Intake of fermentable fibre and body protein deposition in pigs fed methionine or tryptophan limiting diets

摘要

It was demonstrated previously that dietary pectin (purified fermentable fibre) induces endogenous protein secretions into the hindgut and reduces the efficiency of using ileal digestible threonine intake for body protein deposition (PD) in pigs (Zhuet al., 2003 and 2005). Because of the relatively high cysteine (CYS) content in endogenous gut protein, intake of fermentable fibre may also reduce the efficiency of utilising ileal digestible intake of methionine (MET), or MET plus CYS, for PD. In contrast, the content of tryptophan (TRP) in endogenous gut protein secretions is low and microbial protein production in the upper gut may contribute to a net increase in TRP supply to the pig. Nitrogen (N)-balance experiments were conducted to determine the impact of feeding additional pectin on utilisation of ileal digestible intake of MET, MET plus CYS, and TRP for PD in growing pigs.