Effect of Scrophularia striata Extract on Performance, Intestinal Microbial and Histo-morphometry, and Blood Parameters in Broilers under Normal or Challenged Condition with E. Coli

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 500 broilers were evaluated. The experiment was performed in a complete block design with a 2 × 4 factorial arrangement with five replications of 10 birds each for 35 days in two separated halls [include challenge (C) and non-challenge (N)] with similar experimental conditions. Experimental treatments in two breeding halls were: 1) basal diet or control (CONT), 2) basal diet + 0.1 g/kg of herbal extract (EXTR 1), 3) basal diet +0.2 g/kg of herbal extract (EXTR 2), 4) Basal diet +0.1 g/kg an antibiotic (Oxytetracycline) (ANTB). On the 16th and 24th days of the experiment, one dose of 1×107 CFU K99 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 35 and 1-35) in EXTR 2 was better than the control treatment (P < 0.05). The percentage of breast weight in the ANTB was significantly different from the control treatment (P < 0.05). Glutathione peroxidase (GPX) in EXTR 2 was better than the control treatment (P < 0.05). Malondialdehyde (MDA) in EXTR 1 was significantly lower than the control group (P < 0.05). The values of E. coli in the treatment ANTB were less than control treatment (P < 0.05). Lactobacillus value in treatment EXTR 2 was higher than control treatment (P < 0.05). The value of total immunoglobulin in 28 days in ANTB, EXTR 1, and EXTR 2 were significantly higher than that of control treatment (P < 0.05). The length of villi was affected by treatments (P < 0.05). In conclusion, dietary inclusion of 0.2 g/kg of Scrophularia striata extract may improve the health status of the birds during E. coli challenge.