CONCENTRATIONS OF FATTY-ACIDS AND CHOLESTEROL IN INTRAMUSCULAR FAT OF SLAUGHTER BULLS OF DIFFERENT GENOTYPES

Fat quality in slaughter animals and particularly the concentrations of fatty acids and cholesterol content are important with respect to dietary attitudes. Fat quality can be influenced by several factors to a larger or smaller extent. These indicators were determined in a trial on three breeds of slaughter bulls (Slovak Pied, Slovak Pinzgau and Black-pied Lowland) at average pre-slaughter weight of 501 to 545 kg; the indicators were determined in intramuscular fat of the m. longissimus dorsi at the level of the 9th and 10th rib: fatty acid spectrum, cholesterol content, as well as the ratio of the contents of unsaturated to saturated fatty acids (Sigma MK(1,2,3)/Sigma MK(0)) and the index of fat nutritive value (It), which describes the ratio of essential fatty acids (linoleic and linolenic acid) to saturated fatty acids (Sigma MK(2,3)/Sigma MK(0)) Fatty acids of extracted fat were transformed into methyl esters by alkaline transmethylation according to the modified methodology after Bannon et al. (1982). Percentage content of fatty acids was determined by gas chromatography on a PACKARD apparatus, model 419. Total cholesterol content was determined by the method elaborated by Hornakova et al. (1974). Tab. I shows the concentrations of 14 fatty acids with the chain C-12:0-C-22:1, which were found in all breeds, while the concentration of oleic acid was highest of all (40.44-41.49%). There were no significant differences between the breeds besides three, less important fatty acids with minimum concentrations. As for the calculated indexes (Tab. II), the values of fat unsaturation index (II) ranged from 1.02 to 1.06 and those of fat nutritive value index (I-2) ranged from 0.07 to 0.08. The determined average cholesterol content 65.34 to 71.11 mg/100 g is in agreement with the values reported by other authors (Streicher et al., 1984). Average content of saturated fatty acids ranged from 48.60 to 50.28% and that of unsaturated fatty acids from 49.42 to 51.42%.