Minimization of variation in the response to different proteins of the Coomassie blue G dye-binding assay for protein

Kinetic properties of gill (Na+, K+)-ATPase in the Pacific whiteleg shrimp Penaeus vannamei (Decapoda, Penaeidae)

The whiteleg marine shrimp Penaeus vannamei, originally from the Eastern Pacific Ocean, now inhabits tropical waters across Asia and Central and Southern America. This benthic species exhibits rapid growth, wide salinity and temperature tolerance, and disease resistance. These physiological traits have led to extensive research on its osmoregulatory mechanisms, including next-generation sequencing, transcriptomic analyses, and lipidomic responses. In crustaceans, osmotic and ionic homeostasis is primarily maintained by the membrane-bound metalloenzyme (Na+, K+)-ATPase. However, little is known about how various ligands modulate this enzyme in P. vannamei. Here, we examined the kinetic characteristics of the gill (Na+, K+)-ATPase to get biochemical insights into its modulation. A prominent immunoreactive band of ~120 kDa, corresponding to the (Na+, K+)-ATPase alpha-subunit, was identified. The enzyme exhibited two ATP hydrolyzing sites with K0.5 = 0.0003 ± 0.00002 and 0.05 ± 0.003 mmol L-1 and was stimulated by low sodium ion concentrations. Potassium and ammonium ions also stimulated enzyme activity with similar K0.5 values of 0.08 ± 0.004 and 0.06 ± 0.003 mmol L-1, respectively. Ouabain inhibition profile suggested a single enzyme isoform with a KI value of 2.10 ± 0.16 mmol L-1. Our findings showed significant kinetic differences in the (Na+, K+)-ATPase in Penaeus vannamei compared to marine and freshwater crustaceans. We expect our results to enhance understanding of the modulation of gill (Na+, K+)-ATPase in Penaeus vannamei and to provide a valuable tool for studying the shrimp's biochemical acclimation to varying salinity conditions.

Enhanced saccharification levels of corn starch using as a strategy a novel amylolytic complex (AmyHb) from the thermophilic fungus Humicola brevis var. thermoidea in association with commercial enzyme

Amylases represent a versatile group of catalysts that are used for the saccharification of starch because they can hydrolyze the glycosidic bonds of starch molecules to release glucose, maltose, and short-chain oligosaccharides. The amylolytic complex of the thermophilic filamentous fungus Humicola brevis var. thermoidea (AmyHb) was produced, biochemically characterized, and compared with the commercial amylase Termamyl. In addition, the biotechnological application of AmyHb in starch saccharification was investigated. The highest production was achieved using a wheat bran medium at 50 °C for 5-6 days in solid-state fermentation (849.6 ± 18.2 U·g-1) without the addition of inducers. Optimum amylolytic activity occurred at pH 5.0 at 60 °C, and stability was maintained between pH 5.0 and 6.0, with thermal stability at 50-60 °C, especially in the presence of Ca2+. These results were superior to those found with Termamyl. Both enzymes were strongly inhibited by Hg2+, Cu2+, and Ag+; however, AmyHb displayed increased activity in the presence of Mn2+ and Na+. In addition, AmyHb showed greater tolerance to a wide range of ethanol concentrations. AmyHb appears to be a complex consisting of glucoamylase and α-amylase, based on its substrate specificity and TLC. The hydrolysis tests on cornstarch flour showed that the cocktail of AmyHb50% + Termamyl50% significantly increased the release of glucose and total reducing sugars (36.6%) when compared to the enzymes alone. AmyHb exhibited promising physicochemical properties and good performance with commercial amylase; therefore, this complex is a biotechnological alternative candidate for the bioprocessing of starch sources.

Essential oils and capsaicin in the diet of Jersey cows at early lactation and their positive impact on anti-inflammatory, antioxidant and immunological responses

The objective of this work was to determine whether the addition of phytogenic compounds based on essential oils (carvacrol, eugenol, cinnamaldehyde) and resinous pepper oil (capsaicin) to the diet of Jersey cows at the beginning of lactation affects anti-inflammatory, antioxidant and immunomodulatory responses, as well as whether there are effects of EO on blood metabolites, ruminal fermentation, digestibility and milk production and composition. Six primiparous cows (370.00 ± 17 kg body weight (BW); 13.02 kg dry matter intake (DMI); 21 days of lactation and average milk production of 20 ± 2 L per day) were allocated to crossed experimental design (2 × 2) with two experimental periods of 28 days and two treatments. Blood, milk and rumen fluid were collected and, at the end of each period, feed and feces samples were collected to evaluate the apparent digestibility of nutrients. The groups were control (CLT) without supplementation and treated (BEO) with the addition of 150 mg/kg of dry matter of the phytogenic to the concentrated portion of the diet. Cows in the BEO group had lower numbers of leukocytes (P ≤ 0.05) and lymphocytes (P ≤ 0.02), but total protein and globulin levels were higher on days 21 and 28 (P ≤ 0.01). In the BEO group, the levels of immunoglobulin A, immunoglobulin heavy chain and transferrin were higher (P ≤ 0.05). The levels of ceruloplasmin, haptoglobin and C-reactive protein were lower in the BEO group (P ≤ 0.05). Lipid peroxidation levels and protein carbonyl content were lower in the BEO group. The total antioxidant capacity (P ≤ 0.09) and the activity of glutathione S-transferase (P ≤ 0.03) and glutathione peroxidase (P ≤ 0.05) were higher in the BEO group. Cows in the BEO group had lower pH (P ≤ 0.05), acetic acid concentrations (P ≤ 0.01) and higher protozoa counts (P ≤ 0.01). Our results suggest that phytogenic supplementation has positive effects on the health of Jersey cows in early lactation, characterized by immunostimulant, antioxidant and anti-inflammatory effects.

Oxidative responses in small juveniles of Colossoma macropomum anesthetized and sedated with Ocimum gratissimum L. essential oil

This study evaluated the use of essential oil of Ocimum gratissimum (EOOG) for anesthesia and in transport of Colossoma macropomum. Experiment 1, Test 1, anesthesia induction and recovery times were determined using different EOOG concentrations (0, 20, 50, 100, 200, 300 mg L-1), with two size classes: Juveniles I (0.86 g) and Juveniles II (11.46 g) (independent tests in a completely randomized design). Based on the results of Test 1, in Test 2 Juveniles II were exposed to EOOG concentrations: 0, 20, 100 mg L-1. Tissue samples were collected immediately after induction and 1 h post-recovery, to assess oxidative status variables. Experiment 2, Juveniles I (0.91 g) and Juveniles II (14.76 g) were submitted to transport in water with different concentrations of EOOG (0, 5, 10 mg L-1) (independent tests in a completely randomized design). The effects on oxidative status variables were evaluated. Concentrations between 50 and 200 mg L-1 EOOG can be indicated for Juveniles I, while concentrations between 50 and 100 mg L-1 EOOG for Juveniles II. The concentration of 100 mg L-1 EOOG was able to prevent oxidative damage in the liver. In Experiment 2, the concentrations of 5 and 10 mg L-1 EOOG added to the transport water caused sedation for both studied size classes of juveniles and did not cause oscillations in water quality variables nor any mortality. The concentration of 10 mg L-1 EOOG improved the oxidative status. It can be concluded that EOOG can be used for anesthesia and transport of C. macropomum.

Effect of Butyl Paraben on Oxidative Stress in the Liver of Mauremys sinensis

Butyl paraben (BuP) has been widely used as a preservative in the cosmetics, food, and medicine industries. Recently, it has become a new pollutant and has attracted much attention. In order to evaluate the toxic effect of BuP on aquatic animals, Chinese striped-neck turtles (Mauremys sinensis) were exposed to BuP solutions with different concentrations of 0, 5, 50, 500, and 5000 µg/L for 20 weeks. The results showed that with an increase in BuP concentration, the activity of antioxidant enzymes (SOD, CAT and GSH-PX) in liver decreased. The expression of key genes in the Nrf2-Keap1 signal pathways first increased and then decreased, while the expression of the HSP70 and HSP90 genes increased. In addition, the liver had an inflammatory reaction. The expression of the BAFF and IL-6 genes increased and then decreased with an increase in BuP concentration, while the expression of P50 and P65 increased significantly. Oxidative stress induced apoptosis, and the expression of pro-apoptosis genes (BAX, cytc, Caspase3 and Caspase9) increased, while the expression of the anti-apoptosis gene Bcl2 decreased. The results provide an important reference for the comprehensive ecological and health risk assessment of environmental BuP.

