e agosto 2016. O experimento foi realizado no municipio de Lageado, Tocantins, uma regiao com altas temperaturas e duas estacoes no ano: seca e chuvas. A hipotese foi de que haveria uma alta infeccao dos ovinos por parasitos em areas irrigadas de pasto, em funcao da melhor sobrevivencia dos parasitos em locais mais umidos. Os resultados mostraram que a pastagem nao ficou altamente infestada de parasitos, uma vez que os ovinos experimentais apresentaram baixa infestacao parasitaria. O fato de que a area foi mantida sem ruminantes nos ultimos 10 anos teve um efeito positivo, sem o aporte de carga residual de parasitos de outros animais.
Gastrointestinal nematodes significantly affect the ovine industry, andHaemonchus contortusis con... more Gastrointestinal nematodes significantly affect the ovine industry, andHaemonchus contortusis considered the most pathogenic parasite in tropical regions. This situation is aggravated when the main strategy to control worms fails because of the genetic resistance that parasites acquire against anthelmintics. Aiming to anticipate the events involved in anthelmintic resistance, we induced monepantel resistance inH. contortusbyin vivosubdosing of sheep hosts. Four successive passages of a monepantel-susceptibleH. contortusisolate in Santa Ines or Ile de France sheep hosts resulted in three monepantel-resistant (efficacy varying from 0 to 58.5%)H. contortusisolates. Sheep hosts were treated from 0.075 mg/kg to the therapeutic dose of 2.5 mg/kg of monepantel in 19–26 rounds of selection for 112–133 weeks. Success in inducingH. contortusresistance to monepantel may have been affected by worm burden and by host–parasite interactions, including a possible effect of the breed of sheep hosts....
Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 2019
RESUMO Este trabalho teve como objetivo avaliar a fauna parasitária de tambaquis na região do Bai... more RESUMO Este trabalho teve como objetivo avaliar a fauna parasitária de tambaquis na região do Baixo São Francisco-AL/SE-Brasil e correlacionar os índices de prevalência e intensidade média com fatores bióticos e abióticos. Foram coletados 252 espécimes para análise parasitológica de 10 pisciculturas. Os parasitos foram contabilizados, identificados, e determinaram-se os índices de prevalência e intensidade média, que foram correlacionados com fatores bióticos e abióticos. Dos peixes coletados, 65,5% estavam parasitados por pelo menos um táxon. Foram encontrados 10 táxons: Monogeneas, Ichthyophthirius multifiliis, tricodinídeos, Piscinoodinium pillulare, Ichthyobodo sp., Dolops carvalhoi, Lernaea cyprinacea, Procamallanus (Spirocamallanus) inopinatus, Henneguya sp. e Myxobolus sp. As maiores prevalências foram encontradas para Monogeneas (49,2%) e Myxobolus sp. (31,5%). Correlações negativas entre prevalência e fatores bióticos (peso e comprimento) foram observadas para Monogeneas (r...
Among the gastrointestinal nematodes affecting sheep, Haemonchus contortus is the most prevalent ... more Among the gastrointestinal nematodes affecting sheep, Haemonchus contortus is the most prevalent and virulent, resulting in health problems and production losses. Therefore, selecting sheep resistant to H. contortus is a suitable and sustainable strategy for controlling endoparasites in flocks. Here, 287 lambs of the native Brazilian Morada Nova hair sheep breed were subjected to two consecutive artificial infections with H. contortus and assessed for fecal egg count (FEC), packed cell volume (PCV), and live weight (LW). Forty-four animals ranked as having extreme resistance phenotypes were genotyped using the Illumina OvineSNP50v3 chip. A case–control genome-wide association study (GWAS) detected 37 significant (p < 0.001) markers in 12 ovine chromosomes in regions harboring quantitative trait loci (QTL) for FEC, Trichostrongylus spp. adults and larvae, weight, and fat; and candidate genes for immune responses, mucins, hematological parameters, homeostasis, and growth. Four sing...
Additional file 4: Table S4. Sample sequencing data available at the European Nucleotide Archive ... more Additional file 4: Table S4. Sample sequencing data available at the European Nucleotide Archive repository (study accession PRJEB33301).
Additional file 3: Table S3. Significant variants detected by X-QTL mapping of monepantel resista... more Additional file 3: Table S3. Significant variants detected by X-QTL mapping of monepantel resistance in Haemonchus contortus from both the SR and RS populations.
A verminose e um dos principais entraves na producao ovina da regiao Sul do Brasil. Tratamentos q... more A verminose e um dos principais entraves na producao ovina da regiao Sul do Brasil. Tratamentos quimioterapicos tem solucionado o problema, no entanto a crescente resistencia dos parasitas aos antihelminticos utilizados exige novas alternativas de controle.
Vantagens e desvantagens dos testes de campo e laboratoriais serao, portanto, abordados neste Com... more Vantagens e desvantagens dos testes de campo e laboratoriais serao, portanto, abordados neste Comunicado Tecnico, que tem por objetivo mostrar a tecnicos e ovinocultores (a) os fundamentos dos atuais testes de campo para a avaliacao dos isolados de parasitos de animais de campo como resistentes (ou nao) a principios ativos, e (b) os avancos obtidos com os testes laboratoriais de antiparasitarios na esperanca de facilitar a identificacao do antihelmintico mais recomendado, sem a necessidade de testes a campo.
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