The fatty acid composition of tissues from swine fed fresh and oxidized menhaden oil containing certain antioxidants

Graduation date: 1964The lipid composition of swine is characteristic of the species\ud and is also a reflection of their dietary history. Other investigators\ud have established that the physical properties and composition of\ud swine depot fat may be altered by variation of the dietary lipid.\ud Dietary regimens employing vegetable oil-bearing materials and\ud their effect on meat quality has received the attention of animal\ud nutritionists for a considerable period. Less is known about the\ud nutritive value of the more highly unsaturated lipids, such as fish\ud oils, and their effect on the lipid composition of swine tissues.\ud Even less is known about the fate of oxidized fish oil lipids in\ud swine rations.\ud This research had for its purpose the investigation of the fate\ud in swine of the dietary marine lipid, menhaden oil, and its effect on\ud composition of depot lipids. The state of autoxidation of the oil and\ud the effect of certain antioxidants on the fatty acid composition of\ud swine was determined.\ud Growth studies on swine were made using menhaden oil of\ud various oxidation states as the dietary lipid. The effect of antioxidants,\ud ∝-tocopherol acetate and ethoxyquin, was also investigated.\ud At the conclusion of the diet trials, tissue samples, representing\ud the five dietary regimens, were removed for analysis. The fatty\ud tissues examined were outer back fat, inner back fat, and kidney\ud fat. Samples of liver tissue for lipid analysis were also taken. The\ud lipids from the respective tissues were extracted and interesterified\ud with methanol to yield the methyl esters of the fatty acids. Hydrogenation\ud of the unsaturated methyl esters for chain length confirmation\ud was carried out.\ud Qualitative and quantitative gas-liquid chromatographic analysis\ud of the unhydrogenated and hydrogenated methyl esters of the fatty\ud acids were performed on diethylene glycol succinate column.\ud The results of these investigations showed that a particular\ud dietary fatty acid can be selectively deposited in animal tissues.\ud Long chain polyunsaturated fatty acids of menhaden oil, such as\ud 20:5, 22:5, 22:6 were sparsely deposited in adipose tissues. The\ud depot fat composition showed a mixture of characteristic menhaden\ud oil fatty acids with the typical fat synthesized by swine.\ud Fatty acid composition of tissue from swine fed oxidized menhaden\ud oil with and without antioxidants showed very similar fatty\ud acid composition as those fed fresh menhaden oil. The results of\ud this investigation supported the beneficial effect of vitamin E\ud (∝-tocopherol acetate) and ethoxyquin as in vivo antioxidants