Glutamine is the most abundant amino acid in milk, and lactation is associated with increased glutamine utilization both for milk synthesis and as a fuel for the enlarged small intestine. A number of recent studies ha...Glutamine is the most abundant amino acid in milk, and lactation is associated with increased glutamine utilization both for milk synthesis and as a fuel for the enlarged small intestine. A number of recent studies have indicated that lactation is accompanied by a mild catabolic state in which skeletal muscle proteins are degraded to provide amino acids that are used to synthesize additional glutamine. In this study we tested the hypothesis that supplemental L-glutamine or the commercially available glutamine supplement Aminogut （2.5% by weight mixed into daily feed） provided to gilts from 30 days prior to parturition until 21 days post-parturition would prevent a decrease in skeletal muscle glutamine while increasing the glutamine content of the milk. Muscle glutamine content decreased （P 〈 0.05） in control animals during lactation but this was prevented by supplementation with either L-glutamine or Aminogut. In this study, neither lactation nor supplementation had any effect on plasma glutamine or glutamate content. Free glutamine, and the total glutamine plus glutamate concentrations in milk from the control and the Aminogut group rose （P 〈 0.05） during the first 7 days of lactation, with milk concentrations in the L-glutamine supplemented group showing a similar trend （P = 0.053）. Milk glutamate remained constant between day 7 and 21 of lactation in the control and L-glutamine supplemented groups, but by day 21 of lactation the free glutamine, glutamate, and glutamine plus glutamate concentrations in milk from Aminogut-treated gilts were higher than those of control gilts. Thus dietary glutamine supplementation can alleviate the fall in intramuscular glutamine content during lactation in gilts, and may alleviate some of the catabolic effects of lactation. Furthermore, the increased milk glutamine content in the supplemented gilts may provide optimum nutrition for piglet development.展开更多
Glutamine and glutamate are not considered essential amino acids but they play important roles in maintaining growth and health in both neonates and adults. Although glutamine and glutamate are highly abundant in most...Glutamine and glutamate are not considered essential amino acids but they play important roles in maintaining growth and health in both neonates and adults. Although glutamine and glutamate are highly abundant in most feedstuffs there is increasing evidence that they may be limiting during pregnancy, lactation and neonatal growth, particularly when relatively low protein diets are fed. Supplementation of diets with glutamine, glutamate or both at 0.5 to 1.0% to both suckling and recently weaned piglets improves intestinal and immune function and results in better growth. In addition such supplementation to the sow prevents some of the loss of lean body mass during lactation, and increases milk glutamine content. However, a number of important questions related to physiological condition,species under study and the form and amount of the supplements need to be addressed before the full benefits of glutamine and glutamate supplementation in domestic animal production can be realized.展开更多
