High sulfur content in corn dried distillers grains with solubles protects against oxidized lipids by increasing sulfur-containing antioxidants in nursery pigs
2013
Song, R. | Chen, C. | Wang, L. | Johnston, L. J | Kerr, B. J. | Weber, T. E. | Shurson, G. C.
Some sources of corn dried distillers grains with solubles (DDGS) contain relatively high amounts of oxidized lipids produced from PUFA peroxidation during the production process. These oxidized lipids may negatively affect growth performance and metabolic oxidation status of pigs. The objective of this study was to understand the effects of feeding corn-soybean meal diets (CON) or diets containing 30% highly oxidized DDGS with one of 3 levels of vitamin E (a-tocopheryl acetate): none supplemented, NRC level (11 IU/kg), and 10X NRC level (110 IU/kg) on oxidative status of nursery pigs. The DDGS source used in this study contained the highest thiobarbituric acid reactive substances (TBARS) value, peroxide value, and total S content (5.2 ng/mg oil, 84.1 meq/kg oil, and 0.95%, respectively) among 30 other DDGS sources sampled (mean values = 1.8 ng/mg oil, 11.5 meq/kg oil, and 0.50%, respectively). Barrows (n = 54) were housed in pens and fed the experimental diets for 8 wk after weaning and transferred to individual metabolism cages for collection of feces, urine, blood, and liver samples. Total S content was higher in DDGS diets than CON (0.39 vs. 0.19%). Dietary inclusion of 30% DDGS improved apparent total tract digestibility of S (86.8 vs. 84.6%, P < 0.001) and S retained (P < 0.01) compared to CON. Although pigs were fed highly oxidized DDGS in this study, serum TBARS were similar between DDGS and CON treatments. There was no interaction between DDGS and dietary vitamin E concentration in serum TBARS. Serum a-tocopherol concentrations were higher in pigs fed DDGS diets compared with those fed CON when a-tocopheryl acetate was not provided or provided at NRC level (1.61 vs. 0.69 µg/mL). Pigs fed DDGS diets had higher serum concentrations of S-containing AA, particularly Met (P < 0.001) and taurine (P = 0.002), compared with those fed CON. Liver glutathione concentration was higher in pigs fed DDGS diets than CON (56.3 vs. 41.8 nmol/g). Dietary inclusion of DDGS (P < 0.001) and vitamin E (P = 0.03) increased serum enzyme activity of glutathione peroxidase. The elevated concentrations of S-containing antioxidants (Met, taurine, glutathione) in vivo may protect pigs against oxidative stress when feeding highly oxidized DDGS. Therefore, increasing levels of vitamin E in diets may not be necessary to protect pigs against metabolic oxidative stress when feeding high S and high oxidized DDGS.
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