Influence of Keeping Pigs Heavily Fouled with Faeces plus Urine on Skatole and Indole Concentration (Boar Taint) in Subcutaneous Fat

Abstract

Abstract The aim of this study was to investigate the effect on indole and skatole concentrations in subcutaneous fat (boar taint) of two housing conditions: keeping pigs heavily fouled with faeces on a concrete floor versus keeping pigs clean on a wholly slatted floor. Both groups of pigs were kept at a high stocking rate (0.6 m2 per pig) and high temperatures (≥25[ddot]C). This study also aimed to show if changing the treatment a week prior to slaughter is sufficient to change the concentration of indole and skatole in subcutaneous fat. The experimental material consisted of 158 LY (Danish Land-race x Large White) zigzag crossbred and LYD (Danish Land-race x Large White x Duroc) crossbred entire male, castrate, and female pigs. With the exception of the first delivery, where half of the pigs were kept constantly clean and the other half constantly dirty from the start of the experiment, both treatments were changed to the opposite treatment one week before delivery to the abattoir. Post-slaughter the content of indole and skatole in subcutaneous backfat was determined using an HPLC method and the content of skatole equivalents was determined using an automatic spectrophotometric method. The experiment confirmed the hypothesis that heavily fouled pigs at a high stocking rate had higher indole and skatole levels in subcutaneous fat than pigs kept clean on a wholly slatted floor. It was possible within one week to increase or lower the indole and skatole levels depending on the treatment during the last week before slaughter. The experiment showed similar differences in all three sexes. The variation in skatole content between sires was highly significant, which supports the skatole level in subcutaneous fat having a genetic component.