出版社：Japanese Society of Nutrition and Food Science
摘要：Growth-supporting capacity of various non-specific N sources were compared each other and with a non-essential amino acid mixture, when replaced isonitrogenously for the latter. As non-specific N sources, ammonium salts of citric (DAC), stearic (ASt), caproic (ACap), butyric (ABut), acetic (AAc), gluconic (AGlu), bicarbonic (ABc) and sulfuric (ASul) acids and glutamic acid (Glu) were individually incorporated in place of the non-essential amino acid mixture of the diet containing 80% level of amino acids patterned after Rama Rao et al . In all rats fed ammonium salts, considerable weight losses were observed during first 24 hrs., and they restored the weight gain afterwards. In experiment 1, the weight gain in DAC and AAc groups were almost the same and both of them were lower than that of the control group. This difference mainly resulted from the initial growth retardation of the formers. ASt group also lost weight but not so great and grew later at very slow rate. Liver alanine aminotransferase (GPT) and aspartate aminotransferase (GOT) activities in the rats fed ammonium salts were rather lower than those of the control group, even after the ammonium salt-fed groups acquired almost the same growth rate as the control group (at the time, one can suppose that non-essential amino acids necessary for body protein synthesis are being synthesized from nonspecific N source (NH3) at the sufficiently rapid rate); especially, in GPT activity, there being significant differences between the control and ammonium salt-fed groups. In GOT activity, the values of these 2 groups did not differ significantly. In experiment 2, AGlu group showed severe continuous diarrhea and slowly restored. The ABut group gained weight at the rate comparable to the control group with a slight growth retardation on the first day and its final body weight was higher than that of Glu group. In experiment 3, addition of ten times more of water-soluble vitamin mixture did not appear to improve ammonia utilization. When the ABc group was shifted on 15th day to ABc diet in which onethird of nitrogen of ammonium bicarbonate was replaced by glutamic acid, the growth rates of these rats were distinctly improved and when the rats receiving the ABut diet was shifted to ABc diet after 11 days, they successively grew well without any initial retardation. The ASul group showed the greatest initial and prolonged growth retardation and afterwards slowly restored. When shifted to ACap diet, however, they exhibited rapid restoration. Similarly, when ABc group was switched on the ABut die ton 13th day, their growth rate was rapidly increased, gaining upon the control group at 15th day. In adequacy of ASul and AGlu to meet non-essential amino acid requirement would be due to adverse effect of their acid radicals. Of the plasma free amino acids, the level of alanine, glycine, and serine always decreased significantly in rats fed ammonium salts.
