Studies on marsupial nutrition V. the nitrogen requirements of the euro, Macropus robustus

Abstract

The nitrogen requirements of some female euros (Macropus robustus) were determined by means of nitrogen balance feeding trials. The average minimum dietary nitrogen requirement for the maintenance of nitrogen equilibrium was 1.99 g/day or 309 mg/day per kgW*0.73. The metabolic faecal nitrogen output of the euros, determined indirectly, was estimated to be 0.27 g/100 g dry matter intake. The minimum digestible nitrogen requirements of the euros were 160 mg/day per kgW*0.73, equivalent to approximately 1 g digestible nitrogen per day. The minimum urinary nitrogen excretion of the euros, at dietary nitrogen intakes of approximately 1 g/day, was an average of 34 mg/day per kgW*0.73. Comparison of the results obtained with data for eutherian species reported in the literature indicates that the nitrogen requirements and urinary nitrogen excretion of this species is markedly less than that of eutherian species. The results are briefly discussed in relation to survival of the euro in the arid environment of the Pilbara district of Western Australia.