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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #349863
Research Project: Reducing Production Losses due to Oxidative Stress and Bacterial Pathogens in Swine

Location: Agroecosystems Management Research

Title: Influence of feeding thermally peroxidized soybean oil on growth performance, digestibility, and gut integrity in finishing pigs

Author
item OVERHOLT, MARTIN - University Of Illinois
item DILGER, ANNA - University Of Illinois
item BOLER, DUSTIN - University Of Illinois
item Kerr, Brian

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2018
Publication Date: 7/10/2018
Citation: Overholt, M.F., Dilger, A.C., Boler, D.D., Kerr, B.J. 2018. Influence of feeding thermally peroxidized soybean oil on growth performance, digestibility, and gut integrity in finishing pigs. Journal of Animal Science. 96:2789-2803.

Interpretive Summary: Soybean oil and products derived from soybean oil, such as recycled restaurant grease, are an important source of energy in swine feeding programs because they provide a concentrated source of energy compared to other commonly used feedstuffs. The digestibility and caloric value of refined, deodorized, bleached soybean oil is well documented in swine, but there is limited data on the impact of thermally processed (i.e., peroxidized) soybean oil on pig performance, energy and lipid digestibility, gastrointestinal integrity, and oxidative stress in finishing pigs. The current study was conducted to evaluate the effect of thermally processing soybean oil at 45C, 90C, and 180C on pig performance, energy and lipid digestibility, gastrointestinal integrity, and oxidative stress in finishing pigs compared to pigs fed unprocessed soybean oil. Data from this experiment indicate that the presence of lipid peroxidation products contained in the soybean oil thermally processed at 90C reduced pig gain and feed efficiency, reduced energy and lipid digestibility, and increased lipid-based measures of oxidative stress. Feeding thermally processed soybean oil did not appear to have an impact on nitrogen digestibility or retention as well as no impact on gut permeability compared to pigs fed unprocessed soybean oil. This information is important for nutritionists at universities, feed companies, and pig production facilities for the determination of the impact on pig performance and caloric value of thermally processed soybean oil in feed formulations, and provides a basis from which to assess their economic value.

Technical Abstract: Consumption of peroxidized lipids has been shown to reduce pig performance and energy and lipid digestibility. Objectives of the current study were to evaluate the effect of feeding soybean oil (SO) with different levels of peroxidation on growth performance, lipid, N, and GE digestibility, plasma Trp, and gut integrity in finishing pigs. Fifty-six barrows (46.7 ± 5.1 kg initial BW) were randomly assigned to 1 of 4 diets in each of two dietary phases, containing either 10% fresh SO (22.5oC) or thermally processed SO (45oC for 288 h, 90oC for 72 h, or 180oC for 6 h), each infused with of 15 L/min of air. Peroxide values were 2.0, 17.4, 123.6, and 19.4 mEq/kg; 2,4-decadienal values were 2.07, 1.90, 912.15, and 915.49 mg/kg; and 4-hydroxynonenal concentrations were 0.66, 1.49, 170.48, and 82.80 mg/kg, for the 22.5, 45, 90 and 180oC processed SO, respectively. Pigs were individually housed and fed ad libitum for 81 d to measure growth performance, including a metabolism period to collect urine and feces for determination of GE, lipid, N digestibility, and N retention. Following the last day of fecal and urine collection when pigs were in the metabolism crates, lactulose and mannitol were fed and subsequently measured in the urine to evaluate gut permeability, while markers of oxidative stress were evaluated in plasma, urine, and liver. There were no differences observed in ADFI (P = 0.91), but ADG and GF were decreased in pigs fed 90oC SO diet (P = 0.07) compared to pigs fed the other SO diets. Pigs fed the 90oC and 180oC SO had the lowest (P = 0.05) DE as a % of GE compared to pigs fed the 22.5oC SO, with pigs fed the 45oC SO being intermediate. Lipid digestibility was similarly affected (P = 0.01) as energy digestibility, but ME as a % of DE was not affected by dietary treatment (P = 0.16). There were no effects of lipid peroxidation on N digested, N retained, or the urinary lactulose:mannitol ratio (P = 0.25). Pigs fed the SO processed at 90oC and 180oC had lower concentrations (P < 0.01) of plasma Trp compared to pigs fed the 22.5oC and 45oC SO treatments. Pigs fed 90oC SO had the greatest (P < 0.01) concentrations of F2-Isoprostane in plasma and urine TBARS compared to the other SO treatments. These results indicate that the change in FA composition and/or the presence of lipid peroxidation products in peroxidized SO may reduce ADG, GF, and digestibility of GE and ether extract, but has little impact on N digestibility and balance or on gut permeability.