Inclusion of organic and inorganic extractive species improves growth, survival and physiological responses of GIFT fish reared in freshwater integrated multi-trophic aquaculture system

Abstract

The investigation was conducted for 60 days period to evaluate the production performance of GIFT fish in the Freshwater Integrated Multi-Trophic Aquaculture system (FIMTA). GIFT was combined with floating weed Lemna minor as an inorganic extractive and freshwater bivalve Lamellidens marginalis as an organic extractive in 1000l Fiberglass Reinforced Plastic tanks. The treatments included GIFT alone as the control (C) treatment, GIFT and L. minor (T1), GIFT and L. marginalis (T2) and GIFT, L. minor and L. marginalis (T3) (FIMTA). GIFT fry were stocked at 40/m3, L. marginalis was stocked at 250 g/m3 respectively and L. minor was seeded 25% of the tank surface area. Growth, survival, water quality and physiological responses of GIFT were assessed in different treatments. A floating pelleted feed (30% crude protein) was supplied to GIFT at a rate of 4% body weight. Among growth variables, growth, biomass, survival, daily weight gain (DWG) and daily growth index (DGI) were found to be highest in T3. Significant differences (p < 0.05) were observed between different treatments in pH, electrical conductivity, DO, total hardness, and TDS among various water quality parameters. Transparency was found to be relatively high in T3. The control group had higher levels of inorganic nutrients such as ammonia, nitrite, nitrate, phosphate and potassium, whereas T3 and T1 had lower levels, respectively. Calcium and total hardness were found to be reduced in T2 and T3. Among physiological responses, haematological parameters like RBCs, WBCs and haemoglobin were reported to be higher in T1, T3 and T2 respectively. Control had elevated amounts of superoxide dismutase (SOD) enzyme activity, whereas T3 had the lowest levels. Significantly reduced catalase (CAT) activity was detected in T3. Acute stress parameters like cortisol and glucose levels were found to decrease in the T3. Immunity-based Nitro-blue tetrazolium (NBT) and Myeloperoxidase (MPO) activity were lower in control, while highest in FIMTA system. Serum concentrations for total protein, albumin, and globulin were reported to be elevated in T3. AST and ALT levels, which are measures of liver function, were better in the T3 than in other treatments. The overall results indicate that FIMTA of GIFT with L. minor and L. marginalis can improve water quality and physiological responses, raising survival and yield.