ADAPTATION TO THE DIGESTION OF NONSTARCH POLYSACCHARIDE IN GROWING PIGS FED ON CEREAL OR SEMI-PURIFIED BASAL DIETS

Pigs (25-45 kg) were fed on either cereal or semi-purified basal diets supplemented with either high or low levels of sugar-beet pulp or woo d cellulose (Solka-floc). The apparent digestibility and retention of N and apparent digestibility and metabolizability of energy (GE) and t he apparent digestibility of nonstarch polysaccharides (NSP) and their constituent monomers were measured during weeks 2, 4 and 6 of the tri al. N and GE were less well-digested, retained or metabolized from cer eal basal diets than from the corresponding semi-purified diets during all three periods. NSP from sugar-beet pulp was highly digestible, un like that from Soka-floc which was relatively poorly digested. These d ifferences of NSP digestibility were seen more clearly when incorporat ed in semi-purified diets. There was no significant increase in the di gestibility or retention of N, or digestibility or metabolizability of GE, or in the digestibility of sugar-beet pulp NSP with increasing ti me-period on the diets. In contrast, the digestibility of Solka-floc N SP tended to increase with the time-period. The digestibility of NSP f rom the semi-purified diet with the high level of Solka-floc inclusion was much lower than that for the low level of inclusion, indicating t hat microbial activity had been reduced. In conclusion, adaptation to the diets in terms of N and GE balance may be complete after 1 week, b ut 3-5 weeks may be necessary before stability of measurements of the digestibility of resistant NSP monomers can be obtained.