Acute toxicity by water containing hexavalent or trivalent chromium in native Brazilian fish, Piaractus mesopotamicus: anatomopathological alterations and mortality

Using diatom chain length as a bioindicator of heavy-metals contamination in marine environments

The increasing release of toxic heavy metals into marine environments poses significant risks due to their persistence and bioaccumulation. Diatoms are ideal bioindicators because of their sensitivity to environmental changes. Despite traditional methods for detecting these persistent pollutants effectively identify composition and concentration, they are time-consuming, they often require the use of harmful reagents, and do not allow a fast assessment of detrimental impacts on marine organisms. To fill this gap, we have successfully investigated the toxicity of different heavy metals in the marine diatom Skeletonema pseudocostatum thanks to a newly developed high-power terahertz (THz) spectrometer. By combining THz spectroscopy, microscopy and ecotoxicological assays, we found that the formation of long diatom chains is significantly inhibited by the presence of lead, copper, and chromium, which disrupt their metabolism. Although the THz absorption and refractive index spectra were not affected by diatom concentration in undoped samples, THz frequencies were highly sensitive to changes in diatom chain length due to heavy metals exposure. These findings suggest that this approach allows to investigate the biochemical processes involved in chain formation in S. pseudocostatum and related algae. THz spectroscopy could therefore provide deeper insights into the microscopic metabolic activity of diatoms, addressing key biochemical questions surrounding these organisms. Furthermore, we propose this novel approach for environmental pollution monitoring, since it could provide a rapid, harmless and sensitive detection method to assess heavy metal toxicity in marine diatoms, key organisms at the basis of the trophic chain.

Growth disorders, respiratory distress and skin discoloration in zebrafish (Danio rerio) after chronic exposure to Palm Oil Mill Effluent

Understanding the environmental and health impacts of Palm Oil Mill Effluent (POME) contamination is essential for driving sustainable practices and innovation within the industry. In this study, we elaborated the chronic toxicity of POME on growth disorder, respiratory distress, and skin discoloration of zebrafish (Danio rerio). Zebrafish were exposed to three concentrations of POME (0 mL/L, 0.5 mL/L and 1.0 mL/L) for 28 days. Results revealed that an increase in POME concentration significantly reduced the weight gain, length gain, specific growth rate, specific length rate and oxygen consumption rate of zebrafish. In contrast, the opercular rate increased significantly. Skin discoloration in zebrafish exposed to POME were characterized by reduced red percentage value on the body and tail, increased green and blue percentages on the tail, and decreased brightness values. This result suggests crucial insights for the management and regulation of POME.

Acute toxicity of palm oil mill effluent on zebrafish (Danio rerio Hamilton-Buchanan, 1822): Growth performance, behavioral responses and histopathological lesions

Evaluating the toxicity of Palm Oil Mill Effluent (POME) is critical as part of the effort to develop waste management regulations for the palm oil industry. In this study, we investigated the acute toxicity of POME on growth performance, behavioral response, and histopathology of gill and liver tissues of zebrafish (Danio rerio). In total, 550 adult male zebrafish were used for the toxicity experiment including range finding test, acute toxicity test, growth performance and behaviour test. Static non-renewal acute toxicity bioassays were conducted by exposing fish to POME (1.584-9.968 mL/L) for 96 h. Growth performance, behavior response, and histopathological lesions in untreated and POME treated (96-h LC50: 5.156 mL/L) fish were measured at 24, 48, 72 and 96 h. Time-dependent significant decline in body length and body weight of POME-exposed zebrafish was observed. Furthermore, several behavioral changes were recorded, including hyperactivity, loss of balance, excessive mucus secretion, and depigmentation. Decreasing operculum movement and oxygen consumption rate as well as alterations in gill tissues (i.e. hyperplasia, hypertrophy, hemorrhage, and necrosis) of POME-exposed zebrafish were observed, suggesting a dysfunction in respiratory performance. On the other hand, liver tissue alterations (congestion, hemorrhage, hyperplasia, shrinkage of hepatocytes, hydrophilic degeneration, and necrosis) indicated a disruption in detoxification performance. We conclude that exposure to POME at acute concentration caused histopathological lesions both in gill and liver tissue along with changes in fish behaviors which disrupted respiratory and detoxification performance, resulting in mortality and reduced growth of zebrafish. These findings might provide valuable information for guiding POME management and regulation.

