Catalase and lactate dehydrogenase activity in tilapia subjected to contention stress: effect of the background color

Avaliaram-se os efeitos da cor do ambiente sobre o crescimento e a atividade da enzima antioxidante catalase (CAT) e da lactato desidrogenase (LDH) em tilápias do Nilo (n=24; 36,2±3,6g). Oito exemplares foram mortos para determinação da atividade basal das enzimas e os demais permaneceram isolados durante 14 dias sob espectro de luz branca ou azul (n=8 peixes/tratamento). A seguir os peixes foram submetidos a um estresse diário de confinamento de 90 minutos (15° ao 28° dia) e pesados semanalmente para cálculo da taxa de crescimento específico (TCE). A TCE negativa confirmou que o confinamento provocou estresse nos peixes, independentemente da cor do ambiente. O aumento da atividade da LDH no músculo vermelho dos peixes mantidos sob luz branca ou azul indicou mudança do metabolismo aeróbio para anaeróbio. O estresse reduziu a atividade da CAT no músculo branco dos peixes mantidos sob a luz branca ou azul. Na musculatura vermelha, esta redução ocorreu apenas nos animais mantidos sob a luz branca. O confinamento aumenta os processos metabólicos anaeróbios e é adequado para estudos sobre os efeitos do estresse. O espectro de luz azul não evita a redução do crescimento e a demanda energética anaeróbia em situações de estresse, mas preserva a atividade da CAT, contribuindo para o bem-estar da tilápia.We assess the effects of the background color on the growth and antioxidant enzyme catalase (CAT) and lactate dehydrogenase (LDH) in Nile tilapia (n=24; 36.2 +/- 3.6g). Eight fish were killed for assessment of basal activity of the enzymes and the others remained isolated for 14 days under white or blue light spectrum (n=8 fish/treatment). Then each animal were subjected to a daily stress of confinement of 90 minutes (15th to 28th day) and weighed to calculate the specific growth rate (SGR). The negative SGR confirmed that the confinement stressed in fish, regardless of the background color. The increased activity of LDH in red muscle of fish kept under white or blue light indicated replacement of aerobic metabolism to anaerobic. Stress reduced the CAT activity in white muscle of fish kept under white or light blue. In red muscle this reduction occurred only in animals kept under white light. Restraint causes increase in anaerobic metabolic processes and is suitable for studies on the effects of stress in tilapia. Confinement increases the anaerobic metabolic processes and is suitable for studies on the effects of stress. The blue spectrum of light does not prevent the reduction of growth and the anaerobic energetic demand in stressful situations, but preserves the CAT activity, contributing to the tilapia welfare

Effect of Cysticercus cellulosae fractions on the respiratory burst of pig neutrophils

Neutrophils, eosinophils and macrophages are cells that interact with invading parasites and naive hosts have been shown to have anti-parasitic activity. The initial reaction of these leukocytes is the generation of reactive oxygen species (ROS) to play in parasite expulsion. The present work was carried out to study the effect of total extract, scolex and membrane fractions from Cysticercus cellulosae on respiratory burst by pig neutrophils. Hydrogen peroxide (H2O2) production by neutrophils incubated with metacestode fractions from C. cellulosae showed an increase of: 190% (total extract), 120% (scolex) and 44% (membrane). High antioxidant catalatic activity (33%, 28%, 28% by total extract, scolex and membrane, respectively) was observed in neutrophils incubated with metacestode fractions, which could be an attempt at self-protection. Scolex and membrane fractions increased the phagocytic capacity of neutrophils (44% and 28%, respectively). On the other hand, total cysticerci did not alter the phagocytosis, possibly due to modifications in membrane function, caused by high ROS production from neutrophils in the presence of total cysticerci. Total fraction from C. cellulosae is toxic for neutrophils as shown by the decrease in phagocytic capacity, probably caused by high levels of ROS formation. The difference in toxicity of total extract, scolex and membrane fractions on neutrophils can be explained by the presence of an antigenic effect of the vesicular fluid in the total extract of C. cellulosae.Neutrófilos, eosinófilos e macrófagos são células que interagem com os parasitas no corpo do hospedeiro desenvolvendo atividade antiparasitária. A reação inicial destes leucócitos é a geração de espécies reativas de oxigênio (ERO) a fim de expulsar os parasitas. No presente trabalho estudou-se o efeito da fração total, de escolex e de membrana de Cysticercus cellulosae sobre a explosão respiratória de neutrófilos de suínos. A produção de peróxido de hidrogênio (H2O2) pelos neutrófilos incubados com as frações de C. cellulosae apresentou acréscimo de 190% (extrato total), 120% (escolex) e 44% (membrana). Alta atividade de catalase (33%, 28% e 28% para extrato total, escolex e membrana respectivamente) foi observada nos neutrófilos incubados com as frações de metacestodeo, podendo representar a própria proteção celular do neutrófilo. Frações de escolex e de membrana aumentaram a capacidade fagocitária dos neutrófilos (44% e 28%, respectivamente). Por outro lado, a fração total do cisticerco não alterou a capacidade fagocitária dos neutrófilos, o que pode estar relacionada com modificações na função da membrana celular causadas pela alta produção de ERO na presença da fração total. O extrato total de C. cellulosae é tóxico para os neutrófilos, indicada pela diminuição da capacidade fagocitária, provavelmente pela indução de alto nível de ERO. A diferença de toxicidade do extrato total, de escolex e de membrana para os neutrófilos pode ocorrer pelo efeito antigênico presente no fluido vesicular no extrato total de C. cellulosae

