Crescimento do Tambaqui (Colossoma Macropomum) (Cuvier, 1818) em sistema de recirculação de água associado ao cultivo de jambu (Acmella Oleracea L.) para redução de amônia

Abstract

The tambaqui (Colossoma macropomum) (Cuvier, 1818) is the second-largest freshwater fish in South America. The production of tambaqui is quite widespread, mainly in Brazil's northern, northeast, and Central-western regions due to its rusticity and easy adaptation to extreme water quality conditions. The duration of the production cycle, which varies from to 12 months, depends on storage density, type of feed, and water quality. Vegetable cultivation associated with fish farming makes it possible to reuse water for vegetable production and remove excess nutrients from fish production. Water quality in aquaculture is characterized by the dynamic balance of all physical, chemical, and biological variables, which enable the cultivation of aquatic organisms, minimizing environmental impacts and enhancing production. This work aimed to produce tambaqui associated with the cultivation of jambu (Acmella oleracea L.), as a tool for absorbing and reducing ammonia. Four elevated tanks were built, circular in shape, with a capacity of 20 cubic meters of water. Each tank received 500 tambaquis fry that were fed with a diet based on commercial feed with 32% protein. Two groups were used with two replications, two experimental (with association with jambu) and two controls (without association). Water quality parameters (pH, oxygen, and temperature) were monitored manually with portable devices and nitrogen compounds were monitored weekly by photometry. Fish biometrics were carried out biweekly between May and August 2022, totaling 700 records. The association with jambu was not sufficient to remove nutrients from wastewater from production systems, mainly ammonia (average of 0.65 ± 1.15 mg/l in tanks without jambu and 0.67 ± 0.63 mg/l in tanks with jambu) that did not differ between tanks (t = 0.056; df = 42; p = 0.955). Thus, the fish in the experimental group achieved a lower average weight gain of 72.7 ± 33.01 g compared to the fish in the control group, 97.85 ± 52.11 g during the experiment period (t = 7.608; df = 698; p<0.05). The creation of tambaqui in a high-density recirculation system did not present satisfactory results in relation to the production of the species when associated with jambu.