A total of 40 pens containing 22 crossbred barrows (initial BW = 43.07 ± 1.61 kg; PIC 1050 × PIC 337 genetics) were housed in a commercial wean to finish facility. Pens were randomly allotted to dietary treatments in a 2 × 3 factorial arrangement with 2 levels of dried distillers grains with solubles (DDGS; 0% or 20%) and chosen for 1 of 3 marketing cuts removing 4, 8, and 10 animals from each pen. Fat tissue samples were removed from the anterior tip of the jowl and posterior to the sternum on the belly edge 1d postmortem. Fatty acid composition was determined via the Folch method, and iodine values (IV) were calculated from chemical titrations, fatty acid profile (GC IV), and in-plant Bruker near-infrared (NIR) spectroscopy. Pearson's correlation coefficients for IV determination methods were estimated. Inclusion of 20% DDGS did not change ( > 0.05) growth performance, whereas marketing cut affected performance, with the second cut producing the most efficient pigs ( < 0.01). Total SFA and MUFA concentrations were higher ( < 0.01) in belly and jowl fat from pigs fed 0% DDGS. Total PUFA and the PUFA:SFA in belly and jowl fat was higher ( < 0.01) when 20% DDGS was fed. Dried distillers grains with solubles inclusion increased IV in belly and jowl as determined by all 3 methods. Regardless of dietary treatment or fat depot, Pearson correlation coefficients between titration and GC IV, titration and NIR, and GC IV and NIR were 0.46 ( < 0.01), 0.68 ( < 0.01), and 0.43 ( < 0.01), respectively. These correlations suggest methods may rank samples equally but do not provide the same absolute IV. Belly fat had a lower IV ( < 0.01) than jowl fat using titration or GC IV methods, suggesting pigs have varied degrees of physiological maturity at specific fat depots when weight end points are used during the finishing phase. In conclusion, feeding 20% DDGS negatively affected fat quality but not growth performance, and marketing time changed growth performance.

Objectives were to evaluate effects of fat source and formulated fat percentage on fatty acid composition, lean color stability, lipid oxidation, and aerobic microbial load during simulated retail display of ground beef patties. In Experiment 1 beef carcasses (n = 30) were chilled for 2 d and then fabricated. M. semimembranosus muscles were removed along with 2 fat sources (kidney and pelvic = KP and subcutaneous = S from the same carcass) and ground to achieve 75 and 95% lean. Fatty acid profile and thiobarbituric acid reactive substances (TBARS) were determined over a 7 d simulated retail display period. Saturated fat differed (P = 0.0004) by fat source, with KP having a higher percentage than S. Thiobarbituric acid reactive substances were higher for (P < 0.05) for patties made with S compared to KP. In Experiment 2 beef carcasses (n = 20), were fabricated and blended into ground beef as described in Experiment 1. After designated display time patties were removed and instrumental color measurement, myoglobin concentration, TBARS, and aerobic plate counts (APC) were collected. Oxymyoglobin (OMb) percentage decreased (P < 0.0001) by storage day and had source x formulated fat percentage interaction (P = 0.011). Inversely, storage day increased metmyoglobin (MMb) percentage (P < 0.0001) where d 1 < d 3 < d 5 < d 7, respectively. Changes in myoglobin form contributed to decreased a* values (P < 0.0001) over time. However, APC did not differ (P > 0.05) for d, fat source, or fat percentage. Discoloration in ground beef over 7 d of retail display was more a function of muscle pigment oxidation (OMb to MMb) than aerobic microbial spoilage.

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Opportunities to export high quality pork products to trade partners like Japan are economically favorable outlets for US pork producers. Domestic consumers also rely heavily on fresh pork appearance, especially color and marbling, to make initial and repeat purchasing decisions. Two studies were performed to elucidate novel ways to improve pork quality, specifically by altering the lipid profile and increasing intramuscular fat (i.m.). In experiment 1, forty individually reared barrows (100 kg ± 3 kg, PIC C23 x 337) were randomly assigned to 1 of 5 treatments containing dried distillers grains with solubles and 3 percent added fat to determine the resulting carcass characteristics and fresh pork quality. The treatments included 1) a positive control containing a corn and soybean meal base with 3 percent choice white grease (PCON), 2) 30 percent high protein dried distillers grain and 3 percent choice white grease (HPDDG), or 30 percent DDGS with 3) no added fat (DDGS), 4) 3 percent choice white grease (DDGS + CWG), or 5) 3 percent butter oil (DDGS + BO). Postmortem carcasses characteristics and quality attributes were not different between diets (P greater than 0.08) except the semimembranosus muscle from pigs fed HPDDGS had the most basic ultimate pH (P = 0.01) suggesting pigs fed HPDDGS had less glycolytic potential at the time of slaughter. Including DDGS in the diet decreased (P less than 0.01) MUFA and increased (P less than 0.01) PUFA. Butter oil increased (P less than 0.01) CLA content in fat, but did not increase SFA or iodine value. Although added fat in the diet altered fatty acid composition in multiple fat depots, adding additional saturated fat to the diet in the form of butter oil did not mitigate the unsaturation of DDGS. Skycis® (narasin, NAR) is a swine performance ionophore labeled to increase rate of gain in the last 4 weeks of the finishing phase. The objective of experiment 2 was to evaluate inclusion of NAR in pig diets and determine the source of carcass yield, specifically dressing percentage, improvements observed in previous studies. Barrows (n=50) and gilts (n=50) of PIC C22 x 337 genetics were randomly assigned to a diet containing 0 or 15 ppm NAR initiated at 39.5 kg of body weight and continued until slaughter. Barrows tended (P = 0.09) to have heavier viscera, significantly (P less than 0.01) more fat at the 10th rib, and a greater (P = 0.01) percentage of i.m. fat compared to gilts. Gilts were heavier muscled than barrows as evidenced by many gender differences (P less than 0.05) observed in the cutability phase of the study, specifically larger LM (P less than 0.01). Heavy muscled, lean animals such as gilts may have increased organ mass from up regulated metabolic activity, but pigs with greater intake will also have heavier intestinal tract compensating for the increased consumption suggesting barrows in this study ate more, especially late in the growth curve. Pigs fed NAR had heavier (P less than 0.01) hearts, but few treatment differences were observed in carcass quality and cutability. In general, fat content increased and made up a larger percentage of total carcass weight in pigs fed NAR. The current results do not confirm the source of previously observed differences in DP in pigs fed NAR, but could be attributed to the tendency of NAR to increase carcass fatness.