PSIV-5 Can dietary oxidized protein induce oxidative stress in pigs?

Abstract

Abstract Endogenous protein oxidation as a result of oxidative stress is known to reduce the efficiency of livestock species (Boler et al., 2012; DeRouchey et al., 2004; Dibner, Atwell, Kitchell, Shermer, & Ivey, 1996). Additionally, rendered by-products are common feedstuffs in livestock diets. During processing, these sources have the potential to become oxidized. While most research on oxidative stress has focused on consumption of dietary oxidized lipids, little research has been done in the area of dietary oxidized proteins and the potential to induce oxidative stress. The objective of this study was to determine the effects of dietary oxidized protein on oxidative stress in pigs. For this study, 30 pigs 6 weeks old were divided into three dietary treatments of control, medium, and high dietary oxidized protein. Each treatment was fed the same diet, with the exception of the degree of oxidation in bovine plasma which was included in the diet at 10 percent. Pigs were fed for 19 days and then euthanized for tissues collected. Jejunum, liver, and colon were collected along with urine and plasma samples on day 0 and 18. Jejunum samples were also collected for histology. Markers of oxidative stress included protein carbonyls, thiobarbituric acid reactive substance (TBARS), 8-hydroxyguanine, and glutathione peroxidase activity. Pigs in the high oxidation treatment had an increase in crypt depth of 16 percent (p-value less than 0.05) when compared to control further resulting in an 11 percent decrease in villi height to crypt depth ratio (p-value less than 0.05). Additionally, lipid oxidation products, measured by TBARS, was 28 percent greater in the liver of pigs in the medium oxidation treatment (p-value less than 0.05) when compared to control. Even with the short duration of this study, dietary oxidized protein did impact the oxidative status of the animal. Using pigs as a model for companion animals, it could be hypothesized then that long-term exposure could have implications on longevity.