Effects of dietary CLA (Conjugated Linoleic Acid) in pigs

Dietary conjugated linoleic acids (CLA) have been reported to profoundly affect lipid metabolism, to act as a repartitioning agent and to promote body weight gain. We resume in the present review experimental data assessed with pigs (sows, piglets, finishing pigs) fed either a CLA or sunflower oil fortified diet. The CLA source (59 g CLA/100g total fatty acids) used in our experiments contained equal amounts of the cis9,trans11 and trans10,cis12 isomers. The present data clearly demonstrate, that CLA affected the fatty acid composition of the adipose and muscle tissues, by decreasing the amount of deposited monounsaturated fatty acids mainly oleic acid and by increasing the amount of saturated fatty acids (palmitic and stearic acid). These effects were a result of a dramatic down regulation of ?9-desaturase activity. Furthermore, all dietary CLA isomers were incorporated into the fat and muscle tissues in order of the amount supplied. CLA feeding to finishing pigs had only slight positive effects on growth and carcass performance but parameters of meat quality were unaffected. By contrast, weaned piglets born to sows fed during pregnancy and lactation a CLA supplemented diet showed a marked increased growth rate due to significantly higher feed intake, which resulted in higher slaughter weight at 70 days of age. Sows fed CLA during lactation excreted the isomers in the milk. However, compared to the cows neither milk yield nor milk fat content were affected by the dietary CLA supply.