[en] Non-starch polysaccharides (NSP) in isolated form, especially
β-glucans, are reported to have prebiotic effects in pigs. However,
little information is available on the possible functional properties
of these NSP when the latter are still present in the fibrous matrix of
whole cereals. Hulless barleys (HB) are good sources of β-glucans and
the content is quite variable among varieties. In order to evaluate the
potential of HB as functional feeds, an in vitro experiment was carried
out to study the fermentation characteristics of 6 HB varieties varying
in their β-glucan contents (36-99 g/kg DM) in comparison to 3 hulled
barleys and 5 oats. After a pepsin-pancreatin hydrolysis, the ingredients
were incubated in a buffer solution containing minerals and pig feces as
inoculum. The accumulated gas production, proportional to the amount
of fiber fermented, was measured for 48 h and modeled. Short-chain
fatty acid (SCFA) and ammonia concentration were measured in the
fermented solutions. A cereal type effect (P < 0.05) was observed on
the fermentation kinetics parameters. Rates of degradation and total gas
productions were higher in HB than in oats (P < 0.05) but no difference
was observed between HB varieties. On the contrary, differences were
found between HB for lag time and rate of degradation. The production
of SCFA was also higher with HB (6.1 mMol/g DM incubated; P < 0.05)
than with hulled barleys and oats (4.9 and 2.9 mMol/g DM incubated
respectively). In contrast, oats generated higher ammonia (P <0.05)
production (1.4 mMol/g DM incubated, on average) than barley (1.0
mMol/g). In conclusion, HB are better fermented in vitro, produce more
beneficial (SCFA) and less harmful (ammonia) metabolites and have
a better potential than other cereal species to modulate gut microbiota
and improve gut health.