Nitrogen balance (NB, g/kg/day) and nitrogen utilization rate (NUR, %) were studied during total parenteral nutrition on dogs at various levels of amino-nitrogen intake (N, from 0 to 1.0g/kg/ day) and non-protein calorie intake (Cal, from 0 to 120kcal/kg/day). Nitrogen source is a synthetic amino-acids mixture refering to WHO/FAO reference pattern.
A) NB showed a close corelation with N, but not with Cal under various N. A close corelation was observed between NB and Cal, when N was fixed.
B) A formula for the relation of Cal, N and NB is caluculated as:
NB=0.496N+0.003NCal+0.001Cal-0.243
C) Protein-sparing effect of glucose was maximum at 34kcal/kg/day of glucose intake without amino-nitrogen intake.
D) Nitogen utilization rate (NUR) is defined as:
NUR=N- (urinary nitrogen output-basal urinary nitrogen output) /N×100 and this can be converted as:
ifCal<34 kcal/kg/dayNUR= (0.496+0.003Cal) ×100 (%)
if Cal≥34 kcal/kg/dayNUR=0.496N-0.003N·Cal+0.001Cal-0.034/N×100
(NUR≤100%)
E) NUR is based on protein-energy interactions, and it is useful for clinical nutrition, especially for the purpose of parenteral nutrition.