| Salmonella is one of the most important food-borne pathogens in the world.In the system of biosecurity,the purification of Salmonella in poultry is essential for the prevention and control of salmonellosis.Salmonella enteritidis is a zoonotic disease that can settle in adult poultry intestinal and reproductive tracts for a long period of time.It continues to detoxify,presents the recessive infection,further cause the pollution of poultry products.Salmonella was probably infecting human being via food chain from food producing animals and have caused serious food safety problems.This study aimed to study the detoxification of Salmonella enteritidis and the regulating effect of transfer factors and probiotics aganist Salmonella enteritidis,further providing a scientific basis for the prevention and control of Salmonella.Therefore,this study selected the Salmonella enteritidis which isolated from white feather broilers and named L50 as the research object,to explore the detoxification and the effect of probiotics and transfer factors on the pathogenicity of L50 infected SPF chickens.This study mainly conducted the following three aspects:Pathogenicity and detoxification of Salmonella Enteritidis Strain L50.7-day-old SPF chickens were infected with S.enteritidis L50 strain 0.5LD50(LD501.905×109CFU/ML).Buccal swabs were collected from all experimental birds for bacterial isolation at 3h-20d;throats and livers were collected from chickens after 28 days,Spleen,heart,muscle stomach,glands stomach,duodenum,cecum tissue sections were prepared for histopathological.The results showed that Salmonella(2/8)could be isolated from the infected chickens at the third hour,and the infection rate was the highest(4/8)from the buccal swabs at the 14th day after infection.The infected chickens were sacrificed after 28 days and there are different levels of inflammatory cell infiltration in livers and spleens;cecum villous epithelial cell proliferation,lamina propria inflammatory cell infiltration;duodenal villi rupture,epithelial cell shedding.Immune regulating effect of transfer factor(TFA)against Salmonella enteritidis L50strain infection on one-day-old SPF chickens.Sixty 1-day-old SPF chickens were randomly divided into 4 groups with 15 rats in each group:blank control group,experimental group 1(with TFA added to drinking water),experimental group 2(with TFA+L50 added to drinking water),and Salmonella L50 isolate infected group.The results showed that there was no significant effect of TFA on body weight of infected chickens(p>0.05)during 2-20 d after infection.The transfer factor could cause cellimmunity to reach high titer by 4-5 days,and at the same time,it could increase immune body ND antibody and reduce colonization of Salmonella in the cecum.Shedding regulation of 42-day-old SPF chickens infected with Salmonella enteritidis L50and regulated by Clostridium butyricum.42-day-old SPF chickens were used in the test and divided into 3 groups.Each infected group was treated with 3.5×10~9 CFU of Salmonella enterica L50 strain.The results showed that Salmonella enteritidis was isolated from feces/mouth swabs/feathers/cloaca swabs in2d-30d infected chickens.Different materials continued to detoxify in varying degrees,and feces and oral swabs were continuously detoxified.After the use of Clostridium butyricum,the number of detoxified chickens was significantly reduced.The number of Salmonella from cecal was significantly decreased after 28 days of infection(p<0.05),Blood routines showed that the Clostridium butyrate alleviated cell inflammation through increased lymphocyte ratio and decreased the ratio of granulocytes;Clostridium butyricum had no significant effect on the changes of lymphocyte subgroups.In conclusion,Salmonella enteritidis can be isolated from oral swabs,feather sacs,cloacal swabs and feces from 42-day-old chickens which infected with Salmonella enteritidis L50,but the isolation rates varied among different parts and cannot be replaced by each other.Clostridium butyricum can reduce the colonization of Salmonella in different organs and reduce the number of shedding chickens.The Clostridium butyricum could relieve inflammation and increase the lymphocyte ratio.TFA had no significant effect on the body weight of Salmonella-infected one-day-old SPF chickens,but it could promote the function of immune organs,increase the antibody level,reduce the amount of Salmonella in the cecum,delay the shedding of Salmonella.Transfer factor TFA could promote cellular immunity and humoral immunity. |
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