Estimation of microbial protein synthesis from derivatives of purine in cattle and buffaloes that were fed with increased levels of concentrate diets

This work aims to estimate the synthesis of microbial protein and urinary creatinine excretion in four bovine and four bubaline distributed in two 4 × 4 Latin squares. The treatments consisted of different levels of concentrate (0.0, 24.0, 48.0, and 72.0%) composed of grinded (SIM) corn, soybean meal, mineral salt, and Tifton-grass hay. Each period lasted 21 days; 14 days of adaptation and seven days to collect samples. The results presented interaction between species for the urinary volume, uric acid, allantoin, purine derivatives, absorbed purines, microbial nitrogen, microbial crude protein, microbial crude protein efficiency of synthesis microbial, urinary creatinine, for interaction with plasma creatinine and creatinine clearance. Increased levels of concentrate in the diet did not influence the urinary volume, efficiency of microbial protein synthesis, plasma creatinine and creatinine excretion in buffaloes. For the observed concentrate levels’ effect for purine derivatives and microbial protein production, as well as for the plasma creatinine and creatinine excretion in cattle, rising levels of concentrate in the diets of cattle and buffaloes provide increases in both purine derivatives and microbial protein production; the collection of spot urine is a tool to estimate purine derivatives excretion and creatinine, to estimate the urinary volume in animals.