Ivanilson Santos

This study evaluated the immunomodulatory and histological effects of dietary supplementation with an ethanol extract of Limnospira platensis (spirulina) in Penaeus vannamei. Shrimp were fed diets supplemented with 0.5%, 1%, 2%, and 4% spirulina extract for 35 days. Growth performance did not differ significantly among treatments, suggesting no adverse effects on nutrient utilization. However, immune parameters, including granulocyte abundance and hemocyte phagocytic capacity, improved significantly at 0.5–2% inclusion levels, with 0.5% promoting the highest granulocyte counts and 2% maximizing phagocytic activity. In contrast, the 4% treatment led to a decline in both granulocyte levels and phagocytosis, indicating saturation effects at higher doses. Histological analyses supported these findings, as villus length improved with 0.5, 1 and 2% doses but not with 4%. Overall, these results confirm a non-linear immunostimulatory response of L. platensis extract, highlighting low inclusion levels, especially 0.5%, as effective and economically feasible strategies to strengthen shrimp immunity in intensive aquaculture.

This study evaluated the salinity tolerance of the macroalga Ulva ohnoi cultivated in a biofloc system over a 14-day period. Five salinity treatments (10, 15, 20, 25, and 30‰) were tested, using 40-L tanks. Algae were acclimated to the target salinities before the cultivation phase and stocked at the density of 2 g∙L-1. Water quality parameters (ammonia, nitrite, nitrate, orthophosphate, alkalinity, and pH), biomass gain, daily growth rate, phenolic compounds, chlorophyll, and carotenoids were evaluated. Water quality remained within acceptable ranges across treatments, although alkalinity showed significant differences. Complete mortality of U. ohnoi was observed at 10‰, and reduced growth was recorded at 15‰. In contrast, salinities of 20, 25, and 30‰ supported higher biomass gains and daily growth rates, with no significant differences in antioxidant compound concentrations among these treatments. Growth was significantly higher at salinities of 20–30‰, with biomass gains of 318–400 g and daily growth rates of 5.4–6.4% day-1, whereas at 15‰ biomass gain reached only ~111 g and growth rate ~1.2% day-1. These findings highlight the potential of U. ohnoi for integration into low-salinity biofloc systems and multitrophic aquaculture strategies, contributing to sustainable aquaculture practices by recycling nutrients and producing valuable biomass.

This study compared the production of P. vannamei juveniles reared in a low salinity biofloc system during winter in northeastern Brazil in three stocking densities (75, 150, and 301 shrimp m ⁻² ), focusing on water quality and growth performance parameters. Shrimp (0.038 ± 0.08 g) were reared for 75 days in 700-L tanks without artificial heating for water temperature control and fed three times daily. Results illustrated that the treatment with 301 shrimp m ⁻² had higher mean values of total ammonia nitrogen compared with 75 shrimp m ⁻² , while the treatment with 150 shrimp m ⁻² had values similar to both other treatments. Treatments with 150 and 301 shrimp m ⁻² produced higher settleable solids volumes compared with 75 shrimp m ⁻² . Other water quality parameters did not differ significantly among treatments. The treatment with 75 shrimp m ⁻² was more effective in producing P. vannamei juveniles, achieving a survival rate above 82 %, higher growth rate, higher final weight, and a lower feed conversion ratio compared to the treatments with 150 and 301 shrimp m ⁻² . However, overall performance across all treatments was limited by the combined effects of low salinity and low temperature. Thus, maintaining water temperature within the optimal range for P. vannamei is crucial to optimize production and minimize losses, especially in low salinity conditions.

