title: The effect of dietary tryptophan levels on oxidative stress of liver induced by diquat in weaned piglets.
abstract: Oxidative stress can induce abnormal tryptophan metabolism. The present study was mainly conducted to determine the effect of dietary tryptophan levels on oxidative stress in the liver of weaned pigs challenged by diquat. A total of 36 PIC piglets weaned at 21 days of age were randomly allotted to 1 of 3 diets containing dietary tryptophan levels of 0.18, 0.30, and 0.45% for 14 d. On day 8, the piglets were injected intraperitoneally with sterile 0.9% NaCl solution or diquat (10 mg/kg body weight). During the first 7 d of trial, increasing dietary tryptophan levels enhanced average daily gain (P = 0.09) and average daily feed intake (P = 0.08), and decreased the feed efficiency (P < 0.05) of piglets. The growth performance was decreased by diquat injection (P < 0.05). Diquat injection also decreased the activities of the superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the plasma and liver (P < 0.05), increased plasma malondialdehyde (MDA) (P < 0.05) and urea nitrogen (P < 0.05) concentrations, and enhanced MDA concentration (P = 0.09) and tryptophan 2,3-dioxygenase (TDO) activity (P = 0.07) in liver of piglets. Increasing dietary tryptophan levels could attenuate the effects of diquat injection on the MDA (P = 0.06) concentration and the activities of SOD (P = 0.09) and GPx (P = 0.05) of the liver, and plasma urea nitrogen (P = 0.06) concentration in the piglet. There was a synergistic role for increasing TDO activity in the liver between dietary tryptophan levels and diquat injection (P < 0.05). These results suggest that increasing dietary tryptophan levels could attenuate the oxidative stress of the liver in weaned piglets intraperitoneally injected with diquat via enhancing the antioxidant capacity.
authors: Animal Nutrition Institute, Sichuan Agricultural University, Xinkang Road 46#, Ya'an, Sichuan Province 625014 People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, 625014 People's Republic of China.
authors: Xiangbing
authors: X
authors: Mao
authors: Animal Nutrition Institute, Sichuan Agricultural University, Xinkang Road 46#, Ya'an, Sichuan Province 625014 People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, 625014 People's Republic of China.
authors: Mei
authors: M
authors: Lv
authors: Animal Nutrition Institute, Sichuan Agricultural University, Xinkang Road 46#, Ya'an, Sichuan Province 625014 People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, 625014 People's Republic of China.
authors: Bing
authors: B
authors: Yu
authors: Animal Nutrition Institute, Sichuan Agricultural University, Xinkang Road 46#, Ya'an, Sichuan Province 625014 People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, 625014 People's Republic of China.
authors: Jun
authors: J
authors: He
authors: Animal Nutrition Institute, Sichuan Agricultural University, Xinkang Road 46#, Ya'an, Sichuan Province 625014 People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, 625014 People's Republic of China.
authors: Ping
authors: P
authors: Zheng
authors: Animal Nutrition Institute, Sichuan Agricultural University, Xinkang Road 46#, Ya'an, Sichuan Province 625014 People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, 625014 People's Republic of China.
authors: Jie
authors: J
authors: Yu
authors: Animal Nutrition Institute, Sichuan Agricultural University, Xinkang Road 46#, Ya'an, Sichuan Province 625014 People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, 625014 People's Republic of China.
authors: Quyuan
authors: Q
authors: Wang
authors: Animal Nutrition Institute, Sichuan Agricultural University, Xinkang Road 46#, Ya'an, Sichuan Province 625014 People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, 625014 People's Republic of China.
authors: Daiwen
authors: D
authors: Chen
keywords: Antioxidant capacity; Diquat; Oxidative stress of livers; Tryptophan; Weaned piglets