Adolfo Jatobá

The study evaluated the bioremediation potential of a commercial probiotic composed of multi-strain Bacillus (B. subtilis CCT 0089, B. amyloliquefaciens ATCC 31592, B. licheniformis CCT 7836 and B. megaterium CCT 7935) in biofloc technology (BFT). In vitro, the ideal dosage was identified between concentrations [0.01], [0.10], [1.00], and [10.00] g m⁻³. Additionally, the growth of probiotic species was characterised in different temperature and oxygen conditions, resistance in 3.0% sodium chloride culture medium, enzyme production (protease, amylase, and lipase) and antibacterial activity. The in vivo experiment evaluated the bioremediation potential of the probiotic and its impact on the growth performance of Nile tilapia Oreochromis niloticus raised in BFT conditions. The group that received the multi-strain Bacillus probiotic at a dosage of 0.10 g m⁻³ experienced a decrease in floc volume, toxic ammonia, and nitrate levels, leading to environmental enhancements and improved well-being for the cultured organisms. It is advisable to use the multi-strain probiotic at a dosage of 0.10 g m⁻³ in BFT conditions.

The integration of multiple species has been proposed as a strategy to improve resource use efficiency in intensive aquaculture systems. This study evaluated the inclusion of a native fish species, yellowtail lambari (Astyanax bimaculatus), in a biofloc-based aquaponic system co-cultivating Nile tilapia (Oreochromis niloticus) and lettuce (Lactuca sativa var. capitata). The experiment was conducted over 35 days using eight experimental units with two treatments (with and without lambari) and four replicates. Water quality, zootechnical performance, lettuce growth, hematological parameters of tilapia, and nitrogen and phosphorus retention were assessed. The presence of lambari was associated with lower total ammonia nitrogen, toxic ammonia, and total suspended solids, particularly during the final stage of the experimental period (p < 0.05), as well as reduced pH and alkalinity, likely reflecting increased microbial activity. Lettuce cultivated in the lambari treatment showed higher final weight, leaf height, and total biomass (p < 0.05), resulting in increased system productivity. No significant differences were observed in growth performance or hematological parameters of Nile tilapia (p > 0.05). In addition, nitrogen and phosphorus retention at the system level were higher in the lambari treatment (p < 0.05), although no differences were detected when fish and plants were evaluated separately. These results indicate that the inclusion of a native fish species can influence nutrient retention and productivity in biofloc-based aquaponic systems without compromising the performance of the primary cultured species.

Aquaculture continues to expand globally and is now responsible for providing more than half of the aquatic products consumed worldwide

This study evaluated Lactuca sativa performance in an integrated aquaponic–biofloc system with Oreochromis niloticus using 500 L fish tanks, 100 L biofloc units, and NFT hydroponics under three planting strategies. The 30-day experiment showed no differences in water quality or fish performance among treatments. Treatment B (substrate without root cleaning) resulted in superior plant performance, with leaf height of 31.89 cm, lettuce productivity of 2.98 kg/m³, and highest system productivity of 8.15 kg/m³. Root-associated floc accumulation did not negatively affect growth. The integrated system proved efficient, and substrate use improved yield while reducing labor demands.

This study evaluated the effects of Lippia sidoides essential oil (LSEO) as a growth and health promoter for juvenile tilapia subjected to stress induced by air exposure and experimental infection with Aeromonas hydrophila. Juvenile were allocated to 15 tanks (in triplicate) and fed diets containing 0.0% (Control), 0.05%, 0.1%, 0.2%, or 0.4% LSEO for 33 days. For the air exposure challenge, five fish from each tank were exposed to air for five minutes after the feeding period. Blood samples were collected for hematological analysis. For the infection challenge, six fish from each tank were intraperitoneally inoculated with 100 µL of A. hydrophila and monitored for ten days. Hematological and histomorphometric parameters were assessed. The results indicated that the 0.4% LSEO supplementation reduced feed conversion ratios (P < 0.05). Before the challenges, LSEO concentrations influenced total counts of neutrophils, basophils, and monocytes (P < 0.05). After the air exposure and infection challenges, no significant differences were observed among treatments for these parameters (P > 0.05). Regarding hematimetric indices, all parameters were affected by LSEO concentrations prior to the challenges (P < 0.05). Although LSEO supplementation improved feed conversion, it did not mitigate the hematological alterations caused by the stress challenges.

This study evaluated the technical and economic feasibility of the biofloc technology (BFT) system during the fry rearing phase of Nile tilapia (Oreochromis niloticus), focusing on suspended solids management, stocking density, and economic performance at a pilot scale. Three trials were conducted. The first assessed the effects of four total suspended solids (TSS) ranges (0–200, 200–400, 400–600, and 600–800 mg·L⁻¹) on larval performance and water quality. TSS levels between 200 and 600 mg·L⁻¹ promoted improved water quality and zootechnical performance. The second trial tested five stocking densities (2, 4, 6, 8, and 10 larvae·L⁻¹), evaluating their impact on water quality, survival, and size uniformity. Higher densities negatively affected survival (R² = 0.84) and final weight (R² = 0.92), while also increasing solids and nitrogenous compounds, thus impairing performance (p < 0.05). The third trial monitored six production cycles at pilot scale, evaluating zootechnical parameters, sex reversal efficiency, and economic indicators. All cycles showed survival rates above 85%, sex reversal close to 100%, and positive net margins (18.5 to 41.9%), demonstrating the viability of BFT for commercial fry operations. The results emphasize the importance of controlling suspended solids and stocking density to maintain water quality and optimize larval performance. Furthermore, the system proved economically viable, with good feed conversion rates and profitability, even without water exchange. These findings support BFT as a sustainable and efficient alternative for tilapia fry production, offering significant water savings and promising economic returns when properly managed.