The Influence of Cadmium on Fountain Grass Performance Correlates Closely with Metabolite Profiles

The relationship between metabolite changes and biological endpoints in response to cadmium (Cd) stress remains unclear. Fountain grass has good Cd enrichment and tolerance abilities and is widely used in agriculture and landscaping. We analyzed the metabolic responses by detecting the metabolites through UPLC-MS and examined the relationships between metabolite changes and the characteristics of morphology and physiology to different Cd stress in fountain grass. Our results showed that under Cd stress, 102 differential metabolites in roots and 48 differential metabolites in leaves were detected, with 20 shared metabolites. Under Cd stress, most of the carbohydrates in leaves and roots decreased, which contributed to the lowered leaf/root length and fresh weight. In comparison, most of the differential amino acids and lipids decreased in the leaves but increased in the roots. Almost all the differential amino acids in the roots were negatively correlated with root length and root fresh weight, while they were positively correlated with malondialdehyde content. However, most of the differential amino acids in the leaves were positively correlated with leaf length and leaf fresh weight but negatively correlated with malondialdehyde content. Metabolic pathway analysis showed that Cd significantly affects seven and eight metabolic pathways in the leaves and roots, respectively, with only purine metabolism co-existing in the roots and leaves. Our study is the first statement on metabolic responses to Cd stress and the relationships between differential metabolites and biological endpoints in fountain grass. The coordination between various metabolic pathways in fountain grass enables plants to adapt to Cd stress. This study provides a comprehensive framework by explaining the metabolic plasticity and Cd tolerance mechanisms of plants.

Impact of dietary supplementation with Cinnamomum cassia essential oil on silver catfish (Rhamdia quelen): Toxicological effects and muscle antioxidant and fatty acid profiles

The aim of this study was to determine the biological effects of dietary supplementation with 0.05% and 0.1% cinnamon essential oil extracted from Cinnamomum cassia on silver catfish (Rhamdia quelen). The final body weight, weight gain, and specific growth rate were significantly higher in fish supplemented with 0.05% cinnamon essential oil than in the control(untreated) group. Muscle reactive oxygen species and lipid peroxidation levels were significantly lower in fish supplemented with 0.05% cinnamon essential oil but higher at the 0.1% concentration. Muscle antioxidant capacity against peroxyl radicals (ACAP) and superoxide dismutase activity were significantly higher in fish supplemented with 0.05% cinnamon essential oil, while ACAP levels were lower in fish supplemented with 0.1%. The total saturated fatty acid content was significantly higher in the muscle of supplemented fish than in controls, while the total monounsaturated fatty acid content was significantly higher only in fish fed 0.1% cinnamon essential oil. Finally, the total content of polyunsaturated fatty acids was significantly lower in fish fed 0.1% essential oil. Thus, data demonstrated that 0.05% C. cassia essential oil improves fish health by improving performance and muscle oxidant/antioxidant status. Higher doses of cinnamon essential oil produced oxidative stress in muscle, suggesting toxicity at the 0.1% level. Although this cinnamon essential oil diet exerted positive health effects, this diet impaired the muscle fatty acid profile, suggesting adverse impacts on human health.

Addition of a Blend Based on Zinc Chloride and Lignans of Magnolia in the Diet of Broilers to Substitute for a Conventional Antibiotic: Effects on Intestinal Health, Meat Quality, and Performance

This study aimed to determine whether adding a blend based on zinc chloride and lignans from magnolia to the diet of broilers could replace conventional performance enhancers. For this study, 360 chickens were divided into four groups, with six repetitions per group (n = 15), as follows: CN, without promoter; GPC, control, 50 mg/kg of enramycin growth promoter; T-50, additive blend at a dose of 50 g/ton; and T-100, additive blend at a dose of 100 g/ton. Chickens fed with the additive blend at 50 g/ton showed a production efficiency index equal to that in the GPC group (p < 0.05). At 42 days, the lowest total bacterial count (TBC) was found in the T-100 group, followed by that in the GPC group (p < 0.001). For E. coli, the lowest count was observed in the T-100 group, followed by that in the CP and T-50 groups (p < 0.001). Higher villus/crypt ratios were observed in birds belonging to the T-100 and T-50 groups than in the GPC and NC groups (p < 0.001). Greater water retention was found in the T-50 group than in NC and T-100 groups (p < 0.048). The lowest water loss during cooking was also noted in the T-50 group (p < 0.033). We concluded that adding the antimicrobial blend, primarily at 50 g/ton, maintains the efficiency of the index of production and improves the intestinal health and meat quality of the birds.

Comparative Physiological and Transcriptomic Analyses of Two Contrasting Pepper Genotypes under Salt Stress Reveal Complex Salt Tolerance Mechanisms in Seedlings

As a glycophyte plant, pepper (Capsicum annuum L.) is widely cultivated worldwide, but its growth is susceptible to salinity damage, especially at the seedling stage. Here, we conducted a study to determine the physiological and transcriptional differences between two genotype seedlings (P300 and 323F3) with contrasting tolerance under salt stress. The P300 seedlings were more salt-tolerant and had higher K+ contents, higher antioxidase activities, higher compatible solutes, and lower Na+ contents in both their roots and their leaves than the 323F3 seedlings. During RNA-seq analysis of the roots, more up-regulated genes and fewer down-regulated genes were identified between salt-treated P300 seedlings and the controls than between salt-treated 323F3 and the controls. Many ROS-scavenging genes and several SOS pathway genes were significantly induced by salt stress and exhibited higher expressions in the salt-treated roots of the P300 seedlings than those of 323F3 seedlings. Moreover, biosynthesis of the unsaturated fatty acids pathway and protein processing in the endoplasmic reticulum pathway were deeply involved in the responses of P300 to salt stress, and most of the differentially expressed genes involved in the two pathways, including the genes that encode mega-6 fatty acid desaturases and heat-shock proteins, were up-regulated. We also found differences in the hormone synthesis and signaling pathway genes in both the P300 and 323F3 varieties under salt stress. Overall, our results provide valuable insights into the physiological and molecular mechanisms that affect the salt tolerance of pepper seedlings, and present some candidate genes for improving salt tolerance in pepper.

Combining Metabolic Analysis With Biological Endpoints Provides a View Into the Drought Resistance Mechanism of Carex breviculmis

Metabolomics is an effective tool to test the response of plants to environmental stress; however, the relationships between metabolites and biological endpoints remained obscure in response to drought stress. Carex breviculmis is widely used in forage production, turf management, and landscape application and it is particularly resistant to drought stress. We investigated the metabolomic responses of C. breviculmis to drought stress by imposing a 22-day natural soil water loss. The results showed that water-deficit restrained plant growth, reducing plant height, leaf fresh weight, and total weight, however, increasing soluble protein content and malondialdehyde content. In total, 129 differential metabolites in the leaves were detected between drought and control using the Ultrahigh Performance Liquid Chromatography-Mass Spectrometer (UPLC-MS) method. Drought enhanced most of the primary and secondary metabolites in the differential metabolites. Almost all the sugars, amino acids, organic acids, phytohormones, nucleotides, phenylpropanoids and polyketides in the differential metabolites were negatively correlated with plant height and leaf fresh weight, while they were positively correlated with soluble protein content and malondialdehyde content. Metabolic pathway analysis showed that drought stress significantly affected aminoacyl-tRNA biosynthesis, TCA cycling, starch and sucrose metabolism. Our study is the first statement on metabolomic responses to drought stress in the drought-enduring plant C. breviculmis. According to the result, the coordination between diverse metabolic pathways in C. breviculmis enables the plant to adapt to a drought environment. This study will provide a systematic framework for explaining the metabolic plasticity and drought tolerance mechanisms of C. breviculmis under drought stress.

The Use of Cinnamon Essential Oils in Aquaculture: Antibacterial, Anesthetic, Growth-Promoting, and Antioxidant Effects

Cinnamon essential oils (EOs) are widely known for their pharmaceutical properties; however, studies investigating the use of these EOs in aquaculture are scarce. The aims of this study were to evaluate the anesthetic effect of bathing silver catfish (Rhamdia quelen) with Cinnamomum cassia EO (CCEO) and its nanoemulsion (NCCEO); the growth-promoting and antioxidant effects of dietary supplementation with CCEO in silver catfish; and the in vitro antibacterial effect of CCEO, NCCEO, and Cinnamomum zeylanicum EO (CZEO) against bacteria isolated from diseased silver catfish. The two cinnamon EOs showed promising antibacterial activity, which was potentiated by the nanoemulsion. CCEO showed satisfactory anesthetic activity in silver catfish, and its nanoemulsion intensified the sedative activity. Supplementation of 1.0 mL CCEO per kg of diet for 60 days increased weight, length, and weight gain when compared to the control group, evidencing the growth-promoting activity of this EO. Dietary supplementation of CCEO for 30 and 60 days also showed an antioxidant effect, as it decreased levels of thiobarbituric acid reactive species and increased the superoxide dismutase activity in the liver of silver catfish. Therefore, cinnamon EOs have a promising use in aquaculture.

