Evaluation of Antibiotic Residual Concentrations and Their Effects in Broiler Chicks

Antibiotic resistance occurs when bacteria develop the ability to withstand the effects of an antibiotic. The misuse of antibiotics in poultry production has contributed to antibiotic resistance. Antibiotics are commonly used as growth promoters and for therapeutic purposes. A survey of 80 questionnaires was conducted to identify the most commonly used antibiotics in poultry farms. This was done to recreate how antibiotic administration is carried out in poultry farms, which would indicate whether these drugs are being abused by poultry farmers. Seven antibiotics were selected and administered based on the average body weight of 40 broiler chickens. These included Oxytetracycline (400 mg/kg), Tylosin (500 mg/kg), Gentamycin (330 mg/kg), Penicillin (500 mg/kg), Neomycin (220 mg/kg), Sulfonamide (200 mg/kg), and Fluoroquinolone (300 mg/kg), which were compared with a normal control group. Additionally, 15 chickens were purchased from local markets in Keffi, Nasarawa State, for comparison. Samples from the blood, breast, liver, gizzard, and crop were analyzed to determine antibiotic residual concentrations, their effects on haematological parameters, the presence of resistant bacteria in the antibiotic residue, alongside an antibiotic sensitivity test. The results showed a significant difference (p<0.05) in haematological parameters in the local market group compared to the poultry farm group, indicating immune suppression. Both groups exceeded the recommended maximum residue limits. Pathogenic bacteria like Salmonella spp. and E. coli were found in the local market group, and antibiotic sensitivity tests showed reduced efficacy of the antibiotics. The misuse of antibiotics as growth promoters and therapeutics affected the blood of chicks, exceeded the antibiotic residue limit and also contributed to the development of antibiotic-resistant bacteria. This indicates the misuse of antibiotics in local market chickens during administration, rendering the meat unsafe for human consumption.