RESUMO
The aim of this study was to evaluate the effect of the replacement of soybean meal by increasing levels of sugarcane yeast and urea on the energy, enzymatic, protein, mineral, and hormonal profiles of buffalo heifers. Twenty Murrah heifers with an average body weight of 168 ± 2.0 kg and 1 year old were used in a completely randomized design. The treatments consisted of the replacement of soybean meal by increasing levels of sugarcane yeast and urea (0, 33, 67, and 100% dry matter). The animals were weighed at the beginning and end of the experimental period, and blood was collected on the final day. The replacement of soybean meal with sugarcane yeast influenced the performance and metabolic dynamics, with total weight gain (P = 0.005) and average daily gain (P = 0.015), presenting, for both variables, a quadratic effect. Considering the biochemical profile, there was an influence on the serum concentration of triglycerides (P = 0.055), the serum activities of aspartate aminotransferase, gamma-glutamyl transferase, and alkaline phosphatase (P < 0.05), in addition to the serum concentration of phosphorus (P = 0.007) and potassium (P = 0.053), which showed positive linear effects. The hormonal profile was not influenced by diets (P > 0.05). The elements copper, iron, and zinc were able to be quantified at all levels of sugarcane yeast and urea in the diets offered. The use of sugarcane yeast with urea promotes adequate metabolic response of buffalo heifers and can replace up to 100% of soybean meal in the concentrate.
