Effects of a Combined Chinese Herbal Medicine on Growth Performance, Intestinal Barrier Function, Immune Response, and Cecal Microflora in Broilers Infected with Salmonella enteritidis

Abstract

This study investigated the effects of CCHM in drinking water on broilers infected with Salmonella enteritidis. One-day-old male Cobb 500 broilers (n = 300) were randomly assigned to five groups: a control (NC) group, a Salmonella enteritidis challenge (SE) group, an antibiotic (AB) group, a low dose of CCHM (CL) group, and a high dose of CCHM (CH) group. Each group had six replicate cages with ten broilers per cage. The broilers in the NC and SE groups were given normal drinking water. From days 12 to 18, the AB group received water treated with ciprofloxacin lactate injection (1 mL/L), while the CL and CH groups received water containing CCHM at doses of 5 mL/L and 10 mL/L, respectively. Broilers in all groups except the NC group were orally given Salmonella enteritidis daily from days 9 to 11. The experimental period was 28 days. The results showed that, compared with the SE group, the CL and CH groups showed improved growth performance; increased immune organ indices, expressions of ileal occludin and ZO-1 proteins, jejunal and ileal villus heights (except at day 19), and cecal Lactobacillus counts on days 19 and 28 (p < 0.05); and decreased jejunal and ileal lesion scores, ileal interleukin 1β (IL-1β) (except at day 19), interferon-γ (IFN-γ), interleukin 6 (IL-6) (except at day 19), secretory immunoglobulin A (slgA) and tumor necrosis factor α (TNF-α) (except at day 19) levels, serum D-lactic acid and diamine oxidase (DAO) (except at day 19) contents, jejunal and ileal crypt depths (except at day 19), and cecal Salmonella and Escherichia coli counts on days 19 and 28 (p < 0.05). On day 28, except for the levels of ileal interleukin 10 (IL-10), TNF-α, slgA, and serum D-lactic acid content, there were no differences among the NC, AB, and CL groups (p > 0.05). In conclusion, drinking water supplemented with CCHM alleviated the intestinal damage caused by Salmonella enteritidis infection and improved growth performance and cecal microbiota in broilers. The optimal addition rate of CCHM was 5 mL/L.