Abstract:
Daphnia magna Straus, 1820, plays a significant role in food supply for fish farming; thus, it is important to formulate a medium that can increase the D. magna population. This can be achieved by supplying a direct nutrient for D. magna while supporting the growth of the phytoplankton and zooplankton population. However, at certain levels, the nutrient source addition adversely affects the culture medium. This study aims to investigate the effects of different concentrations of poultry excreta included in a culture medium enriched with chlorella powder on the biomass production of D. magna. An experiment was conducted by adding poultry excreta at four concentrations (0, 2, 4, and 6 g•L-1) to the chlorella powder culture medium. The culture was maintained for 15 days, and samples were collected on days 0, 5, 10, and 15 to analyze the D. magna population, water pH, and concentrations of ammonia, nitrate, and dissolved oxygen (DO). Furthermore, a statistical evaluation was conducted using one-way analysis of variance in a completely randomized research design. The results showed that an increase in the poultry excreta concentration reduced the water quality (P < 0.01), as indicated by the water pH and ammonia, nitrate, and DO concentrations. In addition, a longer duration of the experiment substantially improved the qualitative parameters evaluated. Similarly, the population of D. magna was significantly affected (P < 0.01) by both factors. In conclusion, the addition of poultry excreta decreased the water quality of the chlorella powder medium. The water quality improved on prolonged days; thus, the highest population of D. magna was achieved on day 15 using 2 g•L-1 of poultry excreta.
Description:
Nutrient enrichment could change the water environment. This study indicated poultry excreta levels had a significant impact on pH, oxygen conditions, and other water quality parameters that determine D. magna growth and reproduction. Higher levels of poultry excreta caused a decline in the water quality of mediums enriched with chlorella powder. This was, however, in the tolerable range for the growth and reproduction of D. magna. In addition, the quality parameters were observed to have improved after prolonged days of culture, which was followed by an increasing D. magna population, with the highest amount reported on day 15, using a poultry excreta concentration of 2 g.L-1.
