Poultry meat production as a functional food with a voluntary n-6 and n-3 polyunsaturated fatty acids ratio
We studied the effect of different levels of linseed oils made either of the flax cultivar Atalante with a high content of α-linolenic acid (612 g/kg) or of the cultivar Lola with a predominating content of linoleic acid (708 g/kg) in a chicken diet upon the fatty acid pattern in meat. Cockerels Ross 308 were fed the diets containing 1, 3, 5 or 7 per cent of oil in the last 15 days of fattening. Breast meat (BM) and thigh meat (TM) without skin of 8 chickens from each dietary group were used for analyses. The relative proportions of fatty acids were expressed as percentages of total determined fatty acids. When feeding Atalante oil, the proportions of n-6 fatty acids were highly significantly lower while those of n-3 fatty acids were higher; the ratio of n-6/n-3 polyunsaturated fatty acids in meat was narrower (<i>P</i> < 0.001) than in chickens fed oil with a low content of α-linolenic acid. In BM and TM, the relative proportions of α-linolenic and γ-linolenic acids were nearly the same, the proportion of linoleic acid in BM was lower, and the proportions of the other polyunsaturated fatty acids in BM were higher than in TM. In BM, the ratio of n-6/n-3 polyunsaturated fatty acids was significantly (<i>P</i> < 0.001) more favourable than that found in TM. The relative proportions of total saturated and monounsaturated fatty acids in meat decreased and those of polyunsaturated fatty acids increased significantly (<i>P</i> < 0.01) in dependence on the increasing level of dietary oils. When feeding Atalante oil, a significant increase in the proportion of linoleic acid in BM but not in TM was observed. The proportions of the other n-6 fatty acids decreased and those of all determined n-3 fatty acids, with the exception of docosahexaenoic acid, significantly increased with the increasing level of oil in the diet. When feeding Lola oil, its increasing content in the diet increased the relative proportion of linoleic acid as well as its elongation to γ-linolenic acid; however, the proportions of arachidonic and adrenic acid did not change significantly (<i>P</i> > 0.05). The proportion of α-linolenic acid increased in both BM and TM. The proportion of eicosapentaenoic and clupanodonic acids in BM significantly decreased. The ratio of n-6 to n-3 polyunsaturated fatty acids ranged from 0.9 to 13.6 and from 1.0 to 17.2 in BM and TM, respectively. An increase in the level of Lola oil in the diet by 1% caused that the n-6/n-3 polyunsaturated fatty acid ratio extended by 1.00 and 1.19 units in BM and TM, respectively. Dependences of n-6/n-3 ratio on the level of Atalante oil were expressed by equations of convex parabolas with minima at the level of oil 5.8 and 5.9% for BM and TM, respectively. By means of the inclusion of linseed oil with a high content of α-linolenic acid in the feed mixture it would be possible to produce poultry meat as a functional food with a very narrow ratio of n-6/n-3 polyunsaturated fatty acids.
