Effect of supplemental corticosterone and social stress on organophosphorus-induced delayed neuropathy in chickens.

Adult White Leghorn roosters maintained for 3 months in an environment of low social stress (LSS) were given triorthotolyl phosphate (TOTP), 180 mg/kg po, 24 h after initial exposure to either an environment of high social stress (HSS) or exogenously administered corticosterone (200 ppm in diet). The environment of HSS or the administration of corticosterone were continued for 10 days after TOTP administration. It was noted that the heterophil/lymphocyte ratio, a hematological indicator of stress, was similar in both groups and both had similar scores for clinical signs of delayed neuropathy. Both heterophil/lymphocyte ratios and clinical scores were significantly lower in chickens kept in the LSS environment and not fed corticosterone than in chickens kept in the HSS environment or fed corticosterone.