Effects of Chromium Supplementation on Growth Rate and Metabolism in Fattening Bulls

Effects of chromium supplementation on growth rate and selected metabolic indexes including interactions with trace elements (zinc, copper) were investigated in 8-month-old bulls divided into one experimental (E, n = 8) and one control (C, n = 9) groups with mean live weights 284.9 ± 33.9 and 279.6 ± 27.0 kg, respectively. The experimental group was fed a diet supplemented with chromium-enriched yeasts (Co-Factor III Chromium Yeast, Alltech, 0.1 % Cr3+) at a dose corresponding to the intake of 5 mg of Cr per animal per day in the first phase (up to day 136) and 8 g per animal per day in the second phase (days 136 to 220) of the fattening period. The bulls were weighed and blood samples were collected on days 1, 136 and 220 of the experimental period. Favourable effects of chromium supplementation were evident from higher weight gains in the first fattening phase (1.04 ± 0.12 vs. 0.82 ± 0.12 kg; p ≤ 0.01). The between-group difference diminished and became now significant in the second phase of the fattening period (0.82 ± 0.12 vs. 0.74 ± 0.14 kg). Significantly higher concentration of protein (p ≤ 0.01) on days 136 and 220, total cholesterol (p ≤ 0.05) on day 136, copper (p ≤ 0.05) on days 136 and 220, and significantly lower concentration of magnesium (p ≤ 0.05) on day 220, phosphorus (p ≤ 0.05) on day 136 was found in experimenta