Halophyte and bivalve-based integrated multi-trophic aquaculture (IMTA): effect on growth, water quality, digestive and antioxidant enzymes of Penaeus monodon and Chanos chanos reared in brackishwater ponds.

The present study investigated the integration of halophytes in IMTA as extractive species on the water quality, growth, digestive, and antioxidant activity of Penaeus monodon and Chanos chanos in earthen ponds for 120 days. The experimental setup consisted of three treatments: control (C) and two different halophyte-based IMTA treatments, T1 and T2, randomly assigned to nine earthen ponds (200 m−2) in three replicates. All treatments were uniformly stocked with P. monodon (Post larve 12) and C. chanos (13.4–14 g); in addition to these, T1 had Avicennia officinalis and Meretrix casta and T2 had Bruguiera gymnorhiza and Meretrix casta as extractive species. The average final body weights of P. monodon (32.01 ± 0.27 g) and C. chanos (94.18 ± 1 g) were found in the A. officinalis based IMTA treatment (T1). T1 also had shown a significant (p < 0.05) reductions in total ammonia nitrogen (97.5%), nitrite-N (NO2-N) (56.1%), and nitrate (NO3-N) (41.1%). Biological oxygen demand (BOD) (3.17 ± 0.15 ppm), chemical oxygen demand (COD) (25 ± 0.58 mg L−1), and total suspended solids (TSS) (20 ± 1.15 mg L−1) were significantly (P < 0.05) lower in T1. Digestive enzyme activity in shrimp and fish was higher in T1 and T2. A decrease in catalase and SOD enzyme activities was observed in T1 and T2. Halophyte-and M. casta-based IMTA treatments (T1 and T2) showed a decrease in the total Vibrio and heterotrophic bacterial counts. The present research findings elucidated that halophytes as extractive species can be beneficial in brackishwater IMTA systems to maintain water quality, improve the health status of cultivated organisms, and increase aquaculture productivity. [ABSTRACT FROM AUTHOR]