Mechanism Of Supplementary SIJUNZI Decoction On Effect Of Digestive Function In Piglets

In this experiment,eleven kinds of Chinese herbal medicine(Codonopsis pilosula,Largehead atractylodes rhizome,Poria cocos and Liquorice etc.)were processed into supplementary SIJUNZI decoction(SJZD)and added into the diet of piglets in order to study the effects of supplementary SJZD on growth performance,intestinal digestive and absorptive function,the expression levels of epidermal growth factor(EGF)and somatostatin(SS),and their mRNA relative expression values in small intestine of piglets,and further to explore the promoting growth effect and its mechanism of supplementary SJZD.Sixty crossbred piglets “Duroc × Landrace × Yorkshire”(1-day-old)were selected from 6 litters and randomly divided into three groups,two litters of 20 piglets each.Piglets in control group were fed with milk replacer,piglets in 1% supplementary SJZD group and 2% supplementary SJZD group were fed with milk replacer plus 1% and 2% supplementary SJZD from 14-day-old,respectively.All the piglets were weaned at 21 d.The trial was conducted for 14 d.At 14,21 and 28 d,the piglets in empty stomach state were weighed to calculate the average daily gain(ADG),average daily feed intake(ADFI)and the ratio of feed and gain(F/G)at AM 7:00-8:00.Meanwhile,ten piglets from each group were randomly selected and gavaged with 10% Dxylose solution at the dose of 1 mL·kg-1 body weight(BW).After 1 h,blood samples were taken from vena cava anterior and the sera were separated for measuring D-xylose levels.At 28 d,six piglets from each group were selected and slaughtered,the small intestine were collected and stored in 4% paraformaldehyde and liquid nitrogen,respectively,and aimed to detect the expression levels of EGF and SS protein and the relative expression values of EGF and SS mRNA in small intestine,and to determine the digestive enzyme activities of pancreas.The results were as follows:1.Compared with control group,at 21 d,the average body weight(BW)of piglets in 2% supplementary SJZD group was significantly increased(P <0.05);the average BW of piglets in 2% supplementary SJZD group was higher than those of 1% supplementary SJZD group and control group at 28 d(P <0.01),and the average BW of 1% supplementary SJZD group was higher than that of control group(P <0.05).Compared with control group,the ADG of piglets in 2% supplementary SJZD group was significantly increased at 14-21 d(P <0.05);the ADG of piglets in 2% supplementary SJZD group was higher than those of 1% supplementary SJZD group(P <0.05)and control group(P <0.01),while the ADG of 1% supplementary SJZD group was higher than that of control group at d 21-28(P <0.05).ADFI of piglets in 2% supplementary SJZD group was significantly higher than those of 1% supplementary SJZD group and control group(P<0.05).F/G of piglets in supplementary SJZD groups was lower than that of control group,and the F/G of piglets in 2% supplementary SJZD group was lower than those of 1% supplementary SJZD group.2.At of 21 and 28 d,compared with control group,the serum D-xylose contents of piglets in 1% and 2% supplementary SJZD groups were significantly increased(P < 0.01).Although the serum D-xylose contents of piglets in 2% supplementary SJZD group were higher than those of 1% supplementary SJZD group,the difference was not significant(P > 0.05).3.At 28 d,the pancreatic lipase activities of piglets in 1%and 2% supplementary SJZD group were significantly higher than control group(P<0.05),while the difference between 1% SJZD group and 2% modified SJZD group was not significant.Compared with control group,the pancreatic protease activities of piglets in 1% and 2% supplementary SJZD groups were increased,but the difference was not significant(P>0.05).Compared with control group,the pancreatic amylase activities were increased in 1% supplementary SJZD group(P<0.05)and significantly increased in 2% supplementary SJZD group(P<0.01).4.Compared with control group,the EGF mRNA relative expression values in duodenum,distal jejunum and ileum of the piglets were significantly increased in 2% supplementary SJZD group(P<0.01),and the EGF mRNA relative expression values in middle jejunum were significant increased(P<0.05).Compared with control group,the EGF protein expression of small intestine was significantly increased in 2% supplementary SJZD group(P<0.01),the EGF protein expression of distal jejunum and ileum was significantly increased in 1% supplementary SJZD group(P < 0.01),and the EGF protein expression of duodenum was significantly improved(P < 0.05).5.Compared with control group,the SS mRNA relative expression values and SS protein expression in small intestine of piglets were reduced in 1% supplementary SJZD group(P<0.05),while the SS mRNA relative expression values and SS protein expression in small intestine were significantly decreased in 2% supplementary SJZD group(P<0.01).In conclusion,this experimental results suggested that supplementary SJZD could increase growth performance,improve the intestinal absorptive function,enhance the digestive enzyme activities of pancreas,promote EGF gene transcription and EGF protein expression,and reduce SS gene transcription and SS protein expression in small intestine of piglets.The effects of 2% supplementary SJZD were prior to 1% supplementary SJZD.