The reduction in concentrations of odorous volatile fatty acids observed in the distal gastrointestinal tract of pigs offered the β-glucan supplemented wheat diet was correspondingly reflected in manure samples at both 0 and 240 h. Our group has previously noted that patterns of volatile fatty acids production observed in the distal gastrointestinal tract may persist in excreted manure, and may thus offer an indication on the development of subsequent manure odour emissions (O’Shea et al., 2009b, 2010). In contrast to other studies, which have reported greater manure odour emissions associated with consumption of wheat-based diets (Garry et al., 2007b), offering the wheat-based
diet supplemented with purified β-glucans resulted in a numerical decrease in manure odour emissions compared with
the barley-based diet. The improvements in manure odour through supplementation with an exogenous, purified β-glucan
source suggest that a conventional wheat-based diet may be successfully modified to result in odour emissions comparable
with manure from pigs offered a barley-based diet.