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This study aimed to evaluate different feeding rate ratios in a biofloc technology‐based aquaponics system employing sea asparagus (Sarcocornia ambigua) and Pacific white shrimp (Litopenaeus vannamei) in an 83‐day experiment. Two treatments were evaluated: 100 and 50 g feed m−2 day−1, which were achieved by doubling the plant production area from 0.4 m2 to 0.8 m2. Shrimps (1.39 g ± 0.06 g) were reared under an initial density of 250 animals m−3 in 800 L polyethylene tanks, while the plants were cultivated using nutrient film technique hydroponic benches which received water from the shrimp unit through a pumping system. The increase in plant production area allowed for a statistically significant increase in the plant final biomass in approximately 74% (p < 0.05), with the end result that plant productivity was not altered (p ≥ 0.05). Shrimp growth performance and the concentrations of nitrogen compounds and orthophosphate did not differ significantly between treatments (p ≥ 0.05). In conclusion, the reduction in the feeding rate ratio from 100 to 50 g m−2 day−1 did not impair plant productivity, which indicates that the efficiency of the system was improved, as a greater plant biomass was produced with the same amount of shrimp feed inputs. [ABSTRACT FROM AUTHOR]

This study aimed to isolate a yeast strain and evaluate its potential to be inoculated in the biofloc technology culture of Pacific white shrimp employing in vitro and in vivo assays. A yeast strain identified as Meyerozyma guilliermondii (CPQBA 1459/17 DRM‐01) was isolated from the soil of an estuary. Its growth kinetics under different salinities (0%, 1.0%, 2.0%, 3.0% NaCl) and Vibrio alginolyticus inhibition were evaluated in vitro. For the in vivo assay, a factorial design was employed to evaluate the effects of yeast addition and biofloc management strategy in the nursery culture of Litopenaeus vannamei as regards shrimp growth performance, water quality and water microbiology. The two factors evaluated were biofloc (mature and heterotrophic) and yeast (addition or no addition), totaling four treatments. In the in vitro trials, the yeast strain was capable of growing under all salinities evaluated, but no pathogen inhibition was observed. In the in vivo experiment, the addition of yeast significantly reduced the concentration of total suspended solids (p < 0.05), in addition to promoting a higher post‐larvae survival when considering only the two mature biofloc treatments (p < 0.05). No significant effects on water Vibrio spp. and total heterotrophic bacteria counts were found (p ≥ 0.05). In conclusion, the inoculation of yeast in the biofloc culture of L. vannamei exhibited bioremediation potential and improvement in shrimp survival, the latter being modulated by the biofloc management strategy. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of heterotrophic and mature biofloc systems on yield, water quality, sludge production, water bacterial community, recovery of nutrients and fish health in Litopenaeus vannamei and Oreochromis niloticus integrated culture through a 53-day experiment. Two treatments were evaluated: an organic carbon (C) supplemented system (heterotrophic treatment), in which organic C was supplemented throughout the whole experiment and no biofloc inoculum was added at the beginning, and a mature treatment in which half of the volume of shrimp units was filled with biofloc-rich water from a previous rearing cycle before the culture started. Shrimp (3.34 ± 0.03 g) and fish (5.73 ± 0.06 g) were stocked at 300 shrimp m−3 and 344 fish m−3. The former were fed according to a feeding table, while the latter were fed at the rate of 1% of their biomass to stimulate the ingestion of bioflocs. Shrimp growth performance was unaffected (p >.05), but fish reared in the heterotrophic treatment exhibited better values for all growth performance variables evaluated (p <.05). Total ammonia nitrogen and nitrite were lower in the mature treatment (p <.05). Total sludge produced in the heterotrophic treatment was 114% higher than that in the mature treatment (p <.05), which resulted in greater sludge produced per animal biomass (sludge to biomass ratio) (p <.05). Bacterial community diversity was reduced in the heterotrophic treatment, and relative abundance of Vibrionaceae was reduced. The recovery of N and P was higher in the heterotrophic treatment (p <.05). Fish health was unaffected by the biofloc system. This research shows that the organic C supplemented system favored fish growth in the integrated rearing, maintaining water quality suitable for growing organisms and healthy fish. In contrast, the mature system produced less sludge. • Mature and heterotrophic biofloc systems were applied to Litopenaeus vannamei and Oreochromis niloticus integrated rearing. • The heterotrophic treatment resulted in an increased amount of sludge removed. • Shrimp yield was unaffected while the tilapia yield increased by 120% in the heterotrophic treatment. • N and P recoveries were greater in the heterotrophic treatment. • Bacterial community diversity and relative abundance of Vibrionaceae were reduced in the heterotrophic treatment. [ABSTRACT FROM AUTHOR]