Ecotoxicology of hexavalent chromium in fish: An updated review

Chromium (Cr) is prevalently found in trivalent and hexavalent forms. Though the former is toxicologically benign due to its poor cellular permeability, hexavalent chromium i.e. Cr [VI] crosses the biological membrane and induces toxic effects in organisms. While Cr [VI] toxicity in humans is a subject of occupational exposure at industries involved in ferrochrome production, leather tanning, textile dyeing etc., aquatic abundance of Cr [VI] due to discharge of Cr-laden effluents by these industries lead to extensive toxicity in piscine species. The present review aims to discuss the mode of Cr [VI] entry in fish and the several inimical effects that it imparts on fish health. Such effects have been reported in various studies through behavioral, hormonal and hematological alterations. Bio-accumulation of Cr [VI] in vital organs and subsequent perturbation of the oxidative homeostasis leads to organotoxic effects like changes in organo-somatic indices and histo-architecture. At cellular level, Cr [VI] induced genotoxicity is often found to trigger cellular demise including apoptosis. This review also highlights the stress response in fish against Cr [VI] induced toxicity that is mediated through the expressional alteration of a myriad of anti-oxidant and xenobiotic-metabolizing proteins which is, in turn, a function of activated transcription programs including the Nrf2-ARE pathway.

Biogeochemical behaviour and toxicology of chromium in the soil-water-human nexus: A review

Chromium (Cr) affects human health if it accumulates in organs to elevated concentrations. The toxicity risk of Cr in the ecosphere depends upon the dominant Cr species and their bioavailability in the lithosphere, hydrosphere, and biosphere. However, the soil-water-human nexus that controls the biogeochemical behaviour of Cr and its potential toxicity is not fully understood. This paper synthesizes information on different dimensions of Cr ecotoxicological hazards in the soil and water and their subsequent effects on human health. The various routes of environmental exposure of Cr to humans and other organisms are also discussed. Human exposure to Cr(VI) causes both carcinogenic and non-carcinogenic health effects via complicated reactions that include oxidative stress, chromosomal and DNA damage, and mutagenesis. Chromium (VI) inhalation can cause lung cancer; however, incidences of other types of cancer following Cr(VI) exposure are low but probable. The non-carcinogenic health consequences of Cr(VI) exposure are primarily respiratory and cutaneous. Research on the biogeochemical behaviour of Cr and its toxicological hazards on human and other biological routes is therefore urgently needed to develop a holistic approach to understanding the soil-water-human nexus that controls the toxicological hazards of Cr and its detoxification.

Bioaccumulation of dietary CrPic, Cr(III) and Cr(VI) in juvenile coral trout (Plectropomus leopardus)

The form of chromium (Cr) is an important factor that influences its bioavailability and potential toxicity, while the difference of Cr bioaccumulation between organic and inorganic Cr has been rarely investigated. The present study compared the bioaccumulation of organic Cr (e.g., chromium picolinate (CrPic)) and inorganic Cr (e.g., trivalent (Cr(III)) and hexavalent (Cr(VI))) in juvenile coral trout (Plectropomus leopardus). The fish were exposed to a gradient level of different forms of dietary Cr for 66 days. Then the Cr bioaccumulation in fish were comparatively quantified between CrPic, Cr(VI) and Cr(III) groups. The results showed that the Cr bioaccumulation was form- and tissue-specific, dose- and time-dependent. Specifically, the newly bioaccumulated Cr in fish generally increased with the increasing dietary Cr level and exposure time, while the CrPic groups accumulated the highest Cr in most cases, followed by Cr(VI) and Cr(III) groups. The highest Cr content was observed in gut for CrPic groups, while it was highest in heart for Cr(VI) and Cr(III) groups, followed by kidney, skin, fin, liver, gill, bone, eyes and muscle in order. Overall, the results here firstly demonstrated that the dietary organic Cr(III) had significantly higher bioaccumulation than inorganic Cr (Cr(III) and Cr(VI)). Our findings suggested the complexity and variability of form-specific Cr bioavailability and toxicity should be cautiously evaluated in aquatic environments, which has been largely overlooked previously.

