Effects Of Astragalus Membranaceus Ultrafine Particles On The Bile Acid Metabolism And Host Immunity In Young Goats

The purpose of this experiment was to study the effect of astragalus membranaceus ultrafine particles on the growth performance,bile acid metabolism and host immunity of Xiangdong black young goats,to evaluate the application prospect and value of astragalus membranaceus ultrafine particles as a feed additive in goat breeding.A total of 36 healthy Xiangdong black goats weighing 5.17 ± 1.22 kg at 50 days of age were selected and divided into the control group(Control,16)and the astragalus membranaceus ultrafine particles group(AMUP,20).The experimental diet was based on the goat feeding standard NY/T816-2004 and the ratio of concentrate to coarse material was 7:3,the coarse material was alfalfa hay,the astragalus membranaceus ultrafine particles was added at 10 g/goat/day.The experimental pre-feeding period was7 days,the formal period was 36 days,and every goat was kept in a single pen.The formal period was divided into two phases,the first phase was the first 1-28 days,during this period,recorded daily feeding amount and remaining amount of the goats accurately.Fecal samples were collected on the 6th,7th,13 th,14th,20 th,21st,27 th,and 28 th of the test period,and the feed samples before and after feeding were collected.On the 7th,14 th,21st,and 28 th day of the experimental period,blood samples were collected before feeding in the morning to obtain plasma.On the 29 th day of the experimental period,the control group was selected 10 goats,and the astragalus membranaceus ultrafine particles group was selected 14 goats for slaughter.After slaughtering,the tissue of liver,colon,ileum and colonic chyme were collected,and the remaining 6 goats in each group were used for the second stage enteritis model.In the second phase,on days 29-36 of the experimental period,goat intestinal inflammation was induced by continuous oral gavage of 4% dextran sodium sulfate solution(DSS;100 m L/day),the goats were slaughtered on the 37 th day of the experimental period,blood samples were collected before slaughter to obtain plasma.1.Effects of astragalus membranaceus ultrafine particles on growth,apparent digestibility and blood biochemistry in young goatsThe results showed that,compared to the control group,the addition of astragalus membranaceus ultrafine particles in the diet reduced the concentration of triglycerides(days 21 and 28)and the activity of alanine aminotransferase(days 14,and 21)in goat serum(P<0.05),increased the activity of lactate dehydrogenase(days 7,14,and 21);however,the addition of astragalus membranaceus ultrafine particles in the diet had no effect on the average daily feed intake,daily gain,feed-to-weight ratio,Body height,body side length,heart girth and apparent digestibility of crude protein,dry matter,neutral detergent fiber and acid detergent fiber(P>0.05).2.Effects of astragalus membranaceus ultrafine particles on host immunity in young goatsThe results showed that,compared to the control group,dietary supplementation of astragalus membranaceus ultrafine particles significantly increased the concentrations of C1 q,C1s,C4 and C4 BP in the plasma of goats(P<0.01),and up-regulated the m RNA level of C4 BP in the liver(P=0.01).In addition,dietary supplementation of astragalus membranaceus ultrafine particles increased the concentrations of Ig A,Ig G,Ig M(P<0.01)and IL-10(P<0.05)in goat plasma,while decreasing the concentration of IL-1α in serum(P<0.05).After constructing the enteritis model,it was observed that the concentration of C4 BP in plasma and the m RNA level of C4 BP in the liver of goats supplemented with astragalus membranaceus ultrafine particles in the diet increased(P<0.05).There were no significant differences between the two groups for immunoglobulin and inflammatory factors.In addition,the proportions of CD4+ and CD8+ T cells were not affected in the case of dietary supplementation of Astragalus root ultrafine powder and oral DSS-induced disease model.3.Effects of astragalus membranaceus ultrafine particles on bile acid metabolism in young goatsThe results showed that,compared to the control group,dietary supplementation of astragalus membranaceus ultrafine particles increased the m RNA levels of CYP8B1 and SHP in goat liver,and decreased the m RNA level of FXR(P<0.05).Dietary supplementation of astragalus root ultrafine powder increased the m RNA levels of OST-α in ileum and FXR and TGR5 in colon of goats(P<0.05).Dietary supplementation of astragalus membranaceus ultrafine particles increased the content of DCA(P<0.05)and LCA(P=0.051),and decreased the content of CA and CDCA in the colonic chyme of goats(P<0.05).The analysis of microbial diversity in colonic chyme showed that dietary supplementation of astragalus membranaceus ultrafine particles had no significant difference in OTU and Alpha diversity index(P>0.05),but increased the abundance of Akkermansia in colonic chyme(P<0.05).4.Correlation analysis between immune function and bile acid metabolism indexesThe correlation analysis of immune indexes in goat plasma and colonic chymotrypsin bile acid showed that the content of 12-keto LCA was significantly positively correlated with the concentration of IL-10(r = 0.76,P<0.05),and the content of allo LCA was significantly correlated with the concentration of IL-6.The concentration was significantly positively correlated(r = 0.64,P<0.05),the content of iso LCA was significantly positively correlated with the concentration of IL-6(r = 0.67,P<0.05),and the content of 7-keto LCA was significantly positively correlated with the concentration of Ig A(r = 0.63,P < 0.05).The results of correlation analysis between the microbes in colon and the immune indexes in plasma showed that the abundance of Christensenellaceae＿R7＿group was significantly negatively correlated with the concentration of C3(r = 0.67,P<0.01),and the abundance of Akkermansia was significantly negatively correlated with the concentration of C1r(r = 0.67,P<0.01).r = 0.60,P < 0.01),the abundance of Lachnospiraceae＿AC2044＿group was significantly positively correlated with the concentration of C4(r = 0.58,P < 0.05),and the abundance of Prevollaceae＿NK3B31＿group was significantly positively correlated with the concentration of IL-6(r= 0.68,P<0.01).In conclusion,the addition of astragalus membranaceus ultrafine particles in young goat diet can improve the immune function of and promote the metabolism of bile acids.This study provides a theoretical and practical reference for the application of astragalus membranaceus ultrafine particle in ruminants.