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Impact of lipid peroxidation and antioxidants on nursery pig performance and health
The purpose of the current study was to determine the impact of oxidized corn oil with or without addition of a synthetic antioxidant on growth performance, oxidative status and response to vaccination in nursery pigs. A total of 176 nursery pigs (1 week post-weaning; initial BW= 9.11±0.1 kg) were housed in pens with 4 pigs/pen in a RCBD and assigned to 4 dietary treatments. Treatments consisted of a corn-soybean meal basal mix that was supplemented with 6% of either control corn oil (IV=123.2, FFA=0.09%, anisidine value=2.2, peroxide value=0.4 meq/kg oil) or oxidized corn oil (IV=116.9, FFA=0.11%, anisidine value=164.4, peroxide value=146 meq/kg oil) with or without addition of an antioxidant blend containing ethoxyquin (min 3%), BHT and BHA (Endox Dry, Kemin Industries, Inc). Nursery diets consisted of 2 phases; Phase 1 fed for 14 days and Phase 2 fed for 16 days. Pigs were vaccinated with porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae(Mhyo) killed vaccine (Circumvent PCV M, Intervet Inc.) at d 2 and d 16 of the study. Blood samples were collected from 2 pigs per pen prior to vaccination at d 2, d 16 and at the end of the trial (d 30) to determine antibody titers to vaccinations, oxidative status, and vitamin E concentrations. There were no differences in performance among treatments. Serum malondialdehyde concentration, a marker for oxidative stress, did not differ (P=0.7; mean = 3.55 ± 0.2 mmol/L) among treatments. Antibody titers to Mhyo and PCV2 increased following the second vaccination, but not the first vaccination (P<0.001; 0, 0.06, and 1.66 for d 2, d 16, and d 30 for Mhyo; 0, 0.06, and 0.89 for d 2, d 16, and d 30 for PCV2), yet there were no differences due to dietary treatment. Serum vitamin E decreased in pigs fed oxidized oil by 29% on d 16 (0.79 vs. 1.11 mg/kg for oxidized oil and control, resp.) and 36% (1.06 vs. 1.64 mg/kg) on d 30 (interaction, P<0.001). Supplementation of antioxidant increased serum vitamin E concentration (P<0.001; 1.28 vs 1.01 mg/kg) and this effect tended to be greater in pigs fed control oil. Results indicate that pig performance and response to vaccine was not affected by peroxidized corn oil or supplementation of antioxidant. However, serum vitamin E status was reduced by consumption of peroxidized oils, which could be counteracted by the use of antioxidants in the diet.
Keywords: lipid, peroxidation, antioxidant