Growth Performance, Carcass Characteristics, and Shelf-Life of Loin Chops of Finishing Pigs Fed Peroxidized Soybean Oil

Objectives were to determine the effects of feeding peroxidized soybean oil (SO) to finishing pigs on growth performance, carcass characteristics, and loin chop shelf-life. Individually housed pigs (N = 56; initial BW = 46.7 ± 5.1 kg) were randomly allotted to 1 of 4 diets containing 10% SO treated as follows: 1) unheated (CON), or heated at 2) 45°C for 288 h (45C), 3) 90°C for 72 h (90C) or 4) 180°C for 6 h (180C), each aeriated with 15 L air/min, and fed for 81-d. Data were analyzed as a one-way ANOVA with initial BW used as a covariate for growth performance and carcass characteristics. Feeding 90C reduced (P ≤ 0.03) ADG compared with pigs fed 45C and 180C by 11.2 and 9.2%, respectively. There was no difference (P = 0.81) in ADFI, but G:F of pigs fed 90C was reduced (P ≤ 0.03) compared with pigs fed 45C and 180C by 8.6 and 6.4%, respectively. Ending BW of pigs fed 90C diet were reduced (P < 0.01) compared with pigs fed 45C and 180C by 7.3 and 6.2%, respectively. For ADG, G:F, and ending BW, CON-fed pigs were similar to all other treatments (P ≥ 0.09). Feeding pigs 90C reduced (P ≤ 0.03) HCW by 6.3 to 9.0% compared to all other treatments. Livers of 90C-fed pigs were heavier as a proportion of ending BW (P ≤ 0.03) than those from pigs fed 45C or 180C. Livers of CON-fed pigs were proportionally smaller than (P ≤ 0.01) those from pigs fed 90C or 180C, but did not differ (P = 0.15) from those fed 45C. There was no effect (P ≥ 0.18) of diet on BF depth or LMA. Clear plate iodine value of 90C-fed pigs was reduced (P < 0.01) by 15.1, 14.0, and 11.2 units compared with 45C, CON, and 180C, respectively. Iodine value of 180C-fed pigs was 4.1 units less (P < 0.01) than 45C but not different (P = 0.07) from CON. There were no diet × storage time interactions (P ≥ 0.44). Loin chops from 45C-fed pigs had the greatest (P ≤ 0.03) a*, b*, chroma, and 530/680, but were the most (P < 0.01) discolored after 10-d of simulated retail display. In conclusion, feeding SO heated at 180°C reduced growth performance and HCW; whereas, feeding SO heated at 45°C resulted in redder loin chops that discolored more rapidly during simulated retail display.