Dietary conjugated linoleic acids affect tissue lipid composition but not de novo lipogenesis in finishing pigs

Abstract

-Dietary conjugated linoleic acids (CLA) have been reported to profoundly affect lipid metabolism and to act as repartitioning agents. Currently, little is known about their effect on the fatty acid profile of tissue lipids in pigs. In the present study we determined the lipid composition of the backfat inner (BFI) and outer layer (BFO), omental fat (OF) and intramuscular fat (IMF) of the longissimus dorsi muscle in 24 Swiss Large White pigs fed diets supplemented either with 2% CLAenriched oil (containing 58.9 g CLA isomers . 100 g -1 of total fatty acids), linoleic acid-enriched oil (SO), or lard (LA). Animals were individually penned at 70 kg live weight and fed 2.8 kg . d -1 of the respective diet to slaughter at 105 kg. Growth performance, carcass characteristics and muscle measurements were not significantly affected by the dietary fats, although average daily weight gain and feed conversion ratio tended to be numerically improved 5-7% in the CLA-fed pigs compared to pigs of the other two treatments. Independent of the tissue, pigs fed the CLA diet exhibited higher levels of saturated fatty acids (P < 0.05) and lower levels of monounsaturated fatty acids (P < 0.05). By contrast, there was no difference in the distribution pattern of the saturated fatty acids between the LA and SO groups, but pigs fed the SO diet had lower monounsaturated and higher polyunsaturated fatty acid levels compared to those fed the LA diet. The CLA content of the BFO, BFI and OF was similar and did not indicate a preferential incorporation in one of the tissues. Compared to the adipose tissue, approximately 67% lower total CLA concentrations were found in the IMF. The in vitro activity of lipogenic enzymes was not altered by the dietary fat suggesting that lipogenesis was not affected by CLA. The distinct shift towards higher deposition of saturated fatty acids and lower deposition of monounsaturated fatty acids indicated a potential down-regulation of ∆9-desaturase activity by dietary CLA.pig / CLA / fatty acid composition / adipose tissue / loin muscle Résumé -Influence de l'apport des acides linoléiques conjugués dans l'alimentation sur la composition des tissus adipeux et la lipogenèse de novo chez les porcs en finition. Plusieurs travaux ont révélé que les acides linoléiques conjugués (conjugated linoleic acids : CLA) ont une influence importante sur le métabolisme des lipides et des protéines. En revanche, les effets des G. Bee 384

Growth performance, carcass characteristics and meat quality of group-penned surgically castrated, immunocastrated (Improvac®) and entire male pigs and individually penned entire male pigs

“…The weight of the testes, bulbourethral and salivary glands as well as the heart, liver and kidneys were assessed. At 30 min after exsanguination, the carcasses entered the air-chilling system (38C) for 24 h. One day after slaughter, the left side of each carcass was weighed and dissected according to the meat cutting standards applied by the Swiss Performance testing Station (MLP, Sempach, Switzerland), as described earlier (Bee, 2001). …”

Performances, meat quality and boar taint of castrates and entire male pigs fed a standard and a raw potato starch-enriched diet

“…Furthermore, a fat sample over the croup was taken for the determination of the fat score according to the method previously described (Scheeder et al, 1999). Thirty minutes after exsanguination, the carcasses entered the air-chilling system (38C) for 24 h. One day after slaughter, the left side of each carcass was weighed and dissected according to meat cutting standards applied by the Swiss Performance Testing Station (MLP, Sempach, Switzerland), as previously described by Bee (2001).…”

Effects of two supplementation levels of linseed combined with CLA or tallow on meat quality traits and fatty acid profile of adipose and different muscle tissues in slaughter pigs

“…Internal organs were removed and warm carcass weight was obtained. One day after slaughter the left side of each carcass was weighed and dissected according to meat cutting standards applied by the Swiss Pig Performance Testing Station (MLP, Sempach, Switzerland), as previously described (Bee, 2001). …”

“…Dry matter and crude fat content of muscle and adipose tissues and the CP of muscle tissues were quantified according to the AOAC methods (1995). Fatty acid profiles of the adipose tissues and muscles were determined by gas chromatography of the methyl esters as previously described (Bee, 2001).…”