Digestibility by pigs of the major chemical components of diets high in plant cell-wall constituents

Abstract

SUMMARY Digestibility of the major chemical components in diets high in plant cell-wall constituents was determined with four pigs. Two were given a commercial pig meal and two were given, in addition, alkali-treated straw (25% of the diet). Dry-matter digestibility of the straw was 32%, and protein excretion in faeces was increased by the addition of straw to the basal diet. Calculations based on microbial protein synthesis per gram of organic matter fermented showed that the additional nitrogen in the faeces may have been almost entirely microbial in origin. In a second experiment, ground lucerne was progressively introduced into the diet in substitution for commercial pig meal. There was no obvious associative effect on the digestibility of the chemical components examined. Apparent digestibility of dry matter of the all-lucerne diet was 53%.