Pengaruh Konsentrasi Ragi Yang Berbeda Terhadap Pertumbuhan Populasi Daphnia Sp.

Abstract

This experiment was conducted to investigate the effect of yeast Saccharomyces cerevisiae on the population growth of Daphnia. In this experiment, Daphnia were cultured in 12-l culture medium using two kinds of food, namely chicken manure or yeast. In treatment one, three days prior the innoculation of Daphnia, 2.4 g of chicken manure were introduced to 1 litre culture medium. While in treatments 2 till 4, 1g of yeast were fed to either 80 000, 40 000, or 20 000 Daphnia per day. For 1 litre culture medium, 100 Daphnia were inoculated. In treatment one, maximum population density of Daphnia were reached on day 7 of culture period (333 ind./l). On the other hand, maximum population density of Daphnia fed on yeast were reached on day 10 (1 083 - 1 603 ind./l), significantly higher than that in treatment one (p < 0.05). While among yeast’s treatments, those population density was not different. The best feed convertion ratio (0.5) was found in the treatment which 1 g yeast were fed on 80 000 Daphnia. It was also found that total body weight of Daphnia during maximum population density were almost the same among the treatments.