Effect of biofloc system on the water quality of the white leg shrimp Litopenaeus vannamei reared in zero water exchange culture tanks

Abstract

White leg shrimp Biofloc system Water quality Shrimp culture A 90-day trial was conducted to study the effects of different protein levels (25, 30 and 35% CP) and different carbon sources (sugarcane bagasse "SB" and wheat flour "WF") with biofloc and one control (45% CP without biofloc), on water quality parameters of the white leg shrimp Litopenaeus vannamei juveniles (0.23g ± 0.04) in zero-water exchange culture tanks. Six biofloc treatments and one control without BFT were managed. Temperature and salinity did not show any significant difference between the control and biofloc treatments, and they were at the optimum range for L. vannamei cultured. The PH value was unexpected in the bioflocs treatments. BFV and TSS were significantly higher (P ˂ 0.05) in biofloc treatments compared to the control. Concentrations of TAN and NO2 at biofloc treatments were lower compared to the control (P ˂ 0.05), the addition of different levels of protein and different carbon sources into the zero water exchange system for shrimp culture can effectively increase the activities of nitrogen cycle bacteria, which can thus reduce inorganic nitrogen levels and gradual increases of both BFV and TSS levels.