Skatole and indole are two key compounds of boar taint and can be influenced by modifying dietary composition to enhance the flow of fermentable nutrients to the large intestine. As fattening entire male boars will be playing a more important role in the European and global market in the future, means to control boar taint are of key importance to maintain pork quality. A 2 x 2 factorial experiment was conducted to investigate the effects of cereal type (barley v. oat) and exogenous enzyme supplementation (with or without) on intestinal fermentation, and on indole and skatole levels in the intestinal content and the adipose tissue in finisher entire male pigs. The experimental treatments were as follows: (i) barley-based diet, (ii) barley-based diet with enzyme supplement, (iii) oat-based diet and (iv) oat-based diet with enzyme supplement. The enzyme supplement contained endo-1,3(4)-β-glucanase (EC 18.104.22.168) and endo-1,4-β-xylanase (EC 22.214.171.124). The animals were fed ad libitum for 45 days from 76.0 to 113.6 kg live weight.
Feeding barley-based diets led to higher (P < 0.05) total volatile fatty acids concentrations in the large intestine. Proportions of propionic- and butyric-acids were higher and that of acetic acid lower in digesta from barley-based in comparison to oat-based diets (P < 0.001). Consequently, pH in the large intestine was higher after feeding oat-based in comparison to barley-based diets. Animals fed unsupplemented oat-based diet had higher (P < 0.01) indole concentrations in the digesta from the proximal colon than those fed barley-based diets. Feeding oat-based diets led to lower (P < 0.01) skatole and higher (P < 0.001) indole concentrations in the digesta from the terminal colon than barley-based diets. Skatole concentrations in the adipose tissue did not differ (P > 0.05) between the experimental treatments. Pigs offered the barley-based diets had lower (P < 0.001) indole concentrations in the adipose tissue compared with those fed the oat-based diet.
In conclusion, barley-based diets were more efficient than oat-based diets in limiting concentrations of indole in the adipose tissue.
C Pauly, P Spring, D Gahan and JV O?Doherty, 2011. Animal, 5(3): 378?386.