Location: Agroecosystems Management ResearchTitle: Influence of thermally-oxidized vegetable oils and animal fats on intestinal barrier function and immune variables in young pigs Author
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2014
Publication Date: 7/1/2014
Publication URL: http://handle.nal.usda.gov/10113/59417
Citation: Liu, P., Kerr, B.J., Weber, T.E., Chen, C., Johnston, L.J., Shurson, G.C. 2014. Influence of thermally-oxidized vegetable oils and animal fats on intestinal barrier function and immune variables in young pigs. Journal of Animal Science. 92:2971-2979. Interpretive Summary: Lipids produced from food processing or rendering facilities have been thermally processed and are commonly used as economical sources of energy in animal feeds. These lipids, however, may be heated for a considerable length of time and may therefore contain various amounts of peroxidation products. Consumption of these peroxidation products has been shown to cause metabolic oxidative stress, and may therefore affect intestinal health and immune function. The data in this report indicates that feeding weaned pigs diets containing 10% thermally-oxidized lipids, especially vegetable oils containing high concentrations of polyunsaturated fatty acids, impairs their metabolic oxidative status, but did not appreciably affect gut barrier function and immune status. Research results described in this report provides scientists at universities, feed companies, allied industries, and livestock production facilities information that pigs are relatively resilient to certain levels of lipid peroxidation in respect to their intestinal health and immune status.
Technical Abstract: To evaluate the effect of feeding thermally-oxidized lipids on metabolic oxidative status, gut barrier function, and immune response of young pigs, 108 barrows (6.67 ± 0.03 kg BW) were assigned to 12 dietary treatments in a 4 × 3 factorial design in addition to a corn-soybean meal control diet. Main effects were lipid source [n = 4: corn oil (CN), canola oil (CA), poultry fat (PF), and tallow (TL)] and oxidation level [n = 3: original lipids (OL), slow oxidation (SO) of lipids heated for 72 h at 95 degrees C, or rapid oxidation (RO) of lipids heated for 7 h at 185 degrees C]. Pigs were provided ad libitum access to diets for 28 d, followed by controlled feed intake for 10 d. After a 24-h fast on d 38, serum was collected and analyzed for a-tocopherol (a-T), thiobarbituric acid reactive substances (TBARS), endotoxin, haptoglobin, IgA, and IgG. On the same day following serum collection, lactulose and mannitol were fed and subsequently measured in the urine to evaluate gut permeability. There was a source × peroxidation interaction for serum a-T concentration where pigs fed SO or RO had decreased (P < 0.05) serum a-T concentration compared to pigs fed OL in CA and CN diets, but not in pigs fed PF and TL diets. There was no source × peroxidation interaction for serum TBARS, but among all lipid sources, pigs fed SO or RO lipids had increased (P < 0.05) serum TBARS compared with pigs fed OL. In addition, pigs fed CN or CA had higher (P < 0.05) serum TBARS compared to pigs fed PF or TL diets. There was no lipid source × peroxidation level interaction, nor lipid source or peroxidation level effects observed for serum endotoxin, haptoglobin, IgA, or IgG. Pigs fed lipid supplemented diets tended to have increased serum endotoxin (P = 0.06), IgA (P = 0.10), and IgG (P = 0.09) compared to pigs fed the control diet. There was no lipid source × peroxidation level interaction, nor lipid source or peroxidation level effects noted for urinary TBARS and lactulose to mannitol ratio. Compared to pigs fed the control diet, pigs fed diets containing lipids had a lower a lactulose to mannitol ratio (P < 0.01). In conclusion, feeding weaning pigs diets containing 10% thermally-oxidized lipids for 38 d, especially vegetable oils containing high concentration of polyunsaturated fatty acids, appeared to impair oxidative status, but had little influence on gut barrier function or serum immunity parameters.