Evaluating Wood Pulp as Feedstuff for Ruminants and Substrate for Aspergillus Fumigatus

TEN chemical pulps and two mechanical pulps were analyzed for Klason lignin, total carbohydrate, ash, in vitro rumen dry matter digestibility and single-cell protein growth by Aspergillus fumigatus. The pulp fines from each pulp that passed through a 100-mesh wet screening were also analyzed. In vitro digestibility ranged from 67% to 98% for the chemical pulps and pulp fines and from 0% to 7% for the mechanical pulps and pulp fines. Aspergillus fumigatus produced fungal growth with 14.5% to 30% crude protein in 4 days at 35 C when grown on chemical wood pulps from hardwood species with lignin content ranging from 25% to less than 0.1%. The fungus grew only on softwood pulps that had low-lignin content; it did not grow on the mechanical pulps.