Consequential study on different levels of C/N ratios used in biofloc-based aquaculture system

Abstract

Biofloc technology is much highlighted these days because of its tremendous effects on aquaculture. Microbes were enriched on cheapest organic carbon source i. e., powdered banana peels and were incorporated in different aquaria rearing grass carp fingerlings under different C/N treatments (10:1, 15:1 and 20:1) and 10% water daily water exchange. The initial growth of fingerlings was recorded. The experiment was settled in triplicates for 60 days and run parallel to control group provided with commercial feed and daily water exchange. Its effect was evaluated by measuring the growth of fingerlings and water parameters of each aquarium. The average % gain in weight and length of fingerlings was obtained significantly highest (28.12 ± 0.30g and 17.29 ± 0.46cm respectively) in aquaria containing pure powdered banana peels with 10% water exchange and C/N ratio was adjusted at 20: 1 (T3) than other treatments and control. Ammonia and other water parameters were also under control in T3 than other experimental and control groups. By all counts, it was concluded that the highest C/N ratio in biofloc system had the potential to increment C. idella growth rate by reducing toxicity and could be used as fish meal substitute.

Screening of bioflocculant and cellulase-producing bacteria strains for biofloc culture systems with fiber-rich carbon source

“…In regular aquaculture systems, inorganic nitrogen concentration accumulates rapidly due to high protein feeds input and the C/N ratio is too low to support heterotrophic bacteria and the formation of biofloc ( Avnimelech, 1999 ). Therefore, an extra carbon source must be added to the water system to reach an optimal C/N ratio for the biofloc to remove residual nitrogen and recycle nutrients ( Tayyab et al, 2021 ). However, an extra carbon source also means a rise in the cost, which is not acceptable since the limited profit of common farmed fish and shrimps.…”