Study on the Prevention and Treatment of White Diarrhoea Salmonella in Chick by Compound Radix Isatidis Oral Solution

PurposeTo develop Chinese traditional medicine for the prevention and treatment of salmonellosis in livestock and poultry, according to the Chinese traditional veterinary syndrome differentiation of salmonellosis, the traditional Chinese medicine prescription is used to provide a reference for the replacement therapy of antibiotic use in livestock and poultry breeding in the future.

MethodWe detected the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of compound radix isatidis oral solution (CRIOS) by vitro antibacterial activity, and observed the morphological changes of bacteria by scanning electron microscope. One hundred and fifty 1-day-old chicks were selected for clinical trials, 30 chicks were randomly selected into blank group, the remaining 120 chicks were artificially infected the Salmonella pullorum strains for preparing the chicken infection model. Infected chicks were randomly divided into model group, Chinese medicine treatment group, western medicine treatment group, and Chinese medicine prevention group, 30 chicks per group. The morbidity and mortality of chicks were observed. Serum levels of IL-1β and TNF-α were measured at 1 day, 3 days, and 5 days after treatment. The transcriptional levels of avian-β-defensin-6 (AvBD6) and chicken toll-like receptor 15 (ChTLR15) in chicks’ small intestine were detected by Real-time PCR.

ResultsThe MIC and MBC were 62.5 mg/mL and 25 mg/mL, respectively. Scanning electron microscopy showed that the bacteria appeared contractile, and many of the residues were broken and irregularly shaped in vitro. Clinical trials showed that Chinese medicine prevention could reduce the morbidity and mortality of chicks. Compared with the model group, the Chinese medicine prevention group and the Chinese medicine treatment group could reduce the contents of IL-1β and TNF-α. And the AvBD6 and ChTLR15 had a high expression level in the early stage of infection and tend to be normal later in treatment.

ConclusionThe results of this experiment indicate that CRIOS has an obvious inhibitory effect on S. pullorum, and its bactericidal mechanism is to change the morphological structure of the bacteria to make the bacteria lose activity. Clinical trials have confirmed that compound radix isatidis can effectively prevent Salmonella infection in chicks, and can effectively reduce the level of inflammatory factors in the body and reduce the inflammatory response.