Use of corticosterone and ampicillin for treatment of Streptococcus faecalis infection in chickens.
Chickens were selectively bred for either high-antibody (HA) or low-antibody (LA) response to sheep erythrocytes. From 6 to 31 days after Streptococcus faecalis challenge exposure, LA-line chickens maintained a greater percentage of the prechallenge-exposure body weight and had lower heterophil-to-lymphocyte ratio than did HA-line chickens. The optimal dose of corticosterone (30 mg/kg of feed) was effective in maintaining postchallenge-exposure body weight greater than that of controls. Ampicillin (20 mg/d) alone was ineffective in almost all experiments. Treatment with 30 mg of corticosterone/kg of feed plus ampicillin resulted in increased body weight response to S faecalis infection when treatment was initiated 1 day before or 2 days after challenge exposure. Treatment with corticosterone was more effective in HA- than in LA-line chickens. Treatment before challenge exposure was more effective than treatment 2 days after challenge exposure.
Department of Large Animal Clinical Sciences, Virginia Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg 24060.
W B
WB
Gross
D000667:Ampicillin / Q000494:pharmacology / Q000627:therapeutic use*; D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002645:Chickens; D003345:Corticosterone / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D013293:Enterococcus faecalis / Q000187:drug effects*; D011201:Poultry Diseases / Q000188:drug therapy* / Q000517:prevention & control; D013290:Streptococcal Infections / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*
D000667:Ampicillin; D003345:Corticosterone