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ABSTRACT:
The genetic basis of the main components of boar taint was investigated in intact male pigs in a commercial population. We analyzed fat androstenone and skatole concentrations from 217 males of an outbred Landrace population. Records were normalized using a logarithm transformation and tested for normality using a Wilk-Shapiro test. Bayesian analysis was then used to map QTL in 10 candidate regions previously selected on chromosomes 1, 2, 3, 4, 6, 7, 8, 9, 10, and 13. The criterion for QTL detection was the Bayes factor (BF) between polygenic models with and without QTL effects. Both traits had considerable genetic determination, with posterior means of total heritabilities ranging from 0.59 to 0.73 for androstenone and from 0.74 to 0.89 for skatole. Positive evidence for a fat skatole QTL was detected on SSC6 (BF = 5.16); however, no QTL for androstenone were found in any of the 10 chromosomal regions analyzed. With the detection of a QTL for the fat skatole concentration segregating in this population, marker-assisted selection or even gene-assisted selection could be used once the causal mutation of the QTL was identified.
Key Words: Androstenone, Bayes Factor, Boar Taint, Quantitative Trail Loci, Skatole
©2005 American Society of Animal Science. All rights reserved. J. Anim. Sci. 2005. 83:301-307
Introduction
The use of intact males in pork production is limited because of boar taint (Matthews et al., 1997), an unpleasant odor and flavor in the meat (Babol and Squires, 1995). The main causes of boar taint are the high concentrations of androstenone and skatole in fat (Lundstrom and Bonneau, 1996; Bonneau et al., 2000). Androstenone is a steroid pheromone synthesized in the testis (Gower, 1972; Bonneau, 1982), and skatole is produced in the colon from trypthophan, and metabolized in the liver or deposited in fat tissue (Agergaard and Laue, 1993). Genetic variation has been reported for fat androstenone and skatole concentrations, both between breeds (Willeke, 1993; Squires and Lou, 1995; Xue et al., 1996) and within a breed (Willeke, 1993; Sellier, 1998).
Segregation of major genes has been proposed for fat androstenone (Fouilloux et al., 1997) and skatole (Lundström et al., 1996). In addition, QTL have been detected for fat androstenone (Quintanilla et al, 2003; Lee et al., 2004) and skatole concentrations (Lee et...