Studies of boar taint, with an emphasis on testicular function and development

Boar taint is an odour reminiscent of sweat, urine or faeces, perceived as off-flavour when meat from entire male swine is heated. The compunds that cause boar taint are androstenone and skatole/indole. Androstenone is secreted as a testis steroid, while skatole/indole originates in the large intestine. Environmental factors do not have much impact on androstenone levels. Castration is therefore used to eliminate the site of androstenone synthesis. This also influences skatole degradation, which is inhibited by androstenone in the liver. However, surgical castration is being phased out for animal welfare reasons, so that alternative ways of reducing boar taint is needed. Heritability for androstenone levels is high, so that breeding for lower levels is possible. However, this will only be successful if unwanted side effects can be avoided. Side effects include lower levels of other sexual steroids and delayed sexual maturation in both boars and gilts. Breed differences in adrostenone levels and sexual maturation have also been shown. The principal aim of this thesis was to investigate the relationships between levels of androstenone and other testis steroids and testis development, including interactions between genotype, phenotype and breed differences