The present experiment was conducted to study the effect of Yucca schidigera and Oregano oil extracts on growth performance and Salmonella infection in broiler. Our results showed that both Salmonella Typhimurium field and standard strains were susceptible to Yucca schidigera and oregano oil extracts (pro-cocc) ®. The inhibition zones diameter in case of
100% concentration of pro-cocc were 24 mm and 25 mm, but the inhibition zones diameter recorded to ciprofloxacine were 31 mm and 32 mm against Salmonella Typhimurium field and standard strains, respectively. A total of 150 one day old broiler chicks were divided into 6 equal groups.Group (G1) provided with balanced ration without treatment (negative control). Group (G2) infected with Salmonella by dose (0.5 ml×108) orally and provided with basal diet without treatment (positive control). Group (G3) provided with basal diet and supplemented with (Pro-cocc)® in the drinking water by dose 1ml /4 L drinking water for 1week then infected with Salmonella by the same dose.Group (G4) non-infected provided with basal diet and supplemented with (Pro_cocc)® by the same dose.Group (G5) fed the basal diet and infected with Salmonella by the same dose thensupplemented with(Pro_cocc) ® by the same dose after 24 hrs from infection. Group (G6) received basal diet and infected with Salmonella by the same dose then treated with Ciprofoxacin by dose 5mg/kg orally after 24 hrs from infection. The result revealed that body weight on 14 day was non-significantly changed in all treatment groups but it tended to decreased in G2 while G4 showed significant increase in body weight on the 28th day with improvement in body weight gain (BWG), feed intake (FI) and feed conversion rate (FCR). G5 showed significant increase in BW and BWG on the 28th day compared with G2.There were no significant increases in serum aminotransferase (AST and ALT) in G3, G4 and G5. While glutathione peroxidase enzyme (GSH.PX) were significantly increased in G4 with significant decreased in total cholesterol and serum ammonia. G2 showed significant increase in aspartate amino transferase (AST), alanine amino transferase (ALT), Total Cholesterol and serum ammonia with significant decrease in Total Protein and GSH-PX enzyme. G6 showed significant increase in AST and ALT on the14th day followed by significant improvement on 28th day. Also the highest Salmonella spp. colonies count detected in positive control group (G2) followed by group (G5) on day 14th and 28th. Salmonella typhymurium could be detected in examined chicken thigh muscle after 14th days of the experiment in rate of 25% while the rate of isolation of the examined organism decreased after 28th days to be 10%.