Integrating technologies for the sustainable control of gastrointestinal parasites in sheep : The Argentinean case

Gastrointestinal nematode infections in sheep are a major concern among breeders due to the economic losses they cause in terms of a reduction in both productivity and viability of animals. The situation worsens in face of the emergence of anthelmintic-resistant parasites. In this context, breeding and management practices aimed at an integrated control of parasites, such as raising parasiteresistant sheep, are required. This study focused on the genetic variation underlying parasite resistance in sheep, for potential use in breeding programmes. An artificial challenge with infectious H. contortus L3 was carried out in the northeast region of Argentina for more than 10 years in 1 072 Corriedale lambs with an average age of 5.6 months. Body weight, faecal egg count, packed cell volume, and FAMACHA© score were recorded at different time points post-challenge and their heritability and phenotypic and genetic correlations were estimated. Animals were genotyped on 173 single nucleotide polymorphisms belonging to 77 candidate genes for immune response. The results indicate that there is sufficient genetic variability for the four traits studied, which presented moderate heritabilities (in the range 0.29 to 0.44) and increased along the challenge period, with the exception of the hematocrit, which decreased. Association analyses identified seven markers associated with estimated breeding values for faecal egg count, located in genes involved in different stages of the pathogen-host interaction process. The information obtained supports the potential of markerassisted breeding schemes to enable profitable and sustainable sheep production.Instituto de GenéticaFil: Poli, Mario Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Poli, Mario Andres. Universidad del Salvador. Facultad de Ciencias Agrarias y Veterinaria; ArgentinaFil: Caffaro, Marí­a Eugenia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Cetra, Bibiana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes; ArgentinaFil: Raschia, Maria Agustina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Medus, Pablo Daniel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Maizon, Daniel Omar. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Garcia Podesta, Mario. Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency. Animal Production and Health Laboratory; AustriaFil: Donzelli, María Valeria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Bonelli, Rita. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Periasamy, Kathiravan. Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency. Animal Production and Health Laboratory; Austri

Estudio de variables biológicas ante un desafío artificial de L3 de H. contortus en dos majadas de ovinos Corriedale

PosterH. contortus es uno de los parásitos que ocasiona mayores problemas en regiones templadas, tropicales y subtropicales debido a pérdidas productivas y económicas. La utilización de drogas es fundamental para el control de la parasitosis gastrointestinales (PGI) pero su uso excesivo puede acelerar la aparición de la resistencia del parásito. El uso de reproductores resistentes a las PGI contribuiría a la sustentabilidad de los sistemas productivos ovinos. Objetivo evaluar variables biológicas indicadores de resistencia/susceptibilidad a las PGI que surgen de un desafío artificial con L 3 de H contortus.Instituto de GenéticaFil: Donzelli, María Valeria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Donzelli, María Valeria. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Maizon, Daniel Omar. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Maizon, Daniel Omar. Universidad Nacional de La Pampa. Facultad de Agronomía; ArgentinaFil: Cetra, Bibiana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes; ArgentinaFil: Medus, Pablo Daniel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Bonelli, Rita. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Raschia, Maria Agustina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Raschia, Maria Agustina. Universidad Nacional de La Plata. Facultad de Ciencias Médicas; ArgentinaFil: Caffaro, María Eugenia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Poli, Mario Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Poli, Mario Andres. Universidad del Salvador. Facultad de Ciencias Agrarias y Veterinaria; Argentin

Resistencia genética a las parasitosis gastrointestinales en ovinos : resultados en dos majadas Corriedale

En la región noreste de Argentina se crían aproximadamente 2,1 millones de ovinos (14,2% del total de ovinos del país) en 37.288 unidades productivas (31,6% del total de unidades) y en la región central se crían 2,7 millones de ovinos (18,3% del total de país) en 45.298 unidades productivas (38,3% del total de unidades). Las unidades productivas, en su mayoría integradas por estructuras familiares, pertenecen a medianos y pequeños productores. La cría se realiza en pastos naturales y / o cultivados [3]. Las condiciones de temperatura y humedad en ambas regiones favorecen el desarrollo de parásitos y la especie más infecciosa y abundante es Haemonchus contortus.Instituto de GenéticaFil: Poli, Mario Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Cetra, Bibiana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes; ArgentinaFil: Medus, Pablo Daniel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; Argentin

Single nucleotide polymorphisms from candidate genes associated with nematode resistance and resilience in Corriedale and Pampinta sheep in Argentina

Selective breeding of genetically resistant animals is considered a promising strategy to face the problem of nematode resistance to anthelmintics and mitigate concerns about the presence of chemical residues in animal food products and the environment. Gastrointestinal nematode resistance is a complex, multifactorial trait related to host immunity. However, the mechanisms underlying host resistance and response to infection remain to be fully elucidated. In this context, the objective of this study was to provide insight into the chromosomal regions determining nematode resistance and resilience in Corriedale and resistance in Pampinta sheep breeds. A total of 170 single nucleotide polymorphisms (SNP) from 76 candidate genes for immune response were studied in 624 Corriedale and 304 Pampinta animals. Lambs underwent artificial or natural challenges with infective larvae mainly from Haemonchus contortus. Fecal egg counts, estimated breeding values for fecal egg counts, and rate of packed cell volume change and FAMACHA© score change over the challenge were used, when available, as indicators of host parasite resistance or resilience. Phenotype-genotype association studies were conducted and significance values obtained were adjusted for multiple testing errors. Eight SNPs, located on OARs 3, 6, 12, and 20, reached significance in Corriedale sheep under artificial challenge. Those SNP represent allelic variants from the MHC-Ovine Lymphocyte Antigen-DRA, two C-type lectin domain families, the Interleukin 2 receptor β, the Toll-like receptor 10, the Mannan binding lectin serine peptidase 2, and the NLR family, CARD domain containing 4 genes. On Pampinta lambs under natural challenge, we found three significant SNPs, located in the TIMP metallopeptidase inhibitor 3, the FBJ murine osteosarcoma viral oncogene homolog, and the Interleukin 20 receptor alpha genes, on OARs 3, 7, and 8, respectively. The results obtained herein confirm genomic regions previously reported as associated with nematode resistance in other sheep breeds, reinforcing their role in host response to parasites. These findings contribute to gain knowledge on parasite resistance and resilience in Corriedale sheep and report for the first time SNPs associated with resistance to gastrointestinal parasite infections in Pampinta breed.Instituto de GenéticaFil: Raschia, Maria Agustina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina. Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency. Animal Production and Health Laboratory; AustriaFil: Donzelli, María Valeria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Medus, Pablo Daniel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Cetra, Bibiana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes; ArgentinaFil: Maizon, Daniel Omar. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Suarez, Victor Humberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Pichler, Rudolf. Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency. Animal Production and Health Laboratory; AustriaFil: Periasamy, Kathiravan. Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency. Animal Production and Health Laboratory; Austria. Food and Agriculture Organization of the United Nations. Animal Production and Health Division. Animal Genetics Resources Branch; ItaliaFil: Poli, Mario Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentin