In vitro study of the rumen and hindgut fermentation of fibrous materials (meadow hay, beech sawdust, wheat straw) in sheep

The influence of both rumen and hindgut inocula of sheep on fermentation of fibrous materials in vitro has been investigated. Different fibrous materials (meadow hay, beech sawdust, wheat straw) and cellulose were used as substrates. The study was carried out to compare: (1) fermentation of substrates with rumen and hindgut inocula, (2) fermentation of meadow hay (reference substrate) and other substrates, (3) fermentation of the two types of cellulose (amorphous and crystalline), and (4) fermentation of treated fibrous materials (treated beech sawdust by defibration and impregnation and fungal treated wheat straw) and untreated fibrous materials. Hindgut fermentation of fibrous materials was associated with decreased dry matter and neutral detergent fibre degradabilities, and also methane and total gas production. The calculated hydrogen recoveries with hindgut inoculum showed a tendency to lower values as compared to the rumen inoculum. Significant differences were found between meadow hay and other fibrous materials, between both celluloses and between treated and untreated fibrous materials. The positive correlation between hydrogen recoveries and methane production of untreated wheat straw with a hindgut inoculum suggested the presence of reductive acetogenesis with the hindgut inoculum. It can be concluded that reductive acetogenesis with a hindgut inoculum instead of methanogenesis may increase the energetic yield from VFA per substrate, and to some extent also the energetic yield for the host animal.