Survey of Enterobacteria and Variation in Blood Parameters of Birds (Broilers) on Prolonged Treatment with Antimicrobial Agents

The study evaluated the effects of prolonged prophylactic use of common antimicrobial agents on enterobacteria and haematology of broiler chickens. Fifty chicks were randomly assigned to 3 different experimental groups comprising a control (T1) group given only vitastress as chemotherapeutic agent while T2 and T3 had neo-terramycin (neomycin and oxytetracycline) and terramycin antigen 77 and vitastress (oxytetracycline and antistress) as antimicrobial agents respectively over a period of 8 weeks. Faecal and blood samples were collected before and after treatments from each experimental unit. Blood and MacConkey agar were used for isolation of bacteria from the faecal samples. All isolates were identified by standard biochemical procedures. Blood samples were subjected to Hb concentration, PCV and ESR assays. The results showed that Escherichia coli, Klebsiella spp., Proteus spp. and Enterococcus faecalis were enterobacteria present before treatment. Escherichia coli persisted in all the treatment groups. Klebsiella and Enterococcus species persisted in T2, while Proteus species persisted in T3. The study also showed that prolonged use of these antimicrobial agents did not affect the haematology of birds. However, due to the resistance to these antimicrobial agents exhibited by these bacteria, the use of these antimicrobials in poultry production is not recommended Keywords: enterobacteria, antimicrobial agents, haematology, antistress, treatmen