Effect of micronization on energy, starch and amino acid digestibility in hulless barley for young pigs

Abstract

Studies were carried out to determine the effect of micronization on energy, starch and amino acid digestibilities in hulless barley. Six pigs (Canabrid × Camborough) were weaned at 21 d of age and fitted with a simple T-cannula at the distal ileum on days 23 or 24. The pigs were fed one of three diets with major constituents of hulless barley and soybean meal (HB + SBM), micronized hulless barley and soybean meal (MHB + SBM) and corn starch and soybean meal (C + SBM) according to a repeated Latin square design. The pigs were fed three times daily, equal amounts at 8-h intervals. The diets were supplied at a rate of 5% (wt/wt) of body weight. The average body weight of the pigs was 9.3 kg at start and 15.9 kg at the conclusion of the experiment at 58 d of age. Faeces were collected for 48 h on days 6 and 7 and ileal digesta for 24 h on days 8 and 9. Chromic oxide was used as digestibility marker. The apparent ileal amino acid digestibilities in HB and MHB were determined by the difference method. The apparent ileal digestibilities of the indispensable amino acids were higher in MHB than in HB and ranged from 5.3 to 10.0 percentage units. Of the indispensable amino acids, the differences were significant (P < 0.05) for arginine, histidine, isoleucine, phenylalanine and valine. Micronization of HB improved (P < 0.05) the ileal digestibility of starch from 79.0 to 97.3%. Micronization resulted in an increase in the digestion of energy in the small intestine and a decrease in microbial fermentation of energy in the large intestine. This shift in the disappearance of energy from the large to the small intestine should also result in an improvement in the efficiency of energy utilization. These studies show a positive effect of micronization on the digestibilities of energy and amino acids in young pigs fed HB. Key words: Micronization, barley, digestibility, pigs