Dietary fat reduces odd-numbered and branched-chain fatty acids in depot lipids of rabbits

Forty eight Californian x New Zealand White rabbits were randomly distributed in three groups of 16 animals each. A control (with no added fat) and two diets enriched at a rate of 30 g fat kg(-1) were used. Olive oil and sunflower oil were used as sources of fat for the fat-supplemented diets. Branched chain (BCFA) and n-odd-numbered carbon fatty acids (ONFA) in the perirenal fat depots of control animals were respectively 5 and 22 mg g(-1) of total fatty acids, while in fat-enriched diets they were around 3 and 16 mg g(-1), respectively. The ratio of unsaturated: saturated fatty acid in perirenal fat was 1.25:1 when the control diet was administered and around 1.80-1.95:1 in fat-enriched diet groups, which represents approximately a 50% increase (P < 0.01). However the melting points of the fats showed little difference (NS) between the control group and the group with olive oil addition whilst the sunflower oil-supplemented group showed only a 5.7% lower value (P < 0.01). In a second experiment in which diets with equal digestible energy and protein were used, reductions in total amounts of ONFA (P < 0.01) and BCFA (P < 0.05) were observed in the perirenal fat of animals receiving the fat-enriched diets. The addition of fat depressed the concentrations of ONFA and BCFA, which may act to maintain the consistency of fat in a narrow range, avoiding to some extent the production of undesirable soft and floppy carcasses.