Gaber Ramadan*, Tasnim Issa
The purpose of this study is to test the effect of four different powdered food such as Rice (R), Wheat (W), Chickpeas/Hummus (C), Spirulina (S) and a mixture of the previous feed (R+W+C/H+S) on parthenogenesis and resting eggs (ephippia) production in Daphnia carinata (King,1853) hatched from the desert of Abu Dhabi, UAE. The study continued for 21-days at temperature 19°C ± 2°C and under 12:12 hours light/dark conditions. The analysis of the experimental results has shown that test animals fed on a mixture of food resulted in significant (p<0.05) highest production of resting eggs and lowest (p>0.05) production in parthenogenesis in comparison to other food. Meanwhile, Chickpeas/Hummus and Wheat respond similarly and produce nearly the same number (p>0.05) of ephippia and parthenogenesis eggs in comparison to the Spirulina powder. However, the least number of resting eggs and parthenogenesis (p<0.05) has produced by Daphnia carinata fed on Rice powder. Therefore, we concluded that a mixture of highly nutritive feeds strongly induces ephippia production of the Daphnia carinata and shifts its life cycle from asexual to sexual production, which may be useful in the production of Daphnia egg bank. On the other hand, Chickpeas/Hummus, Wheat, or spirulina powder can trigger the cyclic parthenogenesis and each of them can be used for the production of Daphnia carinata as live inexpensive food in aqua hatcheries. Finally, Rice powder did not support Daphnia carinata life cycle and was not a force requirement of shifting from parthenogenesis to ephippia production.