Evaluation of microalgae concentrate produced by flocculation as a safe food for Brachionus plicatilis rotifers and shrimp larvae Litopenaeus vannamei
Microalgae are of great importance in aquaculture, as they are foods of high nutritional value. This work evaluated the use of 2 organic flocculants, Tanfloc and Flopam in obtaining microalgae concentrate, Chaetoceros muelleri and Nannochloropsis oceanica as a food source for Litopenaeus vannamei larvae in the Protozoea I and Brachionus plicatilis, assessing survival. Three experiments were carried out with the addition of microalgae. In experiment 1, the shrimp were subjected to 4 treatments, with different concentrations of flocculants added directly to the water (2.5, 5, 10 and 20 mg / L) and a control treatment without the addition of flocculant. In the experiment, there was no significant difference in any water quality parameter. There was mortality in treatments using both flocculants at concentrations of 5, 10 and 20 mg / l. In experiment 2 the prawns were submitted to 3 treatments, control treatment with microalgae C. muellericentrifuged, treatment with the use of flocculated biomass with Tanfloc and treatment with the use of flocculated biomass with Flopam. No significant difference was observed in any water quality parameter. There was total mortality in treatments using the two flocculants. In experiment 3, the rotifers were subjected to 4 treatments, being a control with the microalga N. oceanica centrifuged, a fasting treatment, one with flocculated biomass with Tanfloc and one with floculated biomass with Flopam. There were significant differences for ammonia, nitrite, density of rotifers and percentage of ovate females. In the parameter ammonia and nitrite, peaks were observed in the control treatment, due to the high growth, thus having a greater excretion of nitrogenates. With the control treatment showing the best results of population density and percentage of ovate females. Based on these results, it is concluded that the flocculate concentrate is not recommended as food in shrimp larviculture or as food for the rotifer.