Pantnagar Journal of Research

Abstract

The effect of selected carbon sources (i.e., Mollasses, Potato & Wheat flour) on biofloc development and fish growth was evaluated during November 2019 to February, 2020 using four treatments in three replicates viz., T¬₀ (Control), T₁ (Molasses as carbon source), T₂ (Potato as carbon source) and T₃ (Wheat flour as carbon source). Healthy and disease-free fish fingerlings of Cyprinus carpio haematopterus (1.633±0.177 g), Labeo catla (10.725±0.177 g), Ctenopharyngodon idella (4.550±0.177 g), Cirrhinus mrigala (1.925±0.177 g), Labeo rohita (4.950±0.177 g) and Hypophthalmichthys molitrix (11.567±0.177 g) were stocked in circular FRP tanks (dia. 2.5 m, water volume 4.0 m³) @ 200 fingerlings/tank (50 fingerlings/ m³) in the ratio of 20:15:10:15:20:20, respectively. Selected water quality parameters (water temperature, electrical conductivity, total dissolved solids, dissolved oxygen, free carbon dioxide, pH, total alkalinity, ammonia and nitrate) were studied weekly. During the experimental period the range of various physico-chemical parameters was demarked from all the tanks viz., temperature (13.3±0.2 to 25.4±0.25^°C), electrical conductivity (302.03±0.16 to 462.69±6.71 µS cm^-1), total dissolved solids (171.17±0.450 to 243.48±11.16 mg L^-1), dissolved oxygen (3.95±1.13 to 10.05±0.33 mg L^-1), free carbon dioxide (0 to 2.96±1.84 mg L^-1), pH (2.527±0.047 to 8.84±0.300 mg L^-1), total alkalinity (50±2 to 193.333±4.16 mg L^-1), ammonia (0.015± 0.013 to 0.18±0.277 mg L ^-1) and nitrate (0.733±0.208 to 3.8±0.6 mg L^-1). The recorded net fish weight gain in different treatments were 15.95 g (T₁), 13.64 g (T₂), 18.04 g (T₃ ) and 16.02 g (T₀). The highest SGR for Cirrhinus mrigala (2.14 % d^-1), Cyprinus carpio haematopterus (2.13 % d^-1), Labeo catla (1.41 % d^-1), Ctenopharyngodon idella (2.09 % d^-1) and Hypophthalmychthys molitrix (1.10 % d^-1) were in T₃ group while Labeo rohita performed best in T₁ group with highest SGR of 1.31 % d^-1. The results clearly indicated that the wheat flour is a good option for carbon supplementation in biofloc systems, which needs to be further tested in natural pond fish culture systems.