Fatty acid composition and adipogenic enzyme activity of muscle and adipose tissue, as affected by Iberian × Duroc pig genotype

The adipogenic potential of subcutaneous fat (SCF) and muscles Longissimus dorsi (LD) and Biceps femoris (BF) were evaluated in three different Iberian × Duroc pig genotypes: GEN1: ♂ Iberian × ♀ Duroc1; GEN2: ♂ Duroc1 × ♀ Iberian; GEN3: ♂ Duroc2 × ♀ Iberian. Reciprocal crosses (GEN1 vs. GEN2) showed similar traits, while the genotype of the Duroc sire line (GEN2 vs. GEN3) significantly influenced the adipogenic character. GEN3 had lower fat depths and a more unsaturated SCF than GEN2. The intramuscular fat (IMF) content of the LD was higher in GEN2 than in GEN3, while BF showed a similar trend. The fatty acid compositions of IMF and neutral lipid fraction (NL) in LD and BF were more unsaturated in GEN3 than in GEN2. Glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME) activities in SCF and in both muscles analysed were higher in GEN2 than in GEN3. The higher fat depths and IMF of GEN1 and GEN2 correspond to higher G6PDH and ME activities, which indicated that the lipid synthesis and deposition in muscles and in SCF were higher in GEN1 and GEN2 than in GEN3; these differences were associated with the Duroc sire line. Therefore, the use of Duroc selected genotypes reduced the adipogenic character of Iberian × Duroc crosses, which could have important repercussions on the quality of meat and dry-cured products.