Association of FTH and EPOR gene polymorphisms with litter size traits in pigs

Worrarak Norseeda,Korawan Sringarm,Guisheng Liu,Nanthana Pothakam,Patcharin Krutmuang,Supamit Mekchay,Tawatchai Teltathum,Watcharapong Naraballobh,Trisadee Khamlor

doi:10.12982/vis.2022.023

Abstract

Ferritin heavy chain (FTH) and erythropoietin receptor (EPOR) are responsible for the iron homeostasis and the erythropoiesis that correlate to the reproductive systems. This study aimed to examine an association of the porcine FTH and EPOR genes with litter size traits in Large White and Landrace pigs. The porcine FTH g.9537834G > A was significantly associated with the total number born (TNB) trait in these pig populations (p < 0.05). The porcine FTH g.9537855T > C was significantly associated with the TNB trait in Large White sows (p < 0.05) as well as the TNB and the number of birth alive (NBA) traits in Landrace sows (p < 0.05). The porcine EPOR g.70066473C > T was significantly associated with the TNB trait in Large White sows (p < 0.05) as well as the TNB, NBA, and the number of piglets weaned alive (NWA) traits in Landrace sows (p < 0.05). Moreover, the accumulated favorable alleles of these three SNPs were increasingly associated with TNB trait in Large White sows (p < 0.05) and TNB, NBA, and NWA traits in Landrace sows (p < 0.05). These findings suggest that porcine FTH and EPOR genes may contribute to the reproductive processes of pigs with regards to litter size and confirm the importance of these genes as candidate genes for improving litter size in pigs.

Highlights

Litter size traits are among the important reproduction traits in industrial pig production
The chi-square test showed that the genotype distributions of the porcine ferritin heavy chain (FTH) g.9537834G > A and FTH g.9537855T > C loci within Large White and Landrace sows deviated from the Hardy-Weinberg equilibrium specifications
We have examined the effects of polymorphisms of the porcine FTH and erythropoietin receptor (EPOR) genes as well as their accumulated favorable allele effects on litter size traits in Large White and Landrace pig breeds

Summary

Introduction

Litter size traits are among the important reproduction traits in industrial pig production. Genome-wide association study (GWAS) and transcriptomic approaches have been used to identify quantitative trait loci (QTL) and to assess various candidate genes for reproductive traits in pigs (Onteru et al, 2012; Trenhaile et al, 2016; Verardo et al, 2016; Wu et al, 2018). Several potential candidate genes for litter size traits of these regions have been reported in pig populations e.g., arylsulfatase family member K (ARSK), purinergic receptor P2X 3 (P2X3R), G protein-coupled receptor 150 (GPR150), metallo-β-lactamase domain containing 2 (MBLAC2), transmembrane protein 161B (TMEM161B), and RAS p21 protein activator 1 (RASA1) (Onteru et al, 2012; Trenhaile et al, 2016). The ferritin heavy chain (FTH) and erythropoietin receptor (EPOR) genes are located on SSC2 (at positions 9.53 and 70.06 Mb, respectively) closely to QTL regions for reproductive traits of pigs. The FTH and EPOR genes are important to the reproductive system in mammals

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