Excretion Rates of Nitrogen by the Rotifer Brachionus plicatilis
1987 Volume 35 Issue 2 Pages 119-124
Details
1987 Volume 35 Issue 2 Pages 119-124
Rates of nitrogenous excretion in the forms of ammonium, urea, and other nitrogen compound (amino acids) were determined for the rotifer at different concentrations of marine Chlorella.
The gross excretion rate of nutrients (ammonium and urea) by the rotifer was estimated by summing the apparent excretion rate and nutrients removed by marine Chlorella. Nutrient uptake rate of the Chlorella was determined by using the Michaelis-Menten kinetic.
The rate of total nitrogenous excretion by the rotifer increases with food concentration to a maximum level. This excretion rate may be expressed as ETot=Eb+Ef, and Ef=Efm [1-exp (-kf⋅ C/R) ] in which Eb=a basal rate due to endogenous excretion (μg/animal day) ; Ef=a rate due to release from digested and metabolized material (μg/animal day) ; Efm=the maximum rate of Ef; kf=a constant rate of change of excretionwith the Chlorella concentration; C/R=the mean concentration of cells per the meandensity of rotifer.
Data from the retifer in this experiments could be expressed with the equations as ETot=0.7×10-2+3.7×10-2 [1-exp (-0.46×10-5× C/R) ] at 20°C, and ETot=0.9×10-2+5.1×10-2 [1-exp (-0.46×10-5× C/R) ] at 30°C.
