Effect of astaxanthin produced by Phaffia rhodozyma on growth performance, meat quality, and fecal noxious gas emission in broilers

A prospective alternative to antibiotics currently being evaluated is yeast and its derivative products. Phaffia rhodozyma is a species of yeast that produces the carotenoid pigment, astaxanthin (AST), which exhibits a wide variety of biological activities, including antioxidation in animals. A total of 432 one-day-old male broilers (Arbor Acres) were used in a 4-wk feeding experiment and each dietary treatment consisted of 9 replicate cages, with 16 broilers per replicate. Birds were randomly allotted to 1 of 3 corn-soybean meal-based diets supplemented with 0 mg (CON, basal diet), 1,000 mg (CON + AST production 0.1%), or 2,000 mg (CON + AST production 0.2%) of P. rhodozyma yeast per kg of feed, giving an intake of approximately 0, 2.3, and 4.6 mg of AST/kg of feed, respectively. The inclusion of AST linearly improved weight gain in the finisher period (linear, P = 0.0264) and during the overall experimental period (linear, P = 0.0194) and linearly decreased feed conversion ratio in the finisher period (linear, P = 0.0422) and tended to decrease during the overall experimental period (linear, P = 0.0568). No significant effects were observed with red blood cell, white blood cell, and lymphocyte numbers in response to 2.3 or 4.6 mg of AST/kg of feed (P > 0.05). The ammonia emission from samples treated with 2.3 and 4.6 mg of AST/kg was significantly lower than that of CON (linear, P = 0.0110). Taken together, these results indicate that supplementation with AST could improve BW gain and decrease feed conversion ratio and fecal noxious gas emission of ammonia in broilers.