Cultivo intensivo de tilápia do Nilo em sistema aquapônico no modelo de bandejas flutuantes com gerador de bolhas ultrafinas de oxigênio

Abstract

The present study aimed to evaluate the superintensive production of Nile tilapia (Oreochromis niloticus) and lettuce (Lactuca sativa), curly variety (BRS Leila), and Luminosa (purple, curly type) in an experimental aquaponic system, a floating model using an ultrafine oxygen bubble generator. The research was conducted at the Aquaculture Station of the Federal University of Ceará (UFC) and lasted for 180 days. The aquaponic experimental system's aquaculture unit consisted of 6 circular tanks of 250 L each. The hydroponic component, in turn, was of the floating tray type made of high-density polystyrene installed in rectangular tanks of approximately 3.5 m². The tanks were stocked in a staggered manner every five weeks with Nile tilapia juveniles weighing between 6 and 8 g. Stocking density in each tank ranged from 100 to 160 individuals/m³. Similarly, lettuces were transplanted into the system in a staggered manner, 18 seedlings each week, to achieve an approximate density of 15 plants/m². Temperature and dissolved oxygen were measured twice a day, and pH was measured only once. Total alkalinity, total ammonia nitrogen, un-ionized ammonia, and nitrite were measured every five days. The final average weight of fish in TAF1 was 312 ± 111 g, and this was the only tank that reached the commercial cycle (6 months), achieving a final density of 26.23 kg/m³. Lettuces reached average fresh aerial part weights of 38.5 ± 2.9 g for the BRS Leila variety and 9.29 ± 6.77 g for Luminosa. However, they obtained unsatisfactory commercial results due to low growth and consequently, lower leaf weight. Water quality parameters remained within the recommended standards, except for nitrite, which reached average values of 1.31 ± 0.40 mg/L. Thus, it can be concluded that the ultrafine bubble generator was effective in maintaining oxygen levels within the optimal range for the development of Nile tilapia maintained at high densities.