BACKGROUND: Salmonella Enteritidis in poultry is one of the main causes of illness that can be controlled effectively by some plant compounds, antibiotics and probiotics. OBJECTIVES: This study compares the effect of rosemary, thyme, propolis, antibiotic and probiotic on the immune system and blood parameters of broilers challenged with Salmonella Enteritidis.  Methods: Four hundred and twenty 1-day- old male broiler chicks Cobb strain were divided into seven groups: including rosemary ethanol extract, ethanol extract of propolis, ethanol extract of thyme, and probiotics, virginiamycin (10%) and positive and negative controls, and were reared for 6 weeks. At the end of experiment chickens were sampled and slaughtered. RESULTS: The results showed that plant extracts with probiotics can improve the immune system, reduce serum lipids, reduce harmful bacteria such as Salmonella and E.coli and increase the beneficial bacteria such as lactic acid bacteria. CONCLUSIONS: This study showed that the herbal extracts and probiotics can be used as an alternative to antibiotics in broiler diets.

The aim of this study was to evaluate the antimicrobial activity and determine the minimum bactericidal concentration (MBC) of the essential oils derived from Origanum vulgare (oregano), Melaleuca alternifolia (tea tree), Cinnamomum cassia (cassia), and Thymus vulgaris (white thyme) against Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis. The study also investigated the ability of these different bacterial strains to develop adaptation after repetitive exposure to sub-lethal concentrations of these essential oils. The MBC of the essential oils studied was determined by disc diffusion and broth dilution methods. All essential oils showed antimicrobial effect against all bacterial strains. In general, the development of adaptation varied according to the bacterial strain and the essential oil (tea tree > white thyme > oregano). Therefore, it is important to use essential oils at efficient bactericidal doses in animal feed, food, and sanitizers, since bacteria can rapidly develop adaptation when exposed to sub-lethal concentrations of these oils.