1. Seventeen pigs were fitted with single re-entrant cannulas in either the duodenum (posterior to the entry of the bile and pancreativ ducts), the mid-jejunum, or the terminal ileum. A further twenty-four pigs were used in a conventional digestibility trial.
2. Three diets were used: these contained barley, fine wheat offal, white fish meal, minerals and vitamins (diet BWF); starch, sucrose, maize oil, cellulose, minerals, vitamins and either groundnut meal (diet SSG) or casein (diet SSC).
3. The quantities of total carbohydrate (TC), total reducing substances (TRS) and glucose (G) passing through the re-entrant cannulas and excreted in the faeces in 24 h were measured. These were used to determine the net absorption of the carbohydrate fractions in the different regions of the intestine.
4. The small intestine was the principal site of absorption of TC, TRS and G, but there were differences between the diets in the quantities of each of these carbohydrate fractions that were absorbed in the different regions of the small intestine studied.
5. The quantities of TRS and G in solution were very low for all diets at all sites, indicating that the rate of absorption of the products of hydrolysis kept pace with their rate of formation.