Translation Series No.997

To find the conditions that would guarantee maximum production
of rotifer Brachionus calyciflorus cultures, which is one of the
most eurytopic species, a series of experiments was carried out
to determine the intensity of alimentation, respiration and the
rate of growth of rotifers at different concentrations of algae
which served as their food.
The experiments in determination of intensity of
alimentation were carried out in test tubes of various sizes
(45, 9, 1 ml) at a density of 20 rotifers per 1 ml ab a
temperature of 19-20 0 C. The duration of the experiment was
20-24 hours. Each experiment was doubly repeated. A total
of 75 experiments were carried out.
When computing the amount of food devoured on a
basis of a reducbion in the amount of algae during the
experiment, account was taken of the increase in algae and
the consumption of it by the rotifers. If the amount of
algae in the control sample at the end of the experiment had
increased insignificantly, then it was assumed that the
increase in algae and the consumption by rotifers was linear.
Increase in the control sample was expressed as (C k- C 0 ),
where Ck- concentration of algae in the control sample at the
end of the experiment; C o - initial concentration of algae
in the experiment and in the control sample. The increase in
the experiment is evidently less by as many times as the
average number of cells in the control sample, therefore,
it equals:
(Ch
Q) . (Co .1 " et)
(: 0
where: C. - concentration of algae in the experiment after
time t .
From this:
2.
(C0 + Ct)
b [ (c - C - I - (Ch - - •
2C 0 (C 1, — C 1 )
'
where: b- number of cells devoured per unit of time;
t- duration of experiment. L22_
In a few cases, when the algae concentration in
the control sample at the end of the experiment had increased
greatly in comparison with the initial amount, the growth of
algae was considered to be exponential: . k ---c o ce, , where
e- base for natural logarithms, a- constant for rate of
growth of algae. Allowing that the rate of consumption during
the experiment did not depend on the concentration of algae,
the change in algae concentration during the experiment can be