Phenoxy-Acid-Induced Renal Changes in the Chicken

Forty-five day-old broiler chicks were equally divided into 3 groups, 2 being fed 2,4-D and 2,4,5-T, respectively, from the fifth day of life for up to 7 months, at 1,000 p.p.m. in the drinking water, and the third serving as a control. From 8 weeks of age 2 of the control animals were fed 2,4-D at the same rate for 7 months. Seven of the treated animals died, or were killed in a moribund state, during the experiment (Table 1), the survivors showing only slight signs of poisoning such as reduced mobility and food and water intakes. Animals were sacrificed after varying time intervals (Table 1). The tissue distribution patterns of 2,4-D and 2,4,5-T, as determined in selected tissues of a few of the animals (Table 2), were similar to that observed earlier with 2,4-D. Both compounds produced qualitatively similar morphological effects, although the action of 2,4,5-T apparently was somewhat more intense. The predominant necropsy finding was kidney enlargement (Table 1) due to hypertrophy of the proximal convoluted tubular epithelium (Fig. 1). Electron-microscopically, increased numbers of mitochondria were demonstrated in the tubular cells, with variations in mitochondrial size, shape and structure (Figs. 4–7). The number of micro-bodies was also definitely increased (Figs. 2 and 4). In the nuclei nuclear bodies were observed (Figs. 2 and 3). The significance of the findings is discussed.