Comparative study on Growth of Leafy Vegetables Grown in a Hybrid BFT-Aquaponics using Yellow Koi Fish, Cyprinus carpio and Hydroponics

Abstract

Aquaponics is a cultivation system that combines aquaculture and agricultural hydroponics. This study investigated the productivity of leafy vegetables cultivated in the hybrid biofloc technology-aquaponics (HBFT-AP) and hydroponics (HP). Yellow koi fish (Cyprinus carpio) were fed an EP diet containing 3% MKP (monobasic potassium phosphate, KH2PO4) for 10 weeks in the HBFT-AP. Leafy vegetables of 2 cultivar (ovired lettuce, volare lettuce) were employed in the experiment and water quality [dissolved oxygen (DO, mg/L), pH, water temperature ( ), electrical conductivity (EC; s/cm), turbidity (NTU), °C μ TAN (NH3 + NH4 ) (mg/L), NO2-N (mg/L), NO3-N (mg/L) and PO4-P (mg/L)] was measured 6 times a week. Leafy vegetables in HBFT-AP using yellow koi fish fed the EP with MKP 3.0% had a productivity somewhat higher (2 kinds of cultivar) compared to those in HP, and the pH in the HBFT-AP was maintained at the range around 6.0 for 7-10 week. During the 10-week feeding trial, concentration of NO2-N was kept low in variability while total TAN, NO3-N and PO4-P levels increased with time in HBFT-AP. Higher values in hematocrit (PCV, %), hemoglobin (Hb, g/dL) and inorganic phosphorus (mg/dL) were found (P<0.05) in fish at the end of the experiment compared to the fish at the beginning of the experiment (initial fish: 27.45%, 12.19 g/dL and 6.39 mg/dL; final fish: 36.26%, 14.52 g/dL and 11.21 mg/dL).