Content and Fatty Acid Composition of Different Fat Depots of Lambs Receiving Fish Oil Supplemented Diet

T. POPOVA, P. MARINOVA, V. BANSKALIEVA and V. VASILEVA
Institute of Animal Science, BG - 2232 Kostinbrod, Bulgaria

Abstract

POPOVA, T., P. MARINOVA, V. BANSKALIEVA and V. VASILEVA, 2008. Content and fatty acid composition of different fat depots of lambs receiving fish oil supplemented diet. Bulg. J. Agric. Sci., 14: 100-107

Two groups of 7 animals (age 75 days) each of local Zapadnostaroplaninska sheep breed were fed for 28 days controlled iso-nitrogenous diets, containing either no added fat (control) or fish oil (experimental) added at 2.5 % as feed of concentrate. The content of subcutaneous fat in the carcass of fish oil treated animals did not change, whereas the intermuscular fat increased by 16%, compared to the control animals. The effect of fish oil differed among the carcass cuts. Besides the leg and abdomen, where the subcutaneous fat slightly increased, in the rest carcass cuts (loin, shoulder, neck) the opposite changes were observed. Fish oil stimulated deposition of more intermuscular fat in shoulder (P < 0.05), leg and abdomen , but did not change the fat proportion in the neck. In loin both – subcutaneous and intermuscular fat were reduced (P < 0.05). No significant changes in the weights of sweetbread and perirenal fat were observed. After fish oil supplementation, the relative part of C16:0 did not change in the triacylglycerol fraction of the most of the studied fat depots, except of the sweetbread where it was significantly elevated (P < 0.01). The contents of C16:1 and C18:1 were increased, more substantially (P < 0.01) in the internal fat depots and in the subcutaneous fat over m. Longissimus dorsi and at the base of the tail, accompanied with a reduction of C18:0. As a result of the changes of the individual fatty acids, the sum of the saturated fatty acids decreased, and the sum of the monounsaturated fatty acid was enhanced in the fat depots of the experimental animals.
The changed deposition and distribution of the carcass fat, and the fatty acid composition of the different fat depots, suggest that fish oil (rich in PUFA) could have a favorable effect on the carcass fatness and quality.

Key words: lambs, fish oil, fat depots, fatty acids

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