Effect of dietary n-3/n-6 ratio on fatty acid composition of liver, meat and perirenal fat in rabbits

The metabolic pathways of dietary fatty acids were studied in rabbits by analysing the fatty acid profile of different tissues (liver, perirenal fat, longissimus lumborum muscle). Four groups of 24 hybrid males each were assigned to four semi-purified diets, varying in the source of lipids which differed in n-3/n-6 ratios: 180 g/kg sunflower (S), 80 g/kg flaxseed +90 g/kg sunflower (SF), 160 g/kg flaxseed (F) and 60 g/kg fish oil (FI). The liver showed a very important role in fatty acid syntheses and was the tissue richest in long-chain (greater than or equal to 20 C) polyunsaturated fatty acids (LCP) of n-3 and n-6 series. The S diet gave the highest mono-unsaturated fatty acids and n-6 LCP (respectively, 201.9 and 384.9 g/kg, P < 0.01) also showing a clear antagonism v, n-3 LCP; the FI diet determined the highest enrichment of n-3 LCP (179.5 g/kg, P < 0.01), alpha-linolenic acid was efficiently converted into n-3 LCP mainly when n-3/n-6 ratio was high (Sigma n-3/C20: 4n-6: 2.74 and 3.61, P < 0.01 in flaxseed and fish-oil diet, respectively). The same trend occurred in the muscle but in a less consistent way. The adipose tissue move closely reflected the composition of the dietary fatty acids, showing variations mainly concerning polyunsaturated fatty acids (S diet), and LCP n-3 (FI diet: 44.9 g/kg, P < 0.01). Results showed the possibility of modifying the fatty acid profile of rabbit meat by dietary means and that the n-3/n-6 ratio of the food is crucial in regulating the relative presence of LCP n-3 or n-6 in meat products.