A comparison of the extent and site of energy and protein digestion of wheat,lupin and meat and bone meal by pigs

The ileal digestibilities of dry matter (DM), nitrogen (N), energy and amino acids were measured using pigs prepared with either re-entrant or simple ileal cannulae and fed a basal wheat diet, a wheat/lupin diet and a wheat/meat and bone meal (MBM) diet. The same pigs were also used to determine the faecal digestibilities of DM, N and energy in these diets. Addition of lupins to the basal diet had no significant effect on the true digestibilities of amino acids but addition of MBM significantly ( <0.01) reduced amino acid digestibility. It was calculated that an average of about 90% of the amino acids in lupin and wheat but only 65% of those in MBM were absorbed from the stomach and small intestine of the pig. Compared to lupin and wheat, a much larger proportion of the protein in MBM disappeared in the large intestine (approximately 4, 6 and 15% respectively). On the other hand, a large proportion of the energy in lupins but little of that in wheat and MBM (32, 8 and 4% respectively) disappeared in the large intestine. There were no significant differences between the re-entrant and simple cannulae for ileal digestibility values of DM, N and amino acids.