ROLE OF SOCIALIZATION, STRESS AND SEX OF CHICKENS ON RESPONSE TO ANESTHESIA AND ON RESPONSE TO AN ORGANOPHOSPHATE NEUROTOXICANT

The influence of socialization of chickens on response to exogenous su bstances in the presence and absence of stress was examined. Chickens of both sexes were habituated to human beings (socialized) by being ta lked to and offered food from the hand of the caretaker. After 19 w, h alf the socialized group and half the unsocialized group were subjecte d to stress (loud noises for 120 sec twice daily) for 2 w. At the end of this period, response to 37 mg pentobarbital/kg iv was evaluated by length of sleeping time. Males slept longer than females, and males t hat were socialized but not stressed slept significantly longer than o ther males. Stress and socialization did not significantly affect pent obarbital sleeping time in females. This indicated that response to pe ntobarbital was dependent on sex and on socialization, with the most n otable effects occurring in socialized males. Socialized and nonsocial ized, stressed and unstressed male and female chickens were also admin istered a single po dose of 360 mg tri-ortho-tolyl phosphate (TOTP)/kg . This organophosphorus ester induced a delayed neuropathy that caused ataxia in all the chickens. The ataxia was significantly more pronoun ced earlier in males than in females, although the sex difference beca me insignificant 18 d after dosing. Socialized chickens were ultimatel y more affected. Noise stress did not affect TOTP-induced ataxia. This indicated that response to an organophosphate neurotoxicant was also dependent on sex and socialization, with the most notable effects agai n seen in socialized males. Response to endogenous substances in chick ens depends both on sex and on familiarity to humans.