Effect Of Dietary SeHLan On Antioxidant Function And Immune Response Of Puppies

Selenohomolanthionine（SeHLan）is a new type of organic selenium.Due to its good palatability,high bioavailability,and low environmental pollution,SeHLan has been popularized and applied in livestock and poultry breeding.In order to explore its effects on puppies,this study took SeHLan as the research object to explore the effects of different levels of SeHLan on the antioxidant function and immune response of puppies,hoping to provide a theoretical basis for the clinical application of SeHLan.In this study,30 beagle dogs aged 7 weeks were selected and randomly divided into 6 groups with 5 dogs in each group.The detailed groupings are:the blank group that is not vaccinated and only fed the basal diet（-Se/-Vacc）;the vaccine group that is vaccinated with the canine five-component vaccine and is fed only the basal diet（-Se/+Vacc）;Sodium（SS）group（SS/+Vacc,0.35 mg/kg DM）;SeHLan addition group（SeHLan-L/+Vacc,0.35 mg/kg DM）,SeHLan（SeHLan-M/+Vacc,1.0 mg/kg DM）,SeHLan（SeHLan-H/+Vacc,2.0 mg/kg DM）.Then blood samples were collected on the 0th,7th,14th,21st,28th,35th and 42nd days of immunization to determine antioxidant indicators,lymphocyte proliferation Index,serum cytokine content（IL-2,IL-4）,canine peripheral blood neutrophil（PMN）phagocytic function and the level of CPV antibody titer.1.SeHLan enhance antioxidant function in puppiesThis study found that SeHLan can effectively improve the antioxidant status of puppies.Compared with the blank control group and the vaccine group during the same period,the GSH-Px and SOD activities of the SeHLan supplement group were significantly increased,and the MDA content was extremely significant Decrease.By comparing the serum selenium content and antioxidant indexes of two groups（SS/+Vacc,SeHLan-L/+Vacc）with the same dose of different selenium sources in the diet,it is found that SeHLan has higher bioavailability in the puppies,and SeHLan is more effective in improving the body’s antioxidant function.Among them,the increase of serum selenium content and GSH-Px activity is dose-dependent with the addition of SeHLan.2.SeHLan enhance immune function in puppiesIn this study,we used flow cytometry to detect the phagocytic function of canine peripheral blood neutrophils and found that SeHLan can effectively enhance the phagocytosis of bacteria by PMN.The PMN phagocytosis rate of each group increased on the 7th day of immunization.Among them,the phagocytosis rate of PMN in the SeHLan supplemented group（SeHLan-L/+Vacc）was significantly higher than that in the immunized group on the 7th day of immunization,while the phagocytosis of PMN in the SS group was not significant until the 21st day of immunization.The enhancement indicates that SeHLan can promote PMN to exert its phagocytosis more effectively.From the 21st day of immunization to the end of the entire experiment,the peripheral blood PMN of the three SeHLan supplemented puppies has been stable at a higher level of phagocytosis rate.Simultaneously,we further explored the relationship between SeHLan and peripheral blood lymphocyte proliferation and cytokine（IL-2,IL-4）levels,and found that SeHLan can significantly increase Con A-induced lymphocyte proliferation index and IL-2 in canine serum And IL-4 level,but its effect is not dose-dependent,and the effect of SeHLan-M/+Vacc group is more significant.Studies have shown that appropriate supplementation of SeHLan in the diet can enhance the immune function of puppies.3.SeHLan enhance the immunity conferred by CPV vaccineIn this study,comparing with the-Se/+Vacc group and SS/+Vacc group during the same period,it was found that SeHLan can effectively increase the level of CPV antibody in immunized puppies.After the first immunization,the CPV antibody titer in puppies increased slowly.On the 7th day of immunization,only the SeHLan-H/+V-acc group CPV antibody titer reached the protective titer of CPV 2^6.3.On the 14th day of immunization,the serum titers of CPV HI antibody in the immune group,the SS group and the three SeHLan-supplemented groups were significantly higher than those in the blank control group（P<0.01）,and the average antibody titer of CPV HI in the SeHLan-supplemented group（SeHLan-H/+Vacc）reached the highest point 2^9.3,far exceeding the protective titer of 2^6.3,and the antibody titers remained constant in the whole study.The serum CPV HI titer of the SS group was only higher than that of the immune group at the 35th day,the second week after the second immunization period,and there was no significant difference between the two groups at other times.Studies have shown that SeHLan can increase the level of CPV antibodies in puppies.Among them,the SeHLan-H/+Vacc group has a more significant effect on enhancing the immune effect conferred by the CPV vaccine.In summary,it was proved that SeHLan could significantly improve the antioxidant capacity of young beagles,and also significantly enhance the immune function of young beagles.The optimal dietary supplemental dose for clinical application was 1.0 mg/kg DM,which provide data support for the application of SeHLan in pet clinics.