Search Results (43)

This study evaluated the physiological condition and health status of triploid tambaqui (Colossoma macropomum) using hematological and biochemical indicators. Hematocrit, hemoglobin concentration, erythrocyte count, glucose, and plasma protein levels (albumin, globulin and albumin/globulin ratio) were assessed in triploid and diploid fish, and mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were calculated. Triploid fish exhibited larger erythrocytes, reduced erythrocyte counts, and slightly lower hemoglobin and hematocrit values compared with diploids. Correspondingly, MCV and MCH were significantly higher in triploids, indicating increased hemoglobin content per erythrocyte. In contrast, MCHC values did not differ between ploidy groups, suggesting that hemoglobin concentration within erythrocytes remained unaffected. No significant differences were observed in the evaluated biochemical parameters. These findings indicate that triploid tambaqui undergo compensatory physiological adjustments associated with increased nuclear DNA content in erythrocytes, enabling the maintenance of efficient oxygen transport and respiratory capacity. Overall, triploid fish displayed normal physiological performance, comparable to that of diploids. The results support the use of triploidy as a viable and sustainable strategy in tambaqui aquaculture. Full article

Morphine is widely used as an analgesic in vertebrates, yet its cardiorespiratory safety and effective therapeutic range remain poorly explored in fish. This study investigated the dose-dependent effects of morphine on cardiac and respiratory parameters of juvenile tambaqui (Colossoma macropomum). Juveniles (25.95 ± 4.08 g) were randomly assigned to control, sham (0.9% saline) or morphine groups (24, 28, 32, 36 and 40 mg kg⁻¹, i.p.). Electrocardiogram (ECG) recordings were used to assess heart rate (HR), PQ, RR and QT intervals, and QRS amplitude, while opercular beat rate (OBR) and opercular beat intensity (OBI) were measured to evaluate respiratory responses. Morphine induced a significant dose-dependent bradycardia and QT prolongation, without affecting QRS amplitude or conduction integrity. Respiratory frequency and intensity also decreased with increasing doses, with responses plateauing above 32 mg kg⁻¹. The EC₅₀ for HR reduction was 27.18 mg kg⁻¹, aligning with a safe therapeutic range of 24–32 mg kg⁻¹. By establishing this dose–response dynamic, the study provides the first characterization of a physiologically safe therapeutic window of morphine in tambaqui and highlights its safety profile for cardiorespiratory parameters. Moreover, the present results demonstrate that the opioid system of juvenile tambaqui is functionally developed, providing a physiological basis for future studies on nociception and analgesic efficacy, with relevance to welfare-oriented practices in aquaculture. Full article

This study quantified nitrogen (N) and phosphorus (P) budgets in tambaqui (Colossoma macropomum) cultured for 10 months in fertilized and unfertilized ponds in a tropical region. Juveniles (94 ± 15 g) were stocked at 0.55 fish m⁻² in 600-m² ponds, with four replicates per treatment. Inputs consisted of water, feed, fish, and fertilizer, whereas outputs included harvested fish, sediment, and outlet water. Feed and inlet water were the primary sources of nutrients in the pond systems, while outlet water and fish biomass represented the major nutrient outputs. Total N input was higher in fertilized ponds, whereas total P input was similar between treatments. Feed contributed a larger proportion of total N and P in unfertilized ponds than in fertilized ponds. In fertilized ponds, fertilizer accounted for 19% of total N and 6% of total P. Total N and P outputs did not differ between treatments, although N output showed high variability due to sediment accumulation. Fish recovered 15–20% of N and 22% of P inputs. Greater N use efficiency was observed in unfertilized ponds. Overall, fertilization did not improve nutrient recovery or total nutrient output but reduced feed inputs, suggesting that fertilizer, particularly nitrogen, should be carefully evaluated regarding its environmental and economic relevance in tambaqui pond culture. Full article

