In aquatic ecosystem, zooplankton represents the channel of transmission of energy and organic matter from primary producers to top consumers. As primary producers, microalgae are the main food source for zooplankton which contributes ultimately in providing nutrients and energy for the aquatic food chain. Rapid reproduction and highly nutritious contents of zooplankton enable them to become effective live feed for the aquaculture industry. In order to become effective live feed, they should be fed using high quality nutritional food source, such as beneficial phytoplankton species. Therefore, the objective of this study is to determine the effect of different microalgae including cyanobacteria on reproductive capacity and population growth of cladoceran zooplankton, Moina micrura.
Moina micrura was treated with six phytoplankton treatments (Diet 1= Chlorella sp., Diet 2=Chlamydomonas sp., Diet 3=Cyclotella sp., Diet 4=Pavlova sp., Diet 5=Microcystis sp. and Diet 6= Planktothrix sp.). Experiments on reproductive capacity (parameters including longevity, age at first reproduction, total clutch, total egg and total offsprings) of each individual neonate were observed for fifteen replicates for each treatment. The population growth study was conducted in triplicates for each treatment. The culture conditions were maintained at room temperature 27.0 ± 2.0° C under a photoperiod of 12 h light: 12 h dark.
Diets 1 to 4 were beneficial for M. micrura because all of them promoted significantly faster maturity, higher number of eggs, offspring and clutch, longer longevity and higher population density (P<0.05) compared to Diet 5 and Diet 6 (Table 1 and Figure 1). The negative effects of cyanobacterial diets (Diet 5 and Diet 6) might be due to their toxin and poor nutritional contents. This study suggested that the highly nutritious microalgae diets can significantly increase the survival, reproductive, and growth performance of M. micrura which in turn can contribute to the refinement of quality live feed production for the aquaculture industry. On the other hand, cyanobacteria, which can be dominant in eutrophic waters, would have negative impacts on zooplankton growth and production