Dietary conjugated linoleic acids increase lean tissue and decrease fat deposition in growing pigs

Conjugated linoleic acids (CLA) decrease the body fat content of rodents; t he aim of this study was to determine whether dietary CLA altered carcass c omposition of pigs. Female Large White x Landrace pigs (n = 66) were used i n this study. To obtain initial body composition, six pigs were slaughtered at 57 kg live weight, whereas the remaining pigs were allocated to one of six dietary treatments (0, 1.25, 2.5, 5.0, 7.5 and 10.0 g/kg CLA, containin g 55% of CLA isomers). The diets, containing 14.3 MJ digestible energy (DE) and 9.3 g available lysine per kg, were fed ad libitum for 8 wk. Dietary C LA had no significant effect on average daily gain (861 vs. 911 g/d for pig s fed diets with and without CLA, P = 0.15) or feed intake (2.83 vs. 2.80 k g/d, P = 0.74). The gain to feed ratio was increased by dietary CLA by 6.3% (0.328 vs. 0.348, P = 0.009). Fat deposition decreased linearly (-8.2 +/- 2.09 g/d for each gram per kilogram increase in CLA concentration; P < 0.00 1) with increasing inclusion of CLA. At the highest level of CLA inclusion, fat deposition was decreased by 88 g/d (-31%). Similarly, the ratio of fat to lean tissue deposition decreased linearly (-0.093 +/- 0.0216 for each g ram per kilogram increase in CLA concentration; P < 0.001) with increasing dietary CLA. The carcass lean tissue deposition response to dietary CLA was quadratic in nature and was maximized (+25%) at 5.0 g/kg dietary CLA. Over all, dietary CLA increased the gain to feed ratio and lean tissue depositio n and decreased fat deposition in finisher pigs.