The study was conducted on 20 Brahman crossbred bulls (217±22.6 kg) to investigate the effect of supplemented chromium, sodium nitrate and mineral mixture on rumen microbes, growth performance and blood biochemical profiles. It was found that the addition of mineral mixture increased the number of total bacteria (10.81x10¹⁰/mL) and Ruminococcus flavefaciens. Sodium nitrate supplementation also increased the number of Ruminococcus albus at the beginning of the trial but sodium nitrate supplementation did not lead to a change of bacterial quantity at the end of the experiment. In addition, better performance in weight gain (62.0kg) and average daily gain (688 g/day) was indicated in cattle fed mineral mixture supplementation. Irrespective of supplementation sources, the blood biochemical profiles of cattle remained unchanged. However, it was observed that mineral mixture supplementation enhanced rumen bacteria and improved cattle growth during the growing stage.