Addition of sodium nitrite and biofilm in a Litopenaeus vannamei biofloc culture system

• DOI: 10.3856/vol44-issue4-fulltext-11
• Publication Date: 2016-10-05T14:24:19Z
• Authors: Gabriele Lara; Plinio Furtado; Barbara Hostins; Luis Poersch; Wilson Wasielesky...
• Keywords: 0301 basic medicine; 03 medical and health sciences; nitrógeno; biofloc; substratos artificiales; shrimp; artificial substrates; camarón; Litopenaeus vannamei; nitrogen; 6. Clean water

This study evaluates the effects of the previous addition of sodium nitrite (NaNO 2 ) and biofilm in a Litopenaeus vannamei biofloc culture. Five treatments were tested in 180 L - tanks: NaNO 2 (-20) addition of NaNO 2 for 20 days before stocking and without artificial substrates; NaNO 2 +B (-20) addition of NaNO 2 for 20 days before stocking, with 150% additional artificial substrates; NaNO 2 (Stocking) addition of NaNO 2 at stocking and no artificial substrates; NaNO 2 +B (Stocking) addition of NaNO 2 at stocking, with 150% additional artificial substrates and; Control, without NaNO2 addition and without artificial substrates. The study was carried out in two phases: shrimps (0.21 ± 0.08 g) were stocked at a density of 400 ind m -2 /1,100 ind m -3 , for 30 days (nursery). After this period, the animals were restocked at a lower density (120 ind m -2 /400 ind m -3 ) for 18 more days (grow-out). The turbidity and seattleable solids were higher in treatments without artificial substrates, independently of the addition of NaNO 2 . The ammonia and nitrite were lower in control, and the nitrate concentrations were higher in treatments with addition of NaNO 2 without biofilm. At the end of the nursery, the survival was lower in treatment NaNO 2 (-20), and at the end of grow-out the final biomasses were higher in treatments with addition of NaNO 2 at the stocking day. In conclusion, the use of a dose of NaNO2 at the stocking day could increase the nitrite-oxidizing bacteria, and the biofilm may contribute to the reduction in suspended particles in water, enhancing shrimp production in biofloc technology system.