GROWTH OF THE FRESHWATER GREEN ALGAE (CHLORELLA SP.) AND THE ROTIFER (BRACHIONUS CALYCIFLORUS) IN VARIOUS ORGANIC MANURE EXTRACTS

摘要

The growth of the freshwater green algae, Chlorella sp. in seven organic manure extracts and in an inorganic culture medium, Bristol's Medium, was investigated for a period of 16 days of culture. The organic manures chosen were cow dung, poultry manure, goat manure, swine manure, biogas-spent slurry, vermicompost and biodynamic compost. The culture of the freshwater rotifer, Brachionus calyciflorus Pallas in these media with Chlorella sp. as its feed was also attempted for a culture period of 10 days. Changes in pH, nitrates and phosphates were analyzed ensuing algal culture. While the effects varied considerably, results indicated that all manures tested promoted growth of Chlorella sp. The maximum density of 3630 X 10~4 cells. ml~(-1) of Chlorellasp. was obtained in treatment with poultry manure. The organic manures promoted the growth of Chlorella sp., which in turn supported the growth of rotifers which showed significantly better result in the poultry manure enriched medium with 125 ind.mL~(-1), obtained on the 6th day after rotifer inoculation. Multiplication of Chlorella sp. in Bristol's Medium was gradual but exponential even up to the final day of culture indicating that the standardized medium is balanced and optimal for healthy algal growth. In comparison to Bristol's Medium, using organic manures for the enrichment of algal medium curtailed the culture period and thereby reduced the cost of maintaining the cultures till it peaks. Treatments with poultry manure and swine manure were found to be an excellent alternative to the more expensive inorganic fertilizers currently used in the culture of live feed organisms required in intensive larval rearing of aquatic animals.