In Vitro Digestion of Soybean Meal Treated with Formaldehyde

Abstract

Summary Effects of treating soybean oil meal (SBOM) with O, .25, .35, .5 or 1.0 g of formaldehyde (HCHO)/100 g of meal were evaluated in terms of in vitro ammonia production and in vitro N and dry matter (DM) digestion. In vitro ammonia production was completely inhibited by .5- and 1.0-g treatments. The effect of the .5-g treatment varied with the length of time after treatment. In vitro digestion of the N and DM components varied (P<.05) with time after HCHO treatment in each trial, indicating a change in susceptibility of treated SBOM to microbial digestion. Each increment of HCHO over .25 g decreased (P<.01) microbial N digestion and increased the amount of N digested in the enzymatic phase. Total N digestion was decreased (P<.01) by HCHO treatment. Values from trial 1 were similar to those from trial 2 in all three in vitro digestion phases. Microbial digestion was lower, enzymatic digestion higher and total digestion lower in trial 3, possibly because of the source of SBOM or the method of applying the HCHO. The pattern of in vitro DM digestion was similar to that of N digestion, but smaller in magnitude. These results suggest that the optimum HCHO level for maximizing N utilization in ruminants is between .35 and .5 g/100 g of SBOM and that the amount of N digested in the microbial and enzymatic phases depend upon the length of time after HCHO treatment.