Effect of pentachloronitrobenzene upon egg production, hatchability, and residue accumulation in the tissues of White Leghorn hens.

Individual groups of White Leghorn female chickens were fed graded concentrations (0, 10, 50, 100, and 1000 ppm) of pentachloronitrobenzene (PCNB), containing hexachlorobenzene (HCB), pentachlorobenzene (PCB), and tetrachloronitrobenzene (TCNB) as contaminants, from 1 day through 35 weeks of age. No concentration of PCNB caused toxic effects or death. Histopathologic examination of 10 organs, including ovaries, failed to reveal abnormalities in either control or treated groups. Onset of egg production was delayed for 1 month, and hatchability of eggs was significantly lower in hens at 1000 ppm PCNB. No embryonic abnormalities were observed. Only small amounts of PCNB and metabolites, pentachloroaniline (PCA) and pentachloro-phenylmethylsulfide (PCMS), were found in eggs. Conversely, HCB and PCB were readily transmitted into eggs. TCNB either was not detected or was present in only trace or finite amounts in eggs. PCNB, contaminates of PCNB (HCB, PCB, and TCNB), and metabolites of PCNB (PCA and PCMS) occurred in the highest concentration in adipose tissue. PCNB was not detectable (<0.05 ppm) in adipose tissue by 6 days following its withdrawal from the diet. In egg, the half-life of PCNB was not determined since only trace amounts were detected. Depletion half-lives of HCB and PCB in eggs were as high as 5.1 and 3.6 weeks, respectively.