汉斯·阿道夫·克雷布斯（Hans Adolf Krebs）（1953年诺贝尔奖获得者）为谷氨酰胺在临床营养的应用开创了新的舞台,本文对其在谷氨酰胺代谢方面的研究贡献进行阐述.本文两位作者在谷氨酰胺代谢方面也进行了多年研究,并在克雷...汉斯·阿道夫·克雷布斯（Hans Adolf Krebs）（1953年诺贝尔奖获得者）为谷氨酰胺在临床营养的应用开创了新的舞台,本文对其在谷氨酰胺代谢方面的研究贡献进行阐述.本文两位作者在谷氨酰胺代谢方面也进行了多年研究,并在克雷布斯教授指导下完成了牛津大学哲学博士学位训练.1923年,克雷布斯成为一名医生,并参加了3年的临床培训.1926年,他进入奥托·沃伯格（Otto Warburg）（1931年诺贝尔奖获得者）实验室开始了他的科研生涯.克雷布斯利用沃伯格测压法等技术对肿瘤相关蛋白降解代谢进行相关研究.1931年克雷布斯开始研究合成反应,并于1932年描述了第一个生化循环路径——尿素循环.1933年克雷布斯移居英格兰,同时将研究集中于氨基酸代谢,从分子水平阐述动物组织谷氨酰胺代谢,为临床营养应用谷氨酰胺奠定了基础.其研究以谷氨酰胺异常代谢为起点,之后,他将注意力转移到谷氨酰胺水解产生谷氨酸与氨的过程.克雷布斯于1935年发表文章阐述谷氨酰胺代谢的重要酶学研究,如谷氨酰胺的合成是一个吸热反应,需要能量供应.同时,他鉴定了谷氨酰胺酶对谷氨酰胺的水解作用,且不同组织含有不同亚型的谷氨酰胺酶.此外,他还阐述了分布最广泛的“脑型”谷氨酰胺酶的基本调节特点,证实其受谷氨酸负反馈调节,而“肝型”谷氨酰胺酶则不受此调节.1935年的文章发表后,克雷布斯仍致力于应用当时最先进的技术方法对氨基酸代谢进行各种研究,并将注意力转移到谷氨酰胺其他代谢过程.20世纪70年代,克雷布斯与其同事合作,发现谷氨酰胺是肝糖异生与尿素合成的底物,肾糖异生与氨的产物,且是小肠上皮细胞的代谢底物.此外,克雷布斯团队还发现骨骼肌可以释放大量谷氨酰胺,同时阐述了肝在谷氨酰胺利用与合成中的作用.直到克雷布斯去世（1981年）前,他仍致力于支链氨基酸与谷氨酰胺代谢关系的研究.在过去的20-30年大量研究中,威尔莫（Wilmor）与弗斯特（Furst）团队最先发表文章描述谷氨酰胺在临床肠外营养中的补充应用.关于在临床营养中补充谷氨酰胺,已发表了大量研究文章与综述,一些研究展示了其非常显著的有效性,更多的研究显示它具有一定效果,也有研究发现它在某些人群中会产生不良反应.总而言之,谷氨酰胺在临床营养的运用在很大程度上应归功于克雷布斯与他的同事和实习生所做的大量工作.描述与克雷布斯工作“个人追忆”的本文作者,非常感谢作为谷氨酰胺之父的汉斯·阿道夫·克雷布斯教授对他们科学研究技术的培养.展开更多
基金Ajinomoto do Brasil/FUNCAP-Fundaao Cearense de Apoio ao Desenvolvimento Científico/CNPq-Conselho Nacional de Desenvolvimento Científico e Tecnológico
文摘Glutamine is the most abundant amino acid in milk, and lactation is associated with increased glutamine utilization both for milk synthesis and as a fuel for the enlarged small intestine. A number of recent studies have indicated that lactation is accompanied by a mild catabolic state in which skeletal muscle proteins are degraded to provide amino acids that are used to synthesize additional glutamine. In this study we tested the hypothesis that supplemental L-glutamine or the commercially available glutamine supplement Aminogut （2.5% by weight mixed into daily feed） provided to gilts from 30 days prior to parturition until 21 days post-parturition would prevent a decrease in skeletal muscle glutamine while increasing the glutamine content of the milk. Muscle glutamine content decreased （P 〈 0.05） in control animals during lactation but this was prevented by supplementation with either L-glutamine or Aminogut. In this study, neither lactation nor supplementation had any effect on plasma glutamine or glutamate content. Free glutamine, and the total glutamine plus glutamate concentrations in milk from the control and the Aminogut group rose （P 〈 0.05） during the first 7 days of lactation, with milk concentrations in the L-glutamine supplemented group showing a similar trend （P = 0.053）. Milk glutamate remained constant between day 7 and 21 of lactation in the control and L-glutamine supplemented groups, but by day 21 of lactation the free glutamine, glutamate, and glutamine plus glutamate concentrations in milk from Aminogut-treated gilts were higher than those of control gilts. Thus dietary glutamine supplementation can alleviate the fall in intramuscular glutamine content during lactation in gilts, and may alleviate some of the catabolic effects of lactation. Furthermore, the increased milk glutamine content in the supplemented gilts may provide optimum nutrition for piglet development.
