Nutritional effects of intravenous infusion solutions on normal rats: effects of increased energy level and deletion of acidic amino acids.

Nutritional effects of intravenous infusion of an amino acid (AA) mixture enriched with the branched chain AA were previously evaluated at a daily level of 45 kcal and 200 mg N using male rats weighing approximately 200 g. The present study was conducted with male rats weighing approximately 200 g to evaluate the nutritional effects of 1) an AA infusion solution at further increased energy level, and 2) an AA solution devoid of aspartic and glutamic acids. By increasing daily energy input from 45 to 55 kcal/rat, the body weight gain of rat was markedly increased and more positive nitrogen balance was observed. Glucose, albumin, and free AA levels were unchanged in plasma of rats after the infusion period, while plasma urea level was somewhat lowered. Organ weights and liver lipid content were also unchanged. The administration of an infusion solution devoid of aspartic and glutamic acids resulted in little alteration in the amounts of urinary excretion and plasma levels of these acidic AA. Furthermore, other parameters measured showed no significant effect of the deletion of the AA. These results indicate that no advantage is expected in the use of acidic AA for parenteral nutrition.