Evaluation of antibiotic combination of Litsea cubeba essential oil on Vibrio parahaemolyticus inhibition mechanism and anti-biofilm ability

Vibrio parahaemolyticus (V. parahaemolyticus) is a common pathogen in seafood. The use of antibiotics is a primary tool to prevent and control V. parahaemolyticus in the aquaculture industry. However, V. parahaemolyticus combats the damage caused by antibiotics by forming biofilms under certain conditions. In this study, we analyzed the antibacterial effect and the characteristics of V. parahaemolyticus by experimentally determining the minimum inhibitory concentration (MIC) and the fractional inhibitory concentration index (FICI) values of a combination of the Litsea cubeba essential oil (LCEO) and several commonly used V. parahaemolyticus antibiotics. The bactericidal effect of the essential oil alone and essential oil in combination with the antibiotics were evaluated with time-kill curves. The damage to cell membranes and cell walls were assessed by measuring the content of macromolecules and alkaline phosphatase (AKP) released into the supernatant using V. parahaemolyticus ATCC17802 as the experimental strain. The membrane structure was observed by transmission electron microscopy. The results showed that the MIC value of the LCEO was 1,024 μg/mL, and the LCEO FICI values in combination with tetracycline or oxytetracycline hydrochloride was 0.3125 and 0.75, respectively, indicating synergistic and additive effects. Moreover, LCEO inhibited the growth and promoted the removal of biofilms by reducing the content of hydrophobic and extracellular polysaccharides on the cell surface. This study provides a reference for studying the antibacterial activity of LCEO and the combination of antibiotics to prevent and control the formation of biofilms by V. parahaemolyticus.

Covalent Immobilization of Chondrostereum purpureum Endopolygalacturonase on Ferromagnetic Nanoparticles: Catalytic Properties and Biotechnological Application

Pectinases are widely used in a variety of industrial processes. However, their application is limited by low catalytic processivity, reduced stability, high cost, and poor re-use compatibility. These drawbacks may be overcome by enzyme immobilization with ferromagnetic nanoparticles, which are easily recovered by a magnetic field. In this work, an endopolygalacturonase from Chondrostereum purpureum (EndoPGCp) expressed in Pichia pastoris was immobilized on glutaraldehyde-activated chitosan ferromagnetic nanoparticles (EndoPGCp-MNP) and used to supplement a commercial enzyme cocktail. No significant differences in biochemical and kinetic properties were observed between EndoPGCp-MNP and EndoPGCp, although the EndoPGCp-MNP showed slightly increased thermostability. Cocktail supplementation with EndoPGCp-MNP increased reducing sugar release from orange wastes by 1.8-fold and showed a synergistic effect as compared to the free enzyme. Furthermore, EndoPGCp-MNP retained 65% of the initial activity after 7 cycles of re-use. These properties suggest that EndoPGCp-MNP may find applications in the processing of pectin-rich agroindustrial residues.

Development and validation of the HPLC-DAD method for the quantification of 16 synthetic dyes in various foods and the use of liquid anion exchange extraction for qualitative expression determination

Synthetic dyes can cause many health problems, and their use as food additives is rigorously regulated worldwide. Two methods for the determination of synthetic dyes in food are described in this article. The visual qualitative expression method was based on the extraction of synthetic dyes using a liquid anion exchanger (0.01 M solution of trioctylmethylammonium chloride in chloroform). Using this reagent, an optimal transition of 15 anionic synthetic dyes from the aqueous to the organic phase was achieved (R > 99.8%). It was applicable for testing food that must not contain synthetic dyes (wines, juices, etc.) in a very short time (5-10 min). In the case of colouring of the organic phase, identification and quantification was carried out using the HPLC-DAD method described. The rapid and simple method allows for simultaneous determination of 16 synthetic dyes from all food types. The LOD and LOQ ranged from 0.026 to 0.086 μg mL^-1 and from 0.077 to 0.262 μg mL^-1 respectively, and recovery was 83.7-107.5%. Hypothesis: anionic synthetic dyes have hydrophobic properties, as a result they are retained on the non-polar stationary phase of the chromatographic column and are easily extracted from aqueous solutions by liquid anion exchangers.

Vegetable biocholine as a hepatoprotectant in laying hens fed with diet contaminated with aflatoxin B1

The aim of the study was to determine whether the addition of vegetable biocholine (VB) in laying hens feed minimises the effects of daily intake of aflatoxin B1 (AFB1). We allocated Hy-line Brown line laying hens into four groups with four replications/group and four birds/repetition. The treatments were as follows: Afla0Bio0: basal feed without aflatoxin and VB (natural contamination: 0.026 mg AFB1/kg), Afla0Bio800, basal feed supplementation of 800 mg VB/kg (natural contamination: 0.024 mg AFB1/kg); Afla2.5Bio0, basal feed contaminated experimentally with aflatoxin (2.51 mg/kg); Afla2.5Bio800, basal feed contaminated with aflatoxin (2.50 mg/kg) and supplemented with 800 mg VB/kg. The experiment took place over a period of 42 days, divided into two cycles of 21 days each. Significance was indicated by P≤0.05. The inclusion of aflatoxin reduced egg production after 42 days of consumption of contaminated feed. VB supplementation in the tested dose was insufficient to minimise the negative effects of the toxin on the laying rate. There was a lower percentage of yolk in Afla2Bio0 than in Afla0Bio0, and a higher percentage of albumen and specific gravity in Afla2.5Bio0 than in Afla0Bio0. Ingestion of aflatoxin in the feed increased lipoperoxidation (LPO) and decreased antioxidant capacity in the egg yolk; however, when VB was added, LPO was similar to the control. Lower total bacterial count (TBC) in the eggshell was observed when the birds consumed VB, as well as higher TBC in the eggshell of the birds was challenged with aflatoxin. In the blood of birds that consumed aflatoxin (Afla2.5Bio0) there was an increase in the activity of alkaline phosphatase and a reduction in the activities of glutathione S-transferase and glutathione peroxidase (GPx). In the birds that consumed VB without aflatoxin challenge, we observed that there was a stimulation of GPx activity. We conclude that the consumption of VB had positive effects on the health of the laying hens and improved the quality of the eggs.

Development of a protein assay with copper chelator chromeazurol B, based on the biuret reaction

This study aimed to provide a novel and highly sensitive protein assay based on the biuret reaction and using chromeazurol B, a metal chelate compound. The method consists of two reagents and an automated analyzer. First, a complex of copper and protein (biuret reaction) is formed. Second, a chelating reagent containing chromeazurol B forms a three-dimensional complex of protein, copper, and chromeazurol B at neutral pH, resulting in highly sensitive coloration. The intra-assay (n = 20) variation for the three levels was 3.54 % or lower at each concentration. Each response with α, β-, and γ-globulin was 103.8 % and 104.3 %, respectively, against albumin. The molar absorption coefficient (ε) of the present method was 2.5 × 10⁵ m²/mol against human albumin, higher than that of the commercially available Lowry method (ε = 8.7 × 10⁴ m²/mol), which is based on the same principle. The correlation test for the pyrogallol method with 30 urine samples showed good performance (r = 0.961). The method described here (the Biuret-based CAB method) is a more sensitive and rapid assay than the Lowry method, and it may also be applied to biological samples because of its similar reactivity towards various proteins.

Protective role of rutin dietary supplementation mediated by purinergic signaling in spleen of silver catfish Rhamdia quelen exposed to organophosphate pesticide trichlorfon

Evidence suggests the involvement of purinergic signaling, a mechanism mediated by extracellular nucleotides and nucleosides, with the impairment of immune and inflammatory responses in silver catfish (Rhamdia quelen) exposed to trichlorfon. Plant-derived substances have been considered potent anti-inflammatory agents due to effects on the purinergic system, such as the use of the flavonoid rutin. The aim of this study was to determine whether a diet containing rutin is able to prevent or reduce trichlorfon-induced impairment of immune responses through alteration of the purinergic pathway. Spleen adenosine triphosphate (ATP) levels were significantly higher in silver catfish exposed to 11 mg/L trichlorfon for 48 h compared to the control group, while adenosine (Ado) levels were significantly lower. Spleen ectonucleoside triphosphate diphosphohydrolase (NTPDase) activity was significantly lower in silver catfish exposed to trichlorfon compared to control group, while adenosine deaminase activity was significantly higher. Spleen metabolites of nitric oxide, interleukin-1, and IL-6 were significantly higher in silver catfish exposed to trichlorfon compared to control group. Diet with 3 mg rutin/kg diet was able to prevent all the alterations elicited by trichlorfon, except restoring spleen ATP levels. The purinergic exposure signaling is involved in impairment of immune and inflammatory responses in fish exposed to trichlorfon due to reduction in ATP hydrolyses and by an increase in Ado deamination, leading to release of pro-inflammatory mediators. Use of rutin-added diet exerted an essential role in protecting the silver catfish spleen from trichlorfon-induced impairment on immune and inflammatory responses, preventing all alterations on splenic purinergic signaling.

