Abstract

Microbial populations in herbivores gut attack, degrade and ferment structural carbohydrates in forage cell walls, producing volatile fatty acids and microbial proteins for the host. Exocellulases, endocellulases and cellobiases are the major cellulolytic enzymes while hemicellulase (xylanase) exposes cellulose for fermentation. This study aimed to isolate proteins that hydrolyse fibre or assist fibrolysis in any way from 11 herbivores gut microbial ecosystems (cow, sheep, horse, camel, elephant, zebra, llama, wildebeest, giraffe, impala and buffalo), optimize their working conditions and compare fibrolytic activities as potential feed additives. Exocellulase, endocellulase, xylanase and cellobiase in rumen and fecal crude enzyme extracts were assayed and compared. A broad in vitro pH range (4.5 to 8.0) of endocellulase activity was observed for all ecosystems. Enzymes from horse, zebra, impala, wildebeest and elephant showed the highest potential for degrading fibre encouraging further investigation as feed additives.

Key words: Crude cellulase extraction, hemicellulase, rumen and faecal inoculum, ungulates.