Effects of chromium yeast on growth performance and serum and carcass traits of broiler chickens

The aim of the experiment was to evaluate the effects of dietary chromium y east supplementation on growth performance, nutrient deposition rate, and s elected serum metabolites in broiler chickens. A basal diet was supplemente d with 0 (Control), 200, 400, or 600 ppb Cr as Cr yeast. For the first grow th period (days 8 to 22) birds fed the 200 ppb diet had greater average dai ly weight gains (P < 0.05) and better feed:gain ratio (P < 0.05) compared w ith birds fed the 600 ppb diet, but growth performance and water consumptio n were not significantly affected by treatment during the overall growth ph ase (days 8 to 40). Birds fed the 200 ppb diet had increased heart (P < 0.0 5) and abdominal fat pad weights (P < 0.05) than those of Control and 600 p ob treatments. Liver weights were not affected (P > 0.05). Hot and cold car cass weights were increased (P < 0.05) in birds fed 200 ppb compared with b irds fed the 600 ppb diet, but not if compared to Control treatment. Protei n, lipid and energy accretion rates were not affected by the treatments. Se rum HDL-cholesterol levels of broiler chicks fed the 200 ppb diet tended (P < 0.1) to be lower compared to birds fed 400 or 600 ppb diet. The results suggest that dietary Cr supplementation above a level of 200 pob could have adverse effects on carcass traits, but not on growth performance and nutri ent deposition.