Assessment of the nitrification process in a culture of pacific white shrimp, using artificial substrate and bacterial inoculum in a biofloc technology system (BFT)

Abstract

Litopenaeus vannamei is the most cultured marine shrimp in all types of systems including the Bioflocs Technology System (BFT). Bioflocs are formed by microorganisms, among these, autotrophic bacteria are responsible for the nitrification process. This study aimed to identify and promote the development of nitrifying bacteria by adding artificial substrates and biofloc inoculum in L. vannamei culture in a BFT system. The experiment consisted of four treatments with three replics (4x3) as follows: (1) Control: clear water in which bioflocs were formed; (2) IN (10%): clear water with biofloc inoculum (10%); (3) IB: clear water with substrate (immature “bioballs”); and (4) MB: clear water with mature “bioballs” inoculum from a recirculation system. Treatments were stocked with shrimp juveniles (4.92±0.45 g) in 12 tanks with 200 L working volume at a stocking density of 200 shrimp/m³. Shrimps were fed twice a day with a commercial feed (38% CP) following a feeding table, and daily observations intake were made over the four weeks of the experiment. Biofloc and “bioballs” samples were collected to detect the growth of the population of nitrifying and heterotrophic bacteria by FISH. There was no significant difference between treatments (P>0.05) for survival, obtaining mean values greater than 88%. The IN (10%) treatment had lower concentrations of ammonia and nitrite, and nitrate concentration increased, while MB had a higher weight and biomass final, productivity, weekly weight gain and lower conversion of apparent feed for production performance results.

Assessment of different ionic adjustment strategies in low‐salinity water on the growth of Litopenaeus vannamei and microbial community stoichiometry in a synbiotic nursery system

“…We observed that the nitrification process was efficient during the experimental period, with higher concentrations of NO − 3 -N compared with TAN and NO − 2 -N. This efficiency is related to the combination of fertilization using anaerobic and aerobic processes in rice bran by microorganisms (Romano et al, 2018). In addition, the use of artificial substrate and biological activator probably have accelerated the system's nitrification processes (Santos et al, 2019;Silva Neto et al, 2012). concentration range for systems that use low-salinity water (<0.81 mg TAN/L and <0.45 mg NO − 2 -N/L; Gross et al, 2004;Lin & Chen, 2001;Valencia-Castañeda et al, 2018).…”

“…This efficiency is related to the combination of fertilization using anaerobic and aerobic processes in rice bran by microorganisms (Romano et al, 2018). In addition, the use of artificial substrate and biological activator probably have accelerated the system's nitrification processes (Santos et al, 2019; Silva Neto et al, 2012).…”

Periphyton use on microbial dynamics, water quality, and Nile tilapia growth in rearing tanks

“…These results are an indicative of the presence of two main groups responsible for the nitrification process: autotrophic bacteria, known as AOB and NOB; and nitrifying heterotrophic bacteria. Santos et al (2019) found a greater number of nitrifying bacteria, compared with heterotrophic bacteria, in artificial substrates (bioballs) in the culture of pacific white shrimp (Litopenaeus vannamei Boone, 1931).…”

Different protein levels in a super-intensive culture of juvenile Pacific white shrimp (Litopenaeus vannamei) in biofloc systems during the early rearing phase

“…Each experimental unit had a heating system (Roxin HT1300, 100 W) for thermal control (27°C), and aeration was provided through a porous hose (15 cm, Aero-tube TM, Swan, Marion, OH) individually connected to a blower (CR8, 7.5 CV, Ibram). The tanks were filled with 80% (40 L) of chlorinated (20 mg•L -1 active chlorine) seawater (salinity 30.38 g•L -1 ) and dechlorinated with constant aeration, and subsequently with 20% (10 L) of previously matured biofloc inoculum, according to the method proposed by Santos et al (2019), in order to ensure the following initial conditions: 0.07 ± 0.04 mg•L -1 TAN, 0.05 ± 0.01 mg•L -1 NO 2 --N, 15.27 ± 2.77 mg•L -1 NO 3 --N, 164.1 ± 12.6 mg•L -1 CaCO 3 , and 137.10 ± 28.70 mg•L -1 SST. In addition, the photoperiod was controlled and maintained at 12:12 light:dark.…”