Nitrogen Metabolism in Lambs Fed Soybean Meal Treated with Heat, Formalin and Tannic Acid

Abstract

A digestion and nitrogen balance trial was conducted with lambs to compare the effect of heat, formalin and tannic acid treatment of soybean meal on nutrient utilization. Cellulose digestibility was significantly (P < 0.05) reduced, but nitrogen retention was highest in lambs consuming heated soybean meal. Lambs consuming formalin-treated soybean meal had significantly (P < 0.05) lower dry matter and crude protein digestibility coefficients, although cellulose digestibility was equal to that observed when normal soybean meal was fed. The resistance of formalin-treated soybean meal to postruminal enzymatic degradation was indicated by the lower percentage dietary nitrogen retained. No differences in digestibilities or nitrogen retention were found between tannic acid-treated and normal soybean meal. Although treatment of soybean meal did not affect the total concentration of blood plasma free amino acids, the molar percentages of alanine, glycine, leucine, valine, aspartic acid, arginine, histidine and lysine were significantly (P < 0.05) altered by soybean meal treatment.