No abstract

Clearance of sulfamethoxazole (SMX, or sulfisomezole) in eggs and tissues of chicken after withdrawal of the drug which was medicated feed additively (at 0.2 or 0.4%) or administered intramuscularly (100 mg./kg., twice daily) for 5 successive days was determined using a fluorescamine reagent. Clearance patterns of SMX were found to be different between albumen and yolk. SMX level in albumen diminished linearly to below 0.1 p.p.m. (sensitivity level) by 5 days after the cessation of medication. On the other hand, SMX level in yolk remained at a plateau until 4 days, and thereafter decreased linearly to below 0.1 p.p.m. by 10 days. SMX levels in most tissues diminished below 0.1 p.p.m. by 3 days and those in kidney and skin by 4 days. Clearance patterns in tissue were quite similar to those in egg albumen. Proportion of acetylated-SMX to total-one in both albumen and yolk tended to increase up to 10% with the lapse of time after drug withdrawal. Acetylation was high in liver (36.5-43.6%), spleen skin and fat, but low in breast muscle and kidney (3.7-11%) in the groups of feed addition; while acetylation was low in liver of the group of intramuscular injection.

Although many antimicrobial agents have been reported to cause immunosuppression in animals, macrolide antibiotics enhance immune function. Tylosin is a macrolide antibiotic approved for the control of mycoplasmosis in poultry. The purpose of this investigation was to determine the effect of tylosin on cellular immune functions in chickens. There was no significant difference in adherent splenocyte chemotaxis between tylosin-treated and untreated (control) chickens. Tylosin increased splenocyte proliferation and splenocyte conditioned medium (CM) proliferative activity above control levels. Removal of adherent splenocytes before preparation of CM caused a reduction in CM proliferative activity. Tylosin also increased antitumor activity of splenocytes. These data are the first to suggest that the macrolide antibiotic, tylosin tartrate, has a modulatory effect in chickens on the immune parameters studied.

While many antimicrobial agents have been reported to cause immunosuppression in animals, macrolide antibiotics enhance the immune function. Tylosin tartrate is a macrolide antibiotic approved for the control of mycoplasmosis in poultry. The purpose of this investigation was to determine the effect of tylosin on the humoral immune functions in chickens. Three days after oral tylosin tartrate administration, 4-or 8-week-old chickens were immunized intravenously with carbolic acid-killed Brrcce/la abortus bacterin or sheep red blood cells. Seven days (plasma antibodies titre) or 4 days (antibody forming cells) postimmunization, there was a significant increase in antibody production as well as in the numbers of antibodyproducing cells in tylosin tamate-administered chickens compared with the untreated controls. However, 3 days after tylosin tartrate administration, there was no difference in the distribution of T-lymphocyte subpopulations (CD4 or CD8 positive cells) or B lymphocytes (surface immunoglobulin positive cells) in either the peripheral blood or spleens of treated or untreated control chickens.