Nitrogen utilization and ruminal fermentation in steers fed soybean meal treated with formaldehyde.
Four rumen-fistulated steers averaging 400 kg in body weight were used in a 4 X 4 Latin square arrangement with 18-d periods to investigate the effect of treating soybean meal (SBM) with formaldehyde on nitrogen (N) utilization and ruminal fermentation. Experimental diets, on a dry matter basis, consisted of 42% corn silage, 48.5% cracked corn-mineral mixture and 9.5% SBM treated with 0, .3, .6 or .9% formaldehyde by weight. Dry matter and organic matter digestibilities were not affected by treatment. Formaldehyde treatment of SBM resulted in a linear decrease in N digestibility (P less than .005) and urinary N excretion (P less than .01) and a quadratic increase (P less than .05) in N retention. The depression in apparent N digestibility was small when SBM was treated with .3% formaldehyde. This level of formaldehyde treatment also had little effect on in vitro enzymatic hydrolysis of SBM. Ruminal ammonia-N concentrations were lower (P less than .05) in steers fed formaldehyde-treated SBM. Ruminal pH was lower (P less than .05) at 6 and 8 h postfeeding while volatile fatty acid concentrations were higher (P less than .05) at 8 and 12 h postfeeding for steers fed untreated SBM. Propionic acid (mol/100 mol) decreased linearly (P less than .05) with increasing level of formaldehyde treatment. Urea-N concentrations in plasma were decreased (P less than .001) and plasma-free essential amino acid concentrations were increased (P less than .10) by formaldehyde treatment. Ruminal disappearance of N from polyester bags containing the SBM supplements was greatly reduced (P less than .005) by formaldehyde treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
D000596:Amino Acids / Q000097:blood; D000818:Animals; D001806:Blood Urea Nitrogen; D002417:Cattle / Q000378:metabolism*; D004044:Dietary Proteins / Q000378:metabolism*; D004063:Digestion / Q000187:drug effects; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005285:Fermentation / Q000187:drug effects; D005557:Formaldehyde / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D012417:Rumen / Q000187:drug effects* / Q000378:metabolism; D013025:Glycine max
D000596:Amino Acids; D004044:Dietary Proteins; D005232:Fatty Acids, Volatile; D005557:Formaldehyde; D009584:Nitrogen