• Chemoautotrophic and mature systems are effective in avoiding high concentrations of ammonia and nitrite in biofloc system. • Chemoautotrophic system begins with a lower bacterial load of Vibrio. • Chemoautotrophic and heterotrophic systems improve the growth of Pacific white shrimp in the nursery phase in biofloc system. In biofloc technology (BFT) rearing systems, nitrogen compounds, specially ammonia and nitrite, have to be controlled by microbial pathways, mainly through the activity of heterotrophic and chemoautotrophic bacteria. The objective of this work was to assess different water preparation strategies (heterotrophic, chemoautotrophic and mature) in BFT system for nursery of Pacific white shrimp (Litopenaeus vannamei). A 35-day study was conducted with post-larvae shrimp (0.08 g) stocked in twelve 300 L tanks at a stocking density of 2000 shrimp m−3. The water preparation strategies for shrimp rearing that were evaluated in this study included: i) Heterotrophic treatment, where the water received sugar as a carbon source; ii) Chemoautotroph treatment, where ammonium and nitrite salts were added to the water; and iii) Mature treatment, which was created by the addition of a significant amount of water containing mature biofloc from another established BFT system. In both mature and chemoautotrophic treatments, the nitrification process was able to keep toxic nitrogen compounds (ammonia and nitrite) at low levels without the addition of carbohydrates. In contrast, heterotrophic system showed peaks of ammonia and nitrite during the rearing cycle, and the level of these compounds were found to be higher in this treatment (relative to the mature and chemoautotrophic treatments). The chemoautotrophic system exhibited a lower abundance of bacteria from the family Vibrionaceae in the beginning of the experiment compared to the heterotrophic and mature treatments. The combination of low Vibrionaceae abundance and good water quality resulted in improved growth performance in this treatment. These findings demonstrate the importance of manipulating the environment of BFT systems to induce an enrichment of nitrifying bacteria before stocking shrimp. We have also found that the addition of a carbon source to BFT systems is necessary only in emergency situations, when ammonia spikes need to be controlled. [ABSTRACT FROM AUTHOR]

We evaluated an integrated system for rearing Pacific white shrimp (Litopenaeus vannamei) and white mullet (Mugil curema) in an experimental-scale biofloc system. Performance of the animals, water quality, phosphorus and nitrogen retention and mass balance, and fish hematology and immunology were compared among two treatments: 1) shrimp with mullet integrated system (Shrimp + Mullet), and ii) shrimp without mullet system (Shrimp). A tank with 800 L of useful volume was used to rear the shrimp with a density of 250 shrimp m−3. Another tank with 90 L of useful volume was maintained for rearing fish (15 mullet tank−1) in the Shrimp + Mullet treatment. The shrimp treatment also used the 90-L tanks, but without the fish. Water was recirculated into the mullet tanks via a submerged pump and returned by gravity to the shrimp tanks. The shrimp were fed four times a day. A feeding table was used to adjust the amount of feed provided, and the fish were fed only once daily with a ratio of 1% initial biomass to stimulate biofloc consumption (BFT). After 53 days, shrimp growth (final weight 12.56 ± 0.22 g) and survival (91.8% ± 2.9%) were similar between treatments. Fish had adequate survival (91.1% ± 10.2%), and adequate growth for Mugil species (0.71 ± 0.05 g week−1) in the integrated system. In the Shrimp + Mullet treatment, animal productivity was increased by 11.9% by combining Shrimp + Mullet biomass, when compared to the Shrimp treatment. The Shrimp + Mullet treatment also demonstrated a 16.8% increase in phosphorus retention compared to the Shrimp treatment. The hemato-immunological parameters showed that fish kept in a biofloc system had adequate values comparable to those reported for Mugil species. Thus, these experimental-scale results demonstrate that the integration of shrimp and mullet in biofloc systems increases yield and phosphorous retention without compromising fish health and shrimp growth. In addition, we recommend reproducing this integrated system over a longer period and at commercial-scale, supporting an economic analysis. • Integration of mullet and shrimp increased biofloc system yield by 11.9%. • Integration of shrimp and mullet in a biofloc was ecologically more efficient and increased phosphorus retention by 16.8% • Feed restriction in the biofloc system did not compromise fish health. [ABSTRACT FROM AUTHOR]

This work aimed to evaluate the effects of integrated culture of sea lettuce (Ulva fasciata) on the shrimp (Litopenaeus vannamei) and mullet (Mugil liza) rearing in a biofloc technology (BFT), on water quality, animal performance and seaweed growth, nitrogen and phosphorus recovery, seaweed bioactive compounds. Two groups were compared: i) Ulva group: cultivation system integrating shrimp and mullet with seaweed, ii) control group: the same without seaweed, both groups used BFT. Each group had four replicates; initial biomass was 618 ± 8 g and 246 ± 34 g for the shrimp and mullet, respectively. Additionally, in the Ulva group, 120 g of sea lettuce per tank was included every two weeks. After 55 days, the integration of seaweed in the system did not influence the shrimp and mullet performance. Shrimps grew, on average, 1.22 g week−1, with 90.6% survival, 2.91 kg m−3 yield and 1.84 FCR. Mullets grew, on average, 1.035 g week−1, with 99.17% survival, and 4.08 kg m−3 yield. At the end 317.01 ± 32.02 g of seaweed per experimental unit was harvested. The total final biomass and yield, considering the whole system, were 12.2% higher in the Ulva group than in the control group. Nitrogen and phosphorus recovery were respectively 5.5% and 7.6% higher in the Ulva group than in the control group. The nitrogen, phosphorus, chlorophyll-a and carotenoids contents in the Ulva group were also higher at the end of the experiment. In conclusion, the integration of sea lettuce can increase the total yield, nitrogen and phosphorus recovery in the biofloc system. Furthermore, the integration of sea lettuce in this system can increase the content of chlorophyll-a and carotenoids, without affecting the yield of ulvan extract. • The integration of Ulva fasciata in the shrimp and mullet culture in biofloc system can improve total productivity in 12.2%. • U. fasciata integrated on shrimp and mullet culture in biofloc increase recovery of nitrogen in 5.5% and phosphorus in 7.6%. • Seaweed in IMTA-BFT system has more bioactive compounds and protein. [ABSTRACT FROM AUTHOR]