The effect of organic acids and enzyme supplementation on the performance of pigs fed barley-based diets

Abstract

Two factorial design experiments (sex × treatment) were conducted to determine the efficacy of enzyme and organic acid supplementation on improving the nutritive value of barley-based diets for both starter and finisher pigs. For exp. 1, 48 crossbred growing pigs (25.1 ± 2.8 kg) were fed either a barley-based control diet or a similar diet supplemented with 0.25% enzyme (Aspergillus niger; 750 units g−1 beta-glucanase), 2.5% propionic acid or a combination of these additives during a 77-d feeding trial. For exp. 2, 120 crossbred weaner pigs (8.1 ± 1.3 kg) were fed a hulless barley-based control diet or a similar diet supplemented with 0.25% enzyme (Aspergillus niger; 750 units g−1 beta-glucanase), 2.0% fumaric acid or both additives in combination for a 35-d feeding period. In exp. 1, supplementation with either enzyme or propionic acid alone, significantly (P < 0.05) increased dry matter digestibility. However, when the additives were fed in combination, the digestibility coefficient for dry matter was not significantly different from the control. Digestibility coefficients for crude protein and energy were not affected by any treatment. Growth rate, feed intake, feed efficiency and carcass traits were also not improved by supplementation with enzyme or propionic acid, either when fed alone or in combination. In exp. 2, digestibility coefficients for dry matter, crude protein and energy were not affected by enzyme or acid treatment. In addition, there were no differences in growth, feed intake or feed efficiency as a result of any treatment. Supplementation with organic acids would therefore appear to be ineffective in potentiating the response to dietary beta-glucanase in pigs fed barley-based diets. Key words: Swine, barley, beta-glucanase, propionic acid, fumaric acid