文摘Glutamine and glutamate are not considered essential amino acids but they play important roles in maintaining growth and health in both neonates and adults. Although glutamine and glutamate are highly abundant in most feedstuffs there is increasing evidence that they may be limiting during pregnancy, lactation and neonatal growth, particularly when relatively low protein diets are fed. Supplementation of diets with glutamine, glutamate or both at 0.5 to 1.0% to both suckling and recently weaned piglets improves intestinal and immune function and results in better growth. In addition such supplementation to the sow prevents some of the loss of lean body mass during lactation, and increases milk glutamine content. However, a number of important questions related to physiological condition,species under study and the form and amount of the supplements need to be addressed before the full benefits of glutamine and glutamate supplementation in domestic animal production can be realized.
文摘汉斯·阿道夫·克雷布斯（Hans Adolf Krebs）（1953年诺贝尔奖获得者）为谷氨酰胺在临床营养的应用开创了新的舞台,本文对其在谷氨酰胺代谢方面的研究贡献进行阐述.本文两位作者在谷氨酰胺代谢方面也进行了多年研究,并在克雷布斯教授指导下完成了牛津大学哲学博士学位训练.1923年,克雷布斯成为一名医生,并参加了3年的临床培训.1926年,他进入奥托·沃伯格（Otto Warburg）（1931年诺贝尔奖获得者）实验室开始了他的科研生涯.克雷布斯利用沃伯格测压法等技术对肿瘤相关蛋白降解代谢进行相关研究.1931年克雷布斯开始研究合成反应,并于1932年描述了第一个生化循环路径——尿素循环.1933年克雷布斯移居英格兰,同时将研究集中于氨基酸代谢,从分子水平阐述动物组织谷氨酰胺代谢,为临床营养应用谷氨酰胺奠定了基础.其研究以谷氨酰胺异常代谢为起点,之后,他将注意力转移到谷氨酰胺水解产生谷氨酸与氨的过程.克雷布斯于1935年发表文章阐述谷氨酰胺代谢的重要酶学研究,如谷氨酰胺的合成是一个吸热反应,需要能量供应.同时,他鉴定了谷氨酰胺酶对谷氨酰胺的水解作用,且不同组织含有不同亚型的谷氨酰胺酶.此外,他还阐述了分布最广泛的“脑型”谷氨酰胺酶的基本调节特点,证实其受谷氨酸负反馈调节,而“肝型”谷氨酰胺酶则不受此调节.1935年的文章发表后,克雷布斯仍致力于应用当时最先进的技术方法对氨基酸代谢进行各种研究,并将注意力转移到谷氨酰胺其他代谢过程.20世纪70年代,克雷布斯与其同事合作,发现谷氨酰胺是肝糖异生与尿素合成的底物,肾糖异生与氨的产物,且是小肠上皮细胞的代谢底物.此外,克雷布斯团队还发现骨骼肌可以释放大量谷氨酰胺,同时阐述了肝在谷氨酰胺利用与合成中的作用.直到克雷布斯去世（1981年）前,他仍致力于支链氨基酸与谷氨酰胺代谢关系的研究.在过去的20-30年大量研究中,威尔莫（Wilmor）与弗斯特（Furst）团队最先发表文章描述谷氨酰胺在临床肠外营养中的补充应用.关于在临床营养中补充谷氨酰胺,已发表了大量研究文章与综述,一些研究展示了其非常显著的有效性,更多的研究显示它具有一定效果,也有研究发现它在某些人群中会产生不良反应.总而言之,谷氨酰胺在临床营养的运用在很大程度上应归功于克雷布斯与他的同事和实习生所做的大量工作.描述与克雷布斯工作“个人追忆”的本文作者,非常感谢作为谷氨酰胺之父的汉斯·阿道夫·克雷布斯教授对他们科学研究技术的培养.
