Ogawa Aki, Murayama Haruka, Hayamizu Kohsuke, Kobayashi Yukiko, Kuwahata Masashi, Kido Yasuhiro
Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University.
J Nutr Sci Vitaminol (Tokyo). 2015;61(2):123-30. doi: 10.3177/jnsv.61.123.
We demonstrated that the indicator amino acid oxidation (IAAO) method could be employed for the evaluation of quality of dietary protein by comparing the protein intakes required to meet metabolic demand in rats fed different proteins. The objective of this study was to validate a simple evaluation method for determining the quality of dietary protein using the IAAO technique. Male Sprague-Dawley rats (5-6 wk old) were fed meals composed of graded protein, using either casein, wheat gluten (WG), soy protein isolate (SPI), or egg white protein (EW), every 3 h from 09:00 to 18:00. Administration of L-[1-(13)C]phenylalanine was performed hourly from 15:00 to 18:00. The (13)CO2 level in breath CO2 was measured at 18:30. The protein intake values required to meet the metabolic demand based on the breath (13)CO2 data for the dietary casein, WG, SPI, and EW intake were 18.0, 22.2, 17.5, and 10.1 g/kg BW/d, respectively. The breath (13)CO2 concentrations corresponding to the protein intake of 7.5 g/kg BW/d for casein, WG, SPI, and EW were 9.8, 10.9, 10.3, and 8.9 (‰)/100 g BW, respectively. A significant correlation was demonstrated between the protein intake required to meet the metabolic demands and the (13)CO2 concentration in the breath for a protein intake of 7.5 g/kg BW/d (r=0.967; p<0.05). These results demonstrated that the protein intake required to meet metabolic demand could be estimated and that the quality of the dietary protein could be evaluated using the (13)CO2 concentration in the breath with a protein intake of 7.5 g/kg BW/d.
我们通过比较喂食不同蛋白质的大鼠满足代谢需求所需的蛋白质摄入量，证明了指示氨基酸氧化（IAAO）方法可用于评估膳食蛋白质质量。本研究的目的是验证一种使用IAAO技术测定膳食蛋白质质量的简单评估方法。雄性Sprague-Dawley大鼠（5-6周龄）从09:00至18:00每3小时喂食一次由分级蛋白质组成的餐食，蛋白质分别使用酪蛋白、小麦面筋（WG）、大豆分离蛋白（SPI）或蛋清蛋白（EW）。从15:00至18:00每小时给予L-[1-（13）C]苯丙氨酸。在18:30测量呼出二氧化碳中的（13）CO2水平。基于膳食酪蛋白、WG、SPI和EW摄入量的呼出（13）CO2数据，满足代谢需求所需的蛋白质摄入量分别为18.0、22.2、17.5和10.1 g/kg体重/天。酪蛋白、WG、SPI和EW蛋白质摄入量为7.5 g/kg体重/天时对应的呼出（13）CO2浓度分别为9.8、10.9、10.3和8.9（‰）/100 g体重。对于蛋白质摄入量为7.5 g/kg体重/天，满足代谢需求所需的蛋白质摄入量与呼出（13）CO2浓度之间存在显著相关性（r = 0.967；p < 0.05）。这些结果表明，可以估计满足代谢需求所需的蛋白质摄入量，并且可以使用蛋白质摄入量为7.5 g/kg体重/天时呼出的（13）CO2浓度来评估膳食蛋白质的质量。
