Ali Dadvand - Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
Hassan Kermanshahi - Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
Reza Majidzadeh Heravi - Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
Ali Javadmanesh - Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran

The effect of different levels of Scrophularia striata extract in normal and challenged conditions with E. coli on performance, carcass characteristics, cellular immune response, blood antioxidant status, intestinal histo-morphometry, and microbial population (E.coli and Lactobacillus) of Cobb ۵۰۰ broilers were evaluated. The experiment was performed in a complete block design with a ۲ × ۴ factorial arrangement with five replications of ۱۰ birds each for ۳۵ days in two separated halls [include challenge (C) and non-challenge (N)] with similar experimental conditions. Experimental treatments in two breeding halls were: ۱) basal diet or control (CONT), ۲) basal diet + ۰.۱ g/kg of herbal extract (EXTR ۱), ۳) basal diet +۰.۲ g/kg of herbal extract (EXTR ۲), ۴) Basal diet +۰.۱ g/kg an antibiotic (Oxytetracycline) (ANTB). On the ۱۶th and ۲۴th days of the experiment, one dose of ۱×۱۰۷ CFU K۹۹ E. Coli was gavaged to chickens in a challenged conditioned hall. The results showed that average body weight and daily weight gain in the whole period (days ۳۵ and ۱-۳۵) in EXTR ۲ was better than the control treatment (P < ۰.۰۵). The percentage of breast weight in the ANTB was significantly different from the control treatment (P < ۰.۰۵). Glutathione peroxidase (GPX) in EXTR ۲ was better than the control treatment (P < ۰.۰۵). Malondialdehyde (MDA) in EXTR ۱ was significantly lower than the control group (P < ۰.۰۵). The values of E. coli in the treatment ANTB were less than control treatment (P < ۰.۰۵). Lactobacillus value in treatment EXTR ۲ was higher than control treatment (P < ۰.۰۵). The value of total immunoglobulin in ۲۸ days in ANTB, EXTR ۱, and EXTR ۲ were significantly higher than that of control treatment (P < ۰.۰۵). The length of villi was affected by treatments (P < ۰.۰۵). In conclusion, dietary inclusion of ۰.۲ g/kg of Scrophularia striata extract may improve the health status of the birds during E. coli challenge.

Broiler, Performance, Immune response, Antioxidant Status, Pharmaceutical plant extract