Association of β-globin polymorphisms and tolerance to haemonchosis in ewes and lambs of different sheep breeds

Autor(es)

Kapritchkoff, Rafaela Tami Ikeda ; Okino, Cintia Hiromi ; Niciura, Simone Cristina Meo ; Bello, Hornblenda Joaquina Silva ; Matos, Renata Silva ; Melito, Glaucia Roberta ; Bressani, Flavia Aline ; Esteves, Sergio Novita ; Chagas, Ana Carolina de Souza

• Tipo de documento: Artigo Científico
• Fonte: Veterinary Parasitology; v. 328, p. 8-pg., 2024-03-21.

Resumo

Gastrointestinal nematodes (GIN), especially Haemonchus contortus, represent a significant challenge for sheep production. Given the global concern about GIN anthelmintic resistance, alternative control methods able to reduce the dependence on these drugs are highly advisable. Since previous studies have shown that sheep carrying the Hb-A allele of beta-globin are more resistant to H. contortus, this study aimed to investigate the relationship between the different haplotypes (Hb-AA, Hb-AB and Hb-BB) and phenotypes in Santa Ines (SI), Texel (TX) and White Dorper (DO) breeds infected with H. contortus. Blood samples were collected from 180 ewes and 123 lambs of the three breeds for DNA extraction followed by qPCR using a hydrolysis probe to identify the beta-globin haplotypes. Phenotypic data, including fecal egg count (FEC), packed cell volume (PCV), FAMACHA score and body condition score for ewes and lambs, as well as weight gain for lambs, were collected. The genotypic frequencies of beta-globin for ewes and lambs were, respectively: 21.7% and 21.4% Hb-AA, 50% and 50% Hb-AB and 28.3% and 28.6% Hb-BB in SI; 0% and 0% Hb-AA, 18.6% and 9.4% Hb-AB and 81.4% and 90.6% Hb-BB in TX; and 0% and 0% Hb-AA, 13.1% and 0% Hb-AB and 86.9% and 100% Hb-BB in DO. In ewes, mean PCV differed (p<0.05) between the three haplotypes, with higher PCV in Hb-AA animals, followed by Hb-AB and Hb-BB. When considering each breed separately, SI Hb-AA ewes presented higher PCV (p<0.05), highlighting that even in a breed already considered resistant, animals with Hb-AA haplotype showed superior performance. Lambs with the Hb-AA haplotype exhibited a higher (p<0.05) mean PCV compared to those with Hb-AB and HbBB. The same pattern was found in SI when analyzing each breed separately. No significant association was found between beta-globin haplotypes and FEC, FAMACHA score, body condition score, or weight gain. Nevertheless, given that anemia is the major clinical sign of haemonchosis, our findings on PCV reinforce that sheep carrying the Hb-A allele of beta-globin are more tolerant to haemonchosis. This study may support the development of a valuable tool, targeting genetic selection for GIN control, reducing the dependence on anthelmintics and boosting sheep production worldwide. (AU)

• Processo FAPESP: 22/00776-8 - Determinação da relação entre haplótipos da ²-globina ovina e resistência à infecção por Haemonchus contortus nas raças Santa Inês, Texel e White Dorper
• Beneficiário: Rafaela Tami Ikeda Kapritchkoff
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 21/02535-5 - Abordagem parasita-hospedeiro-ambiente para controle da resistência anti-helmíntica em rebanhos ovinos
• Beneficiário: Ana Carolina de Souza Chagas
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 22/07720-8 - Estudo do efeito da substituição parasitária sobre a resistência anti-helmíntica de Haemonchus contortus em raças ovinas
• Beneficiário: Hornblenda Joaquina Silva Bello
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado