Preparation Of Litsea Cubeba Oil Oral Liquid And Its Preliminary Clinical Application For Salmonella Infection In Chickens

Salmonella is a human-animal commensal Gram-negative parthenogenic anaerobic bacterium and a common clinical foodborne pathogen.Salmonella is the main pathogen of avian typhoid and chicken dysentery,and infected poultry mainly manifest as anorexia,diarrhea,dehydration,weakness and high mortality,resulting in annual economic losses of about tens of billions of dollars,seriously endangering the healthy development of poultry farming and food safety.Currently,antibiotics are the most commonly used to treat and control Salmonella infections,but they easily induce the development of bacterial resistance,and novel anti-infection strategies are urgently needed in clinical practice.Salmonella gliding motility "assists" the bacteria to reach the surface of the host intestinal epithelial cells,where they survive and proliferate through adhesion and invasion into phagocytic cells,ultimately leading to systemic infections in various organs throughout the body.Therefore,unlike the antibacterial effect of antibiotics,inhibiting the sliding movement of Salmonella and hindering bacterial adhesion and invasion are important potential strategies and targets for anti-Salmonella infection.Chinese medicine is the treasure of our country and contains a variety of biologically active ingredients with antibacterial,antiviral,anti-inflammatory,residuefree and drug-free properties.In this study,we established an inhibitor screening platform based on the sliding motility of Salmonella in semi-solid agar,and found that 32 μg/mL of Litsea cubeba oil significantly inhibited the sliding motility of Salmonella and reduced the adhesion rate of Salmonella to host cells to less than 30%;established an in vivo infection model of Salmonella mice,and found that 100 mg/kg of Litsea cubeba oil could increase the survival rate of Salmonella-infected mice by It was found that 100 mg/kg of Litsea cubeba oil could increase the survival rate of Salmonella-infected mice by 60% and reduce colonization in organs.Due to the volatile,oxidizing and poor water solubility characteristics of volatile oils such as Litsea cubeba oil,it cannot be administered directly through the prototype in clinical practice.In this study,we further prepared the oral solution of Litsea cubeba oil,and initially determined the prescription and preparation process of the oral solution of Litsea cubeba oil: the mixed solvent and surfactant polysorbate 80 were mixed well by the dissolution method,and Litsea cubeba oil,and antioxidant dibutyl hydroxytoluene solution were added under uniform stirring to finally form a homogeneous solution system,and the PH value was adjusted to 6.0 by 10%hydrochloric acid solution,stirred,filtered and dispensed.The product was obtained.Secondly,the content of citral,the main ingredient in the oral solution of Litsea cubeba oil,was determined by high performance liquid chromatography,and the stability of the oral solution of Litsea cubeba oil was examined by antioxidant and anti-volatility indexes,and the validity period of the oral solution of Litsea cubeba oil was determined to be 12 months at room temperature and protected from light.Finally,the therapeutic effect of Litsea cubeba oil oral solution on Salmonella infection was investigated by the model of Salmonella infection in chicks,and the meat ratio,ocular lesion index of dissected organs and colonization of organs were used as testing indexes.There was no significant difference with the healthy control group;at the same time,the intestinal lesion index and organ colonization of chicks were reduced.The results of the safety test showed that the oral solution of Litsea cubeba oil had no significant effect on the clinical symptoms and growth performance of broiler chickens when administered at a dose no less than 5 times the recommended clinical dose for 15 consecutive days.In conclusion,the present study screened to significantly inhibit the sliding movement,adhesion and infection inhibitor of Salmonella;successfully prepared the oral solution of Litsea cubeba oil;and found that the oral solution of Litsea cubeba oil has good preventive effect and safety for Salmonella-infected broilers.This study will provide a new drug development strategy for clinical Salmonella infection and prevention and control,as well as a potential new Chinese medicinal preparation for the prevention and control of Salmonella infection.