Influence of CLA Supplementation on Body Composition of Growing Pigs

Thirty-two crossbred gilts (8 wk, 15.9 kg) of similar breeding were utilized in a randomized complete block design to evaluate the effects of dietary supplementation of conjugated linoleic acid (CLA) on body composition of young, growing pigs. Pigs were blocked by BW and were randomly assigned and evenly distributed among three treatment groups or a control group for an 84-d feeding trial. Diets consisted of a commercially available concentrate (Nutrena, Minneapolis, MN) with CLA supplemented at the rate of 0.33%, 0.66% or 1.0% of the diet. The CLA source (BASF Corp., Florham Park, NJ) contained 55% CLA (mixture of cis-9, trans-11; trans-10, cis-12; and trans-9, trans-11 isomers). The control group received the same pelleted concentrate in addition to soybean oil supplemented at 0.33% of the total diet. Oil was administered as a drench to the control group and all treatment groups at 0600 daily to ensure consumption. Body weight was obtained every 7 d with the intake of concentrate and supplement adjusted accordingly. Fat thickness (cm) was measured at 14-d intervals via ultrasonography at the 10^th rib and longissimus muscle area (LMA) was collected via ultrasonography at d 0, 42, and 84. Data were analyzed using the mixed procedure of SAS. Overall effects were analyzed using repeated measures and data from individual days were analyzed using fat thickness from d 0 as a covariate. Overall, there was no difference between treatments in BW (P=0.74), 10^th rib fat thickness (P=0.36), or LMA (P=0.70). There was a significant treatment x time interaction for fat thickness. Tenth rib fat thickness was lower at d 70 (P<0.03) and d 84 (P<0.04) for pigs consuming 0.66% and 1.0% CLA compared to the control group. These data indicate that CLA supplemented at 0.66% or 1.0% of the diet fed to young, growing pigs has no effect on BW or LMA, but did result in a decrease in back fat thickness after d 70 of treatment. It is likely that this trend would continue if the feeding period had been extended, however, further studies are needed to fully elucidate dietary CLA supplementation to alter body composition when fed to young, growing pigs.