Effects Of Buckwheat Diets With Different Protein And Fiber Levels On Growth,Immunity,Antioxidant,Cholesterol Metabolism And Intestinal Health On Finishing Pigs

Pigs in finishing stage are taken as research object in this study.Supposing in the same energy level,by adjusting protein and fiber content levels of dietary,and adding rutin as the main active substance in buckwheat,we aim to explore the effects of different protein and fiber levels of buckwheat on growth performance,immunity,antioxidant,cholesterol metabolism and intestinal flora of pigs in finishing stage,as well as to find out whether protein and fiber levels have interactive effects on each indicator.This study is designed to provide references on buckwheat dietary which can improve the growth performance,health status and regulate cholesterol metabolism of pigs in finishing stage.192 healthy "Duroc×Landrace×Yorkshire" ternary fattening pigs with similar weight(114.92±3.82kg)were selected and randomly divided into 6 groups with 4 replicates in each group and 8 in each.The settings of feed are as follows:Group A1:CP 16%,CF 3.3%;Group A2:Add 0.068%rutin on the basis of Group A1;Group A3:CP 16%and CF 6%;Group B1:CP 12%and CF 3.3%;Group B2:Add 0.068%reed on the basis of Group B1 D;Group B3:CP 12%,CF 6%.The trial period was 30 days.After the breeding test,6 pigs were randomly selected from each group,and a total of 36 pigs were slaughtered.Samples including serum,liver,and intestinal contents were collected for determination of related indicators.The results of the test are as follows:1.Effects on growth performance of finishing pigs:Compared with low protein levels,the average daily weight gain of high protein levels increased by 6.21%(P<0.05),and the feed/weight ratio decreased by 6.56%(P<0.05);Compared with the low fiber level,the average daily weight gain of the high fiber level was reduced by 4.19%(P<0.05),and the feed/weight ratio was increased by 2.84%(P<0.05);There was no interaction effect between protein and fiber on growth performance(P>0.05);the average daily weight gain of rutin group increased significantly at the same protein level(P<0.05),and the feed/weight ratio decreased significantly(P<0.05).2.Effect on slaughter performance:high protein level significantly increased the leaf fat rate(P<0.05);high fiber level significantly reduces the leaf fat rate;protein and fiber have no interaction effect(P>0.05);In same protein level,adding rutin increased leaf fat rate and Backfat thickness significantly(P<0.05).3.Effects on serum biochemical indicators:the content of Urea was significantly increased at high protein levels(P<0.05);the content of Glu and TG were significantly increased at low fiber levels(P<0.05);TP,Glob,and ALP were significantly increased(P<0.05);There was an interaction effect with the effect of fiber on TG content(P<0.05);the addition of rutin at the same protein level significantly increased serum TP,Glob,and ALP(P<0.05),and the Glu,TG,and Urea contents decreased significantly(P<0.05).4.Effects on serum immune indicators:Serum IgG and IL-4 levels were significantly increased at high protein levels(P<0.05)while IL-2 levels were significantly decreased(P<0.05);IgG and IL-2 levels at high fiber levels were significantly increased(P<0.05)while the IL-4 content was significantly reduced(P<0.05);there was no interaction effect between protein and fiber(P>0.05);the addition of rutin at the same protein level significantly increased the serum IgG and IL-4 content(P<0.05),IL-2 content was significantly reduced(P<0.05).5.Effect on serum antioxidant indexes:Serum T-SOD activity was significantly increased at high protein levels(P<0.05);there was no significant difference between different fiber levels(P>0.05);there was no interaction effect between protein and fiber(P>0.05).When rutin was added at the same protein level,the T-SOD activity was significantly increased(P<0.05),and the MDA content was significantly reduced(P<0.05).6.Effect on cholesterol metabolism:The total cholesterol level of liver and longest muscle significantly decreased in low protein group(P<0.05);high fiber levels of liver and longest muscle total cholesterol significantly decreased(P<0.05);The effect of serum LDL-C had an interaction effect(P<0.05);With the addition of rutin at the same protein level,serum LDL-C,total cholesterol content in the liver,and longissimus longus muscle significantly decreased(P<0.05),and serum HDL-C content increased significantly(P<0.05).Compared with the A1 group,the HMGCR,CYP7α1,LDLR,and LXR mRNA expressions in the A3 and B1 groups were significantly reduced(P<0.05);the HMGCR,LDLR,and LXR mRNA expressions in the rutin added group were significantly reduced(P<0.05)The expression of CYP7α1　mRNA was significantly increased(P<0.05).7.Effect on intestinal health:high fiber level duodenum and jejunum villi height significantly increased(P<0.05);different protein levels were not significantly different(P>0.05);no interaction effect between protein and fiber(P>0.05);High-fiber level intestinal flora Simpson index significantly increased(P<0.05),Shannon index decreased significantly(P<0.05),diversity increased significantly;At the phylum level,Firmicutes,Bacteroidetes,Proteobacteria,Spirochaetae,Actinobacteria and Tenericutes.Among them,Firmicutes and Bacteroidetes are 88-92%,which are the dominant groups in the intestine.High protein level significantly decreased relative abundance of Firmicutes and increased relative abundance of BacteroidetesIn summary,high-protein,low-fiber diets and rutin can significantly improve the growth performance,leaf fat rate,immune index and serum biochemical indicators of finishing pigs;high-protein diets and rutin can enhance the antioxidant capacity of finishing pigs.Low-protein,high-fiber diets and rutin significantly reduced blood lipids,liver cholesterol,and longest muscle cholesterol;high-fiber diets significantly increased intestinal villi height,intestinal flora diversity and improved intestinal health.Different protein levels have significant effects on the structure of intestinal flora.