Effect of Sodium Hydroxide on Efficiency of Rumen Digestion

Abstract

Corn cobs were treated with increasing levels of sodium hydroxide (NaOH) and in vitro and in vivo digestion trials used to measure changes in fiber digestion. Corn cobs were raised to 60% moisture and treated to a final concentration of 0, 2.5, 5.0, 7.5 and 10.0% NaOH. The diets fed contained 80% cobs and 20% supplement (dry basis) giving a complete mixed diet containing 0, 2.0, 4.0, 6.0 and 8.0% NaOH. In vitro dry matter digestibility increased from 45.1% for the control diet to 83.1% for the 8.0% NaOH diet. In vivo dry matter digestibility was 5, 12 and 5 percentage units less than in vitro digestibility at the 4.0, 6.0 and 8.0% level, respectively. Neutral detergent fiber (NDF) on an organic matter basis decreased from 87.8% for the control diet to 68.4% for the 8% NaOH diet while there was only a slight decrease in the percentage acid detergent fiber (ADF) across the five dietary treatments. Five abomasally cannulated lambs were assigned to a 5 × 5 Latin square to measure ruminal fiber digestion as affected by increasing level of NaOH treatment. In vitro digestibility of NDF reaching the abomasum increased linearly with increasing level of treatment. Daily passage of dry matter was measured using indigestible NDF and indigestible ADF as markers. Passage decreased linearly with treatment but is confounded with increasing diet digestibility. Percentage of potentially digestible fiber that was digested in the rumen decreased with greater than 2% NaOH in the diet. These data suggest there are large increases in the potentially digestible fiber with increasing level of NaOH treatment, but some of it escapes microbial digestion in the rumen. Copyright © 1979. American Society of Animal Science . Copyright 1979 by American Society of Animal Science.