Molecular mechanism of heavy metals (Lead, Chromium, Arsenic, Mercury, Nickel and Cadmium) - induced hepatotoxicity - A review

Heavy metals pose a serious threat if they go beyond permissible limits in our bodies. Much heavy metal's viz. Lead, Chromium, Arsenic, Mercury, Nickel, and Cadmium pose a serious threat when they go beyond permissible limits and cause hepatotoxicity. They cause the generation of ROS which in turn causes numerous injuries and undesirable changes in the liver. Epidemiological studies have shown an increase in the levels of such heavy metals in the environment posing a serious threat to human health. Epigenetic alterations have been seen in the event of exposure to such heavy metals. Apoptosis, caspase activation as well as ultrastructural changes in the hepatocytes have also been seen due to heavy metals. Inflammation involving TNF-alpha, pro-inflammatory cytokines, MAPK, ERK pathways have been seen in the event of heavy metal hepatotoxicity. All these have shown that these heavy metals pose a serious threat to human health in particular and the environment as a whole.

Assessing hexavalent chromium tissue-specific accumulation patterns and induced physiological responses to probe chromium toxicity in Coturnix japonica quail

Hexavalent chromium (Cr(VI)) is an environmental pollutant with vast mutagenic and carcinogenic potential. Various past and recent studies confirm the deleterious effects of Cr(VI) in different models, from invertebrates to mammalians. However, there is a lack of studies that comprehensively assess and correlate Cr(VI) accumulation patterns and the resulting physiological responses. Here we used an attractive toxicological model, male Japanese quail (Coturnix japonica), as an alternative probing system to evaluate Cr(VI) accumulation in the vital organs, including the brain, heart, kidneys, liver, and testes after 20 days of exposure to 1.2 μg/mL and 2.4 μg/mL potassium dichromate-K₂Cr₂O₇ ingested in the form of drinking water. The observed effects were correlated with the shift in immune system readiness, hematological indices, serum biochemistry and enzyme activity. Regardless of the exposure dose, the Cr(VI) distribution and accumulation pattern in terms of relative Cr(VI) concentration in tissues was: testes > kidneys > liver > heart > brain. Moreover, Cr(VI) triggered the development of microcytic and hypochromic anemia and reduced the immune system's readiness to cope with challenges. Besides, serum biochemistry presented significant shifts, including reduction of serum electrolytes and proteins and an increase in creatine kinase (CK) and lactate dehydrogenase (LDH) activity. Our study provides novel toxicological data that can be translated to higher animal models to help in the extrapolation of Cr(VI) toxicity in humans.

The acute toxic effects of hexavalent chromium on the liver of marine medaka (Oryzias melastigma)

Chromium is toxic to marine animals and can cause damage to many of their organs, including the liver. To test the toxicity of chromium on marine organisms, we exposed the liver of the marine medaka (Oryzias melastigma) with hexavalent chromium [Cr(VI)]. Our results show that Cr enrichment in the liver demonstrates a positive correlation to the exposure concentration. With the increase of Cr(VI) concentration, pathological changes including nuclear migration, cell vacuolization, blurred intercellular gap, nuclear condensation, become noticeable. To further study changes in gene expression in the liver after Cr(VI) exposure, we used RNA-seq to compare expression profiles before and after Cr(VI) exposure. After acute Cr(VI) exposure (2.61 mg/l) for 96 h, 5862 transcripts significantly changed. It is the first time that the PPAR pathway was found to respond sensitively to Cr(VI) exposure in fish. Finally, combined with other published study, we found that there may be some difference between Cr(VI) toxicity in seawater fish and freshwater fish, due to degree of oxidative stress, distribution patterns and detailed Cr(VI) toxicological mechanisms. Not only does our study explore the mechanisms of Cr(VI) toxicity on the livers of marine medaka, it also points out different Cr(VI) toxicity levels and potential mechanisms between seawater fish and freshwater fish.

Role of neuroendocrine modulation and biochemistry in the sepsis in Piaractus mesopotamicus

