Evaluation of Prevention and Control Effect of Tylvalosin on PRRS
In order to evaluate the prevention and control effect of tylvalosin on porcine reproductive and respiratory syndrome(PRRS),pregnant sows were fed with two kinds of tylvalosin products(A and B)and astragalus polysaccharide to comprehensively evaluate the effect of tylvalosin by means of clinical production indicators,antibody levels in sows and piglets,virus detection rate and expression level of cytokines IL-2 and IFN-γ. The results showed that,compared to astragalus polysaccharide,tylvalosin was more effective for PRRS,for groups tylvalosin A and B,the healthy litter rates of sows were increased from 84.98%(prior to evaluation)to 94.44% and 91.89%,respectively,and the rates of weak fetus,stillbirth or mummified fetus decreased accordingly;the abortion rate decreased,the decline rate of antibody level in vivo slowed down,the stability and uniformity of antibody level in their piglets increased,the detection rate and concentration of PRRS pathogens in sows' blood decreased,the expression level of IL-2 decreased,and that of IFN-γ increased. In conclusion,tylvalosin could reduce the reproductive disorder caused by PRRS in pregnant sows,enhance immunity by regulating the level of cytokines,and consequently prevent and control PRRS. A new idea was thereby provided by the study for PRRS prevention and control.