Background: The intensification of aquaculture has led to increased use of chemical agents, such as trichlorfon, for controlling parasitic infections in farmed fish. While effective, this organophosphate compound may exert toxic effects even at sublethal concentrations, posing risks to economically important species such as tambaqui (C. macropomum). This study investigated the molecular effects of trichlorfon on the expression of genes involved in stress response, energy metabolism, and apoptosis in juvenile tambaqui. Methods: Fish were exposed to two sublethal concentrations of trichlorfon (30% and 50% LC_{50–96 h}, equivalent to 0.261 and 0.435 mg/L) for 48, 72, and 96 h. Expression levels of fkbp5, p53, pim-2, pir, me1, bbox1, and higd1a were quantified in liver tissue using qPCR. Results: fkbp5 and p53 were strongly upregulated at 48 h, indicating acute stress and genotoxic activation. me1 and pim-2 were also upregulated, reflecting activation of compensatory energy metabolism and anti-apoptotic survival pathways. bbox1 showed an early induction followed by collapse at 96 h, while higd1a and pir exhibited delayed overexpression at 96 h, suggesting mitochondrial hypoxia and inflammation. Conclusions: Trichlorfon triggers a multifaceted toxic response characterized by initial activation of compensatory pathways (stress response, antioxidant defense, and anti-apoptotic mechanisms) followed by late-phase metabolic collapse, mitochondrial hypoxia, and inflammation, with both time- and dose-dependent effects. These findings demonstrate that even sublethal concentrations disrupt hepatic homeostasis and support the use of these genes as molecular biomarkers for environmental monitoring in aquaculture. Full article

Tambatinga (Colossoma macropomum × Piaractus brachypomus), a hybrid Amazonian fish recognized for its superior growth performance, represents a valuable and sustainable source of collagen-rich raw material. Due to its tropical origin, the species’ skin may contain higher levels of amino acids, which can enhance the functional and structural properties of gelatin derived from it. The valorization of fish processing residues for biopolymer production not only mitigates environmental impacts but also reinforces the principles of the circular economy within aquaculture systems. This study explores the development of biopolymer films from Tambatinga skin, an abundant by-product of Brazilian aquaculture. The skins were cleaned and subjected to a hot water–acid extraction process to obtain gelatin. The extracted gelatin exhibited high proline and hydroxyproline contents (12.47 and 9.84 g/100 g of amino acids, respectively) and a Bloom strength of 263.9 g, confirming its suitability for film formation. Films were prepared using 2 g of gelatin per 100 g of film-forming solution, with glycerol added at 10 and 20 g/100 g of gelatin. The resulting films were transparent, flexible, and showed uniform surfaces. Increasing the glycerol concentration reduced tensile strength (from 59.4 to 37.9 MPa) but improved elongation at break (from 116% to 159.1%) and modified the films’ thermal behavior. Moreover, Tambatinga gelatin films demonstrated excellent UV-blocking performance (below 300 nm) and lower water vapor permeability compared to other gelatin-based films reported in the literature. These findings highlight the potential of fish skin—typically regarded as industrial waste—as a renewable and high-value raw material for the production of sustainable biopolymers. This approach supports resource efficiency, waste reduction, and the broader goals of sustainable development and circular bioeconomy. Full article

The global demand for sustainable food systems requires innovative strategies that reconcile productivity with environmental stewardship, particularly in biodiversity-rich regions such as the Amazon. This study evaluated the cultivation of Acmella oleracea (jambu) using effluent from Colossoma macropomum (tambaqui) aquaculture as a partial substitute for chemical fertilizer. Five treatments were tested under greenhouse conditions: 100% fertilizer, 75% fertilizer, 50% fertilizer, 25% chemical, and 0% fertilizer. Significant treatment effects were observed for leaf number, plant height, stem diameter, and shoot biomass, while root biomass showed no differences. Treatments with 100%, 75%, and 50% fertilizer exhibited statistically similar performance across several growth parameters, indicating that up to 50% of the chemical fertilizer can be replaced by aquaculture effluent without significant yield reduction. Treatments with 50% fertilizer and 0% fertilizer showed reduced growth and higher tissue accumulation of nitrate and ammonium, reflecting nutritional imbalances. In parallel, tambaqui showed 100% survival and satisfactory growth, confirming the stability of the integrated system. These results highlight that, although exclusive use of effluent is insufficient to match chemical fertilizer, partial substitution represents a viable strategy to reduce input costs and recycle nutrients, reinforcing the bioeconomic potential of aqua-culture–agriculture integration in the Amazon. Full article