Sepsis is a systemic process with multifactorial pathophysiology that affects most animal species. It is responsible for high rates of morbidity and mortality. This work aimed to study the biochemical and neuroendocrine changes of the sepsis process in Piaractus mesopotamicus after Aeromonas hydrophila inoculation analyzing changes in blood leukocyte and differences in neuroendocrine-biochemical modulation using RNA-seq. Fish showed hypercortisolemia, inhibition of glucose absorption, followed by hypocortisolemia and then hyperglycemia. Thyroid hormones (T₃ and T₄) showed immediate decrease in serum and T₄ increased 6 h post-inoculation (HPI). Sepsis-induced hormonal alterations triggered changes in the metabolic pathways increasing protein and lipid catabolism, use of transient anaerobic glycolysis and liver injury. A reference transcriptome was constructed based on blood leukocytes from P. mesopotamicus. The assembly resulted in total 266,272 contigs with a N50 of 2786 bp. There was a reorganization of plasma membrane of leukocytes at the beginning of the septic process with increased expression of neuroendocrine receptors and with continuous flow of neurotransmitters, hormones and solutes with compensatory regulation at 6 HPI. Three and nine HPI seemed to be critical, the expression of a number of transcription factors was increased, including the modulatory DEGs related to glucocorticoid and thyroid hormones induced and suppressed (FDR < 0.05). Neuroendocrine modulation can regulate leukocytes and biochemical parameters of peripheral blood, being important sources for the study of the pathophysiology of sepsis. These finding highlights the importance of further studies focusing on biochemical-neuroendocrine changes in blood leukocytes and systemic sepsis.

Experimental modeling of the acute toxicity and cytogenotoxic fate of composite mixtures of chromate, copper and arsenate oxides associated with CCA preservative using Clarias gariepinus (Burchell 1822)

Concurrent occurrence of chromium (Cr), copper (Cu) and arsenic (As) from chromated copper arsenate (CCA) wood preservative in aquatic ecosystems demands that their joint-actions in eliciting toxic effects be assessed for adequate understanding of the health risk they may pose to biota. Clarias gariepinus was exposed to As₂O₃ , CrO₃ and CuO and their composite mixtures (1:1 and 1:1:1) at various concentrations (0 – 600 mg/L) for 96-h to determine the acute toxicity using OECD (1992) protocol. C. gariepinus was then exposed to sub-lethal concentrations corresponding to 6.25, 12.5, 25.0, 50.0 and 100% of the 96-h LC₅₀ for 7 days to assess the cytogenotoxic effects using piscine micronucleus (MN) test. The 96-h LC₅₀ showed that the metals/metalloid demonstrated differential interactions in a concentration dependent pattern. The 96-h LC₅₀ showed that Cr was the most toxic while Cu and As:Cu were indeterminate (Cr > Cr:Cu > As:Cr > As > As:Cr:Cu > Cu = As:Cu indeterminate). Isobologram and synergistic ratio (SR) models predicted antagonistic interaction between Cu:Cr and As:Cr and synergism between As:Cu in the causation of morbidity and mortality of C. gariepinus. Interaction factor model predicted antagonism as common interactive mechanism among the metal/metalloid mixtures in the induction of MN and abnormal nuclear erythrocytes in C. gariepinus. Predicted interactions among the three metals/ metalloid were largely antagonism and synergism towards the induction of acute toxicity and cytogenotoxicity. The models employed herein may be useful in establishing environmental safe limits for mixtures of metals/metalloids against the induction of acute toxicity and DNA damage in lower aquatic vertebrates.

Hematological and immune changes in Piaractus mesopotamicus in the sepsis induced by Aeromonas hydrophila

The pathogenesis of sepsis involves complex systems and multiple interrelationships between the host and pathogen producing high mortality rates in various animal species. In this study, hematological disturbances, innate immunity and survival during the septic process in Piaractus mesopotamicus inoculated with Aeromonas hydrophila were studied. For this aim, fish blood samples were taken from control and infected groups 1, 3, 6, and 9 h post-inoculation (HPI). Leukogram showed reduction in the number of leukocytes and thrombocytes, followed by cessation of leukocyte chemotaxis 6 HPI and severe morphological changes in leukocytes and erythrocytes. At 3 HPI production of reactive oxygen species increased and at 6 HPI decreased. There was no change in serum lysozyme concentration and lytic activity of the complement system, despite the progressive increase in serum lytic activity and bacterial agglutination. Finally, the changes in clinical signs due to aeromonosis and increasing septicemia resulted in a reduction in survival to 57.14% after 36 HPI. It was possible concluded that these hematological and immune are crucial event in the worsening of sepsis in P. mesopotamicus, and these findings are utility for diagnosing and understanding the pathophysiology sepsis in pacu induced by A. hydrophila.

