Effect And Mechanism Of Oregano Essential Oil Reduce Intestinal Oxidative Stress In Weaned Pigs

Early weanling syndrome has caused great economic losses to the swine industry. In recent years, studies shown that the early weaned piglets reduced antioxidant capacity and increased free radical in the body. Oxidative stress damaged the intestinal barrier function, is considered the important cause leading to the early weaning syndrome. Oregano Essent ial O ils (OEO) has antibacterial and antioxidant effect, so OEO can be used as a dietary antioxidant to improve the harm of oxidative in the intestinal.First, this study established rat model of oxidative stress by diquat, confirmed the feasibility of this model used in the study of the intestinal oxidative damage; Second, we used this model to study the effects of OEO on intestinal antioxidant enzyme activity, inflammatory factors, the epithelial morphology and the tight junction under oxidative stress, in order to reveal the mechanism of OEO alleviate oxidative stress; Finally, an experiment was conducted to study the effects of OEO diets on intestinal antioxidant enzyme activitive, the inflammatory factor, the intestinal permeability, the epithelial morphology and the tight junction, also researched the effect of adding different levels OEO in conservation diet. In order to reveal the mechanism of OEO alleviate oxidative damage in intestinal, and the optimum adding amount in conservation diet. The main results were as follows:(1) The feasibility of the oxidative stress model induced by diquat to study the da made in the intestinal.Seven weeks of healthy female wistar rats were intraperitioneally injected with Diquat at dose of 0.1mmol/kg.bw, succeeded in induced oxidative stress. Compared with the control, rats after injection of diquat plasma cortisol levels were significantly increased (P <0.05), plasma and liver lipid peroxidation products MDA content were significantly increased (P<0.01), but the activitive of antioxidant enzymes SOD, GSH-Px were significantly lower (P<0.01). In the jejunum, MDA content were significantly increased (P<0.01), SOD and GSH-Px enzymes activitive were significantly decreased (P<0.01). We also observed the structure atrophy and damage in the jejunum. The above results shown that the intestinal happe ned oxidative stress.(2) Intervention effects and mechanism of OEO against oxidative damage in intestinal.By using of Diquat stress model, evaluated the OEO to the intervention of oxidative damage in rats. Results shown that supplemented of OEO increased intestinal SOD (P< 0.05) and GSH-Px (P< 0.01) activitive, the population of Lactobacillus also increased (P<0.05). MDA content (P< 0.01) and the population of Ecoli (P<0.05) were decreased, TNF-α and 1L-6 mRNA expression were decreased (P<0.05), the expression of the Occlus ion protein (P<0.05) and the villus height (P<0.05)were increased, cortisol in the plasma and ROS levels in the chyme were decreased (P<0.05) in the high dose of OEO.(3) The mechanism of OEO against oxidative damage in the intestinal and the effects on the production performance in the conservation period of the weanling pigs.Experiment 1.120 weaning piglets with an average initial weight were assigned into two group of six. Two groups of animals were fed with basic diet or basic diet supp lemented with OEO (500mg/t). Six pigs in each group were slaughter, the plasma and intestinal samples were collected.Experiment 2.120 weaning piglets with an average initial weight were assigned into four group of six. The control groups was fed with basic diet, the other three groups were fed with basic diet supplemented with OEO (250mg/t,500mg/t,750mg/t) respectively. Record the weight and feed intake in different stages and calculation production performance and diarrhea index. The results as follows:1) plasma cortisol levels was increased (P<0.05), ROS and MDA content in the jejunum were increased (P<0.05), the activitive of SOD and GSH-Px enzyme were significantly decreased (P<0.01); the population of Enterococcus faecalis and E.coli in jejunum were significantly increased (P<0.01), the population of Lactobacillus was significantly decreased (P<0.01); As the makers of intestinal permeability, plasma DAO activitive was significantly increased (P<0.01), D-lactic acid content was increased (P<0.05), the expression of Occludin and ZO-1 were significantly decreased (P<0.01); villous height was significantly decreased (P<0.01), crypt depth and the villous height:crypt depth ratio were increased (P<0.05).2) Supplementation with OEO, plasma cortisol levels was decreased (P< 0.05), the jejunum MDA content was decreased (P<0.05), the activitive of SOD was increased (P<0.05); the population of Enterococcus faecalis (P<0.01) and E.coli (P<0.05) in jejunum were decreased, but has no effect on the population of Lactobacillus; the expression of TNF-α has a bwer trend (P=0.0917), but have no effect on IL-1β and IL-6 mRNA expression; plasma DAO activitive (P<0.01) and D-lactic acid contents(P< 0.05) were decreased, and have no effect on the expression of Occludin and ZO-1.3) In experiment one, it was found that supplementation with 500 g/t dietary OEO products can significantly reduce diarrhea rates(P< 0.01) and diarrhea index with trend (P=0.085) in the 0-14d after weaning; but feed intake, daily gain and feed conversion ratio was not significant improved(P> 0.05). In experiment two, it was found that supp lementation with dietary OEO products can not significantly reduce diarrhea rates, diarrhea index and feed conversion ratio in the 0-24d after weaning(P> 0.05). Supplementation with 250 g/t,750g/t dietary OEO products have no effects on feed intake and daily gain in the 0-24d after weaning(P> 0.05), but Supplementation with 500g/t dietary OEO products can significantly improve feed intake (P<0.01) and daily gain in the 0-24d after weaning (P<0.05)Insumary, the conclusions of the present study are:(1) Diquat-induced oxidative stress model can be used to study on the damage of intestinal.(2) Diquat-induced oxidative stress caused intestinal to produce a large number of active oxygen, anti-oxidation ability were decreased, inflammation were increased, tight junction were broken, intestinal epithelium were damaged, the diet supplemented of OEO can alleviate these problem.(3) Early weaning caused the intestinal oxidative damage, but the diet supplemented of OEO can alleviate these problem. The optimum adding amount in conservation diet (0 to 24 days after weaning) is 250 g/t～500 g/t.