Aquaculture faces challenges in reducing feed costs while promoting sustainable use of by-products. This study aimed to evaluate the effects of totally replacing soybean oil (SBO) with fish by-product oil (FBO) in the diet of Colossoma macropomum, focusing on growth performance, physiological and hepatic responses, meat composition, and economic viability. A total of 360 juveniles (9.1 ± 0.59) were distributed in a randomized design with six treatments (0–100% SBO replacement) and six replicates each, and fed to apparent satiation for 91 days. Growth performance did not differ significantly among treatments (p > 0.05), although fish receiving 40% FBO achieved the best feed conversion ratio among treatments. Hematological and biochemical analyses indicated that higher FBO levels (particularly 100%) indicating subtle yet adaptive physiological adjustments, such as moderate modulations in lipid metabolism and erythropoietic activity. Liver weight and hepatosomatic index decreased linearly with increasing FBO levels. In meat composition, FBO inclusion enhanced protein and reduced lipid contents. Although economic indicators were not statistically different (p > 0.05), offered the most favorable trade-off between biological performance and economic efficiency. These findings demonstrate that partial replacement of SBO with FBO, particularly at 40%, represents a sustainable and economically viable alternative for C. macropomum farming. Full article

Rapid population growth has increased the demand for sustainable systems to produce protein-rich foods. Aquaculture with native species offers a strategic alternative to enhance food security in the Amazon region. This study evaluated the productive performance of Liposarcus pardalis and Hypostomus hemicochliodon in polyculture with Colossoma macropomum at different stocking densities (1, 3, and 5 fish/m²) for 120 days. Both loricariid species exhibited high survival (>96%) and satisfactory growth, with optimal performance at intermediate densities (3 fish/m²). Polynomial regression estimated optimal stocking densities of 2.45 and 2.42 fish/m² for L. pardalis and H. hemicochliodon, respectively. Polycultures with H. hemicochliodon yielded the highest biomass (22.11 ± 0.09 kg) and best feed conversion efficiency (FCE = 1.4), outperforming those with L. pardalis (19.36 ± 0.19 kg; FCE = 1.9). Although monoculture data for C. macropomum were not included, comparisons with published studies indicate that polyculture did not compromise its growth. The integration of native benthic, iliophagous species improves resource use and nutrient recycling, providing a sustainable strategy to enhance productivity and environmental efficiency in tropical aquaculture systems. Full article

The increasing demand for sustainable and cost-effective animal feed alternatives has stimulated the use of agro-industrial by-products in poultry diets. This study evaluated the effects of tambaqui (Colossoma macropomum) residual oil (TRO), derived from aquaculture waste, on productive performance, physiological responses, and egg quality in commercial laying hens. A total of 144 Hisex Brown hens were assigned to diets containing 0%, 1.5%, 3.0%, or 4.5% TRO for 63 days. While TRO inclusion did not affect overall productivity, moderate levels (1.5% and 3.0%) improved egg weight, yolk pigmentation, and internal quality (Haugh unit). Hematological and biochemical parameters indicated metabolic adaptations, with increased cholesterol and decreased triglycerides in treated groups. The yolk fatty acid profile revealed higher omega-3 content with TRO inclusion, but lipid oxidation (TBARS) also increased, especially at higher levels. Sensory evaluation showed reduced aroma and flavor acceptability in eggs from hens fed 3.0% and 4.5% TRO. These findings suggest that moderate TRO inclusion can enhance egg nutritional value and support sustainable aquaculture waste reuse, though excessive levels may compromise product acceptability. Optimal inclusion levels should be further explored to balance metabolic benefits, oxidative stability, and consumer preferences. Full article

