Effects of Formaldehyde, Glyoxal, or Hexamethylenetetramine Treatment of Soybean Meal on Nitrogen Utilization and Growth in Rats and In Vitro Rumen Ammonia Release

Abstract

A series of rat trials were conducted in an attempt to screen various kinds and levels of aldehyde treatment of soybean meal to find the level of treatment at which digestibility to the animal is lowered. Concurrent trials measuring in vitro rumen ammonia release were run to find the optimum level of treatment which would result in decreased ruminal ammonia production. Soybean meal (SBM) was treated with various levels of formaldehyde (F), glyoxal (GLY), hexamethylenetetramine (HMT), or water (control). One, 2, 3, or 4 ml of 40% formaldehyde solution; 1, 2, 3, 4, or 5 ml of 40% glyoxal solution; or 3, 6, 12, 18, or 36 ml of a 41.6% HMT solution were diluted to a final volume of 18 ml (except HMT-36) with water and sprayed on an amount of SBM equivalent to 100 g C.P. Treated SBM was used in 20 semi-purified diets (26% C.P.) which were fed to 79 g rats in growth and nitrogen balance studies. The lowest level of formaldehyde (F-1) essentially inhibited in vitro rumen ammonia release while gains and nitrogen retention were significantly lowered with treatment F-3 (P < .01). Thus, availability to the rumen was affected before total digestibility. All GLY treatments resulted in gains less than controls (P < .01) but these results were confounded by parallel depressions in intake. The response to increasing levels of HMT was not consistent over three trials. However, rats consuming protein at the highest treatment level (HMT-36) generally gained less than controls and retained less nitrogen. Depression of in vitro ammonia release increased with HMT level and was sufficiently depressed with moderate levels of HMT to warrant further investigations of its use for ruminants. Copyright © 1973. American Society of Animal Science . Copyright 1973 by American Society of Animal Science