Multiple insecticide resistance and associated mechanisms to volatile pyrethroid in an Aedes albopictus population collected in southern China

Conventional and volatile pyrethroids are widely used to control the vectors of dengue arboviral diseases, Aedes albopictus in China. The development of resistance to conventional pyrethroids has become an increasing problem, potentially affecting the use of volatile pyrethroid. The Ae. albopictus dimefluthrin-resistant (R) strain by selecting the field population with dimefluthrin were investigated the multiple and cross-resistance levels between conventional and volatile pyrethroids and analyzed both target-site and metabolic resistant mechanisms to dimefluthrin compared with three volatile pyrethroids metofluthrin, meperfluthrin and esbiothrin and type II pyrethroid deltamethrin. The R strain displayed moderate to low resistance to selected pyrethroids (dimefluthrin, metofluthrin, meperfluthrin, esbiothrin and deltamethrin) associated with metabolic enzymes, but less distinctly to selected pyrethroids (dimefluthrin and metofluthrin) associated with a high frequency of sodium channel gene mutation (F1534S). Profiles of the multiple and cross-resistance of the R strain to other three volatile pyrethroids and type II pyrethroid deltamethrin were detected. Both synergistic and enzyme activity studies indicated that multifunctional oxidase (MFO) played an important role in this resistance.

Effect of Pre-Fermentative Maceration and Fining Agents on Protein Stability, Macromolecular, and Phenolic Composition of Albariño White Wines: Comparative Efficiency of Chitosan, k-Carrageenan and Bentonite as Heat Stabilisers

In this work, the effect of pre-fermentative skin maceration (PFSM) on the chemical composition of the macromolecular fraction, polysaccharides and proteins, phenolic compounds, chromatic characteristics, and protein stability of Albariño monovarietal white wines was studied. PFSM increased the extraction of phenolic compounds and polysaccharides and reduced the extraction of pathogenesis-related proteins (PRPs). PFSM wine showed significantly higher protein instability. Sodium and calcium bentonites were used for protein stabilisation of wines obtained with PFSM (+PFSM) and without PFSM (-PFSM), and their efficiencies compared to fungal chitosan (FCH) and k-carrageenan. k-Carrageenan reduced the content of PRPs and the protein instability in both wines, and it was more efficient than sodium and calcium bentonites. FCH was unable to heat stabilise both wines, and PRPs levels remained unaltered. On the other hand, FCH decreased the levels of wine polysaccharides by 60%. Sodium and calcium bentonite also decreased the levels of wine polysaccharides although to a lower extent (16% to 59%). k-Carrageenan did not affect the wine polysaccharide levels. Overall, k-carrageenan is suitable for white wine protein stabilisation, having a more desirable impact on the wine macromolecular fraction than the other fining agents, reducing the levels of the wine PRPs without impacting polysaccharide composition.

Essential oil of Ocimum gratissimum (Linnaeus, 1753): efficacy for anesthesia and transport of Oreochromis niloticus

This study aimed to evaluate the essential oil of Ocimum gratissimum L. (EOOG) for anesthesia and in the transport of Oreochromis niloticus. Experiment I determined the time of anesthesia induction and recovery during anesthesia of O. niloticus exposed to different concentrations of EOOG (0, 30, 90, 150, and 300 mg L^-1). Based on data from Experiment I, Experiment II evaluated the effect of 0, 30, and 90 mg L^-1 EOOG on blood parameters and oxidative stress immediately after anesthesia induction and 1 h after recovery. Experiment III evaluated the effect of 0, 5, and 10 mg L^-1 EOOG on blood variables immediately after 4.5 h of transport of juveniles. Concentrations between 90 and 150 mg L^-1 EOOG were efficient for anesthesia and recovery. The use of 90 mg L^-1 of EOOG prevented an increase in plasma glucose. Other changes in blood parameters and oxidative stress are discussed. The use of 10 mg L^-1 EOOG in transport increased plasma glucose and decreased hematocrit values immediately after transport. It is concluded that the use of 90 and 150 mg L^-1 EOOG causes anesthesia and recovery in O. niloticus within the time intervals considered ideal. The use of 90 mg L^-1 EOOG favored stable plasma glucose soon after anesthesia induction and 1 h after recovery, but caused changes in the antioxidant defense system by increasing hepatic and kidney ROS. The transport of 12 g O. niloticus for 4.5 h can be performed with concentration of 5 mg L^-1 of EOOG.

Effects of Organic Polymer Compound Material on K+ and Na+ Distribution and Physiological Characteristics of Cotton Under Saline and Alkaline Stresses

Soil salinization and alkalization greatly restrict crop growth and yield. In this study, NaCl (8 g kg^-1) and Na₂CO₃ (8 g kg^-1) were used to create saline stress and alkaline stress on cotton in pot cultivation in the field, and organic polymer compound material (OPCM) and stem girdling were applied before cotton sowing and at flowering and boll-forming stage, respectively, aiming to determine the effects of OPCM on K⁺ and Na⁺ absorption and transport and physiological characteristics of cotton leaf and root. The results showed that after applying the OPCM, the Na⁺ content in leaf of cotton under saline stress and alkaline stress were decreased by 7.72 and 6.49%, respectively, the K⁺/Na⁺ ratio in leaf were increased by 5.65 and 19.10%, respectively, the Na⁺ content in root were decreased by 9.57 and 0.53%, respectively, the K⁺/Na⁺ ratio in root were increased by 65.77 and 55.84%, respectively, and the transport coefficients of K⁺ and Na⁺ from leaf to root were increased by 39.59 and 21.38%, respectively. The activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), and the relative electrical conductivity (REC) in cotton leaf were significantly increased, while the content of malondialdehyde (MDA) was decreased; but the changes in those in root were not significant. The boll weights were increased by 11.40 and 13.37%, respectively, compared with those for the control. After stem girdling, the application of OPCM still promoted the ion transport of cotton organs; moreover, the CAT activity in root was increased by 25.09% under saline stress, and the SOD activity in leaf and CAT in root were increased by 42.22 and 6.91%, respectively under alkaline stress. Therefore, OPCM can significantly change the transport of K⁺ and Na⁺ to maintain the K⁺ and Na⁺ homeostasis in leaf and root, and regulate physiological and biochemical indicators to alleviate the stress-induced damage. Besides, the regulation effect of OPCM on saline stress was better than that on alkaline stress.

Behavioral impairment and neurotoxic responses of silver catfish Rhamdia quelen exposed to organophosphate pesticide trichlorfon: Protective effects of diet containing rutin

Trichlorfon is an organophosphate pesticide used extensively for controlling ectoparasites in aquaculture. Studies have found that trichlorfon caused environmental pollution and severe neurotoxic effects in several freshwater species. Feed additives such as flavonoids may reduce or prevent pesticide-induced toxicity in fish. The aim of the present study was to determine whether acute exposure to trichlorfon impairs behavior and causes oxidative damage in brains of silver catfish (Rhamdia quelen). We also sought to determine whether rutin would be capable of preventing or reducing these effects. Silver catfish were divided into four groups: groups A and C received basal feed, while groups B and D received feed containing 3 mg rutin/kg diet for 21 days. After 21 days, groups C and D were exposed for 48 h to a nominal concentration of 11 mg trichlorfon/L water. Fish exposed to trichlorfon showed significantly longer distances travelled and swimming performances than did unexposed fish. Cerebral levels of reactive oxygen species and lipid peroxidation were significantly higher in fish exposed to trichlorfon than in unexposed fish, while cerebral superoxide dismutase, catalase, glutathione peroxidase, and acetylcholinesterase (AChE) activities were significantly lower. Taken together, our findings suggest that dietary supplementation rutin completely prevented all alterations elicited by trichlorfon, except for cerebral AChE activity; the latter remained significantly lower compared to the unexposed group. In summary, rutin prevents trichlorfon-induced neurotoxicity in silver catfish.

Consequences of oxidative damage on the fatty acid profile in muscle of Cichlasoma amazonarum acutely exposed to copper

Rapid industrialization results in the production of large quantities of waste that are commonly discharged into water bodies, leading to the damage of the aquatic ecosystem and freshwater organisms. Copper (Cu) can induce oxidative damage in fish muscle, the main fish portion that is consumed by humans. However, the responses of the Amazon fish Cichlasoma amazonarum and its capacity to withstand acute Cu concentrations found in Amazon water around mines remain unknown. Thus, the aim of this study was to evaluate whether exposure to Cu causes muscle oxidative stress and/or oxidative damage and impairs the fillet fatty acid profile of C. amazonarum acutely exposed to Cu found in Amazon waters around mines. Muscle reactive oxygen species and protein carbonylation levels were significantly higher in fish exposed to 1500 μg/L Cu compared with the control group, while muscle lipid peroxidation levels were significantly higher in fish exposed to 500, 750, and 1500 μg/L Cu compared with control group. Muscle antioxidant capacity against peroxyl radical's levels and glutathione peroxidase activity were significantly lower in fish exposed to 1500 μg/L Cu compared with the control group, while muscle superoxide dismutase activity was significantly lower in fish exposed to 750 and 1500 μg/L Cu compared with control group. The total content of saturated fatty acids was significantly higher in fish exposed to 1500 μg/L Cu compared with the control group, while the total content of monounsaturated fatty acids and sum of n3 fatty acids were significantly lower in fish exposed to 1500 μg/L Cu compared with control group. No significant difference was observed regarding muscle catalase, glutathione S-transferase, and glutathione reductase activities. Based on these lines of evidence, the results of this comprehensive study agree with the initial hypothesis that the exposure to Cu found in Amazon water around mines induces oxidative damage and inhibits enzymatic and non-enzymatic antioxidant response in the muscle of C. amazonarum exposed to high Cu levels. Moreover, the impairment of the fillet fatty acid profile appears to be mediated by oxidative damage, representing a negative impact on fish health.

