In Vivo Activities of Some Selected Antimicrobial Agents Against Enteric Bacteria Isolated from Chicken Feeds on Broiler Layers

This study focused on in vivo activities of some selected antimicrobial agents against enteric bacteria isolated from chicken feeds sold in Anambra State. A total of 1,536 different chicken feed samples (starter, growers, finisher and layers) were collected from open markets and shops and screened for the presence of enteric bacteria using pour plate technique. The isolates were characterized and identified using their colony descriptions, biochemical and molecular characteristics. The phytochemical constituents of the medicinal plants were carried out using spectrophotometric methods. The protective effects of commercially prepared probiotics (CP), oxy-tetracycline (OXY), ciprofloxacin (CPX) and Zingiber officinale (ZO) were investigated using in vivo method. The result of this study revealed that Escherichia coli O157:H7 SS52 (EC), Salmonella serovar Typhimurium U288 (ST), Escherichia coli SEC470 (ES), Salmonella serovar Enteritidis YU39 (SY) and Salmonella serovar Enteritidis FM366 (SE) were isolated from the feed samples. The results of in vivo activity showed that the CP, CPX, OXY and ZO extract were effective in reducing pathological changes in the experimental chickens, of which CPX and OXY were most effective, and ZO extract was also effective and most safe for protecting the broiler layers against the pathogenic isolates. Their effects were significant (P<0.05) when compared to the infected non treated chickens. Thus, this study has shown that EC, ST, ES, EY and SE were isolated from the studied feed samples. The tested antimicrobial agents have proved to be safe and effective in reducing pathological features associated with the studied isolates in broiler layers. Keywords: In vivo study, Antimicrobial agents, Enteric bacteria, Chicken Feeds