Effect of system indol-3-acetic acid/horseradish peroxidase on the viability of Staphylococcus aureus

O objetivo do presente estudo foi avaliar a ação do ácido indol-3-acético (AIA) combinado com a peroxidase de raiz forte (HRP), formando um sistema gerador de espécies reativas de oxigênio, sobre a viabilidade de Staphylococcus aureus. Para tal, avaliou-se a viabilidade do S. aureus através da contagem das unidades formadoras de colônias após crescimento em ágar manitol, potencial e integridade de membrana por citometria de fluxo e integridade do DNA através de eletroforese em gel de poliacrilamida. Para realização dos ensaios foram utilizadas cepas de S. aureus recuperadas de casos de mastites clínicas. As cepas foram cultivadas em meio BHI (brain-heart-infusion) a 37ºC \"overnight\". Nos ensaios, o microrganismo foi incubado na ausência (controle) e presença de AIA (1 mmol/L)/HRP (1 µmol/L) em diferentes tempos (0, 1,5, 3 e 6 horas) a 37ºC. Foram realizados também ensaios contendo o microrganismo incubado na presença de AIA ou de HRP. O sistema AIA/HRP inibiu em 96%, 98%, 99% a formação de colônias do microrganismo para os tempos de 1,5, 3 e 6 horas, respectivamente, em relação ao controle em cada tempo. Ocorreu uma redução na polarização da membrana do microrganismo em 38, 69 e 99% nos tempos 1,5, 3 e 6 horas, respectivamente e uma diminuição significativa do número de microrganismos com membrana integra de 17 e 22% quando estes foram incubados por 3 e 6 horas, respectivamente em relação ao controle nos respectivos tempos. A adição das enzimas antioxidantes catalase ou superóxido dismutase ao meio de incubação não alterou o efeito deletério promovido pelo sistema AIA/HRP avaliado pelas unidades formadoras de colônias, despolarização e integridade de membrana. O sistema AIA/HRP não induziu a fragmentação do DNA do S. aureus após 3 e 6 horas de incubação. No presente estudo, foi possível verificar que a oxidação do AIA pela HRP produz uma resposta citotóxica potente capaz de promover a inibição do crescimento de S. aureus em ágar manitol, provocar a despolarização e a perda da integridade da membrana do microrganismo, sugerindo a possibilidade da utilização do sistema AIA/HRP como uma possível terapia alternativa contra bactérias.The objective of this study was to evaluate the action of the indole-3-acetic acid (IAA) in combination with horseradish peroxidase (HRP), forming a system generator of reactive oxygen species, on the viability of Staphylococcus aureus. To this end, was evaluated the of viability of S. aureus through the counting of the colony forming units after growth in mannitol agar, membrane potential and membrane integrity by flow cytometry and integrity of the DNA through the polyacrylamide gel electrophoresis. For the tests were used strains of S. aureus recovered from cases of clinical mastitis. The strains were grown in BHI medium (brain-heart-infusion) at 37°C overnight. In the tests, the microorganism was incubated in the absence (control) and presence of IAA (1 mmol/L)/HRP (1 µmol/L) at different times (0, 1.5, 3 and 6 hours) at 37°C. There were also conducted tests containing the microorganism incubated in the presence of IAA or HRP. The system IAA/HRP inhibited at 96%, 98%, 99% colony formation of microorganism to the times of 1.5, 3 and 6 hours, respectively, in relation to the control in every time. There was a decrease in polarization of the membrane of the microorganism on 38, 69 and 99% at times 1.5, 3 and 6 hours, respectively, and a significant decrease in the number of microorganisms with membrane integrity, 17 and 22% when they were incubated for 3 and 6 hours, respectively, in relation to the control in their time. The addition of the antioxidant enzymes catalase and superoxide dismutase in incubation medium did not alter the deleterious effect promoted by the system IAA/HRP assessed by colony forming units, membrane potential and membrane integrity. The system IAA/HRP did not induce the DNA fragmentation of S. aureus after 3 and 6 hours of incubation. In the present study, it was possible to verify that the oxidation of the IAA by HRP produces a potent cytotoxic response capable of promoting the inhibition of growth of S. aureus in mannitol agar, causing depolarization and the loss of integrity of the membrane of the microorganism, suggesting the possibility of using the system IAA/HRP as a possible alternative therapy against bacteria

