Effect of β-glucan source and exogenous enzyme supplementation on intestinal fermentation and manure odour and ammonia emissions from finisher boars

The objective of the current study was to investigate the influence of botanical origin of β-glucan and exogenous enzyme supplementation on intestinal fermentation and manure ammonia and odour emissions from finisher boars. Twenty-eight boars were assigned to one of four dietary treatments in a 2 × 2 factorial arrangement (n = 7): (T1) barley-based diet; (T2) barley-based diet + enzyme; (T3) oat-based diet and (T4) oat-based diet + enzyme. The enzyme supplement used contained Endo-1,3 (4)-β-glucanase (EC 3.2.1.6) and Endo-1,4-β-xylanase (EC 3.2.1.8). Oat-based diets increased populations of Bifidobacteria (7.26 vs 6.38 log10CFU/g digesta (ie log10 CFU/g digesta); sem 0.201; P < 0.01) and Lactobacilli (6.99 vs 6.18 log10CFU/g digesta (ie log10 CFU/g digesta); sem 0.234; P < 0.05) in the proximal colon and decreased manure odour emissions (2179.6 vs 4984.6OuE/m3; sem 653.7; P < 0.05) compared with barley-based diets. There was an interaction between cereal type and enzyme supplementation on manure ammonia emissions from 0 to 96 h (P < 0.05). The addition of an enzyme to the barley-based diet increased manure ammonia emissions. However there was no effect of enzyme inclusion in the oat-based diets. In conclusion, oat-based diets suppressed manure odour emissions. Enzyme supplementation increased manure ammonia emissions from the barley-based diets.