Prevention And Treatment Effect Of Extractions From Physalis Calyx Seu Fructus On Avian Infectious Bronchitis In Chickens

Infectious bronchitis（IB）is an acute respiratory disease that causes coughing,wheezing,rales and other clinical signs in infected chickens and can lead to lesions in the lungs,kidneys and other target organs.Infectious bronchitis virus（IBV）can spread,diffuse and mutate in a short period of time in chicken farms and is considered to be one of the most important epidemics in intensive chicken farms.Physalis Calyx Seu Fructus is cold in nature and belongs to the lung meridian.It has the effect of clearing heat and detoxifying the throat,and modern research has found that the flavonoids,steroids and sterols in it also have anti-inflammatory effects.In this study,we investigated the preventive and curative effects of Physalis Calyx Seu Fructus on IB from the perspective of tissue damage combined with inflammation and other relevant indicators through in vitro and in vivo tests.In order to investigate the alleviating effect of Physalis Calyx Seu Fructus on IBV-induced CEK cell damage,The half infectious dose(50%egg infectious dose,EID₅₀)of IBV M41 was measured at 10^-7.625/0.1 m L in chicken embryos.And the extracts from Physalis Calyx Seu Fructus were prepared,CEK cells were isolated,the optimal concentration of the drug was screened and a model of IBV-infected CEK cells was constructed,and the IBV-N content and inflammation-related gene expression indexes were detected by observing cytoactve.The results showed that:（1）IBV can infect CEK cells.（2）IBV infection of CEK cells up-regulated the levels of inflammatory factors IL-1β,IL-6 and TNF-α.（3）Addition of 400μg/m L of Extractions from Physalis Calyx Seu Fructus inhibited IBV proliferation and down-regulated the levels of IL-1β,IL-6 and TNF-α.In order to clarify the preventive and curative effects of extractions from Physalis Calyx Seu Fructus on IB,in this study,Forty 17-day-old Hyland Brown chickens were randomly divided into a control group,a model group,a group with 1 g/kg extractions from Physalis Calyx Seu Fructus and a group with 3 g/kg extractions from Physalis Calyx Seu Fructus.The test chickens were dosed with the appropriate dose of extractions from Physalis Calyx Seu Fructus before they were infected with IBV,and each dose was administered at 12 h intervals for 96 h.During the test,body temperature and body weight were measured,and at the end of the test,histological lesions were observed and IBV titres and inflammation-related indicators were measured.The test results showed that:（1）the addition of 3 g/kg of extractions from Physalis Calyx Seu Fructus was more effective in suppressing the increase in body temperature caused by IBV.（2）Histopathological sections of trachea,larynx,lung and kidney were observed and found to be alleviated by both 1 g/kg and 3 g/kg of extractions from Physalis Calyx Seu Fructus.（3）The addition of 3 g/kg of extractions from Physalis Calyx Seu Fructus influenced the weight gain of the test chickens.（4）The IBV-N titer was measured and it was found that 3 g/kg had a more significant effect in down-regulating the viral content in the lung and kidney than 1g/kg of extractions from Physalis Calyx Seu Fructus.（5）Both 1 g/kg and 3 g/kg of extractions from Physalis Calyx Seu Fructus down-regulated serum levels of IL-6 and TNF-α,and up-regulated IL-10 levels.（6）The addition of 1 g/kg and 3 g/kg of extractions from Physalis Calyx Seu Fructus down-regulated TNF-αlevels in lung and kidney,with 3 g/kg having a more significant effect.It was found that 3 g/kg of extractions from Physalis Calyx Seu Fructus had a good preventive effect on IB.In the present study,the therapeutic effect of extractions from Physalis Calyx Seu Fructus on IB was further investigated by nasal and ocular injection of IBV and intraperitoneal injection of E.coli lipopolysaccharide（LPS）in test chickens.Thirty 17-day-old Hyland Brown chickens were randomly divided into the control group,the model group and the Physalis Calyx Seu Fructus（3 g/kg）group.The test chickens were injected with LPS at 60h of IBV infection,followed by the administration of extractions from Physalis Calyx Seu Fructus at 12 h intervals for 72 h.During the test,clinical signs were observed,body temperature and body weight were measured,and histopathological changes were observed at the end of the test to determine the IBV content and Histopathological changes were observed at the end of the test,and IBV levels and inflammation-related indexes were measured.The results showed that:（1）The extract reduced the clinical symptoms and alleviated the histopathology of the test chickens.（2）The extract inhibited the increase in body temperature caused by IBV（LPS）.（3）The addition of Physalis Calyx Seu Fructus influenced the weight gain of the test chickens.（4）The extract inhibited the proliferation of IBV in the lungs and kidneys of the test chickens.（5）The addition of Physalis Calyx Seu Fructus could down-regulate the serum levels of IL-6 and TNF-αand up-regulate the level of IL-10.（6）The addition of Physalis Calyx Seu Fructus inhibited the overexpression of TNF-αfactors in the lungs and kidneys of the test chickens.In conclusion,the addition of 400μg/m L of Physalis Calyx Seu Fructus to CEK cells inhibited IBV proliferation in vitro.After prolonging the course of IB with LPS,administration of extractions from Physalis Calyx Seu Fructus（3 g/kg）continued to have a therapeutic effect by reducing clinical signs,alleviating histopathological changes,downregulating body temperature,inhibiting IBV proliferation and regulating inflammation levels in test chickens.In this study,the extractions from Physalis Calyx Seu Fructus was effective against IB,providing an alternative drug for the treatment of respiratory diseases in poultry.