Effects of calcium carbonate nanoparticles on water quality, growth and metabolic activity of Macrobrachium nipponense in zero-water exchange biofloc system

The purpose of the present research was to investigate the effects of adding calcium carbonate nanoparticles to the Macrobrachium nipponense diet in the biofloc system under zero exchange conditions. Oriental River prawn (inital weigh of 0.82 ± 0.07 g) were divided into four groups and fed four levels of calcium carbonate nanoparticles as following 0, 25, 50 and 100  mg kg−1 diet in biofloc system (CN0, CN25, CN50, and CN100) for 28 days. This study was applied complete randomized design with three replications. Water quality parameters were measured during the test period. Feed and growth parameters and some metabolic activities of hepatopancreas were measured. Physico-chemical water factors were in the appropriate range for this species. The concentrations of total ammonia nitrogen (TAN), nitrite, and nitrate were not significantly different between the experimental groups. The growth of prawns was significantly higher and feed conversion ratio was lower in CN25 and CN50 groups compared to the control group. The lowest AST and ALT activities were observed in CN25 and CN50 groups compared to the control. The prawns fed with experiment diets had significantly higher total protein, hemocyanin, glucose, and calcium compared to the control. Overall, the results showed diets containing Nano-calcium carbonate at levels 25-50 mg kg-1 in CN25 and CN50 groups could improve growth performance and metabolic activity of oriental river prawn in the biofloc system.