Túlio Pacheco Boaventura

This study evaluated the physiological impacts of acute-exposure of tambaqui ( Colossoma macropomum ) to different concentrations of cellulose acetate nanoparticles at different sampling times. A total of 120 juvenile C. macropomum (38.91 ± 5.57 g and 13.76 ± 0.74 cm in total length) were distributed in 12 tanks of 150 L, in a recirculating aquaculture system (RAS). The juveniles were kept in water containing cellulose acetate nanoparticles (CANs) at four different concentrations (treatments): 0 mg L ⁻ ¹, 0.01 mg L ⁻ ¹, 0.10 mg L ⁻ ¹ and 1.00 mg L ⁻ ¹. Blood samples were collected after 1 and 24 h of exposure. The juveniles were then relocated to a tank with clean water, where they remained for another 24 h, after which a new blood sample was collected (24 h). Hemoglobin, serum protein and globulin were reduced after 1 h of exposure for the group exposed to 1.00 mg L ⁻ ¹ of CANs. Glucose levels increased after 24 h for the groups exposed to 0.10 and 1.00 mg L ⁻ ¹. Urea increased after 1 h for the groups exposed to 0.10 and 1.00 mg L ⁻ ¹. Triglycerides and cholesterol were reduced both after 1 h and 24 h of exposure for the 1.00 mg L ⁻ ¹ group, returning to baseline levels at 24 h. The activities of aspartate aminotransferase (AST) and alanine aminotransferase were altered after 24 h. Albumin was lower after 1 h and 24 h compared to after 24 h for the 1.00 mg L ⁻ ¹ group. Exposure of juvenile C. macropomum to CANs caused transient physiological changes, with partial recovery being observed after transfer to clean water.

The conversion of agroindustrial waste into functional materials supports sustainable process engineering by enabling controlled phosphorus (P) release to improve nutrient use efficiency and reduce environmental impacts. This study assesses biochar from fish scales as a sustainable P source. Biochars produced at temperatures between 300°C and 600°C were characterized by yield, PZC, TGA, FTIR, SEM, elemental analysis, and total/available P by ICP‐OES. Phosphorus release kinetics were fitted to mathematical models. Increased pyrolysis temperature enhanced available P. The Korsmeyer–Peppas model best described release, indicating diffusion‐controlled slow release. Carbon content decreased with higher pyrolysis temperature. Wheat greenhouse trials confirmed fertilizer efficacy. Fish scale biochar is a promising sustainable phosphate source for process‐oriented agricultural technologies.

Resumo Este estudo investigou a produção de nanopartículas de hidroxiapatita a partir de escamas de peixe calcinadas em diferentes temperaturas (400, 600, 800 e 1000°C), com o objetivo de avaliar o efeito da temperatura de calcinação na cristalinidade e sua influência na liberação de fósforo para aplicações agrícolas. A análise de difração de raios X (XRD) demonstrou que temperaturas de calcinação mais altas levaram ao aumento da cristalinidade e a tamanhos maiores de cristalito. As nanopartículas calcinadas a 600°C exibiram a maior concentração de fósforo e a cinética de liberação mais favorável. Foi descoberto que as nanopartículas de hidroxiapatita fornecem uma quantidade significativa de fósforo biodisponível às plantas. No entanto, o aumento da cristalinidade nas amostras calcinadas em temperaturas mais altas mostrou-se prejudicial ao desenvolvimento da planta, possivelmente devido a efeitos citotóxicos ou disponibilidade reduzida de fósforo.

The tanks used in RASs can be manufactured in any color. RAS tank color can have a great influence on fish, with direct impacts on food capture and, consequently, performance and survival. This study investigated the influence of different tank colors on the performance and coloration of Pangasianodon hypophthalmus. Juvenile were cultivated in tanks of different colors (white, blue, and black) for 60 days.One hundred and forty-four juvenile P. hypophthalmus, weighing 2.18±0.5 g and measuring 6.76±0.17 cm in total length, were distributed among three RASs. Each RAS was equipped with a 200-liter rectangular filter, with mechanical and biological filter, a heating and water pumping system and four 30-liter tanks covered with colored adhesive (white, blue or black) that were filled with 28 liters of water. Therefore, each RAS was considered a color treatment (white, blue or black) with four replicates (tanks), which had a density of 0.43 juveniles per liter (12 juveniles in each replicate). Juveniles cultivated in darker tanks exhibited darker coloration. Juveniles cultivated in blue tanks showed higher final weight (FW), total length (TL), and weight gain (WG) and lower feed conversion ratio (FCR). Juveniles cultivated in white tanks had lower TL and higher FCR. In conclusion, P. hypophthalmus juveniles performed better when cultivated in blue tanks.

This study examines the development and characterization of composites comprising low-density polyethylene (LDPE), thermoplastic starch (TPS), and cellulose fibers sourced from recycled banknotes (BR). The composites were fabricated using extrusion and injection molding techniques, followed by an evaluation of their morphological, thermal, mechanical, and water absorption properties. The inclusion of BR fibers enhanced the mechanical performance of LDPE, notably improving tensile strength and elastic modulus, while the hydrophobic treatment of the fibers ensured minimal water absorption. The incorporation of TPS increased the composites' biodegradability potential but reduced tensile strength and increased water absorption due to its hydrophilic nature. Scanning electron microscopy revealed strong interfacial adhesion between the fibers and matrix and confirmed the complete dispersion of starch in TPS-containing samples. Thermogravimetric analysis highlighted the thermal stability of the composites and identified distinct degradation stages corresponding to the matrix, TPS, and fibers. These results indicate that the developed composites offer a viable solution for agricultural applications, balancing mechanical performance and environmental sustainability.

The feed used in fish farming contains lipids that erode and disperse in water, adversely affecting fish nutrition and contributing to water pollution. This study evaluated the encapsulation of corn and gold linseed oils in polylactic acid (PLA) nanofibers produced via Solution Blow Spinning. The nanofibers were characterized using Fourier-Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), contact angle analysis, and encapsulation efficiency tests. Additionally, the release profiles of the oils were studied under simulated tank water and gastrointestinal conditions. The results demonstrated successful encapsulation of the oils within the PLA matrix. FTIR analysis confirmed the presence of oil in the nanofibers (wavenumbers 2925 and 2853 cm-1), with encapsulation efficiencies ranging from 81.54±10.36% to 99.14±4.55%. SEM revealed uniform nanofiber morphology with smooth surfaces and average diameters between 157±49 and 385±133 nm. All nanofibers exhibited contact angles above 90°, indicating hydrophobic behavior. Feed samples containing free oils showed significantly higher lipid release into water compared to feed incorporating encapsulated oils. The findings suggest that encapsulating vegetable oils in PLA nanofibers reduces lipid dispersion in water while maintaining nutrient availability. This polymeric system offers a sustainable alternative to enhance aquaculture feed efficiency and reduce environmental impacts, contributing to cleaner water and healthier fish.