Translation Series No.997

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, • • DEPARTMENT OF THE SECRETARY OF STATE -TRANSLATION BUREAU FOREIGN LANGUAGES DIVISION -4.;/ ./7‘e•-o , C/ /- SECRÉTARIAT D'ÉTAT BUREAU DES TRADUCTIONS DIVISION DES LANGUES ÉTRANGÈRES • YOUR NO. DEPARTMENT DIVISION/BRANCH CITY . • VOTRE N ° MINISTRE DIVISION/DIRECTION VILLE . 769-18-14 Fisheries Research Editorial Dartmouth, N.S. • Board OUR NO. LANGUAGE TRANSLATOR (INITIALS) DATE NOTRE N° LANGUE TRADUCTEUR (INITIALES) 0478 Russian JTM 28 February 1968 UTILIZATION OF FOOD FOR GROWTH AND CONDITIONS FOR MAXIMUM PRODUCTION OF THE ROTIFER BRACHIONUS CALYCIFLORUS PALLAS. G.A. Galkovskaya (Belorussian State University, Minsk). Quantitative studies of trophic interrelationships among aqueous animals at the oresent time is of great interest for explaining the loss of the production process in water reservoirs and for developing the most rational and economic methods of cultivating aqueous organlens as food for - artificially-reared fish and for other purposes. The most poorly studied in this sense are the rotifers, they frequently make up a significant part of the biomass of the zooplankton in reservoirs, the features of their biology (short life cycle, high reproductivity, etc.) make them an interesting item for large scale propbgation as a food for fish. This article discusses material on utilization of food bY the rotifer Brachionus calyciflorus Pallas with various concentrations of algae Scenedesmus obligmus and . conditions for maximum production of the rotifer when it uses this food. SOS-200-10-s
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
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Translation Series No.997

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