This study focused on evaluating the effect of different concentrations of nutrients and total suspended solids on the removal rate of nutrients and biocompounds from the macroalgae U. lactuca in an integrated system with the shrimp Penaeus vannamei in biofloc. The experiment lasted 45 days and included five treatments with three replicates each, with percentages of 0 (control), 25, 50, 75, and 100% biofloc inoculum (73.3 ± 5.7 and 325.0 ± 21.2 mg L⁻¹ initial nitrate and solids, respectively, in the 100% inoculum), from a shrimp farm, resulting in different concentrations of solids and nutrients. The macroalgae were introduced into 280 L tanks at a density of 0.88 kg m⁻², along with 200 shrimp m⁻³. The algae were separated by a floating structure. Water quality parameters were measured, and the nutrient removal rate was evaluated. The treatment with 75% inoculum showed a removal rate of 55.0 ± 4.0 and 31.0 ± 10.0% of nitrate and phosphate, respectively. There was no difference in macroalgae growth between the treatments; however, macroalgae grown in 75% inoculum had higher protein, chlorophyll-a, and lower ash values compared with the control. The use of macroalgae in integrated production with shrimp under the conditions of the treatment with 75% biofloc inoculum proved to be viable and sustainable.

The present research aims to valorize biofloc waste by extracting polyphenols via alkaline hydrolysis, utilizing them as reducing and stabilizing agents in the optimization of green synthesis of silver nanoparticles (BIOAgNPs). For the alkaline extractions, potassium hydroxide (KOH) concentrations of 0 to 4 M were used in combination with ultrasound. Total polyphenol content and antioxidant activity were evaluated. BIOAgNPs synthesis was optimized using the response surface methodology and central composite design. The parameters time, temperature, AgNO₃ concentration, and the percentage of the biofloc extract (2 M KOH), with measurements taken for the area under the curve (AUC) (400–500 nm) and the mean hydrodynamic diameter (DLS), were evaluated. Antibacterial activity was determined for Gram-negative and Gram-positive bacteria. Higher polyphenol content and antioxidant activity were observed using 2 M KOH. The optimized model for DLS and the AUC was obtained in 4 h, at 40 °C, using 2.4 mM AgNO₃ and obtaining 2.5% of extract. Optimized BIOAgNPs had a diameter of 22.4 nm, hydrodynamic diameter of 106.5 nm, zeta potential of −28 mV, and polydispersity index of 0.26. BIOAgNPs demonstrated bactericidal activities. This study enhanced the valorization of aquaculture residues through improved polyphenol extraction techniques and developed an effective methodology for synthesizing silver nanoparticles with antimicrobial activity.

Lipoic acid (LA) is a mitochondrial coenzyme that, depending on the concentration and exposure time, can behave as an antioxidant or pro-oxidant agent and has a proven ability to modulate metabolism by promoting lipid and glucose oxidation for energy production. To assess the effects of LA on energy metabolism and redox balance over time, Artemia sp. nauplii was used as an animal model. The administered concentrations of the antioxidant were 0.05, 0.1, 0.5, 1.0, 5.0, and 10.0 µM. Therefore, possible differences in protein, triglyceride, glucose, and lactate concentrations in the artemia samples and total ammoniacal nitrogen (TAN) in the culture water were evaluated. We also measured the effects of LA on in vivo activity of the electron transport system (ETS), antioxidant capacity, and production of reactive oxygen species (ROS) at 6, 12, 18, and 24 h post-hatching. There was a decrease in glucose concentration in the LA-treated animals, and a decrease in ammonia production was observed in the 0.5 µM LA treatment. ETS activity was positively regulated by the addition of LA, with the most significant effects at concentrations of 5.0 and 10.0 µM at 12 and 24 h. For ETS activity, treatments with LA presented the highest values at 24 h, a period when ROS production decreased significantly, for the treatment with 10.0 µM. LA showed positive regulation of energy metabolism together with a decrease in ROS and TAN excretion.

The objective of this was to evaluate the ability of bioflocs to assimilate and transfer antioxidant compounds present in açaí Euterpe oleracea to juvenile Penaeus vannamei shrimp grown in a biofloc system. Juvenile shrimp were distributed into four treatment groups (control, 5, 20, and 80 mg açaí L⁻¹), containing 31 shrimps/tank (90 L), and cultivated for 30 days. Every 24 h throughout the experimental period, the respective açaí concentrations were added directly to the cultivation water. The bioflocs and hepatopancreas lost their antioxidant capacity with increasing concentrations of açaí; however, lipid damage was mitigated after treatment with 20 mg of açaí L⁻¹ (p < 0.05). The application of 20 mg açaí L⁻¹ increased the mean height and area of the middle intestinal microvilli (p < 0.05). Mortality and protein and lipid damage in shrimp muscle increased with daily administration of 80 mg açaí L⁻¹ (p < 0.05). It is concluded that the bioflocs were able to assimilate the antioxidants present in açaí and transfer them to the shrimp, and the administration of 20 mg açaí L⁻¹ presented the best performance, demonstrating the possibility of its application in the cultivation of P. vannamei in a biofloc system.

The study analysed the effects of dietary resveratrol supplementation, either alone or in combination, with fumaric acid on the zootechnical performance and bioenergetics parameters of juvenile Litopenaeus vannamei. A dose–response trial was conducted with 0, 10, 60, 110, and 160 mg·kg⁻¹ of resveratrol. Subsequently, a second experiment was performed with shrimp from the control group and the best-performing resveratrol group. The treatments were control (C), fumaric acid 8.47 g·kg⁻¹ (F), resveratrol (R) and R + F (RF). Growth performance (final weight gain (g), specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER)) and the concentration of energy-yielding molecules evaluated. Shrimp fed with 60 mg·kg⁻¹ of resveratrol showed higher weight gain, SGR, protein and glucose concentrations in the muscle, increased PER, and lower FCR (ANOVA and Tukey HSD post hoc test (p < 0.05). Combined supplementation (RF) further enhanced growth performance and protein, glucose, and glycogen concentrations (p < 0.05) (ANCOVA test; p < 0.05). The zootechnical responses were also improved, where in 14 days the animals gained almost three grams of weight, with an FCR of 1.14 ± 0.03 and SGR of 6.99 ± 0.17% per day (p < 0.05). Overall, the combined supplementation of resveratrol and fumaric acid acted as an effective metabolic modulator, improving metabolic status of L. vannamei.