Abstract
Feed efficiency (FE) traits in pigs are of utmost economic importance. Genetic improvement of FE related traits in pigs might significantly reduce production cost and energy consumption. Hence, our study aimed at identifying SNPs and candidate genes associated with FE related traits, including feed conversion ratio (FCR), average daily gain (ADG), average daily feed intake (ADFI), and residual feed intake (RFI). A genome-wide association study (GWAS) was performed for the four FE related traits in 296 Landrace pigs genotyped with PorcineSNP50 BeadChip. Two different single-trait methods, single SNP linear model GWAS (LM-GWAS) and single-step GWAS (ssGWAS), were implemented. Our results showed that the two methods showed high consistency with respect to SNP identification. A total of 32 common significant SNPs associated with the four FE related traits were identified. Bioinformatics analysis revealed eight common QTL regions, of which three QTL regions related to ADFI and RFI traits were overlapped. Gene ontology analysis revealed six common candidate genes (PRELID2, GPER1, PDX1, TEX2, PLCL2, ICAM2) relevant for the four FE related traits. These genes are involved in the processes of fat synthesis and decomposition, lipid transport process, insulin metabolism, among others. Our results provide, new insights into the genetic mechanisms and candidate function genes of FE related traits in pigs. However, further investigations to validate these results are warranted.
Highlights
Feed accounts for about 65% of the total cost in modern pig production and feed efficiency (FE) traits in pigs are critical (Sanchez et al, 2017)
Breeding programs to improve FE have been undertaken for many years, but FE related traits, such as average daily feed intake (ADFI) and residual feed intake (RFI), are still difficult to be improved because they can neither be selected nor directly
FE is evaluated by four traits: feed conversion ratio (FCR), average daily gain (ADG), ADFI, and RFI (Onteru et al, 2013)
Summary
Feed accounts for about 65% of the total cost in modern pig production and feed efficiency (FE) traits in pigs are critical (Sanchez et al, 2017). Breeding programs to improve FE have been undertaken for many years, but FE related traits, such as average daily feed intake (ADFI) and residual feed intake (RFI), are still difficult to be improved because they can neither be selected nor directly. The phenotypic measurements of FCR, ADFI, and RFI are difficult and costly which need an automatic feeding system. The selection of single FE related traits may affect other traits that are valuable for pig production, such as growth rate (Horodyska et al, 2017). This conundrum makes the genetic investigation of FE very important
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