Occurrence of antibiotic residues in raw fish Clarias gariepinus and Oreochromis niloticus from intensive rearing system in Benin

International audienceAn observational cross-sectional study was carriedy out to investigate antibiotic residues in Clarias gariepinus and Oreochromis niloticus from the intensive rearing system in Southern Benin. The targeted antibiotic families were tetracyclins, amphenicols, beta-lactams and macrolides. One hundred and forty-four (144) samples were used per antibiotic family for residue detection in the fish muscle, making 576 treated samples. The Charm II method based on radioimmunoassay was used. The results showed an overall residue prevalence of 11.1%, which is attributable to tetracyclines alone. There was no residue of the other antibiotic families in the treated fish muscles. The adult fish were the only contaminated age group with 22.2% residue prevalence compared to the fingerlings (p < 0.05). Likewise, the antibiotic residues were significantly (p< 0.05) more prevalent in Clarias gariepinus (16.7%) than in Oreochromis niloticus (5.6%). The adult fishes are generally fattier than the young ones, and that can lower the fish body antibiotic elimination capability. This first detection of tetracyclines residues in fish produced in Benin shows the need to rule and control antibiotic use in the developing fish industry to preserve consumers' health

Trypanosomiasis challenge estimation using the diminazene-aceturate (Berenil) index in Zebu in Gabon

A longitudinal study was conducted within a cattle ranch in Gabon to determine the diminazene aceturate (Berenil) index (DAI) in a group of Zebu, raised under low tsetse density; this measure providing an assessment of trypanosomiasis risk. The objective was to evaluate the trypanosomiasis pressure thus informing trypanosomiasis control methods and cattle management. Twenty female adult Zebu were monitored for 24 weeks during the dry season. Blood samples were collected on aweekly basis and subjected to parasitological and haematological analysis (n = 480), using the buffy-coat method and the packed cell volume value (PCV), respectively, infected animals were treated with a single intramuscular injection of diminazene aceturate (8 mg/kg). Twenty-nine single infectious events were recorded and a DAI of 1.45 was calculated. Two trypanosome species were identified: Trypanosoma congolense (96.2%) and Trypanosoma vivax (3.8%). The mean PCV value of the infected animals was lower (26.6) compared to non-infected animals (32.0). This study shows that DAI may be a useful tool to assess trypanosomiasis. However, this is a time-consumingmethod that may be improved by using randomly selected sentinel animals to adapt the chemoprophylactic schemes, hence decreasing the costs and the drug resistance risk