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Fat quality of pigs is altered when 20% DDGS are fed over three industry standard marketing cuts
Fat quality is important in meat products as it can influence further processing characteristics and pork export potential. The use of non-traditional fat sources such as dried distillers grain with solubles (DDGS) changes pork fat quality and has created challenges for end users of pork chain products. An experiment was designed to evaluate the effects of DDGS and split marketing cuts in a commercial swine facility on growth performance, fat quality and the relationship between iodine value (IV) determined by three methods in two fat depots. Pen (n=40) was the experimental unit with 20 replications per treatment and 22 pigs per pen. Pigs were randomly allotted to dietary treatments in a 2 x 3 factorial arrangement with two levels of DDGS (0 or 20%) and chosen for one of three marketing cuts removing 4, 8 and 10 head 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 IVs were calculated from chemical titrations, fatty acid profile (GC IV) and in-plant Bruker® near infrared (NIR) spectroscopy. Correlations between IV determination methods were calculated. Inclusion of 20% DDGS did not change (P>0.05) growth performance while marketing cut affected performance with the second cut producing the heaviest and most efficient hogs (P<0.01). Total SFA and MUFA concentrations were higher (P<0.01) in belly and jowl fat from hogs fed 0% DDGS. Total PUFA and the PUFA:SFA in belly and jowl fat was higher (P<0.01) when 20% DDGS was fed. DDGS inclusion increased IV in belly and jowl fat regardless of IV determination method. 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 (P<0.01), 0.68 (P<0.01) and 0.43 (P<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 (P<0.01) compared to jowl fat using titration or GC IV methods suggesting pigs have varied degrees of physiological maturity at specific fat depots during the finishing phase. In conclusion, feeding 20% DDGS negatively affected fat quality, but not growth performance and marketing time changed growth performance.
Keywords: DDGS, fat quality, pork, iodine value