In vitro antioxidant activity of olive leaf extract (Olea europaea L.) and its protective effect on oxidative damage in human erythrocytes

Aims: This study aimed to evaluate in vitro antioxidant capacity of olive leaf extract (OLE), Olea europaea L., and its protective effect on peroxyl radical-induced oxidative damage in human erythrocytes. Main methods: The OLE was evaluated by the following assays: i) total phenolic and flavonoid content; ii) oleuropein content; iii) Ferric reducing antioxidant power (FRAP); iv) antioxidant activity against ABTS·+, DPPH· and reactive oxygen and nitrogen species: superoxide anion (O2·−), hypochlorous acid (HOCl) and nitric oxide (NO·) and v) protective effect on peroxyl radical-induced oxidative damages in human erythrocytes as hemolysis, thiobarbituric acid reactive substances (TBARS) formation and oxyhemoglobin oxidation. Key findings: Total phenolic and flavonoid contents were 131.7 ± 9.4 mg gallic acid equivalents/g dry weight (dw) and 19.4 ± 1.3 mg quercetin equivalents/g dw, respectively. Oleuropein content was 25.5 ± 5.2 mg/g dw. FRAP analysis was 281.8 ± 22.8 mg trolox equivalent/g dw and OLE inhibited ABTS·+ (50% effective concentration (EC50) = 16.1 ± 1.2 μg/mL) and DPPH· (EC50 = 13.8 ± 0.8 μg/mL). The extract demonstrated effective ability to scavenge O2·− (EC50 = 52.6 ± 2.1 μg/mL), NO· (EC50 = 48.4 ± 6.8 μg/mL) and HOCl (EC50 = 714.1 ± 31.4 μg/mL). The extract inhibited peroxyl radical-induced hemolysis (EC50 = 11.5 ± 1.5 μg/mL), TBARS formation (EC50 = 38.0 ± 11.7 μg/mL) and hemoglobin oxidation (EC50 = 186.3 ± 29.7 μg/mL) in erythrocytes. Significance: OLE is an important source of natural antioxidants; it has effective antioxidant activity against different reactive species and protects human erythrocytes against oxidative damage

Copper and selenium supplementation in the diet of Brangus steers on the nutritional characteristics of meat

Twenty-eight Brangus cattle were used to determine the effect of copper and selenium supplementation on the carcass characteristics, fatty acid composition of the longissimus dorsi muscle and on the copper and selenium concentrations in the liver. The treatments were: no supplementation of copper or selenium; 2 mg Se/kg DM as sodium selenite; 40 mg Cu/kg DM as copper sulfate; and 2 mg Se/kg DM as sodium selenite and 40 mg Cu/kg DM as copper sulfate. The fat thickness, rib eye area and fatty acid composition of the longissimus dorsi muscle were not affected by treatments. There was no effect on carcass yield and cooling loss with the supplementation of copper, selenium or selenium × copper in the levels studied. For the ether extract concentration in the longissimus dorsi muscle, no differences were found according to the treatments with selenium, copper or selenium × copper. The treatments with selenium and selenium × copper showed higher selenium concentrations in the liver than the control and copper treatments. For the copper concentration in the liver, the copper and selenium × copper treatments showed higher values than the control and selenium treatments. Despite the little effect on the meat composition, the results of this experiment demonstrate no interaction between selenium and copper in the levels studied

