Effects of white rot fungi on the composition and in vitro digestibility of crop by-products

Abstract

Eleven species of white rot fungi were inoculated on to samples of barley straw, pea straw, sugar cane bagasse and sunflower hulls and incubated at room temperature (14–25°C) for 21 days. In barley straw, Peniophora gigantea caused the greatest depression in lignin content of the dry matter and the greatest increase in in vitro dry matter digestibility (IVDMD) (10 units). Sporotrichum pruinosum caused the greatest depression in cellulose content and the greatest depression in IVDMD (13 units). In pea straw, Ganoderma lucidum caused the greatest depression in lignin content and the greatest increase in IVDMD (8 units); Peniophora gigantea caused the greatest depression in cellulose content but Sporotrichum pruinosum caused the greatest depression in IVDMD (2 units). In bagasse, Peniophora gigantea caused the greatest depression in lignin content and the greatest increase in IVDMD (7 units). Grifola berkleyi caused the greatest depression in cellulose content and the greatest depression in IVDMD (12 units). In sunflower hulls, Stereum frustulatum caused the greatest depression in lignin content but Peniophora cremea caused the greatest increase in IVDMD (7 units). Peniophora gigantea caused the greatest depression in cellulose content and the greatest depression in IVDMD (3 units). It was concluded that fungi needed to be selected specifically for particular by-products and that some control over the conditions of incubation may need to be exercised in order to achieve more substantial increases in digestibility.