author(s)
Castro MJ, Castro MG, Rivera RAO, Flores GAF and Castro CAE

abstract
This study was focused to know the population density growth of Simocephalus vetulus fed with four experimental diets using chlorophytes and diatoms during 60 days of culture, in 12 L plastic beakers filled with 10 L of water, with an initial density of 20 organisms. Diets were: 1) Chlorophyte 100%, 2) Diatoms 100%; 3) Chlorophytes 25% and Diatoms 75%, and 4) Chlorophytes 75% and Diatoms 25%. Organisms fed with Chlorophytes 75% and Diatoms 25% obtained the highest density with 6,041±18 org 10L^-1, while the lowest density value was for Chlorophytes 100% with 1,109±10 org 10 L^-1. Highest value of Ro was obtained with diet Chlorophytes 75% and Diatoms 25% with 1,287 org female^-1, Tc = 16.15 days, and r = 0.43. Lowest reproductive potential values were shown in Chlorophyte diet with 148 org female^-1), Tc = 21.98 days, and r = 0.23. ANOVA and Tukey test shown significant differences (P<0.05) between all treatments. For S. vetulus cladoceran specie, it is necessary to make cultures using mixed diets with Diatoms and Chlorophytes microalgae to obtain better density results in laboratory conditions.