Organic selenium increases PHGPx, but does not affect quality sperm in raw boar semen

This study assessed the effects of feeding organic selenium (Se) on sperm morphology, motility, membrane integrity and lipidic peroxidation, also on sperm ATP and phospholipid hydroperoxide glutathione peroxidase (PHGPx) in raw semen of mature boars. Twelve boars were divided into three groups: Control, 0.3 ppm sodium selenite, Inorganic, 0.5 ppm sodium selenite and Organic, 0.5 ppm Se yeast for 11 weeks. Organic diet presented a higher total sperm number (P<0.05) when compared to the inorganic treatment; however, no difference was observed regarding volume, sperm concentration, number of cells with plasma and/or acrosomal membrane integrity, membrane mitochondrial potential, ATP assay and Se concentration in seminal and blood content. Also, no difference was observed on motility parameters, sperm morphology and membrane peroxidation, however, PHGPx was influenced (P<0.05) in organic treatment. Thus organic Se feeding influenced none of the analyzed seminal characteristics in raw semen, except for PHGPx and total number of sperm.This research was supported by FAPESP (Grant numbers 07/55613-6 and 08/55059-1), Alltech Inc., Vet life Veterinary Products and Agroceres Multimix Nutrição Animal Ltda

Effect of Cysticercus cellulosae fractions on the respiratory burst of pig neutrophils Efeito de frações de Cysticercus cellulosae sobre a explosão respiratória de neutrófilos de suínos

Neutrophils, eosinophils and macrophages are cells that interact with invading parasites and naive hosts have been shown to have anti-parasitic activity. The initial reaction of these leukocytes is the generation of reactive oxygen species (ROS) to play in parasite expulsion. The present work was carried out to study the effect of total extract, scolex and membrane fractions from Cysticercus cellulosae on respiratory burst by pig neutrophils. Hydrogen peroxide (H2O2) production by neutrophils incubated with metacestode fractions from C. cellulosae showed an increase of: 190% (total extract), 120% (scolex) and 44% (membrane). High antioxidant catalatic activity (33%, 28%, 28% by total extract, scolex and membrane, respectively) was observed in neutrophils incubated with metacestode fractions, which could be an attempt at self-protection. Scolex and membrane fractions increased the phagocytic capacity of neutrophils (44% and 28%, respectively). On the other hand, total cysticerci did not alter the phagocytosis, possibly due to modifications in membrane function, caused by high ROS production from neutrophils in the presence of total cysticerci. Total fraction from C. cellulosae is toxic for neutrophils as shown by the decrease in phagocytic capacity, probably caused by high levels of ROS formation. The difference in toxicity of total extract, scolex and membrane fractions on neutrophils can be explained by the presence of an antigenic effect of the vesicular fluid in the total extract of C. cellulosae.<br>Neutrófilos, eosinófilos e macrófagos são células que interagem com os parasitas no corpo do hospedeiro desenvolvendo atividade antiparasitária. A reação inicial destes leucócitos é a geração de espécies reativas de oxigênio (ERO) a fim de expulsar os parasitas. No presente trabalho estudou-se o efeito da fração total, de escolex e de membrana de Cysticercus cellulosae sobre a explosão respiratória de neutrófilos de suínos. A produção de peróxido de hidrogênio (H2O2) pelos neutrófilos incubados com as frações de C. cellulosae apresentou acréscimo de 190% (extrato total), 120% (escolex) e 44% (membrana). Alta atividade de catalase (33%, 28% e 28% para extrato total, escolex e membrana respectivamente) foi observada nos neutrófilos incubados com as frações de metacestodeo, podendo representar a própria proteção celular do neutrófilo. Frações de escolex e de membrana aumentaram a capacidade fagocitária dos neutrófilos (44% e 28%, respectivamente). Por outro lado, a fração total do cisticerco não alterou a capacidade fagocitária dos neutrófilos, o que pode estar relacionada com modificações na função da membrana celular causadas pela alta produção de ERO na presença da fração total. O extrato total de C. cellulosae é tóxico para os neutrófilos, indicada pela diminuição da capacidade fagocitária, provavelmente pela indução de alto nível de ERO. A diferença de toxicidade do extrato total, de escolex e de membrana para os neutrófilos pode ocorrer pelo efeito antigênico presente no fluido vesicular no extrato total de C. cellulosae