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A major problem with meat from entire male pigs is boar taint. To avoid this problem, castration of piglets is an established routine in the industry. Concerns about animal welfare have led to restrictions on castration routines of male pigs in some European countries. Therefore, two experiments were conducted to evaluate the effects of feeding different sources of easily fermentable carbohydrates to entire male pigs during the last weeks before slaughter. In Exp. 1, 48 entire male pigs were used to evaluate the effect of adding 0, 3, 6, or 9% chicory inulin to diets during the last 30 days before slaughter on skatole concentration in the hind-gut and adipose tissue and on the composition of microbiota and mucosa morphology in the hind-gut. In Exp. 2, 66 entire male pigs were used to evaluate the effect of adding 20% raw potato starch to diets as a top dressing or adding increasing levels of potato starch (0, 5, 10, 15, and 20%) to diets prior to pelleting during the last 14 days before slaughter on skatole concentrations in hind-gut and adipose tissue and on the composition of microbiota in the hind-gut.
Results from Exp. 1 showed a significant reduction in skatole levels in colon and rectum with increasing dietary levels of inulin (linear, P ≤ 0.002). In these diets there was also a reduction of enterobacteria counts in colon descendens (linear, P = 0.04) and rectum (linear, P = 0.02), and a tendency towards reduced levels of Enterococcus spp. in colon descendens (linear, P = 0.09) and rectum (linear, P = 0.08). Results from Exp. 2 showed that adding raw potato starch as a top dressing reduced skatole levels in rectum and adipose tissue compared with the control, while adding increasing levels of potato starch to diets prior to pelleting did not affect skatole levels. Adding potato starch as a top dressing or to diets before pelleting did not affect the cultured bacteria in the hind-gut of pigs. Feeding inulin or potato starch did not affect mucosal epithelial cell counts in the cecum or colon in Exp. 1 and Exp. 2, respectively.
In conclusion, feeding increasing levels of chicory inulin to entire male pigs during the last period before slaughter reduced the level of skatole in the distal intestine and in adipose tissue, feeding pelleted diets containing up to 20% potato starch had no effect, while feeding 20% raw potato starch as top dressing reduced the level of skatole in the distal intestine and the adipose tissue of the entire male pigs.
M Øverland, NK Kjos, AK Fauske, J Teige and H Sørum, 2011. Livestock Science, 140: 206?21.
