EFFECT OF GENOTYPE ON ESTIMATED INDEXES OF FATTY ACID METABOLISM IN RABBITS

To analyse the effect of rabbit genotype on fatty acid metabolism, 60 weaned rabbits (30 d old, sex ratio 1:1; 20 New Zealand White, 20 Leprino of Viterbo and 20 rabbits of a Local grey population) were reared in bicellular standard cages. At 80 d, 10 rabbits per group were selected and slaughtered. The muscle fatty acid composition and relative indexes of metabolism of the longissmus lumborum of these rabbits were determined. The New Zealand White and Leprino rabbits exhibited lower percentages of myristic acid and higher percentages of palmitic acid and palmitoleic acid, and the levels of monounsaturated fatty acids were significantly higher in these rabbits. The grey-coloured rabbits exhibited the highest values of total n-3 fatty acids. With respect to fatty acid metabolism, the New Zealand White and Leprino rabbits exhibited higher thioesterase and Δ9-desaturase indexes and lower elongase and Δ5- Δ6-desaturase indexes. The estimated Δ5- Δ6-desaturase activity was significantly higher in the Local grey rabbits, suggesting a genetic effect on the desaturase and elongase mechanisms responsible for the synthesis of long-chain n-3 fatty acids.