Study On The Model Of Oxidative Stress And Antioxidative Effects Of Tea Polyphenols In Pigs

The study included two experiments. In experiment l,we established oxidation stress model by determing serum anti-oxidant parameters and growth performance of growing pigs with Diquat injection (i.p.). In experiment 2, we studied the effects of tea polyphenol supplement on growth performance, digestibility and anti-oxidative capability in weaning piglets under oxidative stress or normal condition.Experiment 1. The study on oxidation stress model of growing pigs by Diquat.Eight DLY growing pigs with body weight(BW) 36.43±0.17kg were randomly allotted to two groups with 4 replicates per group and one pig per replicate. Pigs in Group 1 or 2 were intraperitoneally injected with Diquat at dose of 8mg/kg BW or saline. The whole duration was 35 days. Serum samples were collected at d 0,1,2,3,7,14,21,28 and 35 for analysis of superoxides and anti-oxidative enzyme activities. The results indicated Diquat reduced growth performance (P＜0.05) of pigs at early and whole period of the trial, decreased serum Glutathione peroxidase (GSH-Px) (P＜0.01) and Superoxide Dismutase(SOD) (P＜0.01) activities, reduced capacity of inhibiting production of hydroxy radical (P＜0.05), superoxide anion (P＜0.01) and increased malondialdehyde (MDA) concentration(P＜0.05). The conclusion is oxidation stress response to intraperitoneal injection of Diquat (8mg/kg) could last for 28 days and serum SOD, GSH-Px, CAT activity and MDA concentration could be sensitive indicators for oxidative stress.Experiment 2. Effects of Tea Polyphenol Supplementation on Performance and Anti-oxidative Capability in Weaning Piglets.A 2 X 2 factor design was conducted to determine the effects of tea polyphenol on performance, digestibility and anti-oxidative stress in piglets using the animal model of oxidative stress that was established in experiment 1. Twenty-eight 28-day old weaning piglets were assigned into 2 groups. Two groups of animals were fed with basic diet or basic diet supplied with tea polyphenol (500 mg/kg). Seven pigs in each group were treated with Diquat by intraperitoneal injection, the other 7 pigs were injected with saline The study lasted for 21 days. The results indicated that oxidative stress decreased performance, digestibility, anti-oxidative enzyme activity, and increased serum free radical concentration. Supplementation of tea polyphenol improved the performance, apparent digestibility of CP, EE and dry matter, also increased serum SOD, GSH-Px and CAT activities, however, tea polyphenol supplementation reduced the concentration of hydroxy radical, hydrogen peroxide and MDA. Taken together, the inclusion of tea polyphenol in diet could improve the performance and anti-oxidative capability of weaning piglets under oxidative stress.