Influence of Feeding Duration and Dietary Level of Phaffia rhodozyma, a Yeast Containing High Concentrations of Astaxanthin, with or without Supplementation of Lecithin and α-Tocopherol on Meat Color Development in Broiler Chickens

Two experiments were conducted if the meat color-modifying potential of Phaffia rhodozyma, a yeast containing high levels of astaxanthin (Ax), is influenced by the feeding duration and the dietary concentration and if the potential is enhanced by an addition of lecithin+α-tocopherol in broiler chickens. Experimental diets supplemented with cell wall-fractured yeast to provide 10, 20 and 30ppm Ax were fed to 3, 5 and 7 week-old chickens for 5, 3 and 1 weeks, respectively, prior to market in Experiment 1. In Experiment 2, Phaffia yeast-supplemented diets (20ppm Ax), which were supplemented with or without lecithin (5g/kg diet)+α-tocopherol (0.1g/kg diet), were fed to 5 week-old chickens for 3 weeks prior to market. Feeding of Phaffia yeast influenced neither performance of broilers nor edible meat yields, irrespective of either the feeding duration, the dietary concentration or the addition of lecithin+α-tocopherol. Concern-ing the color analysis of edible meats using with Minolta reflectance colorimeter, light-ness (L* value) was not essentially influenced by feeding of the yeast-supplemented diets, while yellowness (b* value) was slightly increased by the yeast feeding. On the other hand, the redness (a* value) of edible meats and abdominal adipose tissues was significantly or numerically increased by feeding of the yeast-supplemented diets, in which the increase was less extent in chickens received the yeast-supplemented diet (30ppm Ax) for 1 week prior to market than chickens received the yeast-supplemented diets (20ppm Ax) for 3 weeks. The extent of increase in a* values of edible meats was relatively dependent on the total Ax intake. Addition of lecithin+α-tocopherol did not intensify the coloration (redness) of edible meats by the feeding of yeast-supplemented diets. These results show that cell wall-fractured Phaffia yeast containing high concen-trations of Ax can be a useful source for modification of meat color and the effect is briefly due to the total Ax intake in broiler chickens.