Esteatose hepática altera acúmulo celular em tilápias do Nilo durante aerocistite infecciosa

RESUMO: O presente estudo avaliou a hepatotoxicidade induzida pelo CCl4 durante o efeito glicocorticoide da dexametasona (DEX) na fisiopatologia da reação inflamatória aguda em tilápias do Nilo, Oreochromis niloticus, correlacionando a funcionalidade hepática à cinética de acúmulo celular em aerocistite infecciosa. Para tal, utilizou-se 84 tilápias do Nilo distribuídas em 4 tratamentos: controle, CCl4, DEX e CCl4+DEX. Sendo amostrados 7 animais por tratamento em três períodos, isto é: seis, 24 e 48h após indução de inflamação. Utilizou-se CCl4 em dose única de 0,5mL/kg, via intraperitoneal para causar o transtorno hepático. Para indução da aerocistite utilizou-se inóculo de Aeromonas hydrophila. A dexametasona foi administrada via intramuscular na dose de 2 mg/kg de peso vivo. Os resultados revelaram que quanto maior foi à atividade sérica de aspartato aminotransferase (AST) maior foi a alteração somática do fígado, sendo estes achados inversamente proporcionais ao acúmulo celular no foco inflamatório, demonstrando menor número de células inflamatórias nos animais acometidos com maior grau de distúrbios hepáticos induzidos pelo CCl4. O estudo histopatológico revelou alterações degenerativas transitórias na fase mais aguda, pois os fígados das tilápias revelaram o acúmulo lipídeos nos hepatócitos 6h após administração de CCl4, sendo esta degeneração gordurosa não mais observada nos tempos de 24 e 48h. Contudo, a administração de CCl4 em tilápias do Nilo resultou em degeneração hepática aguda e transitória, caracterizada pelo acúmulo de gordura nos hepatócitos, aumento de AST no sangue e hepatomegalia. Com a disfunção hepática houve comprometimento do recrutamento celular em aerocistite infecciosa, indicando que há participação do fígado na resposta imune inata em peixes.

Development of an indirect ELISA assay to evaluation of the adaptive immune response of pacu (Piaractus mesopotamicus)

The pacu is one of the most important species for Brazilian fish farming and is considered emerging in the global aquaculture. Despite its importance, no effective tool for evaluation of the adaptive immune response of this species has been developed. Therefore, this study aimed the development and standardization of indirect ELISA for the measurement of pacu antigen-specific antibodies using polyclonal rabbit anti-pacu IgM used as detector antibody. For this purpose was isolated and purificated of pacu IgM using mannose-binding protein affinity chromatography and produced specific polyclonal antibodies against heavy and light chains pacu IgM, that showed a molecular weight of 72 kDa and 26 kDa, respectively. Polyclonal antibodies obtained demonstrated specificity with heavy and light Ig chains of pacu serum in western blotting. These polyclonal antibodies allowed the development of an indirect ELISA assay of high sensitivity and specificity for the detection and quantification of pacu IgM antibodies immunized with bovine IgG. In conclusion, this approach has great potential to improve the monitoring of vaccine-induced immune responses and help develop immunodiagnostic and epidemiological studies of infectious diseases in pacu systems.

Transcriptome analysis reveals the molecular mechanism of hepatic metabolism disorder caused by chromium poisoning in chickens

Chromium (Cr) is one of the most important environmental pollutants which are released into the environment due to their wide usage in numerous industries. The excess of Cr (VI) can induce hepatotoxicity, while the molecular mechanism that is involved in Cr (VI)-induced hepatotoxicity is unclear. We demonstrated the induction of chromium poisoning model in chickens to identify the differentially expressed genes (DEGs), and their functions were analyzed under different physiological and pathological conditions. Histopathological examination and transcriptome data for chromium-poisoned livers and control livers were annotated with Illumina® HiSeq 2000. The histopathological examination in chromium poisoning groups showed diapedesis, hemolysis, degeneration, nucleus pycnosis, and central phlebectasia in the liver. A total of 334 genes were upregulated and 509 genes were downregulated. The most strongly upregulated genes were HKDC1, DDX4, ACACA, FDFT1, CYYR1, PPP1R3C, and SLC16A14, while the most downregulated genes were MYBPC3, CCKAR, PCK1, and CPT1A. A Gene Ontology (GO) term with the highest enrichment of DEGs is small molecule metabolic process. In cell component domain, the term with the highest enrichment is extracellular matrix. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways showed that glucose metabolism, lipid metabolism, and protein metabolism were the most important metabolic pathways in the liver. The current study first time provides important clues and evidence for identifying the differentially expressed genes in livers due to Cr (VI)-induced liver injury in chickens.

