Candidate SNPs for meat quality and carcass composition in free-range Iberian pigs

Several genetic markers, previously associated with meat quality traits, have been proposed to be included in Iberian pig breeding programs. However, before being implemented, effects of these candidate SNPs on premium cuts' yield should be evaluated to avoid potential undesirable antagonistic effects. Therefore, the main goals of this study were to evaluate the effects of a set of 26 polymorphisms on premium cuts weights and to corroborate their effects on meat quality in a larger population. Phenotypic data of approximately 1550 Iberian pigs were recorded. The PRKAG3_rs319678464C and PRKAG3_rs1108399077G alleles were associated with an increase of shear force, water losses and color values and a reduction of average daily gain (ADG). The CAST_rs196949783G > A and ADIPOQ_rs3476515794T > G SNPs mainly affected IMF content, with this last SNP being the only one with significant effects on any of the carcass measures, specifically Longissimus thoracis et lumborum (LTL) weight. The ELOVL6_rs3473714672A, FASN_rs331694510A, MTTP_rs335896411C and ACACA_rs340781986C alleles were linked to a higher percentage of oleic acid and monounsaturated FA and a decrease in palmitic, palmitoleic and saturated FA. Besides, suggestive effects were observed between ELOVL6_rs3473714672A > G and ham and shoulder weights, and between MTTP_rs335896411T > C and LTL muscle weight. Finally, the NR6A1_rs326780270T allele was associated with a significant increase in ADG and tended to reduce the ham weight. The SNPs mapped to PRKAG3 (rs319678464G > C), ACACA, FASN and CAST genes could be implemented in breeding programs to improve meat quality traits without undesirable effects on carcass composition. The SNPs mapped to PRKAG3 (rs1108399077G > A) ELOVL6, MTTP and NR6A1 should continue to be tested in a larger number of animals.