THE COMPOSITION OF FATTY-ACIDS IN INTRAMU SCULAR FAT OF THE M-LONGISSIMUS-LUMBORUM-ET-THORACIS IN PIGS OF VARIOUS SLAUGHTER WEIGHTS

The fatty acid composition in intramuscular fat of the m. longissimus lumborum and thoracis was determined in slaughter pigs of the White Po rk breed, in young boars and gilts at the slaughter weights of 100, 12 00, 140 and 160 kg. The experiment included 27 slaughter pigs (I 2 boa rs and 15 gilts). The fattening from the live weight of 30 kg using ad semi-libitum feeding with Al and VVL mixtures. Fatty acids were extra cted from homogenized samples by multi-stage extraction in petroleum e ther and they were converted to methyl esters through alkaline transme thylation. Fatty acid percentual contents were determined by methyl es ter analysis using gas chromatography on a PACKARD instrument, model 4 19. A flame iodization detector (FID) was used to detect the fatty aci s. The whole procedure applied calibration using PolyScience Corporati on standard substances: the determined retention times were applied to the NELSON evaluation routine. The proportions of fatty acids are giv en as percent of the total amount of fatty acids. The obtained results were processed by mathematico-statistical methods and the differences depending on slaughter weight and sex were tested by t-test and F-tes t. The presence of 17 fatty acids with the chain C-8 - C22 was determi ned, while nine of them were saturated acids and six were monoenic fat ty acids. As for polyenic fatty acids, so called essential ones, linol eic acid C18 : 2 and linolenic acid C18 : 3, Were detected. Increases in the contents of palmitic acid C16 : 0 (1 : 3 P < 0.05; 3 : 4 P < 0. 05) and linoleic acid C18 : 2 (1 : 4 P < 0.05; 2 : 4 P < 0.05) were re corded within the range of weight categories of groups 1 (100 kg), 2 ( 120 kg), 3 (140 kg) and 4 (160 kg). The values of index I for so calle d unsaturation of intramuscular fat (SIGMA M(K1,2,3)/ SIGMA M(K0)), Wh ich ranged from 0.927 to 0.915, were not influenced by carcass weight. One the contrary, the values of index II for nutritive value (SIGMA M (K2, 3)/ SIGMA M(K0)) were within the increasing range of 0.075 to 0.0 92 (2 : 4 P < 0.05). The values of the index for nutritive value (SIGM A M(K2,3)/SIGMA M(K16 : 0)) also showed a growing trend from 0.163 to 0.201 (2:4 P < 0.01; 3:4 P < 0.05). The differences between the male a nd female sex were determined only in myristoleic acid C14 : 1, linole ic acid C18: 3 and behenic acid C22: 0 (P < 0.05). The values of all i nvestigated indexes were insignificant with respect to the sex and the y were in the following range: SIGMA M(K1, 2,3)/ SIGMA M(K0) (0.911 - 0.914), SIGMA M(K1, 2, 3)/ SIGMA M(K0) (0.073 - 0.075), SIGMA M(K2,3) / SIGMA M(K16 : 0) (0.158 - 0.157). The results have indicated that th e pig sex did not influence fat unsaturation nor the nutritive value o f intramuscular fat.