The effect of genotype on the chemical and fatty acid composition of the Quadriceps femoris muscle in extensively fattened lambs

Abstract. The aim of the experiment was to define the effect of a Suffolk-sired genotype on the chemical composition and fatty acid profile of the Quadriceps femoris muscle in fattened lambs reared under organic farming conditions. Three different genotypes of Suffolk-sired crossbreds were included in the experiment: F1 Suffolk-Charollais (SF 50 CH 50, n=10), F11 Suffolk-Charollais (SF 75 CH 25, n=10) and F1 Suffolk-Improved Walachian (SF 50 IW 50, n=10). The genotype did not have any effect on age at slaughter, average daily gain or carcass dressing percentages. However, the SF 75 CH 25 lambs displayed a lower live weight at slaughter (P<0.05), lower cold carcass weight (P<0.05) and lower protein content in muscle (P<0.05) than both of the other genotypes. They also had a lower content of kidney fat compared to the SF 50 CH 50 (P<0.01). The F11 Suffolk-Charollais lambs showed a higher proportion of C12:0 (P<0.01), C14:0 (P<0.01) and C16:0 (P<0.05) than the other two genotypes. A higher proportion of C18:0 was found in the SF 50 CH 50 lambs (P<0.05). The total content of saturated fatty acids (SFA) was higher in the SF 75 CH 25 crossbreds (P<0.05). The genotype also affected the content of C16:1 having its highest presence in the SF 75 CH 25 lambs while the lowest presence was found in the SF 50 CH 50 lambs (P<0.01). Between these two genotypes there were also found different proportions of C18:1 having its higher presence in SF 50 CH 50 lambs (P<0.05). Moreover, the IW type lambs had a lower SFA proportion and lower values of atherogenic and thrombogenic indexes and a higher polyunsaturated/saturated fatty acid (P/S) ratio in their meat than lambs of the CH genotypes (P<0.05). As for crossing between the Suffolk and Charollais breeds, a favourable fatty acids profile of meat was observed in the F1 crossbred as compared to the F11 crossbred.