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

Abstract

Consumption of highly peroxidized oils has been shown to affect pig performance and oxidative status through the development of compounds which differ according to how oils are thermally processed. The objective of this study was to evaluate the effect of feeding varying degrees of peroxidized soybean oil (SO) on parameters of growth performance; lipid, N, and GE digestibility, gut integrity in growing pigs, and plasma Trp. Fifty-six barrows (25.3 ± 3.3 kg initial BW) were randomly assigned to one of four diets containing either 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each with an air infusion of 15 L/min. Peroxide values for the 22.5, 45, 90, and 180 °C processed SO were 2.0, 96, 145, and 4.0 mEq/kg, respectively; 2,4-decadienal values for 22.5, 45, 90, and 180 °C processed SO were 2.11,5.05, 547.62, and 323.57 mg/kg, respectively; and 4-hydroxynonenal concentrations of 0.05, 1.05, 39.46, and 25.71 mg/kg with increasing SO processing temperature. Pigs were individually housed and fed ad libitum for a 49 d period to determine the effects of SO peroxidation status on growth performance, including a metabolism period for assessing GE and N digestibility, and N retention. In vivo urinary lactulose to mannitol ratio was also assessed to evaluate potential changes in small intestinal integrity. Although there were no differences observed in ADFI (P = 0.19), ADG was decreased in pigs fed 90 °C SO diet (P = 0.01), while G:F was increased (P = 0.02) in pigs fed 45 °C SO diet compared to the other SO diets. Pigs fed the 90 °C processed SO had the lowest (P = 0.01) DE as a percentage of GE, whereas ME as a percentage of DE was lowest (P = 0.05) in pigs fed the 180 °C SO and 90 °C SO followed by 45 °C SO and fresh SO. Ether extract (EE) digestibility was lowest (P = 0.01) in pigs fed 90 °C SO followed by pigs fed 180 °C SO, 45 °C SO, and fresh SO. The percent of N retained was greatest (P = 0.01) in pigs fed fresh SO followed by pigs fed 45 °C SO, 180 °C SO, and 90 °C, respectively. There were no differences observed among SO treatments for urinary lactulose to mannitol ratio (P = 0.60). Pigs fed SO processed at 90 °C and 180 °C had lower concentrations (P < 0.01) of serum Trp compared to pigs fed the 22.5 °C and 45 °C SO treatments. The presence of lipid peroxidation products, namely several aldehydes, contained in the 90 °C SO diet reduced ADG, GE and EE digestibility, and N balance, but had no impact on gut permeability.

Impacts of feeding peroxidized oils on growth and oxidative status in swine and poultry

“…During the experimental period, 1 pig fed the 45 o C SO and 1 pig fed the 180 o C SO died due to causes unrelated to dietary SO treatment; therefore, data are reported using 14 observations for 22.5 o C and 90 o C SO and 13 observations for 45 o C and 180 o C SO. The effects of SO peroxidation on pig performance, digestibility and intestinal integrity were previously reported (Chapter 2, Lindblom et al, 2017) where pigs fed the 90 o C SO had reduced ADG and N retention, and reduced energy and ether extract digestibility.…”

“…Methodologies regarding lipid peroxidation of SO, formulation of diets, and animal management have been described previously (Chapter 2, Lindblom et al, 2017).…”

“…The composition of experimental SO have been described in detail previously (Chapter 2, Lindblom et al, 2017) and highlighted in Table 3.2. In brief, thermal processing decreased the unsaturated:saturated fatty acid ratio (UFA:SFA) of the dietary FA with a corresponding increase in the production of lipid peroxidation products including peroxide value (PV), p-anisidine value (AnV), and multiple aldehydes, including 2,4-decadienal (DDE), and 4-hydroxynonenal (HNE).…”

“…In conclusion, oil source and peroxidation status differentially affected growth performance, oil source increased plasma TBARS, PC, and 8-OH-2dG, and lipid peroxidation increased plasma 8-OH-2dG and decreased plasma GPx. Lindblom, N. K. Gabler, B. J. Kerr. (2017) Influence of thermally peroxidized soybean oil on growth performance and oxidative status in growing pigs.…”

“…Each pig was individually penned with ad libitum access to feed and water for a 49 d experimental period. Pigs were blocked into groups of 20, 20, and 16 and moved to metabolism crates on d 21, 25, and 29; respectively, for a 5 d period for digestibility analyses (Chapter 2,Lindblom et al, 2017) and for collections of urine and serum for oxidative stress analyses. During this period, pigs were fed their treatment diet equivalent to 4% of their average BW twice daily (2% at 0700 h and 2% at 1700 h) with constant access to water.…”