Relationships between intake of PUFA n-3 fatty acids and their quantitative content in the carcass tissues of pigs

The mathematical relation between intake of C18:3 n-3 (linolenic acid, ALA), 20:5 n-3 (eicosapentaenoic acid, EPA), and 22:6 n-3 (docosahexaenoic acid, DHA) acids and their content in the Musculus longissimus dorsi (MLD) and backfat (BF) of pigs growing from 60 to 105 kg body weight (BW) was investigated.At 60 kg BW, 32 crossbred pigs were allotted to 4 diets/groups (A, B, C, and D, respectively) and fed isoenergetic and isoprotein diets, where 10% of metabolizable energy was replaced by fat mixtures for a total of 3.5% per kg diet.All feeds had a similar amount of C18:2 n-6 (linoleic acid, LA), but due to the composition of the particular fat mixtures, differed in the amounts of ALA, EPA, and DHA.The ratio of Ʃn-6/Ʃn-3 was 3.87, 4.80, 1.77, and 2.20 in diets A, B, C, and D, respectively.Growth and carcass performance, intramuscular fat, and MUFA and SFA contents in both investigated tissues did not differ among groups.The ALA content (g/100 g tissue) and LA:ALA ratio in the MLD and BF of group B pigs differed (P<0.01)from the remaining groups.The EPA and DHA contents in the MLD did not differ among groups, but the BF was lower (P<0.01) in A and D compared with B and C pigs.Relationships between ALA intake and its content in BF was stronger than in the MLD and the coefficients of regression ('b') and correlation ('r') were : b=0.127 and r=0.85 for BF, and b=0.002 and r=0.59 for MLD.For the remaining long-chain n-3 PUFA, a linear relationship between their intake and tissue concentration was found only in BF, where the coefficients of regression and correlation ranged from: b=0.035 and r=0.64 for EPA and b=0.089 to r=0.89 for DHA.