FERMENTATIVE DIGESTION IN THE OSTRICH (STRUTHIO-CAMELUS VAR DOMESTICUS), A LARGE AVIAN SPECIES THAT UTILIZES CELLULOSE

The production of volatile fatty acids (VFA) was studied in vitro to a ssess the possible contribution of microbial fermentation to the energ y economy of growing ostrich chicks. Structure, capacity and contents of the gastro-intestinal track were examined to identify major sites o f microbial activity and VFA energy yield. Radioactive substrates were used to confirm that the products derived from fermentative digestion could provide nutrients to the host animals. In this experiment the t heoretical energy contribution of VFA could be as high as 76% of the m etabolizable energy intake of the growing ostrich chick. The absorptio n and oxidative metabolism of end products from cellulose fer-mentatio n was demonstrated to contribute to the metabolizable energy requireme nts of the growing ostrich.