GROWTH, FEED EFFICIENCY AND LEVELS OF MERCURY IN TISSUES OF TWO BREEDS OF CHICKENS FED METHYL MERCURY DICYANDIAMIDE

Abstract

Males of two breeds of chickens, Single Comb White Leghorns (SCWL) and broiler-type, were fed rations containing eight levels of added mercury from methyl mercury dicyandiamide (0.0, 0.33, 0.66, 1.32, 2.64, 5.29, 10.58, and 21.16 ppm Hg) from hatching to 8 weeks of age. Samples of heart, kidney, breast, and liver tissues were taken at the end of the 8-week growing period and their mercury content was determined. The growth rate of the broiler-type chickens was depressed with the three highest levels of dietary mercury, but the growth rate of the SCWL was influenced only by the highest level of mercury. The dietary mercury level did not affect feed efficiency, although the widest feed-to-gain ratios were obtained with both breeds of chickens fed the highest dietary mercury level (21.16 ppm). Except for the broiler chickens fed the highest level of mercury, dietary mercury had no effect on mortality. The mercury level of the four tissues increased with increases in dietary mercury. The highest levels of mercury were found in the kidney and liver. The level of mercury in the breast meat was about one-half of that in the kidney and liver and twice that in the heart. Rhodamine B dye was not deposited in the tissues of the chickens.