Effects of chromium picolinate on fat deposition, activity and genetic expression of lipid metabolism-related enzymes in 21 day old Ross broilers

Objective

This experiment was conducted to investigate the effects of chromium picolinate (CrP) on fat deposition, genetic expression and enzymatic activity of lipid metabolism-related enzymes.

Methods

Two hundred forty one-day-old Ross broilers were randomly divided into 5 groups with 4 replicates per group and 12 Ross broiler chicks per replicate. The normal control group was fed a basal diet, and the other groups fed the same basal diet supplemented with 0.1, 0.2, 0.4, and 0.8 mg/kg CrP respectively. The experiment lasted for 21 days.

Results

Added CrP in the basal diet decreased the abdominal fat, had no effects on subcutaneous fat thickness and inter-muscular fat width; 0.2 mg/kg CrP significantly decreased the fatty acid synthase (FAS) enzymatic (p<0.05); acetyl-CoA carboxylase (ACC) enzymatic activity decreased in all CrP groups (p<0.05); hormone-sensitive lipase (HSL) enzymatic activity also decreased, but the change was not significant (p>0.05); 0.4 mg/kg CrP group significantly decreased the lipoprotein lipase (LPL) enzymatic activity. FAS mRNA expression increased in all experimental groups, and the LPL mRNA expression significantly increased in all experimental groups (p<0.05), but not 0.2 mg/kg CrP group.

Conclusion

The results indicated that adding CrP in basal diet decreased the abdominal fat percentage, had no effects on subcutaneous fat thickness and inter-muscular fat width, decreased the enzymatic activity of FAS, ACC, LPL and HSL and increased the genetic expression levels of FAS and LPL.

Myxobolus sp. and Henneguya sp. (Cnidaria: Myxobolidae) natural co-infection in the kidney of Piaractus mesopotamicus (Characiformes: Serrasalmidae)

This study evaluated the myxozoan infection and histopathology of the kidney of freshwater fish Piaractus mesopotamicus from intensive fish farming in Brazil. A total of 55 fish were examined for myxozoan infection. Infected organs were processed by usual histology and stained with hematoxylin-eosin (H&E) and Ziehl-Neelsen (ZN). From the total of 55 fish analyzed, 47 (85.45%) presented myxospores, being 9.09% (5/55) only with Myxobolus sp., 5.45% (3/55) only with Henneguya sp., and 70.91% (39/55) presenting both parasites. The presence of myxospores was associated with histological alterations in both stromal and renal parenchyma. Myxospores were found mostly in the peritubular interstitial tissue and in low intensity in the glomerulus which caused nuclear hypertrophy and loss of Bowman space. An increase in the glomerular tuft and a reduction in the lumen of the collector tubules were also observed, besides the high number of melanomacrophage cells in the glomerulus. This study reports for the first time detection of myxozoan mixed infection in one organ of pacu and discuss the possible transportation of myxospores in the circulating blood.

Na2EDTA anticoagulant impaired blood samples from the teleost Piaractus mesopotamicus

Abstract: The present study aimed to evaluate the effects of Na heparin and Na2EDTA on blood of Piaractus mesopotamicus (360.7±42.4g, 26.4±1.0cm). Twenty fishes were sampled in two experiment trials, ten for erythrocyte fragility analysis and ten for hematologic and plasma biochemical study. The blood collected by venous-caudal puncture was fractioned and stored in anticoagulants solution: Na2EDTA 10%, Na2EDTA 3%, Na heparin 5000 IU and Na heparin 100 IU. Plasmatic levels of calcium presented in the Na2EDTA stored samples were about 80% lower than both heparin groups. Blood samples of P. mesopotamicus stored with Na2EDTA demonstrated increase in the hematocrit and MCV, and decrease in MCHC. The dose-response effect was observed in this study. The results are reinforced by the higher levels of plasmatic protein and hemolysis presented in the Na2EDTA 10% stored blood, confirming the deleterious effect of this anticoagulant treatment on the quality of blood samples. Na2EDTA is not indicated to store P. mesopotamicus blood samples, but sodium heparin at 100 IU is the most recommended anticoagulant, since this treatment presented the lower rate of alterations in the stored blood.

