Effect of ensiling on chemical composition and rumen degradability of apple pomace

Abstract

The effect of ensiling on the degradation dinamics of dry matter (DM) and chemical composition of apple pomace was evaluated. Rumen degradability was determined in situ by the nylon bag technique at 2, 6, 12, 24 and 36 hrs fermentation with 6 replicates per time and apple pomace type. Ensiling increased the relative contents of DM, crude protein (CP), crude fiber (CF) and acid detergent fiber (ADF) (43.7, 13.0, 14.3 and 18.4% respectively) and reduced the metabolizable energy content (4.9%). Degradability was greater in fresh compared to ensiled apple pomace (p<0.05), however, the advantage decreased from 26% at 2 hrs to 3.3% at 36 hrs fermentation (84.9 vs 82.2 %), 93-95% of the potential degradability was obtained at 36 hrs fermentation.

Values for soluble, slowly degradable and undegradable fractions of fresh and ensiled pomace, respectively were: 26.5 and 13.8%; 62.3 and 75.7%; 11.2 and 10.5%; potential degradability and degradation rates were: 88.8 and 89.5%; 0.076 and 0.065 hr-1, respectively. In ensiled pomace the insoluble fraction contributed more to DM degraded at 36 hrs (73.4 vs 92.1%) suggesting a greater fiber degradability and a more uniform degradation pattern with time. Due to its higher fiber and insoluble fraction content, effective degradability was lower in ensiled apple pomace.