Conjugated linoleic acid in combination with supplemental dietary fat alters pork fat quality

Interest in fortification of human foods, including pork, with conjugated linoleic acid (CLA) is growing and may provide benefits as a neutraceutical based on research evaluating CLA as an anticarcinogen, immune modulator, antiatherogenic agent and a body composition modulator. This study evaluated the combined effects of dietary CLA and supplemental fat source on growth, fatty acid composition and belly quality of lean genotype gilts (n = 144). Pigs (49.3 kg) were randomly assigned to six diets (3 X 2 factorial) varying in supplemental fat (none, 4 g/100 g yellow grease or 4 g/100 g tallow) and linoleic acid [1 g/100 g corn oil (CO) or 1 g/100 g CLA (CLA-60)] for 47 d. Both the cis-9, trans-11 and the trans-10, cis-12 isomers of CLA were increased in belly and longissimus fat depots from pigs fed CLA, and that increase was up to 92% greater when CLA was fed with 4 g/100 g supplemental fat (fat source X linoleic acid interaction, P < 0.05). Pigs fed CLA had a greater concentration of 18:0 and less 18:1 cis-9 (P < 0.01) in various fat depots, suggesting a reduction in Delta(9) desaturase activity. The iodine value of belly fat from pigs consuming tallow and CLA combined was reduced to 62.0 from an initial value of 70.4. CLA supplementation also increased belly weights (P < 0.05). CLA did not affect longissimus muscle area, backfat depth and the percentage of fat-free lean (P > 0.10), but it increased the subjective intramuscular fat score by 18.8% (P < 0.01). In conclusion, CLA enrichment of pork products may be enhanced when combined with additional supplemental dietary fat, and together with tallow can be used to increase the saturated fatty acid content of pork.