Genetic association of sequence variation in exon 3 of the swine leukocyte antigen-DQA gene with piglet diarrhea in Large White, Landrace, and Duroc piglets

Abstract

ABSTRACT. Piglet diarrhea is one of the primary factors that affects the benefits of the swine industry. Recent studies have shown that exon 2 of the swine leukocyte antigen-DQA gene is associated with piglet resistance to diarrhea; however, the contributions of additional exon coding regions of this gene remain unclear. Here, we detected and sequenced variants in the exon 3 region and examined their associations with diarrhea infection in 425 suckling piglets using the polymerase chain reaction-single-strand conformational polymorphism and sequencing analysis. The results revealed that exon 3 of the swine leukocyte antigen-DQA gene is highly polymorphic and pivotal to both diarrhea susceptibility and resistance in piglets. We identified 14 genotypes (AA, AB, BB, BC, CC, EE, EF, BE, BF, CF, DD, DH, GG, and GF) and eight alleles (A-H) that were generated by 14 nucleotide variants, eight of which were novel, and three nucleotide deletions. Statistical analyses revealed that the genotypes AB and EF were associated with resistance to diarrheal disease (P < 0.05), and the genotype DD may contribute to diarrhea susceptibility but was unique to Large White pigs (P > 0.05). These results elucidate the genetic and immunological background to piglet diarrhea, and provide useful information for resistance breeding programs.

Diversity of the Swine Leukocyte Antigen Class I and II in Commercial Pig Populations

“…The SLA complex is one of the key determinants of swine immune responses (24)(25)(26)(27)(28). Additionally, some studies have reported impact of SLA on other traits including bodyweight (29), meat production (27) and reproductive traits such as fertility index, ovulation rate and litter size (28,30,31).…”

Molecular Cloning and Bioinformatics Analysis of DQA Gene from Mink (Neovison vison)

“…The DQA gene presents foreign peptide antigens from infectious agents, including bacteria, viruses, and autoimmune antigens [21], providing a valuable source of genetic markers for examining the correlations between host variants and disease resistance or susceptibility [22]. As a functional unit, exon 3 of the swine leukocyte antigen DQA ( SLA-DQA ) gene is pivotal to both diarrhea susceptibility and resistance based on the effects on diarrheal infection in 425 suckling piglets [23,24]. The correlation between the polymorphisms of SLA-DQA exon 2 and piglet diarrhea in three Chinese native pig breeds indicated that the amino acid variations in the pepetide binding pockets play a critical role in the antigen-binding groove in piglet diarrhea resistance [25].…”