Effects Of Curcumin On Growth Performance And Intestinal Mucosal Barrier Function Of Weaned Piglets Challenged With Escherichia Coli

The experiment were conducted to determine effects of dietary addition of curcumin on growth performance, antioxidant, and intestinal mucosal barrier function of weaned piglets, and to explore the feasibility of curcumin applied to feed additive replacing antibiotics. Fifty piglets were challenged with enterotoxigenic Escherichia coli (1*109cell per head) during adaptation period and randomly assigned to five groups with ten replicates per group and each piglet in individual pens. The dietary treatments were as follows:(1) basal control diet (A group);(2) basal diet+50mg/kg quinocetone (B group);(3) basal diet+200mg/kg curcumin (C group),(4) basal diet+300mg/kg curcumin (D group)(5) basal diet+400mg/kg curcumin (E group). The experiment lasted for21days.1In order to know the effects of curcumin on growth performance and antioxidant properties, the average daily gains (ADG), average daily feed intake (ADFI) and fee/gain (F/G) were counted, the concentrations of glutathione peroxidase (GSH-PX), catalase (CAT), superoxide dismutase (SOD) activities and total antioxidant capacity (T-AOC) in serum were detected. The results showed as follows:supplementation with50mg/kg quinocetone,300mg/kg or400mg/kg curcumin significantly reduced the ratio of feed to gain (Ρ<0.05); The activity of GSH-PX, CAT, SOD were significantly increased (Ρ<0.05) and the concentrations of MDA was significantly decreased (Ρ＜0.05) by addition of quinocetone;300mg/kg or400mg/kg curcumin groups improved the activity of GSH-PX, CAT, SOD and T-AOC (Ρ<0.05), and MDA content was significantly decreased (Ρ＜0.05) by addition of400mg/kg curcumin. These results suggest that addition of quinocetone,300mg/kg or400mg/kg curcumin promote growth performance, as well as enhance antioxidant ability of piglets.2In order to explore the effect of curcumin on intestinal mechanical barrier, the villus height and width, crypt depth and villus height:crypt depth ratio in jejunum and ileum were detected under light microscop. The levels of DAO activity and D-lactate in plasma were detected by ELISA. Claudin-1, Occludin and ZO-1mRNA and protein expression in jejunal mucosa were detected by immunohistchemical method and Real-time PCR. The result showed:1) Supplementation with300mg/kg or400mg/kg curcumin significantly increase jejunum and ileum villus height (P<0.05) and villus height:crypt depth ratio and crypt depth (P<0.05), and reduce the villus width (Ρ＜0.05) and crypt depth (Ρ＜0.05). Supplementation with quinocetone significantly reduce jejunum and ileum villus width (Ρ＜0.05), and increase the jejunum villus height:crypt depth ratio (Ρ＜0.05);2) plasma d-lactate and diamine oxidase activity were decreased significantly (Ρ＜0.05) in300or400 mg/kg curcumin group. Supplementation of quinocetone or200mg/kg had no effect onplasma d-lactate and diamine oxidase activity (Ρ>0.05);3) Supplementation with300or400mg/kg curcumin significantly increase Occludin and ZO-1protein expressions (Ρ＜0.05). Claudin-1protein was not affected (P>0.05). There were no difference (P>0.05) in Claudin-1, Occludin and ZO-1protein expression between200mg/kg and quinocetone groups (P>0.05);4) Occludin and ZO-1mRNA expression were increased (Ρ＜0.05) in300or400mg/kg curcumin groups compared with the control. Supplementation with400mg/kg curcumin increased the Claudin-1mRNA expression (Ρ＜0.055). ZO-1mRNA expression was increased (Ρ＜0.05) in200mg/kg curcumin group compared with the control, Claudin-1, Occludin and ZO-1mRNA expression were not affected (P>0.05) by quinocetone addition. The results indicated that supplementation with300or400mg/kg curcumin improved intestinal mucosal mechanical barrier function in piglet by improving intestinal mucosal membrane integrity, morphology and increasing Claudin-1, Occludin and ZO-1expression.3In order to study the effect of curcumin on intestinal immunologic barrier, the quantities of goblet cells were counted by PAS staining method. The relative expression of IL-lβ、IL-6、IL-10、TNF-α and TLR4mRNA in jejunal mucosa were detected by Real-time PCR in this experiment. The result showed:The integral optical density of jejunal mucosal slgA was higher (Ρ＜0.05) in300and400mg/kg curcumin groups than control, quinocetone and200mg/kg curcumin groups. Supplementation with300or400mg/kg curcumin increased (Ρ＜0.05) the number of GCs and mRNA levels of IL-10, and decreased (Ρ＜0.05) mRNA levels of IL-1(3, TLR4and TNF-a compared with the control group. Supplementation with quinocetone decreased (Ρ＜0.05) mRNA levels of TLR4compared with the control. These results suggest that the addition of300or400mg/kg curcumin can alleviate intestinal inflammation and improve intestinal mucosal immunological barrier.The results of the present study showed that supplementing weaned pigs diets with300mg/kg or400mg/kg curcumin can promote growth performance, enhance antioxidant ability, maintain intestinal structure, decrease intestinal permeability, increase intestinal mucosa close connectivity and intestinal mucosa immunity, so as to protect the intestinal barrier of weanling piglets. It would appear that curcumin could be a potential alternative to quinocetone in diets fed to weaned piglets.