The effect of dietary 3-nitro4-hydroxyphenylarsonic acid (roxarsone) on the total arsenic level in broiler excreta and broiler litter

Broiler chickens are routinely fed diets containing the growth promotant 3-nitro-4-hydroxyphenylarsonic acid (roxarsone; ROX). Four trials were conducted to determine the amount of arsenic present in broiler excreta and broiler litter when broilers were fed a diet containing ROX. Two experimental diets were utilized in all four experiments: the control diet (CON) that contained no added ROX and the ROX diet that contained 45.4 g of ROX per ton. The CON and ROX diets were fed from 1 d of age until 42 d of age. From 42 to 47 d of age, both treatments received a withdrawal diet that contained no ROX. Weekly fecal samples were taken during Experiment 1. In Experiments 2,3, and 4, litter samples were collected prior to each chick placement and at the end of each growout. All fecal and litter samples were analyzed for total arsenic content. In Trial 1, the total arsenic level in the feces of birds receiving the ROX diet increased from 1 to 4 wk; the total arsenic level decreased from 4 to 6 wk, and continued to decrease through the withdrawal period (42 to 47 d). In addition, the ROX birds exhibited a greater level of total arsenic in the feces than the CON birds during each week of Trial 1. The total arsenic level in the feces of the birds receiving the CON diet remained constant throughout Trial 1. In Trials 2, 3, and 4, the total arsenic level in ROX built-up litter did not exhibit a continuous increase with multiple growouts and remained constant in the CON built-up litter.