Acute exposure to environmentally relevant concentrations of copper affects branchial and hepatic phosphoryl transfer network of Cichlasoma amazonarum: Impacts on bioenergetics homeostasis

The toxic effects of copper (Cu) are linked to dysfunction of metabolism and depletion of adenosine triphosphate (ATP). Nevertheless, the effects related to phosphoryl transfer network, a network of enzymes to precise coupling of the ATP-production and ATP-consuming process for maintenance of bioenergetic, remain unknown. Therefore, the aim of this study was to determine whether the phosphoryl transfer network could be one pathway involved in the bioenergetic imbalance of Cichlasoma amazonarum exposed for 96 h to environmentally relevant concentrations of Cu found in Amazonia water around mines. Branchial mitochondrial creatine kinase (CK) activity was significantly lower in fish exposed to 1500 μg/L Cu than in the control group, while branchial cytosolic CK activity was significantly greater. Branchial (exposed to 750 and 1500 μg/L Cu) and hepatic (exposed to 1500 μg/L Cu) pyruvate kinase (PK) activity was significantly lower in fish exposed to Cu than in the control group. Branchial and hepatic ATP levels were significantly lower in fish exposed to 1500 μg/L than in the control group. Branchial reactive oxygen species (ROS) and lipid peroxidation (LPO) levels were significantly higher in fish exposed to 750 and 1500 μg/L Cu compared to control. Hepatic ROS and LPO levels were significantly higher in fish exposed to 1500 μg/L than in the control group. Branchial and hepatic Cu levels were significantly higher in fish exposed to 1500 μg/L compared to other groups. Exposure to 750 and 1500 μg/L Cu impairs bioenergetics homeostasis, which appears to be mediated by ROS overproduction and lipid peroxidation.

Effect of Temperature and Humidity on Oil Quality of Harvested Torreya grandis cv. Merrillii Nuts During the After-Ripening Stage

Temperature and relative humidity (RH) influence post-harvest ripening, a crucial stage for quality promotion in some oil plants or fruits. Torreya grandis cv. Merrillii nuts, which are rich in unsaturated fatty acids (UFA), are easily affected by temperature and humidity, and they oxidize quickly during the post-harvest ripening stage, leading to the deterioration of nut quality. In this study, the main nutraceutical components, fatty acid composition, and related metabolic parameters of lipid rancidity under four treatments (20°C and 70% RH, T20-LH; 30°C and 70% RH, T30-LH; 20°C and 90% RH, T20-HH; 30°C and 90% RH, T30-HH) were measured. The post-harvest ripening process was advanced under HH treatments (T20-HH and T30-HH) compared to LH treatments (T20-LH and T30-LH) and was associated with a shorter time for the seed coat to turn dark black and a faster reduction in starch content. The amount of unsaturated fatty acids significantly increased under the T20-HH treatment, but significantly decreased under the T30-HH treatment from 12 to 16 d of ripening time. The acid value (AV) and lipase activity under the T30-HH treatment remained virtually constant from 12 to 16 d of ripening time, and this was accompanied by a dramatic increase in peroxide value (POV), lipoxygenase (LOX) activity, and relative expression of the LOX2 gene. Meanwhile, a significant positive correlation between LOX activity and POV, malondialdehyde (MDA) content, and O2⋅- content was observed. The results imply that the lower amount of oxidative rancidity induced by the T20-HH treatment is related to the LOX activity induced by down-regulation of the LOX2 gene during the late after-ripening stage. Therefore, the T20-HH treatment not only promoted the post-harvest process of T. grandis 'Merrillii' nuts but also delayed lipid oxidation, which was ultimately associated with better oil quality at the late after-ripening stage.

Dietary ochratoxin A (OTA) decreases growth performance and impairs muscle antioxidant system and meat fatty acid profiles in juvenile tambaqui (Colossoma macropomum)

Plant-based ingredients are successfully replacing fishmeal in fish feeds. However, this practice increases the risk of feed contamination by mycotoxins that reduce production and heath associated with oxidative damage. The aim of this study was to determine whether feed contaminated with environmentally relevant concentrations of ochratoxin A (OTA) causes muscle oxidative damage in tambaqui (Colossoma macropomum), and to determine whether this feed impairs fatty acid profiles in fish meat. Final mean weight, weight gain, daily weight gain, feed efficiency, and specific growth rate were significantly lower in fish fed 1.6 and 2.4 mg OTA/kg compared to those fed basal diet, while feed conversion was significantly higher in these same groups compared to the basal group. Levels of reactive oxygen species and lipid peroxidation in muscle were significantly higher in fish fed 1.6 and 2.4 mg OTA/kg compared to those in the basal group. Likewise, muscle superoxide dismutase and glutathione peroxidase activities were significantly higher in fish fed 1.6 and 2.4 mg OTA/kg then in those fed basal feed. The total content of saturated fatty acids was significantly higher, and total content of polyunsaturated fatty acids was significantly lower in fish fed 2.4 mg OTA/kg compared to those fed basal feed. Taken together, the data suggest that OTA-contaminated feed induces oxidative damage and disturbs enzymatic and non-enzymatic antioxidant responses in tambaqui meat. The perturbations of fatty acid profiles in fish meat appears to mediated by oxidative damage, representing negative impact on fish health and presenting concerns for consumers of fish.

Dog food production using curcumin as antioxidant: effects of intake on animal growth, health and feed conservation

The objectives of this study were to produce dog food containing curcumin replacing synthetic antioxidants, to evaluate its beneficial effects on animal growth and health. Curcumin (100 mg/kg) was added after the extrusion process along with the other micronutrients. The final concentration of curcumin was 32.9 mg/kg. The control feed was composed of the same ingredients without curcumin. After a storage of 6 months, feed composition and pH did not differ; however, the feed with curcumin showed lower protein oxidation, lipid peroxidation and higher total antioxidant capacity. After 2 months of feed production, 12 young Beagle dogs received either curcumin-containing food (n = 6)  or the control diet (n = 6). The animals were fed twice a day using individual kennels. Blood samples were taken on d 1, 35 and 42. During the first 30 d of the study, the animals had natural infectious diseases that were controlled with anti-protozoals and antibiotics. Greater numbers of red blood cells were observed in dogs fed with curcumin (d 35 and 45), and there were greater numbers of white blood cells as a consequence of increased neutrophils on d 42. At the end of the experiment, a significant reduction in the number of lymphocytes was observed in dogs that ingested curcumin (d 42), suggesting an anti-inflammatory effect, manifested as a decrease in globulin levels. In the final 15 d of the experiment, the animals were clinical healthy. Higher serum levels of glucose, urea, triglycerides and cholesterol were observed in dogs fed with curcumin. Curcumin increased the activity of several antioxidant enzymes in addition to non-protein thiols and the total antioxidant capacity in the serum, consequently reducing levels of oxygen reactive species. Curcumin supplementation of dogs did not favour growth or weight gain. Neverthless, it was concluded that curcumin improved animal health, with emphasis on the stimulation of the antioxidant system and evidence of an anti-inflammatory effect.

Biochemical Characterization and Allosteric Modulation by Magnesium of (Na+, K+)-ATPase Activity in the Gills of the Red Mangrove Crab Goniopsis cruentata (Brachyura, Grapsidae)

We provide a kinetic characterization of (Na⁺, K⁺)-ATPase activity in a posterior gill microsomal fraction from the grapsid crab Goniopsis cruentata. (Na⁺, K⁺)-ATPase activity constitutes 95% of total ATPase activity, and sucrose density centrifugation reveals an ATPase activity peak between 25 and 35% sucrose, distributed into two, partially separated protein fractions. The (Na⁺, K⁺)-ATPase α-subunit is localized throughout the ionocyte cytoplasm and has an M_r of ≈ 10 kDa and hydrolyzes ATP obeying cooperative kinetics. Low (V_M = 186.0 ± 9.3 nmol Pi min^-1 mg^-1 protein and K_0.5 = 0.085 ± 0.004 mmol L^-1) and high (V_M = 153.4 ± 7.7 nmol Pi min^-1 mg^-1 protein and K_0.5 = 0.013 ± 0.0006 mmol L^-1) affinity ATP binding sites were characterized. At low ATP concentrations, excess Mg²⁺ stimulates the enzyme, triggering exposure of a high-affinity binding site that accounts for 50% of (Na⁺, K⁺)-ATPase activity. Stimulation by Mg²⁺ (V_M = 425.9 ± 25.5 nmol Pi min^-1 mg^-1 protein, K_0.5 = 0.16 ± 0.01 mmol L^-1), K⁺ (V_M = 485.3 ± 24.3 nmol Pi min^-1 mg^-1 protein, K_0.5 = 0.9 ± 0.05 mmol L^-1), Na⁺ (V_M = 425.0 ± 23.4 nmol Pi min^-1 mg^-1 protein, K_0.5 = 5.1 ± 0.3 mmol L^-1) and NH₄⁺ (V_M = 497.9 ± 24.9 nmol Pi min^-1 mg^-1 protein, K_0.5 = 9.7 ± 0.5 mmol L^-1) obeys cooperative kinetics. Ouabain inhibits up to 95% of ATPase activity with K_I = 196.6 ± 9.8 µmol L^-1. This first kinetic characterization of the gill (Na⁺, K⁺)-ATPase in Goniopsis cruentata enables better comprehension of the biochemical underpinnings of osmoregulatory ability in this semi-terrestrial mangrove crab.