The aim of this study was to evaluate Viligen® NE (Alltech®, USA) as a feed additive for Penaeus vannamei reared in a biofloc system during the nursery phase, focusing on growth performance, intestinal microbiological analysis, and resistance tocold challenge. Shrimp post-larvae (41 mg) were fed for 6 weeks with four experimental diets: (a) 0.5 g Viligen® NE kg⁻ ¹ , (b) 1 g Viligen® NE kg⁻ ¹ , (c) 2 g Viligen® NE kg⁻ ¹ , and (d) a control diet (0 g Viligen® NE kg⁻ ¹ ). The experiment was conducted in quadruplicate, totaling 16 experimental tanks, with a stocking density of 2000 post-larvae m⁻ ³ . Shrimp growth performance parameters were positively influenced by the inclusion of Viligen® NE in the diet. Polynomial regression indicated an optimal inclusion level of 1.17 g kg⁻ ¹ for maximizing specific growth rate and weight gain. Additionally, supplementation at 1 g kg⁻ ¹ enhanced shrimp resistance to cold challenge. However, no significant differences were observed in intestinal counts of total heterotrophic bacteria or Vibrio spp. among treatments. In conclusion, dietary supplementation with Viligen® NE at an optimal level of 1.17 g kg⁻ ¹ improved growth performance, and 1 g kg⁻ ¹ enhanced cold challenge resistance of nursery-phase shrimp reared in a biofloc system.

Integrated multitrophic aquaculture (IMTA) emerges as a sustainable strategy to control the excess of solids and inorganic nutrients that tend to increase in the biofloc system (BFT) cycle, since the model integrates organisms from different trophic levels sharing the same system and nutrients. Thus, this study compared a Penaeus vannamei monoculture system with an integrated biofloc system including Mugil liza, Holothuria grisea, Crassostrea tulipa, and Salicornia neei, focusing on water quality and the performance of organisms and systems. This study consisted of three monoculture systems (16 m³; 375 shrimp m⁻³) and three IMTA systems, composed of a shrimp tank (16 m³), a mullet tank (4 m³; 30 ind m⁻³), a combined tank (3 m³) for oysters (45 ind m⁻³) and sea cucumbers (3 ind m⁻²), and a Salicornia neei bed (2.78 m²; 37 ind m⁻²). All IMTA systems operated in recirculation without water exchange, using 10% of the established biofloc inoculum. The IMTA system had half the hydrated lime use (2.13 vs. 4.29 kg), lower solids (299.56 vs. 373.33 mg L⁻¹), and reduced sludge production (9.37 vs. 15.87 kg). Shrimp growth was similar in both systems. Mullet grew adequately with a survival rate of 95.8%, but oysters showed a survival rate of 45.7%. Sea cucumber had a survival rate of 100% until day 28, when a marked decline appeared, strongly correlated with rising temperature (>28 °C; r = −0.71). This resulted in a significant increase in solids in the last weeks, suggesting that the population decline reduces solids control capacity. Furthermore, the biofloc in IMTA was dominated by coccoid forms, with lower proportions of filamentous and cyanobacterial forms.

The growing concern about the shortage of fossil fuels drives the search for new sources of sustainable energy. Microalgae are considered promising in this area, since they are sources of third generation biofuels and protein. The present study aimed at describing and isolating species from the native phytoplankton communities of four reservoirs in the Pernambuco semiarid, making them available for experiments that can evaluate the biotechnological potential and meet the demands of the region. The collections occurred in water bodies located in the Pernambuco semiarid and the identification of the taxa occurred based on morphological characters using specific literature. A total of twenty-one taxa were identified, eight of them Cyanophyceae (Anabaena sp., Aphanocapsa elachista, Chroococcus dispersus, Dolichospermum sp., Merismopedia sp., Microcystis aeruginosa, Pseudanabaena limnetica, Synechococcus sp.), ten Chlorophyceae (Chlorella sp., Cosmarium bioculatum, Desmodesmus spp., Dictyosphaerium sp., Pediastrum duplex, Pediastrum simplex, Pseudokirchineriella subcapitata, Scenedesmus sp., Staurastrum leptocladum, Trochiscia sp) and only one of the following classes Bacillariophyceae (Aulacoseira granulata), Euglenophyceae (Trachelomonas volvocida) and Dinophyceae (Ceratium furcoides). The bioprospection of microalgae in the semiarid region of Pernambuco has made possible the formation of a bank of strains, important for fictional studies and obtaining biomass of species with biotechnological potential.