COPEPODS Acartia tonsa CULTIVATED USING ISOLATED SHRIMP PROBIOTICS IN ESPIRITO SANTO STATE, BRAZIL

Copepods have great ecological importance as a nutritional source, being a link between the nutrients available in phytoplankton and the demands for the healthy development of marine organisms' larvae. For this reason, studies using copepods in aquaculture are necessary because they bioencapsulate nutrients and transmit them to the larvae, which is essential for the hatchery success. The use of probiotics in copepod cultures have already proved to help on their maintenance. The MG, a shrimp isolated gram negative probiotic, has been previously tested and proved capable of inhibiting pathogenic bacteria genus Vibrio in cultures. This study aimed to compare the effects of the MG on copepod density of three different diets: A) Microalgae Nannochloropsis oculata in proportion 100,000 cell/mL; B) S. Parkle 1g/10⁶ copepod; C) 50% S. Parkle + 50% Red Pepper 1g/10⁶ copepod. The experiment lasted 30 days and was developed in nine 50-L tanks, corresponding the three different treatments in triplicates.  The tanks were populated with Acartia tonsa copepods at initial density of ± 0.5 cop/mL. The first step of the experiment was performed without the addition of probiotic and the latter was made using the addition of probiotic MG in concentration of 10⁶ cfu mL^-1, which was daily added at volume of 1 mL/L at each tank of the tested treatments. Water quality parameters were regularly measured and presented values within aquaculture standards (temperature 23.3 ± 0.4°C, salinity 30.9 ± 0.4 psu, dissolved oxygen 5.7 ± 0.2 mg/L). Results showed significantly higher values of copepod density with the S. Parkle + Red Pepper treatment when MG probiotic was added, but no differences between the mixed diet and the S. Parkle only treatments were found when the probiotic was absent (Fig. 1a and 1b). Further studies are necessary to verify MG probiotics effectiveness in improving copepods cultivation.