Diphenyl diselenide dietary supplementation protects against fumonisin B1-induced oxidative stress in brains of the silver catfish Rhamdia quelen

The trend toward using plant-based ingredients in aquafeeds has raised important concerns for aquaculture owing to the negative impacts of mycotoxins on fish health; with emphasis for contamination by fumonisin B₁ (FB₁). The brain is an important target of FB₁; however, study of the pathways linked to brain damage is limited to an analysis of histopathological alterations. Reports have demonstrated the protective effects of dietary supplementation with diphenyl diselenide (Ph₂Se₂) in the brains of fish subjected to several environmental insults; nevertheless, its neuroprotective effects in fish fed with diets contaminated with FB₁ remain unknown. Therefore, the aim of this study was to evaluate whether oxidative damage may be a pathway associated with FB₁-induced neurotoxicity, as well as to evaluate whether dietary supplementation with Ph₂Se₂ prevents or reduces FB₁-mediated brain oxidative damage in silver catfish. Brain reactive oxygen species (ROS), lipid peroxidation (LOOH) and protein carbonylation increased on day 30 post-feeding in animals that received FB₁-contaminated diets compared to the control group, while brain antioxidant capacity against peroxyl radicals (ACAP) levels and catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities were lower. Diphenyl diselenide dietary supplementation avoid increases in brain ROS levels, as well minimizing the augmentation of LOOH levels. Furthermore, Ph₂Se₂ prevented impairment of brain ACAP levels, as well as GPx and GST activities elicited by FB₁-contaminated diets. These data suggest that dietary supplementation with 3 mg/kg Ph₂Se₂ prevented FB₁-induced brain damage in silver catfish, and this protective effect occurred through avoided of excessive ROS production, as well as via prevention of brain lipid damage. Furthermore, Ph₂Se₂ exerted its neuroprotective effects via ameliorative effects on the enzymatic and non-enzymatic antioxidant defense systems, and may be an approach to prevent FB₁-induced brain oxidative stress; however, is not an alternative to prevent the impairment on performance caused by FB₁.

Living on the Edge: Physiological and Kinetic Trade-Offs Shape Thermal Tolerance in Intertidal Crabs From Tropical to Sub-Antarctic South America

Temperature is an important abiotic factor that drives the evolution of ectotherms owing to its pervasive effects at all levels of organization. Although a species' thermal tolerance is environmentally driven within a spatial cline, it may be constrained over time due to differential phylogenetic inheritance. At the limits of thermal tolerance, hemolymph oxygen is reduced and lactate formation is increased due to mismatch between oxygen supply and demand; imbalance between enzyme flexibility/stability also impairs the ability to generate energy. Here, we characterized the effects of lower (LL₅₀) and upper (UL₅₀) critical thermal limits on selected descriptors of aerobic and anaerobic metabolism in 12 intertidal crab species distributed from northern Brazil (≈7.8°S) to southern Patagonia (≈53.2°S), considering their phylogeny. We tested for (i) functional trade-offs regarding aerobic and anaerobic metabolism and LDH kinetics in shaping thermal tolerance; (ii) influence of shared ancestry and thermal province on metabolic evolution; and (iii) presence of evolutionary convergences and adaptive peaks in the crab phylogeny. The tropical and subtropical species showed similar systemic and kinetic responses, both differing from the sub-Antarctic crabs. The lower UL₅₀'s of the sub-Antarctic crabs may reflect mismatch between the evolution of aerobic and anaerobic metabolism since these crabs exhibit lower oxygen consumption but higher lactate formation than tropical and subtropical species also at their respective UL₅₀'s. LDH activity increased with temperature increase, while K_m ^Pyr remained fairly constant; catalytic coefficient correlated negatively with thermal niche. Thermal tolerance may rely on a putative evolutionary trade-off between aerobic and anaerobic metabolism regarding energy supply, while temperature compensation of kinetic performance is driven by thermal habitat as revealed by the LDH affinity/efficiency equilibrium. The overall physiological evolution revealed two homoplastic adaptive peaks in the sub-Antarctic crabs with a further shift in the tropical/subtropical clade. The physiological traits at UL₅₀ have evolved in a phylogenetic manner while all others were more plastic. Thus, shared inheritance and thermal environment have driven the crabs' thermal tolerance and metabolic evolution, revealing physiological transformations that have arisen in both colder and warmer climes, especially at higher levels of biological organization and phylogenetic diversity.

Purine levels and purinergic signaling in plasma and spleen of Brycon amazonicus exposed to acute heat thermal stress: An attempt to regulate the immune response

Amazon fish are vulnerable to climate change. Several lines of evidence suggest that the temperature of Amazonian rivers will increase in the coming years. Elevated temperature disturbs homeostasis and subjects fish to physiological stress; however, the effects of temperature on immunity remain poorly understood, particularly those effects involving purinergic signaling. This system fine-tunes the inflammatory and immune responses triggered by stress. Therefore, the aims of this study were to determine whether acute heat stress induces the release of nucleotides into extracellular compartment and to determine whether purinergic enzymes modulate the proinflammatory effects of adenosine triphosphate (ATP) in plasma and spleen of matrinxã (Brycon amazonicus) exposed to acute heat stress. We exposed juvenile matrinxã to four temperature regimes (28 °C as control, 30, 32 and 34 °C) for 72 h and observed the effects on purinergic signaling. Plasma cortisol levels were significantly higher in fish exposed to 34 °C than in the control group, while spleen ATP, adenosine diphosphate (ADP) and adenosine monophosphate (AMP) levels were significantly higher in this group than in controls. Activities of spleen nucleoside triphosphate diphosphohydrolase (NTPDase) and 5'-nucleotidase were significantly higher in fish exposed to 34 °C than those of the control group, while spleen interleukin-1 (IL-1) and interleukin-6 (IL-6) levels were higher in this same group than in the control group. No significant differences were observed between the groups regarding plasma parameters. Based on these data, we concluded that acute heat stress at 34 °C caused physiological stress in matrinxã, manifesting as elevated plasma cortisol levels. The most important finding is that purinergic enzymes were modulated, though not efficiently, in response to the excessive release of nucleotides into the extracellular space. In summary, the purinergic signaling pathway may be involved in the impairment of immune and inflammatory responses in matrinxã exposed acutely to 34 °C.

Diphenyl diselenide dietary supplementation alleviates behavior impairment and brain damage in grass carp (Ctenopharyngodon idella) exposed to methylmercury chloride

Mercury (Hg) induces neurobehavioral disorders through reactive oxygen species (ROS) elevation and impairment of brain key enzyme activities. Nevertheless, the therapeutic and toxic selenium concentrations for fish are very close; diphenyl diselenide (Ph₂Se₂), an organoselenium compound with neuroprotective effects, may be an alternative to elemental Se. Therefore, the aim of this study was to determine whether dietary supplementation with Ph₂Se₂ prevented or reduced the neurobehavioral alterations and oxidative damage elicited by CH₃HgCl in grass carp Ctenopharyngodon idella. Fish exposed to CH₃HgCl exhibited significantly reduced distance travelled and swimming speed compared to the control group, as well as augmented cortisol and ROS levels and xanthine oxidase (XO) activities. CH₃HgCl exposure significantly increased lipid peroxidation (LOOH) and protein carbonylation (PC) levels compared to those of the control group, while acetylcholinesterase (AChE) and sodium-potassium pump (Na⁺, K⁺-ATPase) activities were inhibited. Dietary supplementation with 3 mg/kg Ph₂Se₂ ameliorated locomotor activity impairment and prevented the augmented brain cortisol and ROS levels as well as XO activity. The supplement reduced lipid and protein damage elicited by CH₃HgCl and exerted protective effects on brain AChE and Na⁺, K⁺-ATPase activities. Exposure to an environmental concentration of CH₃HgCl elicited neurobehavioral alterations linked to reduced locomotor activity, a finding that can be explained by oxidative damage and reduced activity of AChE and Na⁺, K⁺-ATPase in telencephalon and mesencephalon structures. Dietary supplementation with Ph₂Se₂ prevented CH₃HgCl-induced locomotor impairment. This effect appeared to be mediated by antioxidant action. Ph₂Se₂ may be a viable approach to prevention or reduction CH₃HgCl-mediated neurotoxic effects.

