Effect of Dietary Mercury Concentrations on Growth Performance and Relative Organ Weight in Male Broiler Chickens

An experiment was conducted to investigate the effect of dietary mercury concentrations on growth performance and relative organ weight in male broiler chickens. A total of 400 2-d-old Ross 308 male broiler chicks were housed in 40 battery cages for a 5-wk feeding trial. Birds were randomly allotted to 1 of 5 dietary treatments with 8 replicated cages. Each replicate had 10 birds per cage. Dietary mercury concentrations were set to 0, 50, 100, 250, or 500 mg/kg by adding mercury chloride (≥ 73.9%) at the expense of the celite. The experimental diets were mash form. At the end of the experiment, 1 bird from each replicate was euthanized. The breast, liver, heart, kidney, spleen, lung, bursa of Fabricius, and small intestine were collected and weighed individually. The relative organ weights were calculated as a percentage of live body weight. Results indicated that increasing mercury concentrations in diets decreased (linear and quadratic, P < 0.05) body weight gain and feed intake of male broiler chickens. Birds fed diets containing greater than 250 mg/kg mercury showed significantly less body weight gain and feed intake (P < 0.05) than those fed the control diets. However, there were no differences in feed efficiency and mortality among dietary treatments. The relative weights of the small intestine were decreased (quadratic, P < 0.05) with increasing mercury concentrations in diets, whereas those of other organs were not affected by dietary treatments. In conclusion, a greater than 250 mg/kg mercury in diets is toxic to male broiler chickens. The small intestine is likely the most sensitive organ to the toxic concentrations of mercury in diets for male broiler chickens.