| Infectious diseases resulted in great economic loss of total livestock production in the pig industry of China,such as 122.7 billion yuan caused by Porcine Reproductive and Respiratory Syndrome(PRRS)in 2006,117 billion yuan caused by swine H1N1influenza in 2009,and more than 100 billion yuan caused by African Swine Fever in2018.Authough some diseases and the total loss of livestock production are effectively controll when kinds of vaccines successfully developed and applied.However,there are still many pathogens without effective vaccines.Developing new vaccines relies on basic research about pathogenic microorganisms,which is a process with long periods,complex operation and large investment of scientific research funds and talents.In addition,therapies and vaccines are not always effective for all of diseases.Many types of pathogens are constantly threatening the health of pig.Therefore,it is more important to improve the natural immunity defense ability of pig.Interferon is a common and effective drug for the prevention and treatment of animal diseases,especially for virus infectious diseases.It consists of typeⅠand II interferon.All of then have antiviral,anti-tumor and immunomodulatory effects.However,interferon has short half-life and requires multiple injections,which increases the costs of pig breeding.Excessive supply might also affect meat safety and ecological environment.It has been reported that Chinese herbal medicines and their active ingredients can active mouse lymphocytes and IFNs expression by indigo naturalis or indigowoad leaf.The herbal medicines,astragalus membranaceus and radix isatidis,have same effects on pig.Furthermore,herbal medicines are characterized by natural origin,functional diversity,safety,and economic.The study prepared a Chinese herbal compound"Daiqing Powder",in which the main components are indigo naturalis,indigowoad leaf,astragalus membranaceus and radix isatidis.The experiment was divided into two parts.The first part was designed to investigate the immunomodulatory effect of"Daiqing powder"on mice,while the second one aimed at the immune regulation effect of"Daiqing powder"on pigs.The immune regulation function of"Daiqing powder"was determined by measuring the concentrations of IFN-α,IFN-β,IFN-γ,IL-2 and IL-4 in serum.The main experimental results are as follows:1.Immune regulation effects of"Daiqing powder"on mice.After 7 days`supplementing with"Daiqing powder"to mice,the body weights in all experimental groups significantly decreased(P<0.05).Adding 4%of"Daiqing powder"significantly increased the numbers of LYM/WBC(P<0.05),while there were no significant difference in thymus indexs.Adding 8%of"Daiqing powder"significantly decreased the numbers of WOB,MON and NEU(P<0.05),while significantly increased the thymus index(P<0.05)in mice.According to those results before,supplemention of"Daiqing powder"could effectively regulate the expression of IL-2,IL-4,IFN-α,IFN-βand IFN-γin mice.Those results indicated that"Daiqing powder"could enhance the lymphocytes proportion and IFNs expression,and improve immune functions of cellular immunity and humoral immunity in mice.2.Immune induce by"Daiqing powder"in mice infected with S.typhimurium1×10~7 CFU was intraperitoneally injected into abdomen of mice after feeding with"Daiqing powder"for 7 days.Compared with the negative control group,S.typhimurium induced immune response and significantly elevated the levels of three IFNs(P<0.05).Compared with S.typhimurium positive control group,the level of IFNs in 8%group were significantly increased(P<0.05).Furthermore,the mortality of mice was count after infected for 24 hours.Compared with the positive control group,the survival rates of mice were increased up to 20%and 50%in 4%、8%groups,respectively.Those results showed that"Daiqing powder"could promote the release of IFNs,and improve the survival rates of mice infected by S.typhimurium.3.Immune regulation effects of"Daiqing powder"on pigs.After 7 days’supplementing with 2%and 4%of"Daiqing powder"to piglets,adding 2%of"Daiqing powder"significantly decreased the level of IL-2,IFN-βand IFN-γlevels in serum of pigs(P<0.05).Adding 4%of"Daiqing powder"decreased the concentrations of IL-2,IFN-αand IFN-γ(P<0.05).4.Immune enhancement effects by"Daiqing powder"on pigs attacked by antigens.Pigs were feded by basal diet adding"Daiqing powder"for 7 days.Then intramuscular injected 1 m L vaccine against NDV(Newcastle disease virus strain La Sota),which is equal to the dosage of 20 chickens(0.05 m L/bird).The negative control group injected with an equal volume of normal saline.Compared with the negative control group,the concentrations of IFN-αand IFN-γwere significantly increased in the positive control group(P<0.05).The level of IFNs in serum of pig were obviously risen in 4%"Daiqing powder"group(P<0.05)compared with the positive control group.In conclusion,"Daiqing powder"presents strong protective effects on mice infected with Salmonella typhimurium.It could significantly increase the expressions of INF-αand IFN-γ,and reduce the 24h mortality of mice.After adding 4%"Daiqing powder"to pigs for 7 days,the inactivated vaccine against NDV could stimulate the non-specific immune system by elevating the levels of IFN-α,IFN-βand IFN-γ.It suggested that"Daiqing powder"could improve the immune function of animals,in order to improve the ability on resisting diseases and could be much helpful for the health in pig industry. |
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