@misc{oai:niigata-u.repo.nii.ac.jp:00005432,
 author = {Perenlei, Ganzaya},
 month = {Mar},
 note = {We evaluated effects of dietary supplementation with astaxanthin (Ax)-rich yeast, Phaffia rhodozyma, on the broiler chicken meat quality under normal ambient temperature and high ambient temperature condition. I. Effect of dietary Ax-rich yeast, Phaffia rhodozyma, on meat quality of the broiler chicken under normal ambient temperature Experiment 1: Fourteen-day-old female Ross broilers were divided into three groups: control group: Ax-free diet, Ax 10 group: 10 mg/kg Ax diet, and Ax 20 group: 20 mg/kg Ax diet for 28 days. At 42 days old, chickens were slaughtered, and then growth performance, meat quality, and sensory attributes were analyzed. Compared with the control, a* values increased significantly just after slaughter and 48 h post-mortem storage for Ax 20 samples (P < 0.05) and for b* values in Ax 20 and Ax 10 groups (P < 0.05). Cooking loss decreased in the Ax 20 group (P < 0.05). After 120 h aging, contents of several free amino acids and total free amino acid content of Ax 20 group were significantly higher than the control (P < 0.05). In sensory evaluation, meat texture attributes improved significantly in the Ax 20 group (P < 0.01). No significant changes occurred in flavor attribute scores of meat soup from the Ax 20 group compared with the control even though most assessors preferred meat soup from the Ax 20 group. Overall, Ax-rich yeast in the diet improves broiler chicken meat quality. Experiment 2: High concentration Thirty-two-day-old female Ross broilers were divided into three groups: control group: Ax-free diet, Ax 50 group: 50 mg/kg Ax diet, and Ax 100 group: 100 mg/kg Ax diet for 10 days. At 42 days old, chickens were slaughtered, and then growth performance, meat quality and sensory attributes were analyzed. Compared with the control, Ax 100 group was significantly higher daily body weight gain, and feed intake (P < 0.05). Ax groups had significant high a* values and b* values comparing to the control either from just after slaughter or 48 h postmortem storage (P < 0.05). No significant differences were observed in results of meat shear force value analysis between all groups (P > 0.05). However, in sensory evaluation, meat texture attributes improved significantly in the Ax 50 group (P < 0.01), but not in Ax 100 group. Overall, high concentration and short period feeding of Ax-rich yeast improves broiler performance and has a tendency to improve meat quality., II. Effect of dietary Ax-rich yeast, Phaffia rhodozyma, on meat quality of the broiler chicken under heat stress condition Chronic heat stress: Thirty two-day-old female Ross broilers were divided into three groups: control group: Ax-free diet at normal temperature (24.5 ± 0.3°C), HS group: Ax-free diet at high ambient temperature (31.5 ± 1.3°C), and HS+Ax group: 20 mg/kg Ax diet at high ambient temperature (31.5 ± 1.3°C) for 10 days. Ax pre-feeding with 20 mg/kg Ax was for 18 days at normal ambient temperature. Three days ago before slaughter, blood samples were taken. At 42 days old, chickens were slaughtered, and then growth performance, meat quality, oxidative stress parameters, and sensory attributes were analyzed. However, compared to control group HS group had significantly lower daily body weight gain and feed intake, and feed efficiency (P < 0.05), but HS+Ax group dramatically inhibited the heat stress effect on feed efficiency (P > 0.05). Under chronic heat stress, drip loss increased significantly in HS group (P < 0.05) but HS+Ax group was no difference were observed comparing to control (P > 0.05). The main indicating parameter of lipid peroxidation, malondialdehyde (MDA) content was tend to increase in HS group, but HS+Ax group successfully decreased the MDA content from HS group (P < 0.05). However heat stress did not influence on breast meat color from either just after slaughter or 48 h post-mortem (P > 0.05), Ax-rich yeast can effectively increase meat a* values and b* values in 48 h post-mortem (P < 0.05) and b* values in just after slaughter muscles (P < 0.05). Furthermore, some free amino acid contents in blood plasma and breast muscle from heat stressed groups were significantly lower than control group (P < 0.05), but after 48 h postmortem storage the increase of total free amino acid content from HS+Ax group had elevated more effectively than HS group but not same as control. In addition, there were not observed any significant differences in other meat quality parameter includes water binding capacity, cooking loss, shear force value, pH and in sensory evaluation revealed also no differences some sensory attributes such as tenderness, juiciness, fibrousness, and overall preference (P > 0.05) in three groups but first bite of meat from heat stressed groups were significantly higher than the control (P < 0.05). There are totally 120 compounds in control group, 122 compounds in HS group, and 123 compounds in HS+Ax group were detected in analysis of metabolites. The results revealed that comparing to control group, downregulated compounds were 58 and 52 in HS group and HS+Ax group respectively, and upregulated compounds were 11 and 28 in HS group and HS+Ax group respectively. Comparing to HS group, 41 compounds were upregulted in HS+Ax group. The pyruvate and lactic acid which are the final products of glycolitic metabolism that is main altering metabolism during heat exposure were not altered in between all groups in chronic heat stress. However, fructose-1-6-phosphate and dihydroxyacetone phosphate was downregulated in HS group and upregulated in HS+Ax group. In TCA cycle, comparing to control group, citric acid in HS group was decreased and in HS+AX group was increased. Malic acid of HS+AX group was increased comparing to HS group. In addition, ATP was downregulated in HS group comparing to the control but in HS+Ax group it was upregulated comparing to HS group. Finally, one of the main antioxidant compounds in organism, glutathione is upregulated in HS+AX group comparing to others., Acute heat stress: Fourteen-day-old female Ross broilers were divided into two groups: control group: Axfree diet and Ax group: 20 mg/kg Ax diet for 28 days at normal ambient temperature. After feeding trial, at forty-two-day old, removed feed and chickens were exposed in two ambient temperatures: 24°C (Control group) and 34°C (HS group and HS+Ax group) for two hours before slaughter. After heat exposure, blood samples were taken and chickens were slaughtered, and then body organ weights measured and meat quality, sensory attributes were analyzed. Under acute heat stress, drip loss increased significantly in HS group (P < 0.05) but HS+Ax group was no difference were observed comparing to control (P > 0.05). However acute heat stress did not influence on breast meat color from either just after slaughter or 48 h post-mortem (P > 0.05), Ax-rich yeast can effectively increase meat b* values in just after slaughter and 48 h postmortem (P < 0.05) comparing to other groups. The ultimate pH value of HS group was significantly decreased comparing to control group (P < 0.05). In addition, some free amino acid contents in heat stressed groups were significantly lower than the control (P < 0.05). The main indicating parameter of protein oxidation, protein carbonyl content was tend to increase in HS group, but HS+Ax group significantly decreased the protein carbonyl content from HS group (P < 0.05) under acute heat exposure, but malondialdehyde (MDA) content was not differed significantly between all groups (P > 0.05) Overall, Ax-rich yeast can improve meat quality even under heat stress, especially this influence more effective in chronic heat stress condition. In conclusion, Phaffia yeast that contains high amount of astaxanthin is an effective dietary supplementation for the improvement of meat quality of broiler chicken in either normal environment or high temperature environment., 学位の種類: 博士（学術）. 報告番号: 甲第3906号. 学位記番号: 新大院博（学）甲第203号. 学位授与年月日: 平成26年3月24日, 新大院博（学）甲第203号},
 title = {Study of dietary astaxanthin rich yeast, Phaffia Rhodozyma, on meat quality of the broiler chicken},
 year = {2014}
}