Dietary conjugated linoleic acid alters fatty acid composition of pig skeletal muscle and fat

The dietary dose responsiveness of conjugated linoleic acid (CIA) addition relative to the fatty acid profile of edible lean tissue was examined in gr ower pigs treated with or without porcine somatotropin (pST). Gilts and bar rows were fed CLA at 0, 0.25, 0.5, 1.0, or 2.0% of diet by weight from 20 t o 55 kg BW. Additional pigs were administered (pST) at 0 or 100 mug.kg BW.d (-1) and fed either 0.5 or 2.0% CLA. Animals were fed diets containing 18% CP, 1.2% lysine, and 3.5 Mcal of DE/kg at 110% of ad libitum intake. The fa tty acid profile in latissimus dorsi and dorsal s.c. adipose tissue samples was determined by gas chromatography. Dietary CIA replacement of corn oil increased the percentage of total fatty acids as stearic acid, whereas the percentages as oleic and linolenic acids were reduced in lattisimus muscle. Treatment with CLA + pST increased the percentages of linoleic and arachid onic acids while reducing the percentages of palmitic and oleic acids in la ttisimus muscle. Dietary CIA increased the percentages of palmitic and stea ric acids in s.c. adipose tissue while reducing the percentages of oleic, l inoleic, linolenic, and arachidonic acids. The percentage of palmitic acid was reduced in s.c. adipose tissue, whereas linoleic acid was increased wit h CIA + pST. No synergistic effect was detected between CLA and pST for red ucing carcass lipid content in grower pigs. However, pST increased the perc entage of polyunsaturated fatty acids in lattisimus muscle and s.c. adipose tissue while reducing the percentages of saturated fatty acids in swine fe d CLA.