1Dr. M.G.R. Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Ponneri-601 204, Tamil Nadu, India
*Corresponding Author: M. Kavitha, Dr. M.G.R. Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Ponneri-601 204, Tamil Nadu, India. Email: mkavithamurugesan1999@gmail.com
The present study was conducted to evaluate the effect of stocking density in biofloc system on the water quality, growth performance, skin pigmentation and anti-oxidant activity of Koi carp (Cyprinus carpio var. koi).
The study was performed by three different stocking densities such as 100, 150 and 200 fish/m3 in control (C) and biofloc system (B) (designated as C100 (100 fish/m3), C150 (150 fish/m3), C200 (200 fish/m3), B100 (100 fish/m3), B150 (150 fish/m3) and B200 (200 fish/m3). Koi carp juveniles (average body weight of 0.64±0.003 g) were stocked in 19 fiberglass-reinforced plastic (FRP) tanks of 500 L capacity and reared for 60 days.
The water quality parameters, viz., ammonia, nitrite and nitrate, were significantly lower in B100. At the end of the experiment, a significantly higher weight gain (4.74±0.306 g) and survival rate (91.54±0.584%) were recorded in the B100 group and lower growth performance and survival rate (64.05±0.796%) were noticed in the C200 group. Lower anti-oxidant enzyme activity of superoxide dismutase (1.53±0.022 U/mg protein) and catalase activity (1.51±0.054 U/mg protein) was observed in the C200 group. The total carotenoid content of Koi carp was significantly higher (2.57±0.039 μg/g wet weight) in the B100 treatment. Hence, the present study concluded that the biofloc system stocked with 100 fish/m3 enhanced growth performance, survival rate, water quality and coloraton in Koi carp.
Anti-oxidant enzyme, Biofloc system, Carotenoids, Ornamental fish, Stocking density
