Mapping Quantitative Trait Loci affecting Carcass and Meat Quality Traits in Norwegian Duroc Pigs

The economic value and consumer awareness of high quality pork meat make traits such as carcass and meat quality important. In the breeding program, several traits are routinely collected. Backfat thickness (BT) is recorded by ultrasound at 100 kg performance test whereas drip loss, pH and intramuscular fat (IMF) is measured at a dissection line after end of boar test. Lean meat percentage (meat%) and yield (%) are measured by computer tomography in vivo. In this study, 5651 pigs were included with their breeding values for BT, drip loss, pH, IMF, meat% and yield. All pigs were genotyped using the Illumina 60k SNPchip and 37,633 SNPs passed quality control. The R package GenABEL was used to run genome-wide association analyses and ASReml was used to estimate genetic parameters. For drip loss, IMF, BT, meat% and yield, a significant QTL was identified on SSC1 with a peak at ~179 Mb. The most significant SNP within this QTL explained 7.5-14.9% of the genetic variance for the traits. Unfavorable correlations were found between the favorable allele for the carcass quality traits and the meat quality traits at this QTL. For meat%, drip loss and pH, other QTLs were also obtained on SSC1, 3, 13 and 15. The knowledge of markers simultaneously affecting the meat and carcass quality traits of interest could be used to increase accuracy of selection for these traits and/or sorting of high-meat/carcass quality on GN boars, however, simultaneous improvement of all traits requires balanced weighting in the breeding goal.