Feeding conjugated linoleic acid partially recovers carcass quality in pigs fed dried corn distillers grains with solubles

Dried corn distillers grains with solubles (DDGS) fed to swine may adversely affect carcass quality due to the high concentration of unsaturated fat. Feeding CLA enhances pork quality when unsaturated fat is contained in the diet. The effects of CLA on growth and pork quality were evaluated in pigs fed DDGS. Diets containing 0, 20, or 40% DDGS were fed to pigs beginning 30 d before slaughter. At 10 d before slaughter, one-half of each DDGS treatment group was fed 0.6% CLA or 1% choice white grease. Carcass data, liver- and backfat-samples were collected at slaughter. Longissimus muscle area, 10th-rib backfat depth, last rib midline backfat depth, LM color, marbling, firmness and drip loss, and bacon collagen content were not altered by DDGS or CLA. Outer layer backfat iodine values were increased (P [less than or equal to] 0.05) with DDGS feeding and were 65.07, 69.75, and 74.25 for 0, 20, and 40% DDGS, respectively. Addition of CLA decreased (P [less than or equal to] 0.05) outer layer backfat iodine values from 71.11 to 68.31. Diets containing DDGS decreased (P [less than or equal to] 0.05) percent lean tissue contained in bacon from 48% for controls to 38% for pigs fed 40%. Abundance of fatty acid synthase, carnitine palmitoyl transferase Ia, acetyl-CoA-carboxylase, stearoyl-CoA desaturase, and glycerol-3-phosphate dehydrogenase mRNA in adipose or liver were not different (P > 0.05) for pigs fed DDGS. Feeding CLA decreased (P [less than or equal to] 0.05) the [[DELTA].sup.9] desaturase index in adipose tissue. The data indicate that decreased carcass firmness with DDGS feeding is not reflected by changes in lipogenic gene expression. Feeding 20% or more DDGS to finishing swine decreases bacon leanness, but inclusion of 0.6% CLA in the finishing diet can partially reverse these effects. Key words: conjugated linoleic acid, distiller grain, pork quality, swine