PSII-26 Effects of diquat injection on growth performance and blood and liver redox status in growing pigs

Abstract

Abstract Oxidative stress, caused by excessive reactive oxygen species generation, impairs health and production performance of pigs. A number of nutrients and feed additives have antioxidative property. Our current research project is to study the antioxidative roles of methionine (a sulfur-containing amino acid) in pigs, and this abstract is to report our setup of an oxidative-stressed model by injection of diquat (dibromide monohydrate), a bipyridyl herbicide, to the pig. Barrows [n = 20, body weight (BW) = 21.5 ± 2.50 kg] were randomly allotted to two treatment groups fed a corn-and-soybean-meal-based diet that met or slightly exceeded the NRC (2012) recommended requirements of nutrients and energy. After 3 wk of feeding (Phase 1), while Group-1 pigs were intraperitoneally injected with 10 mL saline, Group-2 pigs were injected with 10 mg/kg BW diquat in 10 mL saline. After the injection, pigs were continually fed for 7 d more (Phase 2). At the end of Phases 1 and 2, average daily gain (ADG), average daily feed intake (ADFI), and gain to feed (G:F) ratios were respectively determined. Blood samples were collected on d 1, 22, and 29 of the experiment, and liver samples were collected on d 29. Commercial assay kits were used to determine the blood and liver redox status, for which the malondialdehyde (MDA) and glutathione (GSH) contents, the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities, and the total antioxidant capacity (TAC) were measured. The data was statistically analyzed using Student’s t-test. During Phase 1, there were no differences (P > 0.10) in initial BW, final BW, ADFI, ADG, and G:F ratio. There were no differences (P > 0.10) in the serum MDA contents, the serum GPX, SOD, and CAT activities, and the serum TAC and GSH contents between the two dietary treatment groups. By the end of Phase 2, however, the AFDI and ADG in Group 2 were less (P < 0.001) than that in Group 1. The serum MDA content in Group 2 was greater (P < 0.05) than in Group 1, the serum GPX activity and liver SOD activity in Group 2 was less (P < 0.05) than in Group 1, and the liver GPX activity in Group 2 tended to be greater (P = 0.10) than in Group 1, although there were no differences (P > 0.10) in serum SOD activity, serum TAC, and serum and liver CAT activities between the two treatment groups. In conclusion, the results of this study confirmed that young growing pigs intraperitoneally injected with diquat can lead to oxidative stress and serve as a model for studying antioxidant nutrients or feed additives in pigs.