Effect of microbial enzyme supplementation on energy, amino acid digestibility and performance of pigs fed hulless barley based diets

Two experiments were conducted to investigate the influence of a microbial enzyme preparation on the digestibility and performance of starter-growing pigs fed hulless barley based diets. In the digestibility trial, eight pigs with an average initial body weight of 14.3 +/- 0.4 kg initial liveweight were surgically fitted with steered ileo-cecal valve cannulas at the terminal ileum. Two hulless barley varieties (Condor and CDC Buck) were separately used as the dietary energy source (77.6%) with canola meal as the protein supplement (20%). Enzyme supplementation improved (P < 0.05) the ileal dry matter (DM) digestibility by 15.2%, gross energy (GE) by 11.0% and protein by 7.6%. The average apparent ileal digestibility of the indispensable amino acids was improved by 6.9% (P < 0.05), and of nonstarch polysaccharides (NSP) was improved by 90%. The total-tract digestibility of DM was increased by 6.2%, GE by 6% and crude protein (CP) by 9.4% (P < 0.05). Enzyme supplementation tended to enhance digestion in the small intestine instead of the hind-gut as expected. In the growth performance trial, positive responses from enzyme supplementation were observed from both mash and pelleted diets fed to 48 pigs grown from 9 to 60 kg liveweight. The ADG was improved by 8.6% (P < 0.05) and feed conversion by 8.7% (P = 0.09). Pelleting had no adverse effect on enzyme activity. The results demonstrated that the enzyme supplementation improved (P < 0.5) nutrient utilization and performance of pigs fed diets containing hulless barley.