This study evaluated the efficacy of dietary supplementation with Biotronic® Top 3—a blend of selected organic acids, their salts, and a phytochemical—on the zootechnical performance and immune response of fish during a natural outbreak of francisellosis caused by Francisella spp., an intracellular bacterium that leads to high mortality in aquaculture systems. The trial was conducted in a commercial fish farm using 24 net cages (20,000 fish each) divided into two treatments: one group received feed supplemented with Biotronic (without antibiotics), while the control group was fed a standard diet and treated with Florfenicol (40 mg kg−1) after clinical diagnosis of the disease. The results showed that fish in the Biotronic group achieved significantly higher final body weight and daily weight gain (p < 0.05) compared to the control. However, no significant differences were observed in feed conversion ratio or survival rates. Histopathological analyses of the spleen indicated the presence of retroactive granulomas exclusively in the Biotronic group, suggesting an enhanced immune response and possible recovery stage of the infection. These findings indicate that Biotronic® Top 3 supplementation improves growth performance and stimulates the immune system during bacterial challenge, supporting its use as a prophylactic strategy in aquaculture. This approach may contribute to reducing antibiotic use and promoting more sustainable and health-conscious fish production systems.

This study evaluated the zootechnical performance, cost per kilogram of fish produced and hematological parameters of yellowtail lambari (A. bimaculatus) fed different diets. The diets comprised four treatments: formulated powdered diet with premix (A); formulated powdered diet without premix (B); commercial powdered diet (C) and commercial powdered diet until the fish reached an average weight of 3 g, after which a 1.5 mm extruded commercial diet was fed (D). The fish were fed for 54 days. Diet D resulted in fish with a higher average final weight, weight gain and yield, with a reduction in apparent feed conversion. There was no difference between the treatments in terms of survival before and after purification, carcass yield and hematological parameters of the lambari. However, the cost of the diet per kilo of fish for diet D was higher (R$2.57 per kg) than for diet B (R$1.77 per kg). According to the data obtained in this study, it is possible to provide a formulated diet without harming the growth of the species; however, it may be interesting to combine it with the provision of an extruded diet for fish of at least 3g, to reduce rearing time in excavated ponds.

The purpose of this research was to assess the effectiveness of a combination of monoterpenes (thymol and carvacrol) in treating juvenile Nile tilapia ( Oreochromis niloticus ) infected with Edwardsiella tarda as a potential substitute for the antibiotic oxytetracycline. The study utilised different concentrations of the monoterpenes blend (MTs): 0.4, 0.6 and 0.8 g kg ⁻¹ of feed. A negative control group received a diet without the additive, while a positive control group was given medicated feed containing oxytetracycline (OTC) (11.85 g kg ⁻¹ ) for a 10‐day treatment period. Cumulative mortality (%), haematological and immunological parameters were assessed after the feed administration. The negative control group experienced a mortality rate of 53%, while fish treated with medicated feed had a significantly lower mortality rate of 3%. The addition of MTs at concentrations of 0.4 g kg ⁻¹ (13% mortality), 0.6 g kg ⁻¹ (8% mortality) and 0.8 g kg ⁻¹ (0% mortality) also resulted in reduced mortality rates, with the highest concentration showing survival rates comparable to the oxytetracycline group. Following the 10‐day treatment period, no mortality was observed in the treated groups, indicating the efficacy of MTs‐supplemented feed in alleviating the clinical symptoms of Edwardsiellosis. The haematological parameters indicated that as the dosage of MTs increased, the mean corpuscular volume (MCV) decreased. The MCV was significantly lower in the 0.6 and 0.8 g kg ⁻¹ treatments compared to the control. Mean corpuscular haemoglobin initially increased with the 0.4 g kg ⁻¹ MTs treatment but then decreased with higher doses. The mean corpuscular haemoglobin concentration was higher in the treated groups compared to the control. Red blood cell levels were higher in the 0.8 g kg ⁻¹ MTs treatment and lower in the 0.4 g kg ⁻¹ treatment. Ht was higher in the control group and lower in the 0.4 g kg ⁻¹ MTs treatment. Haemoglobin levels followed a similar trend, with higher values in the control group. The 0.8 g kg ⁻¹ MTs treatment had the highest number of total leucocytes and lymphocytes. The control group had the highest number of neutrophils, while the 0.8 g kg ⁻¹ MTs group had higher numbers of monocytes, eosinophils, basophils and thrombocytes. The negative control exhibited the lowest antimicrobial titre compared to the OTC and the various concentrations of MTs. The concentrations of MTs (0.4, 0.6 and 0.8 g kg ⁻¹ ) demonstrated similar average values and were more effective than the control and OTC. There was no significant difference in agglutinating titre among MTs, control and OTC. Thymol and carvacrol notably decreased the mortality of tilapia infected with E. tarda , with a dosage as high as 0.8 g kg ⁻¹ showing equivalent effectiveness to oxytetracycline. Furthermore, they enhanced haematological and immunological parameters, indicating that MTs could be a promising alternative to antibiotic use.