Liu Y., Tang G., Yang J., Li W. (2017): Effects of dietary conjugated linoleic acid on lipid peroxidation in breast and thigh muscles of broiler chickens. Czech J. Anim. Sci., 62, 331-338.The effect of dietary supplementation with conjugated linoleic acid (CLA) on lipid peroxidation in the breast muscles (Pectoralis major and Pectoralis minor) and thigh muscles of broiler chickens was investigated. A total of ninety-six 21-day-old Arbor Acres male broiler chickens were assigned to 2 dietary treatments (0 and 1.5% CLA) with 8 replicates per 6 chickens each. The left breast and thigh muscles of broiler chickens were excised on day 42. The broilers receiving the CLA diet exhibited lower malondialdehyde content and reactive oxygen species production (P < 0.01) in the breast and thigh muscles than the broilers receiving the control diet. After the dietary CLA supplementation, the glutathione (GSH) content in the breast and thigh muscles of the broiler chickens fed the CLA diet increased by 21.89 and 21.56%, respectively (P < 0.05) while the γ-glutamylcysteine synthetase（γ-GCS）activity increased by 28.57 and 25.80% (P < 0.05), respectively. Dietary CLA significantly increased the CLA content (P < 0.01) and saturated fatty acid content (P < 0.05), and decreased the monounsaturated fatty acid content (P < 0.01) in the breast and thigh muscles. These results showed that dietary CLA may decrease the lipid peroxidation level in the breast and thigh muscles of broiler chickens perhaps through increasing the γ-GCS activity to induce GSH synthesis and changing the fatty acid composition to increase oxidative stability.