PSVIII-22 - Genome-wide association studies for immune response and resilience to aleutian disease in mink

Abstract: Aleutian disease (AD) is a severe health issue for the mink industry, causing high mortality and adversely impacting several economically important traits, resulting in substantial economic losses. AD has been characterized as an immune complex disease, which indicates that the higher levels of anti-AMDV antibodies produced more harmful to the host. Resilience is defined as the ability the animals have to maintain their performance under exposure to disease-causing agents and disruptions. The phenotypic selection of AD-resilient mink based on immune response and/or indicator traits is practiced by some mink farms, but the genetic architecture of immune response and resilience to AD has not been widely explored. In this study, a total of 1,411 mink from the Canadian Centre for Fur Animal Research (Truro, Nova Scotia, Canada), which is an AD-positive facility, were used to detect potential genomic regions and genes related to immune response and feed-intake-related resilience of mink to AD through genome-wide association studies (GWAS) analyses. The studied individuals were genotyped using the Axiom Affymetrix Mink 70K single nucleotide polymorphism (SNP) panel. The studied phenotypes included two immune response traits measured by antigen-based enzyme-linked immunosorbent assay (ELISA-G) and iodine agglutination test (IAT) and two feed-intake-related resilience traits measured by the daily variation in feed intake (Varf) and proportion of off-feed days (DOF). The de-regressed breeding values were derived from the estimated breeding values for each trait and utilized as pseudo-phenotypes to perform GWAS analyses using a single SNP univariate mixed linear animal model in SNP1101 software. A total of 17 significant (false-discovery-rate-adjusted-p-value (q) < 0.01) SNPs were detected to be associated with ELISA-G, and 141 genes were annotated from the detected SNPs. Among all the annotated genes, three genes, MPIG6B, RUNX2, and C4A, were found to have important roles in immune-mediated responses to AD. Eight SNPs were detected to be significantly associated with IAT, and 44 genes were annotated from these eight SNPs. Two (TNFRSF11A and C4A) of the 44 genes were involved in the immune system process. For DOF, seven significant associated SNPs were detected, and 42 genes were annotated from these SNPs. Two annotated genes, ADCY7 and CNDP2, were related to feed intake or appetite. Five significant (q < 0.05) overrepresented gene ontology enrichment terms, including TAP complex, Classical-complement-pathway C3/C5 convertase complex, MHC class I peptide loading complex, extracellular region, and ABC-type peptide transporter activity, were detected for ELISA-G, and they play important roles in the adaptive immune response or complement system. The newly detected significant SNPs and identified candidate genes in this study would provide a better understanding of the genetic architecture and biological mechanisms underlying AD resilience in mink, which offers an opportunity for increasing the resilience of mink to AD using marker-assisted/genomic selection in mink.