DIFFERENCES BETWEEN DUCKS, PHEASANTS, AND CHICKENS IN TISSUE MERCURY RETENTION, DEPLETION, AND TOLERANCE TO INCREASING LEVELS OF DIETARY MERCURY

Abstract

Ducks, pheasants, and broiler-type chickens were fed from 5 days of age diets containing four levels of added mercury (0.0, 0.33, 3.3, and 33 ppm) from methyl mercury dicyandiamide. At 35 days of age, heart, liver, kidney, and breast tissues were taken for mercury analyses. Birds receiving 0.33 and 3.3 ppm of mercury were changed to the 0.0 ppm diet after 35 days and the four tissues were removed weekly for 9 weeks. Body weight at 35 days was lower in all three species on the 33 ppm diet than on the other three diets. Mortality on the 33 ppm diet was 90, 85, and 7.5% for pheasants, ducks, and chickens, respectively. Background tissue mercury levels (0.0 ppm added mercury diet) were higher in liver and kidney than in heart and breast. Relative tissue mercury levels for the other three treatments at 35 days of age were: heart < breast < liver < kidney. Tissue mercury levels were generally higher in ducks than in pheasants and higher in pheasants than in chickens. Ducks retained more mercury in their tissues over time after they were placed on the 0.0 ppm diet than pheasants, and pheasants retained more than chickens.