Dietary supplementation with vegetable oils with low n-6:n-3 polyunsaturated fatty acid ratios improves the intramuscular fat and fatty acid composition of growingfinishing pigs

This study investigated the effects of different n-6:n-3 polyunsaturated fatty acid (PUFA) ratios in pig diets using vegetable oil supplementation on growth  performance, carcass characteristics, meat quality, and fatty acid composition in the longissimus dorsi muscle (LM) and subcutaneous adipose  tissue (SAT) of pigs. Fiftyfour cross-bred growing pigs (Large White × Landrace × Duroc; 45.03 ± 1.72 kg) were randomly assigned to one of three  isoenergetic diets: the 1) basal diet (control), 2) RAPO diet (diet supplemented with 4.5% rapeseed oil), and 3) MIXO diet (diet supplemented with 2.25%  rapeseed oil and 2.25% linseed oil), with n-6:n-3 PUFA ratios of approximately 13:1, 7:1, and 2:1, respectively. The experiment lasted 42 days. The RAPO  and MIXO diets did not affect the growth performance and carcass characteristics of pigs, while the content of low-density lipoprotein (LDL), triglycerides  (TGs), and glucose (GLU) in the serum decreased substantially. Intramuscular fat (IMF) content increased by 19.25% and 20.11% in the LM of pigs fed the  RAPO and MIXO diets, respectively, and lower cooking loss and drip loss of meat were observed only in pigs fed the MIXO diet. The RAPO and MIXO diets  decreased the stearic acid and palmitoleic acid levels, increased the total PUFA levels (including those of α-linolenic and linoleic acid), and decreased the  n-6:n-3 PUFA ratios in LM and SAT. However, the MIXO diet was more effective in improving the fatty acid composition. A mixed oil diet with an n6:n-3  PUFA ratio of 2:1 is an effective measure for improving meat quality.