Effects Of Chlorogenic Acid Addition In Diet On Growth Performance,gut Health And Anti-oxidantion Ability Of Piglets

Chlorogenic acid(CA),which also has a synonym of caffetannic acid,is a depside that is a secondary metabolic product synthesized by condensation of caffeic acid and quininic acid via Shikimic acid circle pathway during the aerobic respiration of plants.It has been reported that CA has multiple physiological and pharmacological effects including anti-oxidation and anti-inflammation.At present,there are few reports on the application of CA in piglets.The current study is aimed to investigate the effects of CA supplemention in weaning piglet diets on the growth performance,physiology and biochemistry of blood,anti-oxidation ability,histological morphology of intestine,and microflora in intestinal lumen of weaning piglets so as to evaluate the application effects of CA in weaning piglets,providing scientific experimental basis for the feasibility of CA supplemention in weaning piglet diets.Twenty-four weaning DLY piglets,weighing at 9.45±0.2kg,were enrolled in the current experiment,and randomly divided into 4 groups,including basal diet group(control group),basal diet with 250mg/kg CA supplemention group(CA250 group),basal diet with 500mg/kg CA supplemention group(CA500 group)and basal diet with 1000mg/kg CA supplemention group(CA1000 group).There were 6 repetitions in each group,and 1 piglet in each repetition.The experiment lasted for 14 days.The digestion experiment was carried out on day 11 to day 14 with endogenous indicator.The body weight was weighed in the morning on day 14.The blood samples were collected on day 14,and the piglets were sacrificed for tissue sample collection on day 15.The effects ofCA on growth performance,nutrient digestibility,physiology and biochemistry of blood,histological morphology,gene expression and disaccharidase activities of intestinal mucosa,and antioxidase activities in tissues were investigated.The main experimental results are as follows:1.When compared with control group,F/G ratio of the piglets was significantly increased(P<0.05)in CA1000 group,whereas ADG and ADFI were not significantly different.2.When compared with control group,the apparent digestibility of ash was slightly increased in CA1000 group,but there was no statistical difference.The energy,dry matter,ether extract and crude protein were not significantly different.3.When compared with control group,the intestine index increased significantly(P<0.05),and the pancreas index has an increasing trend(P=0.061)in CA1000 group.The liver,spleen,kidney and pancreas index,as well as pH of jejunum,cecum and colon were not significantly different.4.When compared with control group,the percentage of lymphocytes in blood was significantly increased(P<0.05)in CA1000 group.The hemoglobin content of piglets blood was increased significantly(P<0.05)in CA250,CA500 and CA1000 groups.The IgG content of piglets serum was significantly increased in CA1000 group(P<0.05).5.When compared with control group,the villus height of duodenum and jejunum in CA1000 group increased significantly(P<0.05).The crypt depth of duodenum was significantly decreased(P<0.05)in CA250,CA500 and CA1000 groups.In CA1000 group,there was a significant increase in villus/crypt ratio of duodenum(P<0.05).The duodenal wall thickness increased significantly in CA500 and CA1000 groups(P<0.05).There was an increasing tendency of duodenal villus width in CA 1000 group(P=0.084).The thickness of jejunal wall was increased significantly in CA250,CA500 and CA 1000 groups(P<0.05).The villus width of jejunum was significantly increased in CA 1000 group(P<0.05).The number of ileal columnar epithelial cells in CA250 group was increased significantly(P<0.05).6.When compared with control group,the duodenal maltase activity in CA250,CA500 and CA1000 groups was significantly increased as compared with control group(P<0.05).The ileal maltase activity in CA1000 group increased significantly(P<0.05).7.When compared with control group,the expression of GLUT2 gene in jejunum increased significantly in CA1000 group(P<0.050),and the expression of SGLT1 gene in ileum was also significantly increased in CA1000 group(P<0.050).8.When compared with control group,the content of cecal acetic acid decreased significantly in CA500 and CA1000 groups(P<0.05).The content of colonic acetic acid increased significantly in CA250 and CA500 groups(P<0.05).The content of cecal propionic acid decreased significantly in CA250,CA500 and CA1000 groups(P<0.05).The content of colonic propionic acid in CA250 and CA500 groups increased significantly(P<0.05).The content of cecal butyric acid in CA1000 group decreased significantly(P<0.05).The content of colonic butyric acid in CA250 and CA500 groups increased significantly(P<0.05).9.When compared with control group,the number of bacillus in cecum in CA250 and CA500 groups increased significantly(P<0.05).There were no significant differences in the number of Escherichia coli,Lactobacillus and total bacteria in jejum and colun,as well as Bacillus in colon.10.Compared with control group,there was an increasing tendency of serum GSH activity in CA250,CA500 and CA1000 groups(P=0.090,P=0.081,P=0.087).In CA1000 group,the serum MDA level had a decreasing tendency(P=0.073),the serum level of blocking hydroxyl radicals had an increasing tendency(P=0.106),the GSH activity in duodenum and jejunum increased significantly(P<0.05),and the level of jejunal T-AOC was also increased significantly(P<0.05).In CA500 and CA1000 groups,the activity of ileal SOD was significantly increased(P<0.05),while the content of jejunal and ileal MDA was decreased significantly(P<0.05).The activity of ileal CAT was significantly increased(P<0.05)in CA250,CA500 and CA1000 groups.In CA500 and CA1000 groups,the content of MDA in pancreas had a decreasing tendency(P=0.090,P=0.084),and the activity of CAT in pancreas was increased significantly(P<0.05).In CA1000 group,the level of T-AOC in spleen was significantly increased(P<0.05).In CA250,CA500 and CA1000 groups,the content of MDA in liver was significantly decreased(P<0.05),the expression level of SOD gene in pancreas increased significantly,the expression level of CAT gene in spleen and liver increased significantly,and the expression level of GPX,GST,Gr,Nrf2,Keapl in liver and pancreas increased significantly(P<0.05).In summary,the main conclusions of this study are as follows:CA supplementation does not significantly affect the growth performance and nutrient digestibility in weaning piglets,but has a decreasing tendency in F/G ratio.Supplementing CA in weaning piglet diets can improve the structural morphology of intestinal mucosa,elevate the intestine index,villus/crypt ratio and activity of digestive enzymes in intestine.It also increases the number of beneficial microorganism,and upregulates the expression of transport protein and tight junction protein mRNAs in the intestine of weaning piglets,then accelerates the growth and development of intestine.Supplementing CA in weaning piglet diets has markedly enhanced ability of anti-oxidation in serum,intestine,liver,spleens and pancreas,and thus,in general,it is beneficial to strengthen the ability of anti-oxidation in weaning piglets.The optimal dosage of CA supplemention is 1000mg/kg under the conditions of this study.