Supplementation of broiler diets with retinol acetate, ß‐carotene or canthaxanthin: Effect on vitamin status and oxidative status of broilers in vivo and on meat stability

Abstract

The oxidative status of live chickens and of the chicken meat was evaluated for 5 groups of broilers fed a diet optimized with respect to all nutrients and energy content and rich in unsaturated fatty acids from rapeseed and soybean oil. The six diets varied in dietary content of ß‐carotene (5.1 or 10.2 mg kg−1 diet), canthaxanthin (2.0 mg kg−1diet) or retinol (8400 or 16800 IU kg−1 diet). Analyses of blood plasma taken from the live chicken showed no differences in their oxidative status, as regards haemolysis, creatin kinase (CK), glutamic‐oxaloacetic transaminase (GOT) and glutathione peroxidase (GSH‐Px). At slaughter α‐tocopherol in plasma (P< 0.01) and liver (P<0.05) decreased with increasing dietary retinol or ß‐carotene levels, whereas analysis of breast and thigh muscles did not show any change. Dietary canthaxanthin caused a decrease in the concentration of retinol in breast muscles (P≤ 0.01), whereas γ‐tocopherol content in thigh muscles (P< 0.001) increased with increasing dietary retinol and ß‐carotene content. Most of the ß‐carotene was converted to retinol at the intestinal mucosa during absorption, and ß‐carotene was detected only in small amounts in the liver. However, canthaxanthin and natural lutein from the feed were both readily absorbed and deposited unchanged in the tissues. The oxidative stability during chill (1, 7 and 14 days) and freezer storage (5 and 10 months) of raw muscles measured as TBARS values showed no significant differences related to the dietary treatment.