Qualidade da água e desenvolvimento inicial de recria em tilápias (Orechromisniloticus) cultivadas em sisteminha EMBRAPA-UFU-Fapemig, com renovação parcial da água do tanque de cultivo, nas condições climáticas do Semiárido piauiense

Abstract

The Embrapa - UFU - FAPEMIG System is a model for fish farming that uses intensive aquaculture in small tanks constructed with masonry or alternative materials, aimed at ensuring food security for families through the use of resources available in their surroundings with low investment. It is suitable for small spaces (from 100 m²), in peri urban and/or rural areas, constituting a scaled solution. The project was submitted to and approved by the Animal Ethics Committee of the Federal Institute of Piauí (CEUA/IFPI), with a protocol number adjusted weekly according to the growth stage of the fish, using different types of feed. The water recirculation system included a sedimentation tank, biofilter, and aeration to control water quality. Partial water renewal was used for agricultural crop management. Water quality parameters were monitored, and biometric analysis and statistical analysis of the fish were carried out to assess performance and cultivation conditions in the semi-arid region. Water quality parameters, such as dissolved oxygen, pH, and conductivity, remained within the suitable limits for tilapia farming, except for temperature, which showed a decrease due to the onset of the rainy season. Water transparency was maintained, despite the presence of microalgae in the final weeks. Total and toxic ammonia levels were controlled by the biofilter, and no nitrite was detected. Total hardness and alkalinity decreased with rainfall. Biometric data indicated proper growth of the fish, with an average final weight of 55.3g and efficient feed conversion (0.98). The tilapia farming in the Embrapa-UFU-FAPEMIG System proved to be efficient, ensuring good water quality and proper fish development up to the initial rearing phase.