Cowey C B, Cooke D J, Matty A J, Adron J W
J Nutr. 1981 Feb;111(2):336-45. doi: 10.1093/jn/111.2.336.
The effects of variation in quality and quantity of dietary protein on certain tissue enzymes in rainbow trout (Salmo gairdneri) were examined. Trout were given for 9 weeks diets containing proteins of different quality (fish-meal, casein and corn gluten) and with protein energy levels ranging from 26 to 74% of total metabolizable energy. In the first experiment, activities of a number of enzymes were monitored by only hepatic serine pyruvate transaminase (SPT) activity changed in response to the dietary treatments--increasing as protein energy level was raised. In the second experiment, opposing glycolytic an gluconeogenic enzyme activities [pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK); phosphofructokinase (PFK) and fructose diphosphatase (FDP)] were measured. Gluconeogenic enzyme activities correlated positively and significantly with dietary protein energy level; glycolytic enzymes correlated negatively and significantly with this parameter for all three proteins. There was no consistent relationship between presumed equilibrium point of opposing enzyme activities and maximum weight gain for the three proteins. It is suggested that hepatic activities of SPT, PFK, PK, FDP and PEPCK will provide useful indices of protein status in trout.
研究了日粮蛋白质质量和数量的变化对虹鳟（Salmo gairdneri）某些组织酶的影响。给虹鳟投喂含不同质量蛋白质（鱼粉、酪蛋白和玉米麸质）且蛋白质能量水平占总可代谢能量26%至74%的日粮，为期9周。在第一个实验中，监测了多种酶的活性，只有肝脏丝氨酸丙酮酸转氨酶（SPT）的活性因日粮处理而发生变化，随着蛋白质能量水平的提高而增加。在第二个实验中，测定了糖酵解和糖异生酶的相反活性[丙酮酸激酶（PK）和磷酸烯醇式丙酮酸羧激酶（PEPCK）；磷酸果糖激酶（PFK）和果糖二磷酸酶（FDP）]。糖异生酶活性与日粮蛋白质能量水平呈显著正相关；对于所有三种蛋白质，糖酵解酶与该参数呈显著负相关。三种蛋白质的相反酶活性的假定平衡点与最大体重增加之间没有一致的关系。研究表明，肝脏中SPT、PFK、PK、FDP和PEPCK的活性将为虹鳟蛋白质状态提供有用的指标。