Background: Salmonellosis is a foodborne illness typically associated with gastroenteritis following the ingestion of products contaminated with Salmonella enterica. Although the aquatic environment is not a natural reservoir for Salmonella spp., its occurrence has been reported in various aquacultured species worldwide, including species from the Amazon Basin in South America. The World Health Organization has classified the emergence of multidrug-resistant (MDR) Salmonella strains as a global priority, underscoring the importance of monitoring antimicrobial resistance to mitigate public health risks. This study aimed to detect Salmonella spp. serotypes of clinical relevance to humans (S. Typhi, S. Paratyphi, S. Typhimurium, and S. Enteritidis) in farmed tambaqui hybrids and to assess the antimicrobial susceptibility of the isolates. Methods: A total of 55 Salmonella spp. strains, previously isolated from tambaqui hybrids (Colossoma macropomum) produced in fish farms in Mato Grosso, Brazil, were evaluated. Identification and susceptibility profiling were performed using the VITEK^®2 Compact automated system (BioMérieux, Marcy l’Étoile, France), testing 14 commonly used antimicrobials, including amoxicillin–clavulanic acid, piperacillin–tazobactam, cephalexin, cefuroxime axetil, ceftriaxone, cefepime, meropenem, ertapenem, amikacin, gentamicin, ciprofloxacin, and sulfamethoxazole–trimethoprim. Results: All isolates were confirmed as Salmonella spp., with no detection of clinically important serotypes. Moreover, all 55 strains were susceptible to the 14 antimicrobials tested. Conclusions: These findings indicate a low risk of pathogenic or resistant Salmonella from farmed tambaqui hybrids under the evaluated conditions. Nevertheless, ongoing microbiological monitoring remains essential, particularly in light of regulatory standards that prohibit the presence of Salmonella spp. in fish products and the potential emergence of MDR strains. Full article

Hesperozygis ringens essential oil (HREO), rich in pulegone and limonene, has potential application in aquaculture due to its beneficial properties. This study evaluated the effects of dietary supplementation with HREO (0.0, 0.75, 1.0, and 2.0 g HREO kg feed⁻¹) for 30 days on the physiological responses of Colossoma macropomum before and after a simulated 4 h transport. Fish were sampled at four time points: before transport (Basal), immediately after transport (IAT), and at 24 h (AT24) and 48 h (AT48) post-transport. Growth performance and survival (>96%) were not affected by HREO. Hemoglobin concentration, mean corpuscular hemoglobin concentration (MCHC), and intestinal coefficient showed significant responses to dietary HREO. After transport, survival was 100% for all treatments, and hematological and biochemical parameters varied according to dose and recovery time, with 2.0 g HREO kg feed⁻¹ showing the most consistent benefits, such as stabilization of hemoglobin, MCHC, and plasma proteins during recovery at AT₂₄ and AT₄₈. Water quality parameters did not differ between treatments at transportation end. These findings suggest that dietary HREO may contribute to enhance the physiological responses to transport in C. macropomum, supporting its potential use as a sustainable nutritional strategy. Full article

This study evaluated the effectiveness of essential oil from Aloysia citrodora (EOAC) (48% citral and 19% limonene) for use in anesthesia and simulated transport of tambaqui (Colossoma macropomum) juveniles at two cargo densities (CDs). Concentrations of 0 (control), 10, 25, 50, 100, 150, 200, and 250 µL EOAC L⁻¹ were tested for use in anesthesia induction and recovery, while 0 (control) and 20 µL EOAC L⁻¹ were tested for their effects on the ventilatory rate (VR) and during 6 h simulated transport at a low CD (LCD, 65 g L⁻¹) and standard CD (SCD, 130 g L⁻¹). Fish were anesthetized at EOAC concentrations above 50 µL L⁻¹, with the optimal anesthesia (141.83 s) and recovery times (160.00 s) at 250 µL L⁻¹. The water unionized ammonia was lowest in the EOAC-LCD group. Using 20 µL EOAC L⁻¹ during transport minimized changes in the hematological parameters (erythrocytes, hemoglobin, hematocrit, total leukocytes, and heterophils) and reduced the liver aspartate aminotransferase activity at both CDs. Transport at an SCD, regardless of EOAC use, increased the plasma glucose, hepatic glycogen, and alanine transaminase activity. The VR was higher with 20 µL EOAC L⁻¹ than in the control group. In conclusion, our findings confirm that 20 µL EOAC L⁻¹ can effectively be used to transport tambaqui for up to 6 h without impairing fish health. Full article

