Effect of feeding dried distillers grains with solubles and restaurant grease on gilt growth, carcass characteristics, bacon quality, and consumer bacon evaluation

The purpose of the present study was to evaluate the influence of using dried distillers grains with solubles (DDGS) and restaurant grease (RG) in gilt diets on growth, carcass characteristics, belly and bacon quality (Chapter 2), and on consumer bacon evaluation and acceptability (Chapter 3). Crossbred gilts (n=132) were randomly assigned to one of 3 dietary treatments. The 3 dietary treatments were corn-SBM based diets differing in concentrations of DDGS and supplemental RG to alter carcass fat and attain target carcass iodine values (IV) of 65, 75, and 85. Dietary treatments were: 1) Control, 0% DDGS, 1% RG; 2) 25% DDGS, 1% RG; and 3) 25% DDGS, 5.3% RG. Overall (d 0-104) ADG decreased for 25% DDGS fed pigs compared to pigs fed the corn-SBM control with pigs fed 25% DDGS + 5.3% RG being intermediate and not different from the other treatments. Overall ADFI decreased while overall G:F increased for pigs fed 25% DDGS + 5.3% RG compared to those fed the corn-SBM control and 25% DDGS. Hot carcass weight and loin depth were decreased for 25% DDGS fed pigs compared to pigs fed the corn- SBM control with pigs fed 25% DDGS + 5.3% RG being intermediate and not different from the other treatments. Feeding DDGS and RG resulted in shifts in the belly fatty acid profile. There were linear increases in linoleic acid, IV (63, 71, 79, diets 1-3 respectively), the n6:n3 ratio, and a linear decrease in saturated and monounsaturated fatty acids and the saturated to unsaturated fatty acid ratio from corn-SBM control to 25% DDGS to 25% DDGS + 5.3% RG fed pigs, respectively. The increased dietary IV negatively affected bacon from these gilts by increasing belly width during transport, bacon package purge, bacon slice length, and cooked bacon shrink, while reducing cooked bacon weights and yields. There was no effect of dietary IV on cooked bacon visual scores. Consumers perceived raw bacon slices from the highest IV treatment as being more greasy and stretchy than raw bacon slices from the other treatments. As dietary IV increased, there was a linear increase in the perceived sliminess of raw bacon slices. Cooked bacon slices from the highest IV treatment were perceived to have a poorer appearance and increased shrink compared to cooked bacon slices from the other treatments. Overall liking, overall cooking experience, and overall flavor were lower for the highest IV bacon. Based on the overall raw and cooked bacon characteristics, consumers would reduce their preference for raw and cooked bacon from the highest IV treatment by 11-13% and 6.5-8%, respectively. In conclusion, feeding DDGS and RG resulted in some decrease in growth performance and carcass parameters with greater negative effects on belly and bacon quality and consumer bacon acceptability, with the greatest impact on bacon quality occurring with the combination of DDGS and RG in the highest IV diet.