Comparação de duas densidades de estocagem de tilápia do Nilo (Oreochromis niloticus) em sistema aquapônico com quatro variedades de alface

Abstract

The objective of this work was to compare two storage densities (1.5 kg m⁻³ and 3.0 kg m⁻³) of Nile tilapia (Oreochromis niloticus) associated with four lettuce varieties (Lactuca sativa L.) being they: Regina of Summer, Simpsom Black Seed, White Roman Paris and Crespa Palmas in aquaponic system in the Station of Aquaculture Prof. Dr. Raimundo Saraiva da Costa during the 45-day period, in which 3 replicates of the storage densities tested were evaluated and 30 seeds of each lettuce variety were placed per system. Treatment 1 (1.5 kg m⁻³) was initially populated totaling a biomass of 9.0 kg, while treatment 2 (3.0 kg m⁻³) had 18.2 kg. Daily pH, dissolved oxygen and temperature were measured, while other parameters such as alkalinity, ammonia and nitrite were evaluated on a weekly basis. The final weight of fish in treatment 1 averaged 309.089 ± 28.410 g fish⁻¹ and in treatment 2, 279.425 ± 11.831 g fish⁻¹. Lettuces did not obtain satisfactory commercial results except for the Simpsom Black Seed variety in treatment 1, which obtained the best growth values, with a mean productivity of 186.883 g m⁻², head diameter 26.150 ± 3.960 cm and leaf length 13.400 ± 1.200 cm. Among the parameters of water quality, the dissolved oxygen of the two treatments was adequate, but presenting a statistical difference (p≤0.05), as well as all other parameters. The evaluated zootechnical parameters practically did not differ statistically (p> 0.05) with the exception of the feed conversion factor and allometric condition factor.