Lettuce (Lactuca sativa) production with effluent from a tilapia culture maintained in BFT and low salinity

Abstract

This experiment evaluated the effect of salinity on growth performance of different lettuce cultivars (Lactuca sativa) in an aquaponics system with biofloc technology. The device contained two independent systems with two different salinities: 0 ppt and 3 ppt. Juvenile tilapia (Oreochromis niloticus) 6.1 kg m^-3 and three varieties of lettuce: red leaf and smooth and crisp 20 plants m^-2 were stored in the floating system. All fish performance parameters showed no statistical differences, except for the hepatosomatic index, higher in 3 ppt (4.35%) versus (3.07%) in 0 ppt (P<0.05). In general, the productivity of lettuce cultivars was superior in fresh water (1.21 kg m^-2) compared to brackish water (0.8 kg m^-2) (P<0.05). In most phyto-technical parameters evaluated, the purple variety had better performance than the smooth and crisped varieties. In relation to plant quality index (IQP), purple variety in brackish water had the best score, presenting leafs with higher integrity and intense coloration. The results demonstrated that it is possible to integrate the production of red leaf variety in aquaponics systems with the technology of bioflocs in low salinity.