Effect of linseed and the combination of conjugated linoleic acid and linseed on the quality and oxidative stability of pig meat and subcutaneous fat

The aim of this experiment was to test the hypothesis that conjugated linoleic acid (CLA) in diets of finishing pigs fed linseed can improve the quality and oxidative stability of meat and subcutaneous fat. Twenty-four Prestice Black-Pied pigs (barrows and gilts) were divided into three groups and were fed a basal diet and diets supplemented with ground linseed (70 g/kg), or linseed combined with conjugated linoleic acid (20 g CLA-oil/kg). The trial duration was 53 days. Measurements included slaughter and meat quality parameters, oxidative stability determination, and fatty acid profile of meat and subcutaneous fat. The experimental data were analysed using one-way analysis of variance. Neither linseed nor linseed with CLA significantly influenced weight gain, lean percentage, muscle depth, backfat thickness, drip loss, meat shear force, dry matter, intramuscular fat or cholesterol (P > 0.05). Dietary supplementation with linseed increased the percentage of linolenic acid in the fatty acids of meat and backfat and resulted in higher production of aldehydes. Dietary CLA did not influence the susceptibility of lipids to oxidation. Supplementation with CLA significantly increased CLA proportions in fatty acids of meat and backfat, reduced proportions of monounsaturated fatty acids, and increased proportions of saturated fatty acids in backfat (P < 0.05). The concentration of CLA (in mg/100 g of fresh tissue) in backfat was almost fifty times higher than in meat. Both meat and backfat of pigs fed CLA-free diets contained CLA, probably as a result of microbial conversion of linoleic acid in the intestine. It can be concluded that CLA changed the fatty acid profile of meat and backfat, but did not improve oxidative stability and other meat quality traits of pigs fed linseed.