A compound plant extract and its antibacterial and antioxidant properties in vitro and in vivo.

The present study was conducted to prepare a compound plant extract as a candidate animal feed additive. Firstly, (ER), (SS), (PG) and (AA) were screened out from 17 plants as materials of candidate compound plant extracts by measuring the antibacterial rate on and , and the scavenging capability on 2,2 diphenyl-1-picrylhydrazine radical in vitro. Secondly, proportions of the four materials were optimized with an L (4) orthogonal experiment. By range analysis of experimental results, two compound extracts (named as F1 and F2) with the strongest antibacterial and antioxidant functions were obtained. The ratio of ER: SS: PG: AA is 9:9:1:3 in F1 and 9:9:9:3 in F2, respectively. Finally, the effects of F1 and F2 on security and efficacy in vivo were evaluated. In healthy mice, F1 had no significant effects ( > 0.05) on all blood parameters and viscera indices, and at 1000 mg/kg bw dose significantly increased ( < 0.05) the average daily gain (ADG). F2 decreased ( < 0.05) white blood cell count at 3000 mg/kg bw and increased ( < 0.05) red blood cell count at 333 mg/kg bw. In immunosuppressed mice, both F1 and F2 improved ADG ( < 0.05) and the feed intake to gain ratio ( < 0.01), and increased the activities of hepatic superoxide dismutase ( < 0.05), catalase ( < 0.05) and total antioxygen capacity ( < 0.05), and the content of malonaldehyde ( < 0.01). In mice challenged with , the antidiarrhea and reducing mortality effects of F1 were equivalent to the antibiotic. F2 failed to protect the experimental mice. These results suggested F1, a compound plant extract, show a great potential as a substitute for antibiotics in animal feed.