Effects Of Codonopsis Pilosula Polysaccharide On Immune Function In Piglets

In this experiment,Codonopsis pilosula polysaccharide(CPP)was extracted by water extracting and alcohol precipitation method,and added to diets with different doses of CPP in order to study the effective mechanism of CPP on immune function in piglets.Sixty crossbred piglets “Duroc × Landrace × Yorkshire”(1 day old)were selected from 6 litters and randomly divided into three groups of 20 piglets each.Piglets in control group were fed with milk replacer,low dosage group were fed with milk replacer plus 1% CPP,high dosage group were fed with milk replacer plus 2%CPP from 14-day-old,respectively.All piglets were weaned at 21 d.The trial was conducted for 14 d.Blood samples of ten piglets from each group were taken from vena cava anterior on 14,21 and 28 d,and the sera were separated for measuring the levels of IFN-?,IL-2,IL-4 and IL-6.Meanwhile,the piglets were weighed to calculate the average daily gain(ADG),average daily feed intake(ADFI)and the ratio of feed and gain(F/G).At the end of trial,six piglets from each group were slaughtered,and the intestinal mucosa was collected and stored at-20 ? for measuring SIgA levels.Each segment of the intestine was also collected and placed in4% paraformaldehyde and liquid nitrogen for determining the positive expression and distribution of SIgA,IgG and IgM,and the relative expression of SIgA,IgG and IgM mRNA,respectively.The results were as follows:1.At the age of 21 days,the average BW of piglets in high dosage group of CPP was higher than that of control group(P <0.01)and low dosage group of CPP(P<0.05).At the age of 28 days,the average BW of piglets in CPP groups was higher than that of control group(P <0.05 or P <0.05),and high dosage group of CPP was higher than low dosage group of CPP(P <0.01).At the age of 21-28,the ADG of piglets in CPP groups was higher than that of control group(P <0.05 or P <0.05).The ADFI of piglets in high dosage group of CPP was higher than that of control group(P<0.05).Compared with control group,the F/G of piglets in CPP groups was decreased.2.At the age of 21 days,serum IFN-? levels of piglets in high dosage group of CPP were higher than those of control group(P <0.05).At the age of 28 days,serum IFN-? levels of piglets in CPP groups were higher than those of control group(P<0.05 or P <0.01),and high dosage group of CPP was significantly higher than lowdosage group of CPP(P <0.05).At the age of 21 days,serum IL-2 levels of piglets in high dosage group of CPP were higher than those of control group(P <0.05).At the age of 28 days,serum IL-2 levels of piglets in high dosage group of CPP were significantly higher than those of control group(P <0.01),and high dosage group of CPP was significantly higher than low dosage group of CPP(P <0.05).At the age of28 days,Serum IL-4 levels of piglets in high dosage group of CPP were higher than those of control group(P <0.05 or P <0.01).At the age of 21 days,serum IL-6 levels of high dosage group of CPP were significantly higher than those of control group(P<0.05).At the age of 28 days,serum IL-6 levels of high dosage group of CPP were higher than those of control group(P <0.05 or P <0.01),and high dosage group of CPP was higher than low dosage group of CPP(P <0.05).3.Intestinal mucosal SIgA levels of piglets in high dosage group of CPP were significantly higher than those of control group(P <0.01),and obviously higher than those of low dosage group of CPP(P <0.01 or P <0.05).4.SIgA positive expression in intestinal tissues of piglets in high dosage group of CPP was significantly higher than those of control group(P <0.01),and higher than low dosage group of CPP(P <0.01 or P <0.05),meanwhile,low dosage of CPP was higher than control group(P <0.01 or P <0.05).IgG positive expression in intestinal tissues of piglets in high dosage group of CPP was higher than those of control group(P <0.01),and higher than those of low dosage group of CPP(P <0.01 or P <0.05).IgM positive expression in intestinal tissues of piglets in high dosage group of CPP was higher than those of control group(P <0.01),and higher than those of low dosage group of CPP(P <0.01 or P <0.05),low dosage group of CPP was higher than control group(P <0.05 or P >0.05).5.SIgA,IgG and IgM mRNA relative expression values in intestinal tissues of piglets in CPP groups were higher than those of control group(P <0.01 or P <0.05),and high dosage of CPP was higher than low dosage group(P <0.01 or P <0.05).In conclusion,these experimental results suggest that CPP can improve growth performance,increase the levels of serum cytokines and intestinal mucosal SIgA levels,enhance the OD values of SIgA,IgG and IgM positive expression,and mRNA relative expression values of IgA,IgG and IgM in small intestine,and enhance the immune function of piglets.The effects of 2% CPP were prior to 1% CPP.