The effects of exogenous fibrolytic enzymes on the in vitro generation of xylooligosaccharides and monosaccharides is dependent upon cereal type

Abstract

Fibrolytic enzymes are routinely added to non-ruminant livestock feeds to help degrade the non-starch polysaccharide (NSP) contents and thereby improve feed efficiency. This study investigated the range of xylooligosaccharides (XOS) and monosaccharides produced from four cereal samples (barley, maize, oats and wheat) over a 72 h in vitro incubation using 3 commercially available (AB Vista, Marlborough, Wiltshire, United Kingdom) fibrolytic enzymes, Econase XT, Econase MP1000 and Barley P700, all containing endo-xylanase with other combinations of enzymes. Complete non-starch acid hydrolysis showed there were differences between cereals in the total monosaccharide (P < 0.01). There was a cereal x enzyme x incubation time 3-way interaction in the generation of XOS (xylotetraose, xylotriose and xylobiose) (P < 0.01) indicating the generation of XOS varies dependent on both the cereal and the enzyme used. The enzymes failed to generate any detectable xylose from maize. For xylose there was also a cereal x enzyme x incubation time 3-way interaction (P < 0.05). Econase XT generated the greatest quantity of xylose, with 38% of available xylose from wheat being released after 72 h, 11% from barley and 9% from oats, whilst no xylose was detected from maize using any of the 3 commercial enzyme preparations. For arabinose and galactose production there was a cereal x enzyme x incubation time 3-way interaction (P < 0.01), whilst glucose release was only significantly affected by cereal (P < 0.05) or time (P < 0.05). These findings suggest that the fibrolytic enzymes tested have some specificity for certain cereals and therefore it might be possible to optimise the combinations used in animal feeds, to help maximise the feed efficiency of livestock.