1509
Effect of astaxanthin production by the yeast phaffiarhodozyma on growth performance, blood profiles, meat quality, and slurry noxious gas emission in broilers
A ban on specific antibiotic growth promoters in animal diets was introduced in the world from 1980s, on the basis of the ‘Precautionary Principle’. A prospective alternative to antibiotics that is currently being evaluated is yeast and its derivative products. Phaffia rhodozyma is discovered from the yeast that is strikingly different from the other pigmented yeasts in producing the carotenoid pigment astaxanthin. Astaxanthin exhibits a wide variety of biological activities, including antioxidative, anti-Helicobacter pylori, anticancer and anti-inflammatory effects in animals. A total of 432 1-d-old male broilers (Arbor Acres) were used in a 29 d 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), 1000mg (TRT 1, CON + astaxanthin production 0.1%) or 2000mg (TRT 2, CON + astaxanthin production 0.2%) per kg feed, giving an intake of approximately 0 mg, 2.3 mg, and 4.6 mg astaxanthin/kg feed, respectively. All broilers were fed maize-soybean meal-based diets that were formulated to meet or exceed the National Research Council (1994), nutrient recommendations. The broilers were weighed and feed intake were recorded on d 14 and 29 for calculating BW gain (BWG), feed intake (FI), and feed conversion ratio (FCR). At d 29, 2 birds were randomly selected from each replication (18 broilers per treatment) and slaughtered by cervical dislocation for meat quality. All data were subjected to GLM procedures of SAS (1996) as a randomized complete block design, with pen as the experimental unit. Differences among treatments were separated by Duncan's multiple range tests; P < 0.05 was considered statistically significant. The inclusion of astaxanthin linearly improved (P <0.05) body weight gain in the phase 2 (969, 989, 1024 g; 15~29 d) and during the overall experimental period (1377, 1401, 1439 g; 1~29 d).No significant linear effects were observed in the red blood cells, white blood cells, and lymphocytes in response to TRT1 and TRT2 (P >0.05). The ammonia emission from slurry obtained from broilers in the CON group was significantly higher than that of slurry obtained from broilers in the TRT1 and TRT2 (17.98 vs. 14.42, 14.32 ppm; P<0.05). Taken together, these results indicated that supplementation with astaxanthin could improve body weight gain and reduced slurry ammonia emission in broilers.
Keywords: blood profiles, broiler, noxious gas emission, Phaffia rhodozyma