Evaluation of the Reproductive Toxicity, Glycometabolism, Glycometabolism-Related Enzyme Levels and Lipid Metabolism of Chromium Malate Supplementation in Sprague-Dawley Rats

Our previous study showed that chromium malate improved the regulation of blood glucose in mice with alloxan-induced diabetes. The present study was designed to evaluate the reproductive toxicity of chromium malate in Sprague-Dawley rats and then inspected the effect of chromium malate on glycometabolism, glycometabolism-related enzymes, and lipid metabolism. The results showed that no pathological, toxic feces and urine changes were observed in clinical signs of parental and fetal rats in chromium malate groups. The fasting blood glucose, serum insulin, insulin resistance index, C-peptide, hepatic glycogen, glucose-6-phosphate dehydrogenase, glucokinase, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride levels of chromium malate groups have no significant change compared with control group and chromium picolinate group. The serum and organ contents of Cr in chromium malate groups have no significant change when compared with control group. No measurable damage on liver, brain, kidney, and testis/uterus of chromium malate groups was found. No significant change in body mass, absolute and relative organ weights, and hematological and biochemical changes of rats were observed compared with the control and chromium picolinate groups. The results indicated that supplements with chromium malate does not cause obvious damage and has no obvious effect on glycometabolism, glycometabolism-related enzyme, and lipid metabolism on female and male rats. The results of this study suggested that chromium malate is safe for human consumption and has the potential for application as a functional food ingredient and dietary supplement.

Evaluation of 90-day Repeated Dose Oral Toxicity, Glycometabolism, Learning and Memory Ability, and Related Enzyme of Chromium Malate Supplementation in Sprague-Dawley Rats

Our previous study showed that chromium malate improved the regulation of blood glucose in mice with alloxan-induced diabetes. The present study was designed to evaluate the 90-day oral toxicity of chromium malate in Sprague-Dawley rats. The present study inspected the effect of chromium malate on glycometabolism, glycometabolism-related enzymes, lipid metabolism, and learning and memory ability in metabolically healthy Sprague-Dawley rats. The results showed that all rats survived and pathological, toxic, feces, and urine changes were not observed. Chromium malate did not cause measurable damage on liver, brain, and kidney. The fasting blood glucose, serum insulin, insulin resistance index, C-peptide, hepatic glycogen, glucose-6-phosphate dehydrogenase, glucokinase, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride levels of normal rats in chromium malate groups had no significant change when compared with control group and chromium picolinate group under physiologically relevant conditions. The serum and organ content of Cr in chromium malate groups had no significant change compared with control group. No significant changes were found in morris water maze test and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and true choline esterase (TChE) activity. The results indicated that supplementation with chromium malate did not cause measurable toxicity and has no obvious effect on glycometabolism and related enzymes, learning and memory ability, and related enzymes and lipid metabolism of female and male rats. The results of this study suggest that chromium malate is safe for human consumption.

Expression of cellular components in granulomatous inflammatory response in Piaractus mesopotamicus model

The present study aimed to describe and characterize the cellular components during the evolution of chronic granulomatous inflammation in the teleost fish pacus (P. mesopotamicus) induced by Bacillus Calmette-Guerin (BCG), using S-100, iNOS and cytokeratin antibodies. 50 fish (120±5.0 g) were anesthetized and 45 inoculated with 20 μL (40 mg/mL) (2.0 x 10⁶ CFU/mg) and five inoculated with saline (0,65%) into muscle tissue in the laterodorsal region. To evaluate the inflammatory process, nine fish inoculated with BCG and one control were sampled in five periods: 3^rd, 7^th, 14^th, 21^st and 33^rd days post-inoculation (DPI). Immunohistochemical examination showed that the marking with anti-S-100 protein and anti-iNOS antibodies was weak, with a diffuse pattern, between the third and seventh DPI. From the 14^th to the 33^rd day, the marking became stronger and marked the cytoplasm of the macrophages. Positivity for cytokeratin was initially observed in the 14^th DPI, and the stronger immunostaining in the 33^rd day, period in which the epithelioid cells were more evident and the granuloma was fully formed. Also after the 14^th day, a certain degree of cellular organization was observed, due to the arrangement of the macrophages around the inoculated material, with little evidence of edema. The arrangement of the macrophages around the inoculum, the fibroblasts, the lymphocytes and, in most cases, the presence of melanomacrophages formed the granuloma and kept the inoculum isolated in the 33^rd DPI. The present study suggested that the granulomatous experimental model using teleost fish P. mesopotamicus presented a similar response to those observed in mammals, confirming its importance for studies of chronic inflammatory reaction.