Ammonia anabolizing enzymes in cattle and buffalo fed varied nonprotein nitrogen and carbohydrates

Abstract

Adult male fistulated crossbred cattle and buffalo, four each, were on rations with ratios of nonprotein nitrogen to carbohydrates of 1:45, 1:37.5, and 1:30 and a control of no urea in a 4×4 Latin square switchover design. The influence of various test diets on enzymes assimilating ruminal ammonia was elucidated to find an optimum ratio of nonprotein nitrogen to soluble carbohydrates for efficient utilization of dietary nitrogen. Inclusion of urea in graded amounts in the ration induced activities of aminotransferases. Specific activities of transaminases were higher in cattle and buffalo for rations with ratios of 1:45 and 1:30 compared to control and 1:37.5 (nonprotein nitrogen to carbohydrate ratio). This indicates a better adaptation of rumen microbes on two former rations which did not differ in augmentation of enzyme activities. Peak enzyme activity of cattle and buffalo at 2h postfeeding did not differ for microbial enzymes. The ration with narrowest nonprotein nitrogen and carbohydrate ratio (1:30) may be optimum for microbial synthesis of amino acid. It will be worthwhile to study whether a still narrower ratio can make feeding of ruminants more economical.