Fibre digestion and digesta retention from different physical forms of the feed in the rabbit.

1. Digestibility of fibre was higher in guinea-pigs than in rabbits, however, the digestibility of hemicellulose fraction containing agar was similar in both animals. 2. The digestibility of fibre of a fine particle diet was higher than that of a large particle diet in the rabbit permitted coprophagy, whereas it was lower in the rabbit prevented from coprophagy. 3. The fine particle diet tended to cause shorter retention time of digesta in the rabbit prevented from coprophagy. 4. These suggest that the digestibility of fine components relates to their physical properties which affect the retention time of digesta in the rabbit.