Purinergic signaling and gene expression of purinoceptors in the head kidney of the silver catfish Rhamdia quelen experimentally infected by Flavobacterium columnare

The head kidney is a lymphoid immune organ that plays a key role in the immune and inflammatory responses of teleost fish. It is associated with immunoglobulin G production and differentiation of B cells. The presence of a multi-enzymatic complex found anchored in the plasma membrane makes the head kidney an important purinergic-dependent tissue. Purinergic signaling has been associated with these responses under pathological conditions via regulation of extracellular adenosine triphosphate (ATP), the main damage molecular associated pattern agent released during bacterial infections. The aim of this study was to determine whether purinergic signaling is a pathway associated with impairment of immune responses in silver catfish (Rhamdia quelen) experimentally infected by Flavobacterium columnare, as well as to evaluate the role of P2 purine receptors in this response. Triphosphate diphosphohydrolase (NTPDase) activity in the head kidney was significantly lower in silver catfish experimentally-infected F. columnare 72 h post-infection (hpi) than in the control group, while no significant difference was observed with respect NTPDase activity on adenosine diphosphate, as well as on 5'-nucleotidase and adenosine deaminase activities. Extracellular ATP levels were significantly higher in the head kidney of experimentally-infected fish than in the control group at 72 hpi. Finally, p2ry11 and p2rx3 purine receptor levels were significantly higher in experimentally-infected fish than in the control group at 72 hpi. We conclude that purinergic signaling in the head kidney of silver catfish infected by F. columnare creates a pro-inflammatory profile that may contribute to impairment of immune and inflammatory responses via reduction of ATP hydrolysis and its accumulation in the extracellular milieu, accompanied by upregulation of p2ry11 and p2rx3 purine receptors, leading to pro-inflammatory status.

Benefits of thymol supplementation on performance, the hepatic antioxidant system, and energetic metabolism in grass carp

Thymol is an herbal food additive used to improve animal performance. Thymol acts via its potential to enhance productive and reproductive performance, and by improving bioavailability of nutrients in fish. Nevertheless, the exact mechanisms associated with these phenomena remain poorly understood, although recent evidence has suggested the involvement of the phosphotransfer network and antioxidant status. Therefore, the aim of this study was to determine whether the improvement of the antioxidant/oxidant status and the phosphoryl transfer network may be involved in enhanced growth performance in grass carp (Ctenopharyngodon idella) fed with various levels of thymol (100, 200, and 300 mg/kg feed). Thymol-supplementation (100 mg/kg feed) produced higher body weight and weight gain for 60-day post-feeding compared to the control group. Specific growth rate was higher; while feed conversion ratio was lower in fish that consumed 100 mg of thymol/kg compared to other groups. Hepatic lactate dehydrogenase activity and lipid peroxidation levels were lower in the thymol-supplemented group (100 mg/kg feed) than in the control group, while reactive oxygen species were lower in all supplemented groups than in the control group. Hepatic superoxide dismutase (300 mg/kg feed) and glutathione peroxidase (100, 200, and 300 mg/kg feed) activities, as well as antioxidant capacity against peroxyl radicals (100 mg/kg feed) were higher in these groups than in the control group. Based on these data, we conclude that 100 mg thymol/kg dietary supplementation increased growth performance of fingerling grass carp. Finally, hepatic adenylate kinase activity was lower in the thymol supplemented group (100 mg/kg feed) than in the control group. Thymol supplementation (100 mg/kg feed) improved hepatic energy metabolism, while practically all tested concentrations of thymol enhanced hepatic antioxidant status, all of which may be pathways involved in increased growth performance in fingerling grass carp.

Benefits of nanotechnology: Dietary supplementation with nerolidol-loaded nanospheres increases survival rates, reduces bacterial loads and prevents oxidative damage in brains of Nile tilapia experimentally infected by Streptococcus agalactiae

Rampant and uncontrolled use of antibiotics is a major concern for aquaculture; the practice foments the emergence of resistant strains of Streptococcus agalactiae, among other negative impacts. Constituents of plant essential oils such as nerolidol are being considered as replacements for synthetic drugs to support fish nutrition and health. There is evidence to suggest that nanotechnology may enhance the efficacy of natural bioactive compounds; this is a substantial advance for the development and sustainability of aquaculture. Against the backdrop of this evidence, we aimed determine whether dietary supplementation with free nerolidol and nerolidol-loaded nanospheres would exert bactericidal effects against S. agalactiae, as well as prevent S. agalactiae-induced brain oxidative damage. In Experiment I, we measured the antimicrobial properties of dietary supplementation of nerolidol and nerolidol nanosphere in terms of mortality, longevity and relative percent survival. Fish infected with S. agalactiae fed 0.5 and 1.0 mL nerolidol nanospheres kg/diet demonstrated lower mortality and higher relative percent survival than the control group, while longevity was higher in all infected plus supplementation groups. Experiment II showed significantly lower microbial loads in brains of fish infected with S. agalactiae that were fed 1.0 mL nerolidol nanospheres kg/diet than in the control group. Brain nerolidol levels were significantly higher in uninfected as well as infected fish supplemented with nerolidol nanospheres than in fish supplemented with free nerolidol. Finally, brain reactive oxygen species and lipid peroxidation levels were higher in infected fish supplemented with basal diet compared to uninfected fish and supplemented with basal diet, and the supplementation with 1.0 mL/kg nerolidol nanospheres prevented this augmentation caused by infection. These data suggest that dietary supplementation with nerolidol nanospheres (1.0 mL/kg diet) has potent bactericidal effects in terms of augmentation of fish longevity and survival, and reduction of brain microbial loads. Also, S. agalactiae-induced brain oxidative damage that contributed to disease pathogenesis, and the dietary supplementation with nerolidol nanospheres (1.0 mL/kg diet) prevented this alteration. In summary, nanotechnology is a compelling approach to enhancing the efficacy of nerolidol, giving rise to reduction of S. agalactiae loads in fish brains.

Nanospheres as a technological alternative to suppress hepatic cellular damage and impaired bioenergetics caused by nerolidol in Nile tilapia (Oreochromis niloticus)

Nerolidol is a sesquiterpene found in essential oils of several plant species. It is found commonly in human and animal diets and is approved by the US Food and Drug Administration as a flavoring agent. Nevertheless, recent studies have suggested that nerolidol has potent hepatotoxic effects. Because use of plant-based products in human and animal food has expanded considerably, it is essential to develop approaches such as nanotechnology to avoid or reduce hepatic toxic effects. Therefore, the aim of the study was to determine whether nerolidol dietary supplementation elicited hepatic damage associated with impairment of energy homeostasis, as well as whether supplementation with nerolidol-loaded in nanospheres prevented hepatotoxic effects in Nile tilapia (Oreochromis niloticus). Nile tilapia were divided into five groups (A-E, n = 10 per group) with four replicates each, as follows: group A received basal feed (without supplementation); group B received feed containing 0.5 mL free nerolidol/kg; group C received feed containing 1.0 mL free nerolidol/kg; group D received feed containing 0.5 mL nanospheres nerolidol/kg; and group E received feed containing 1.0 mL nanospheres nerolidol/kg. All groups received experimental feed once a day (10% total biomass) at 2 p.m. for 60 consecutive days. Hepatic liver weight and relative liver weight were significantly lower in fish fed 1.0 mL free nerolidol/kg feed than in fish given basal diet (control group). Hepatic pyruvate kinase (1.0 mL free nerolidol/kg) and adenylate kinase (0.5 and 1.0 mL free nerolidol/kg) activities were significantly lower than in the control group, while hepatic reactive oxygen species and lipid damage levels were significantly higher. Finally, the comet assay revealed significant increases in the frequency of damage and the damage index in fish given 0.5 and 1.0 mL free nerolidol/kg in a dose-dependent manner. Nerolidol-loaded in nanospheres prevented all alterations elicited by free nerolidol. Based on these data, we concluded that dietary supplementation with free nerolidol elicited severe impairment of hepatic bioenergetics homeostasis that appeared to be mediated by excessive ROS production and lipid damage, contributing to a genotoxic effect. Dietary supplementation with nerolidol-loaded in nanospheres did not elicit hepatic damage, and therefore, should be considered as a replacement so as to limit toxicity, permitting its continued use as a dietary supplement.

