Microbiological Quality, Antibiotic Residues and Heavy Metal Contamination of Clarias gariepinus Farmed under Two Aquaculture Production Systems

Abstract

Background: The intensification of the aquaculture sector in Africa, which significantly contributes to global aquatic production, is increasingly confronted with public health concerns related to the quality of farmed fish marketed and to unregulated aquaculture practices. Therefore, the present study aimed to evaluate the influence of aquaculture production systems on the microbiological quality and the levels of antibiotic residues and heavy metals in Clarias gariepinus produced in Douala, Cameroon. Methods: To achieve this, a preliminary survey was conducted among fish farmers, followed by sample collection and the determination of microbiological quality, antibiotic residues, essential trace elements, and toxic heavy metals. Results: The results revealed that 75% of fish farmers used antibiotics, mainly tetracyclines (66.7%), without observing withdrawal periods. Regarding microbiological analyses, among all the targeted microorganisms, only Staphylococcus aureus was detected and exceeded acceptable limits in 75% of the samples. Concerning antibiotic residues, penicillin G was not detected, whereas oxytetracycline was detected in all analyzed tissues, with extremely high concentrations ranging from 2,737 to 42,578 µg/kg. Similarly, among the toxic metals analyzed, only lead levels exceeded the permissible limit in 75% of skin–muscle samples. Conclusion: These findings demonstrate that the intensive aquaculture production systems implemented at these sites pose increased risks to consumer health and highlight the urgent need to enforce strict monitoring measures within this sector.