Association between major histocompatibility complex microsatellites, fecal egg count, blood packed cell volume and blood eosinophilia in Pelibuey sheep infected with Haemonchus contortus

• Published in: Veterinary parasitology 2011-05, Vol.177 (3), p.339-344
• Main Authors: Figueroa Castillo, Juan Antonio, Medina, Rubén Danilo Méndez, Villalobos, José Manuel Berruecos, Gayosso-Vázquez, Amanda, Ulloa-Arvízu, Raúl, Rodríguez, Rebeca Acosta, Ramírez, Hugo Pérez, Alonso Morales, Rogelio A.
• Format: Article
• Language: English
• Subjects: alleles; Animals; antibodies; Antibodies, Helminth - blood; blood cells; blood proteins; Blood Proteins - analysis; disease resistance; Disease Susceptibility - veterinary; DNA - chemistry; DNA - genetics; eosinophilia; Eosinophilia - veterinary; fecal egg count; Feces - parasitology; Female; Gastrointestinal Diseases - immunology; Gastrointestinal Diseases - parasitology; Gastrointestinal Diseases - veterinary; genetic markers; Genetic resistance; Haemonchiasis - blood; Haemonchiasis - immunology; Haemonchiasis - parasitology; Haemonchiasis - veterinary; Haemonchus - immunology; Haemonchus contortus; Hematocrit - veterinary; homozygosity; lambs; major histocompatibility complex; Major Histocompatibility Complex - genetics; Major Histocompatibility Complex - immunology; Male; marker-assisted selection; Mexico; MHC; Microsatellite Repeats; Microsatellites; nematode infections; Parasite Egg Count - veterinary; parasites; Pelibuey sheep; Polymerase Chain Reaction - veterinary; Polymorphism, Genetic; Sheep; sheep diseases; Sheep Diseases - immunology; Sheep Diseases - parasitology; Statistics, Nonparametric; Tropical Climate
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/j.vetpar.2010.11.056

The objective of this study was to assess the correlation among traits associated with resistance or susceptibility to Haemonchus contortus infestation and to evaluate the participation of the ovine major histocompatibility complex (MHC) in Pelibuey sheep, a prevalent breed in tropical and sub-tropical regions in Mexico and elsewhere. Association among the fecal egg count (FEC), blood packed cell volume (PCV), antibody (AB) levels, serum proteins (SP) and blood eosinophil count (EOS) was assessed in 52 lambs experimentally infected with H. contortus, and the participation of the MHC was evaluated using polymorphisms in three microsatellites, located at the class I (OMHC1) and class II (OLADRB1, OLADRB2) regions of the MHC. Spearman correlation analysis among the traits showed a negative association ( P < 0.01) between FEC and PCV (−0.35), EOS (−0.50), SP (−0.30) and AB (−0.57), and a positive correlation of antibodies with EOS (0.50). The homozygotes for the OMHC1-188 and OLADRB2-282 alleles were associated with a reduction in FEC (−813 and −551, respectively). Conversely, the OMHC1-200 and OMHC1-206 alleles were associated with an increase in FEC (1704 and 1008, respectively). Furthermore, the OLADRB1-482 allele was associated with an increase of 163 EOS by allele copy, while the OMHC1-200 allele showed a reduction of 95 EOS in homozygotes. The associations among microsatellite MHC loci and the remaining variables were not significant. These results reinforce the evidence that MHC polymorphisms have an important role in parasite resistance or susceptibility in Pelibuey sheep and could be used as genetic markers to assist selection and improve parasite resistance to H. contortus.