Aquaponic production of sea asparagus and Pacific white shrimp using biofloc technology: Different irrigation regimes affect plant production of bioactive compounds and antioxidant capacity

This study aimed to evaluate the production of phenolic compounds, antioxidant activity and growth performance of Sarcocornia ambigua exposed to different periods of continuous irrigation in an aquaponics system with Litopenaeus vannamei reared in a biofloc technology (BFT) system, in addition to possible effects on shrimp growth performance, nitrogen recovery and water quality. Four treatments were evaluated as follows: 6, 12, 18 and 24 h of continuous irrigation per day, all set up in triplicate. Plants from the 12 and 24 h of irrigation treatments exhibited significantly higher values of phenolic compounds, 48.4 +/- 1.8 and 47.7 +/- 1.6 mg Gallic acid equivalent (GAE) 100 g(-1) FW (fresh weight), respectively, when compared with the 6 and 18 h treatments, 42.6 +/- 1.1 and 42.6 +/- 1.3 mg GAE 100 g(-1) FW, respectively (p < 0.05). Antioxidant activity also differed significantly between treatments (p < 0.05). The highest concentrations were found in treatments of 12 and 24 h of irrigation, which presented 41.3 +/- 0.6 and 42.7 +/- 0.8 mu mol Trolox Equivalent Antioxidant Capacity (TEAC) 100 g(-1) FW, respectively. For treatments of 6 and 18 h of irrigation, the concentrations were 29.9 +/- 0.8 and 31.1 +/- 1.5 mu mol TEAC 100 g(-1) FW. No significant differences between treatments were observed for plant and shrimp growth performance (p >= 0.05). There was also no significant effect of the different irrigation periods on water quality (p >= 0.05). The overall mean nitrogen recovery was 29.3% for all treatments. In conclusion, S. ambigua cultivated under 12 and 24 h of continuous irrigation exhibited higher production of bioactive compounds and antioxidant activity.