Characterizing developmental changes in plasma and tissue skatole concentrations in the prepubescent intact male pig

The accumulation of skatole in boars to concentrations resulting in carcass taint has been associated with elevated concentrations of steroid hormones in plasma. Studying boar taint in vivo has been challenging because steroid hormones are highly variable between individual boars. However, a peak in steroid hormones occurs between 2 and 4 wk postpartum; therefore, skatole production was investigated in the prepubescent pig. Plasma concentrations of estrone sulphate, dehydroepiandrosterone sulphate, and testosterone peaked between 2 and 4 wk postpartum in intact male pigs, whereas plasma concentrations of these steroid hormones remained low or undetectable in gilts and barrows. However, plasma skatole concentration peaked in all 3 groups of animals between 2 and 3 wk postweaning. The effects of weaning time, intestinal cell turnover, and diet on tissue skatole concentrations were then investigated. Intact male piglets were weaned at 14, 21, 28, or 35 d of age. Plasma skatole concentrations were measured weekly for a period of 63 d and peaked at 17 +/- 1, 14 +/- 1, 13 +/- 1, and 10 +/- 2 d postweaning, respectively. Intestinal cell turnover, as evaluated by villous height:crypt depth ratio, was not correlated with skatole concentrations in cecal contents, suggesting that cellular debris did not constitute a gross source of tryptophan for hindgut fermentation. The inclusion of 10% chicory inulin to piglet diets suppressed the postweaning increase in plasma skatole. Cecal skatole concentrations were also 3.3-fold lower in inulin-supplemented piglets compared with controls. The rise in plasma skatole in the prepubescent intact male pig was not associated with increased steroidogenesis but is likely due to the postweaning adaptation of the intestinal flora to an abrupt dietary change.