Biofloc technology (BFT) is a novel ecological farming technique used to reduce nitrogen concentration, serve as in
situ food source and remove pollutants through processes such as adding carbon to control C/N ratio in aquaculture
water. The purpose of this work is to explore the potential of the BFT in crucian carp, Carassius auratus aquaculture.
The impact of biofloc with different C/N ratios on water quality was studied including the concentrations
of ammonia nitrogen (NH4
+–N), nitrite nitrogen (NO2
−–N) and nitrate nitrogen (NO3
−–N). Then the relationship
between different C/N ratio and C. auratus growth was identified. Finally, the effects of biofloc serving as feed
supplement on the growth of C. auratus, feed utilization and antioxidant indicators were explored. The results
demonstrated that BFT could effectively reduce ammonia nitrogen, nitrite and nitrate concentration in
C. auratus ponds when C/N ratio was greater than 15:1. In addition, weight gain rate (WGR), specific growth
rate (SGR) and protein efficiency ratio (PER) of C. auratus were considerately increased when C/N = 20:1 or C/
N = 25:1. Finally, as the protein source, 10% biofloc added to the feed of C. auratus was shown to promote the
growth performance and liver antioxidation capability demonstrated by the increase of t-superoxide dismutase
(T-SOD), glutathione S-transferase (GST), catalase (CAT) and malondialdehyde (MDA). Our findings demonstrate
that BFT is effective and highly potential technology in C. auratus aquaculture from for water quality control and
producing proteinaceous feed production