A total of 120 barrows (initial BW = 47.9 kg; PIC 1050) were used in an 83-d study to determine the effects of dietary iodine value (IV) product (IVP) on growth performance and fat quality. Pigs were blocked by BW and randomly allotted to 1 of 6 treatments with 2 pigs per pen and 10 pens per treatment. Dietary treatments were fed in 3 phases and formulated to 3 IVP concentrations (low, medium, and high) in each phase. Treatments were 1) corn-soybean meal control diet with no added fat (low IVP), 2) corn-extruded expelled soybean meal (EESM) diet with no added fat (medium IVP), 3) corn-soybean meal diet with 15% distillers dried grains with solubles and choice white grease (DDGS + CWG; medium IVP), 4) corn-soybean meal diet with low CWG (medium IVP), 5) corn-EESM diet with 15% DDGS (high IVP), and 6) corn-soybean meal diet with high CWG (high IVP) On d 83, pigs were slaughtered and backfat and jowl fat samples were collected and analyzed. The calculated and analyzed dietary IVP values were highly correlated (r2 = 0.86). Pigs fed the control diet, EESM, or high CWG had greater ADG than pigs fed EESM + DDGS. Pigs fed the control diet had greater ADFI than pigs fed all other diets. Pigs fed EESM + DDGS and high CWG had improved G:F compared with pigs fed the control diet or DDGS + CWG. Pigs fed diets with DDGS had greater backfat and jowl fat IV, C18:2n-6, and PUFA and less SFA than pigs fed all other treatments. Pigs fed EESM had greater backfat and jowl fat IV, C18:2n-6, and PUFA than pigs fed the control diet, low CWG, or high CWG. Pigs fed low CWG or high CWG had greater jowl fat IV than control pigs. Feeding ingredients high in unsaturated fatty acids, such as DDGS and EESM, had a greater impact on fat IV than CWG, even when diet IVP was similar. Therefore, IVP was a poor predictor of carcass fat IV in pigs fed diets with different fat sources and amounts of unsaturated fats formulated with similar IVP. Dietary C18:2n-6 content was a better predictor of carcass fat IV than diet IVP.

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