Krajcovicová M, Dibák O
Vet Med (Praha). 1982 Jan;27(1):45-56.
For 14-day periods, 30-day-old and 90-day-old male rats were fed ad libitum the diets with a constant protein content (casein) of 10 p. c. and with an increased fat content (margarine) of 10, 20. 30, 40 and 50 p.c. (first experiment) and then the diets with a constant protein content (casein) of 10 p. c. and with a constant fat content (margarine) of 30 p. c. (30-day rats) and of 11 p. c. (90-day rats) and with an increasing saccharide content of 31, 36, 41, 46 and 51 p. c. (90-day rats were further fed by 56, 61 and 66 p. c.) composed of rice starch, sugar and potato starch at a ratio of 6.4 : 1.2 :1 (second experiment). Net protein utilization (NPU) was determined on the basis of body nitrogen content and protein intake. The animal liver was examined for the gluconeogenesis by measuring the specific activity of phosphoenolpyruvate carboxykinase (PEPCK). The highest NPU value can be achieved as follows: in 30-day animals by administration of the feeds containing 30 p. c. of fat, 36 p. c. of saccharides; in 90-day animals by 10 p. c. of fat and 51 p. c. of saccharides. Under the optimum nutrition conditions, both age groups utilize protein in the same way. The extreme nutrition conditions are better tolerated by the just weaned animals than by 90-day animals. The results of this biological method were also proved by the course of gluconeogenesis (activated at 40 and 50 p. c. fat content and 31 p. c. saccharide content in the diet fed to 30-day animals; in 90-day animals the activation occurred beginning 20 p. c. fat content and at 31 to 46 p. c. saccharide content). This paper contributes to the determination of optimum physiological nutrient rates by biological and biochemical methods.
在为期14天的时间段内，给30日龄和90日龄的雄性大鼠随意喂食蛋白质含量恒定（酪蛋白）为10%、脂肪含量增加（人造黄油）分别为10%、20%、30%、40%和50%的日粮（第一个实验），然后给30日龄大鼠喂食蛋白质含量恒定（酪蛋白）为10%、脂肪含量恒定（人造黄油）为30%，给90日龄大鼠喂食脂肪含量恒定（人造黄油）为11%，且糖类含量逐渐增加分别为31%、36%、41%、46%和51%（90日龄大鼠还进一步喂食糖类含量为56%、61%和66%）的日粮，这些日粮由大米淀粉、糖和马铃薯淀粉按6.4:1.2:1的比例组成（第二个实验）。根据动物体内氮含量和蛋白质摄入量测定净蛋白质利用率（NPU）。通过测量磷酸烯醇式丙酮酸羧激酶（PEPCK）的比活性来检测动物肝脏的糖异生作用。最高NPU值可通过以下方式实现：30日龄动物通过喂食脂肪含量为30%、糖类含量为36%的饲料；90日龄动物通过喂食脂肪含量为10%、糖类含量为51%的饲料。在最佳营养条件下，两个年龄组利用蛋白质的方式相同。刚断奶的动物比90日龄动物更能耐受极端营养条件。糖异生过程也证实了这种生物学方法的结果（在喂食给30日龄动物的日粮中，脂肪含量为40%和50%、糖类含量为31%时糖异生活性增强；在90日龄动物中，脂肪含量从20%开始、糖类含量为31%至46%时糖异生活性增强）。本文有助于通过生物学和生物化学方法确定最佳生理营养比率。
