THE EFFECT OF GRAZING ON FATTY ACID COMPOSITION AND OXIDATIVE STABILITY OF CHICKEN MEAT

The study evaluated the breast meat quality of Hubbard JA757 cockerels housed on litter under intensive conditions (13.5 chickens/m(2); L) and in free-range with a higher (8.30 chickens/m(2); FRI) or lower stocking density (4.15 chickens/m(2); FRII). The chickens of all groups were kept until 28 days of age in indoor pens, and then the free-range groups were moved to the floorless portable pens. The rapeseed oil was the source of fatty acids in diet. The rearing system had little effect on the fatty acid composition of the breast meat. The pasture of chickens with lower stocking density significantly decreased the polyunsaturated fatty acid (PUFA) content (P = 0.029) and linoleic acid content (P = 0.031) in breast meat contrary to chickens from litter. The stocking density affect the alpha-linolenic acid content (P < 0.001), which was significantly lower in the group with lower stocking density. In addition, both free-range groups decreased the n-3 PUFA content (P = 0.002) and the hypocholesterolemic/Hypercholesterolemic index (P < 0.001) and increased the thrombogenic index (P < 0.001) and the atherogenic index (P < 0.001). The n-6/n-3 PUFA ratio was not influenced. Oxidative stability of meat stored at 4 degrees C for 0 (P = 0.020) and 5 days (P = 0.003) was higher in chickens housed on litter under intensive conditions. In the ninth day of storage, meat oxidative stability of chickens from FRII increased (P < 0.001) contrary to group FRI. In case of fatty acids and oxidative stability, good source of fatty acids in diet can offset or surpass the positive influence of grazing.