Trichlorfon is an antiparasitic agent widely used to control pests and parasites in farmed fish. Tambaqui (C. macropomum) is the most commercially important characid species farmed in the Amazon region. Trichlorfon exposure is known to cause physiological damage in fish due to its organophosphate nature. In this study, we used RNA-Seq to investigate the hepatic response of tambaqui following exposure to 0.435 mg/L of trichlorfon. The analysis revealed activation of several metabolic pathways, particularly those related to tumor processes, immune responses, and apoptosis. Additionally, we identified upregulation of solute carrier (SLC) genes, which may facilitate trichlorfon entry into hepatocytes. These findings enhance our understanding of fish responses to antiparasitic agents and support further research into the molecular impacts of organophosphate compounds in aquaculture species. Full article

Background/Objectives: Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism, crucial for the hydrolysis of triglycerides in lipoproteins and maintaining lipid homeostasis in vertebrates. This study aims to characterize the lipoprotein lipase genes in the tambaqui (Colossoma macropomum) genome, investigating their evolutionary history from a phylogenomic perspective. Methods: Phylogenetic and syntenic analyses were used to identify the lpl gene copies in the tambaqui genome and expression patterns were examined across different tissues. A comparative analysis with lpl genes from other vertebrates was also conducted to assess evolutionary relationships and functional diversification. Results: We identified three lpl gene copies in the tambaqui genome: lpl1a, lpl1b, and the lesser-known member of the lipoprotein lipase subfamily, lpl2a. These proteins possess conserved sites essential for lipoprotein lipase function, with variations that may affect their physicochemical properties and lipolytic activity. Key amino acid variations, such as in the lid region and glycosylation sites, were observed among orthologs. Gene expression analysis showed high lpl1a and lpl2a expression in the liver, and lpl1b expression in the gonads, suggesting tissue-specific roles. Comparative analysis revealed distinct expression patterns among teleost fish, with tambaqui exhibiting a unique profile consistent with its migratory lifestyle and varied diet. Conclusions: This study offers new insights into the evolution and functional diversification of lipoprotein lipases in vertebrates, highlighting the complexity of lipid metabolism in fish. These findings contribute to understanding the adaptability of teleost fish to diverse environments and lay the foundation for future research in lipid metabolism regulation, including Neotropical species, with potential applications in aquaculture and conservation. Full article

This study investigated the growth performance and physiological and intestinal histomorphometry of juvenile tambaqui Colossoma macropomum (51.68 ± 3.87 g), fed continuously or subjected to weekly cycles of feed restriction (one day of no feeding followed by six days of feeding) associated with feeding frequencies of two or three times a day, for 84 days, in a recirculating aquaculture system (RAS). Growth performance and blood parameters were determined after 42 and 84 days. Liver, adipose tissue and intestine were collected after 84 days to determine the somatic indices, liver lipid levels and intestinal histomorphometry. Restricted fish had greater feed intake compared to continuously fed after 42 days, as well as greater specific growth rate (SGR) and better feed conversion between 43 and 84 days. No significant differences were observed for restriction, feeding frequency or the interaction for blood parameters after 42 and 84 days, somatic indices and liver lipid levels after 84 days, with the exception of plasma glucose, which was higher for restricted fish after 84 days. The feed restriction promoted a greater intestinal villi perimeter and height compared to continuously fed fish, as did fish fed twice a day compared to those fed three times a day, with an interaction between factors. We concluded that six days of feeding per week and twice-daily feeding frequency can be used as a feeding protocol for tambaqui juveniles over an 84-day period in RAS and this management protocol can also help reduce feed and labor costs in the production of this species. Full article