The practice of antimicrobial usage in African catfish (Clarias gariepenius) production and the
presence of antimicrobial residue in catfish in Oyo State were investigated by cross sectional study. Twenty
commercial fish farmers were interviewed using interviewers administered semi-structured questionnaire on the
pattern of antibiotic usage, knowledge of occurrence and risks of antimicrobial residues in catfish produced for
public consumption. In addition, 165 samples of Clarias gariepenius were obtained from ready to eat fish
restaurants and farms for screening for antimicrobial residues using Premi®Test kit while oxytetracycline
residue was determined by high performance liquid chromatography (HPLC). The results showed that majority
(95%) of the respondents frequently administered drugs (in feed and water) to their fish without veterinary
prescription and not observing withdrawal period. Oxytetracycline is the commonly used, extra-label drug usage
were frequently practiced. Ninety eight (61.3%) liver and 84 (52.5%) muscle of catfish screened contained
detectable antimicrobial residues, while 62 (38.8%) liver and 48 (30.0%) muscle had oxytetracycline residue by
HPLC method. Oxytetracycline concentrations in the positive samples ranged between 234.3 and 987.5 µg kg 1
(mean = 875.32±45µg kg ) in the liver and 22.5 and 553.2 µg kg (mean = 257.2±133µg kg ) in the fillets. Forty 1 1 1
three (26.9%) liver and 30 (18.8%) fillets contained oxytetracycline residues above the Codex Alimentarius
Commission established maximum residue limit of 600 and 200 µg kg respectively. This implied that 1
appreciable quantity of catfish consumed in Ibadan, Nigeria posed antibiotic residue risks and food safety
consequences. Misuse of antibiotics in aquaculture production without veterinary prescription and control
coupled with lack of awareness of the food safety consequences were the contributing factors for the high level
of residue violation. Therefore, there is need for veterinary supervision of drug use in fish, residue monitoring
and food safety education of producers and consumers.