| Abstrakt: |
Alkalization has been used in aquaculture to improve water quality and increase production. With its intensification, there is a demand for new alkalizing agents or the same agents but with different purities and particle sizes. Therefore, this study aimed to evaluate the effect of alkalizing on the cultivation of juvenile jundiá Rhamdia quelen in a recirculation system. The juveniles were cultured to four alkalization procedures: water without alkalization, water with sodium silicate, water with sodium bicarbonate, and water with calcium carbonate. At the end of the experiment, the biomass and biomass gain of the fish grown in sodium bicarbonate water were higher than those in the environment without alkalizing. There were no differences in other performance parameters such as weight, total length, head length, weight gain, length gain, survival, Fulton, or specific growth rate. The alkalinization doubled the alkalinity and increased the water pH, with the pH of calcium carbonate having the highest value and higher stability over time. The ammonia, nitrite, and nitrate concentrations demonstrated greater nitrification efficiency in waters that received alkalinization, mainly with calcium carbonate and sodium bicarbonate. Calcium carbonate water resulted in the highest hardness due to calcium, which provided the lowest phosphate concentration. The results, associated with the ease of obtaining and the price, suggest that sodium silicate has potential to alkalize and should be further studied. Sodium bicarbonate should be utilized as an alkalizing agent in the intensive cultivation of R. quelen juveniles. [ABSTRACT FROM AUTHOR] |
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