Dietary vegetable choline improves hepatic health of Nile tilapia (Oreochromis niloticus) fed aflatoxin-contaminated diet

Aflatoxin B_{1 (}AFB₁) is one of the most important mycotoxins due to its hepatotoxic and carcinogenic effects on animals. The effect of dietary supplementation with vegetable choline (VC) at 400, 800, and 1200 mg/kg against the deleterious effects of AFB₁ (2 ppm/kg diet) in the liver of Nile tilapia (Oreochromis niloticus) was studied. The experimental period was 81 days, and the diet with VC was offered to the fish for 60 days prior to challenge with AFB₁. Diets with AFB₁ were tested in three replications and animals were analyzed at days 14 and 21 of dietary intake. The addition of VC to tilapia diet increased body weight (days 30 and 60 pre-challenge and day 21 post-challenge). The group fed aflatoxin-contaminated diet presented significantly reduced antioxidant enzymes and increased reactive oxygen species (ROS) levels, thiobarbituric acid reactive species (TBARS) levels, and protein carbonyl (PC) content in the liver. Dietary supplementation with VC at 800 and 1200 mg/kg demonstrated a significant protective effect, avoiding the increase of ROS, TBARS, and PC levels in the liver of tilapia from the aflatoxin contaminated groups. Thus, dietary VC supplementation may be used in tilapia to increase antioxidant status and reduce the negative effects caused by AFB₁ toxicity. Based on the findings, it is recommended to use VC as a food supplement for Nile tilapia in order to avoid AFB₁ toxication. In addition, decreased aflatoxin toxicity can be attributed to the VC antioxidant property.

Effects of thymol supplementation on performance, mortality and branchial energetic metabolism in grass carp experimentally infected by Aeromonas hydrophila

We determined whether thymol supplementation of would minimize the negative effects of Aeromonas hydrophila infection on branchial energy metabolism, weight loss and mortality in grass carp (Ctenopharyngodon idella). We found that the infected fish all died, while 62.5% of those supplemented with 100 mg/kg thymol survived. Cytosolic and mitochondrial creatine kinase (CK) activities, as well as adenylate kinase (AK) and pyruvate kinase (PK) activities were significant lower in gills of A. hydrophila-infected fish than those of the control group, and adenosine triphosphate (ATP) levels were significant lower in the infected group. Finally, branchial reactive oxygen species (ROS) were significant higher in A. hydrophila-infected fish than in the control group. Supplementation with 100 and 300 mg thymol/kg diet prevented inhibition of branchial cytosolic and mitochondrial CK activities caused by infection, and also inhibited the reduction of branchial ATP levels. Supplementation with 100, 200 and 300 mg thymol/kg prevented the inhibition of branchial AK and PK activities induced by aeromonosis. Supplementation of 100 mg thymol/kg prevented weight loss after A. hydrophila infection. These data suggest that supplementation with 100 mg thymol/kg exerts potent bactericidal properties and augments longevity. Supplementation at all concentrations of thymol prevented A. hydrophila-induced branchial bioenergetics; nevertheless, higher concentrations were associated with side-effects.

Branchial bioenergetics dysfunction as a relevant pathophysiological mechanism in freshwater silver catfish (Rhamdia quelen) experimentally infected with Flavobacterium columnare

Flavobacterium columnare, the causative agent of columnaris disease, is a serious bacterial disease responsible for causing devastating mortality rates in several species of freshwater fish, leading to severe economic losses in the aquaculture industry. Notwithstanding the enormous impacts this disease can have, very little is known regarding the interaction between the host and bacterium in terms of the mortality rate of silver catfish (Rhamdia quelen), as well its linkage to gill energetic homeostasis. Therefore, we conducted independent experiments to evaluate the mortality rates caused by F. columnare in silver catfish, as well as whether columnaris disease impairs the enzymes of the phosphoryl transfer network in gills of silver catfish and the pathways involved in this inhibition. Experiment I revealed that clinical signs started to appear 72 h post-infection (hpi), manifesting as lethargy, skin necrosis, fin erosion and gill discoloration. Silver catfish began to die at 96 hpi, and 100% mortality was observed at 120 hpi. Experiment II revealed that creatine kinase (CK, cytosolic and mitochondrial) and pyruvate kinase (PK) activities were inhibited in silver catfish experimentally infected with F. columnare, while no significant difference was observed between experimental and control groups with respect to adenylate kinase activity. Activity of the branchial sodium-potassium pump (Na⁺, K⁺-ATPase) was inhibited while reactive oxygen species (ROS) and lipid peroxidation levels were higher in silver catfish experimentally infected with F. columnare than in the control group at 72 hpi. Based on these data, the impairment of CK activity elicited by F. columnare caused a disruption in branchial energetic balance, possibly reducing ATP availability in the gills and provoking impairment of Na⁺, K ⁺ATPase activity. The inhibition of CK and PK activities appears to be mediated by ROS overproduction and lipid peroxidation, both of which contribute to disease pathogenesis associated with branchial tissue.

Changes in cardiac and hepatic energetic metabolism in gerbils infected by Listeria monocytogenes

Energy metabolism is a sensitive indicator of cellular disorders. Therefore, the objective of this study was to investigate changes in cardiac and hepatic energy metabolism during listeriosis using an experimental model. We divided gerbils into two groups: Control (n = 11) and orally Infected (n = 12) with 5 × 10⁹ CFU/mL of Listeria monocytogenes. Euthanasia and sampling were performed on days 6 and 12 post-infection (PI). Histopathological lesions were not found in the heart; however, the liver showed pyogranuloma. In the hearts of infected animals, cytosolic creatine kinase activity was lower on day 6 and 12 PI; mitochondrial creatine kinase/pyruvate kinase (PK), and sodium potassium pump (Na⁺/K⁺-ATPase) activities were lower on day 12 PI. Hepatic PK and Na⁺/K⁺-ATPase activities were lower in the infected group on day 12 PI. Lipoperoxidation was higher in the livers and hearts of infected animals on day 12 PI, and antioxidant capacity against peroxyl radicals (ACAP) was also higher in this group. These data suggest that subclinical listeriosis alters hepatic and cardiac energy metabolism, possibly related to decreased activity of phosphotransferases and ATPase. Subsequent antioxidant responses are not sufficient to correct alterations in lipid peroxidation and bioenergetics, possibly leading to important cellular pathological mechanisms.

Caffeine supplementation in diet mitigates Aeromonas hydrophila-induced impairment of the gill phosphotransfer network in grass carp Ctenopharyngodon idella

Some evidence suggests the involvement of phosphotransfer network in the pathogenesis of fish bacterial diseases, catalyzed by creatine kinase (CK), pyruvate kinase (PK) and adenylate kinase (AK); nevertheless, the effects on fish affected by Aeromonas hydrophila remain unknown. Recent evidence suggested a potent protective effect of caffeine on the branchial phosphotransfer network of fish subjected to challenge conditions. Therefore, the aim of this study was to evaluate whether A. hydrophila infection impaired branchial bioenergetics. We also determined whether dietary supplementation with caffeine protected against A. hydrophila-induced gill bioenergetic imbalance. We found that branchial cytosolic CK and AK activities were significant lower in fish experimentally infected with A. hydrophila than in uninfected fish, while mitochondrial CK activity was significant higher. Branchial lactate dehydrogenase (LDH) activity and lactate levels were significant higher in fish experimentally infected by A. hydrophila than in uninfected fish, while sodium-potassium ion pump (Na⁺, K⁺-ATPase) activity and adenosine triphosphate (ATP) levels were significant lower. No significant difference was observed between groups with respect to branchial PK activity. The dietary supplementation with 8% caffeine improved the branchial CK (cytosolic and mitochondrial), AK, and LDH activities, as well as ATP levels, but did not prevent increases in branchial lactate levels or the inhibition of Na⁺, K⁺-ATPase activity elicited by aeromonosis. Based on this evidence, we believe that reduction of CK (cytosolic) and AK activities contributes to impairment of bioenergetic homeostasis, while augmentation of mitochondrial CK activity can be considered an attempt to prevent or reduce the energetic imbalance during aeromonosis caused by A. hydrophila. The use of 8% caffeine dietary supplementation improved the energetic metabolism via protective effects on CK and AK activities, avoiding the necessity of using anaerobic metabolism. In summary, 8% dietary caffeine can be used to improve branchial energetic homeostasis during aeromonosis caused by A. hydrophila.

Impacts of the supplementation of açai lump flour in the diet of laying hens on productive performance, and fatty acid profiles and antioxidant capacity in the fresh and stocked eggs

The aim of this study was to evaluate whether the supplementation with açaí flour in the feed of laying hens at the end of the production cycle has beneficial effects on the health and performance of the birds and on the quality of the eggs. Groups received basal diets supplemented with 0%, 0.25%, 0.5%, 1.0%, and 2.0% açaí lump flour. We observed better productivity linked to oviposition and egg mass in a dose-dependent manner. We also observed higher shell resistance in stored eggs and higher % albumen and peel in fresh eggs. Lower levels of lipoperoxidation were observed in fresh eggs (2.0%). In stored eggs, lipoperoxidation levels were lower in all supplemented groups. The antioxidant capacity levels in fresh or stored eggs was higher (2.0%). We also observed a higher content of monounsaturated fatty acids in the supplemented groups, whereas saturated fatty acids were lower in the egg yolks. PRACTICAL APPLICATIONS: Based on a regression analysis, we verified that 1.47% of açaí flour is ideal in terms of productive efficiency. Dietary supplementation with açaí flour improved performance, egg quality, and had positive effects on the health of hens. Supplementation with açaí flour increased egg shelf life, reducing lipid peroxidation, biochemical reaction responsible for egg putrefaction.