Vaccination against GnRH: pros and cons

The meat of intact male pigs may exhibit odours, known as boar taint. The compounds responsible for boar taint include skatole (3-methylindole), a product of tryptophan breakdown in the gut and testicular 16-androstene steroids, mainly androstenone (5α-androst-16-en-3-one), and these compounds are accumulated in fat tissue. Active immunization against androstenone has been tried, but the effects on fat androstenone level and boar odour intensity were insufficient [ 1 ]. Other methods which have been tried in several species are pharmacological manipulations of gonadotropin releasing hormone (GnRH) activity, such as GnRH antagonists or large doses of agonists to block the activity of GnRH and thereby "switch-off" the reproductive endocrine systems. More successful method of inhibiting sexual development in young boars and boar taint is immunization against GnRH. In most experimental studies using GnRH vaccines during the eighties and early nineties several injections were required and/or severe local reactions at the site of injection were obtained due to the adjuvans (e.g. Falvo et al. [ 2 ]; Hagen et al. [ 3 ]; Bonneau et al. [ 4 ]. In this paper GnRH vaccine developed during late nineties and early twenties is presented and discussed.