RN gene polymorphisms effect in a family based-structure scheme in French purebred pig populations

The study was based on performance recording (with 23 meat quality traits) in progenytesting station of half-sib families composed of 50 offspring (castrates and females) frompurebred sires. The aim of this scheme was to estimate, in French purebred pig populations,the effect of polymorphisms. Data will be presented for 1,740 genotyped animals belonging to4 groups of breeds: LW (3 Large-White type populations), LF (French Landrace), D (3 Durocpopulations) and CH (4 Chinese-European lines). Eight polymorphisms in RN (PRKAG3)gene were analyzed: R200Q, V199I, G52S, K131R, P134L, T30N, V41I, L53P. Nopolymorphism was found for R200Q and L53P. Six haplotypes were defined with theremaining mutations. Effect of haplotypes was estimated with MIXED procedure (SASsoftware) with sex and slaughter date as fixed effects, mother and father as random effects andcarcass weight as covariate. Most significant results were observed for pHSM(semimembraneouspH 24 h post mortem) and MQI (Meat Quality Index combining pHSM,Minolta L* and water holding capacity both on gluteus superficialis) in LW, LF, and D, fordrip loss in LW and LF and for color traits (Minolta L*, a*, b*) in LW, LF and CH. Resultswill be illustrated focusing on 2 meat quality traits (MQI, and drip loss) and 2 haplotypes.Haplotypic frequencies estimated on parents are 26% and 10% in LW, 64% and 20% in LF,40% and 47% in D and 12% and 21% in CH for haplotype 1 and 2 respectively. Haplotype 1is favorable for the 2 considered traits. Regarding combinations of haplotypes, 11 issignificantly better than 16 in LW, LF and D and even more than 66 in D. Estimated effectsbetween 11 and 16 are between 0.2 and 0.8 phenotypic standard deviation; the highest beingobserved in LW. In D, differences between 11 and 66 animals are estimated to be 0.9phenotypic standard deviation for MQI