The antioxidant effect of Aronia melanocarpa extract in rats oxidative stress induced by cisplatin administration

BackgroundThe reactive oxygen species generated by numerous xenobiotic substances has as consequences the impairment of different organs normal function. Many plants pose antioxidant activity to counteract oxidative stress, among them being the chokeberry (Aronia melanocarpa). The purpose of present study was to determine if the use of A. melanocarpa extract can counteract the oxidative stress induced by cisplatin administration in rats.Material and methodsThe study was made on forty Wistar rats divided in four groups as follows: C (control): receiving i.p. 1 mL of saline solution; E1: receiving cisplatin 20 mg/kg bw, i.p.; E2: receiving cisplatin 20 mg/kg bw, i.p and A. melanocarpa berry 6 % aqueous extract as drinking water, and CB (control blank): i.p 1 mL saline solution and A. melanocarpa 6 % aqueous extract for four weeks. Results. Administration of Cisplatin was followed by the increase of serum superoxide dismutase (+21.18 %, P < 0.05), catalase (+25.44 %, P < 0.001), glutathione peroxidase (+17.88 %, P < 0.05) and thiobarbituric reactive substances (+28.17 %, P < 0.01) but significantly decreased glutathione reductase (−22.35 %, P < 0.001) level comparative to control, pointing out that administration of cisplatin induced oxidative stress in rats. In groups that received A. melanocarpa extract as drinking water, we noted that the levels of the oxidative stress biomarkers tended to be restored almost to normal levels, which could be a possible good antioxidant used in condition to cisplatin use. Also, we noted a significant (P < 0.001) decrease of total antioxidant capacity in liver and kidney of rats exposed to cisplatin, recovered in those that received chokeberry. Studied trace elements important for the stress oxidative enzymes (Cu, Zn, Fe and Mn) were decreased in cisplatin exposed groups compared to control and mainly all were almost to normal level in groups receiving A. melanocarpa. Conclusion. A. melanocarpa extract due to its antioxidants content could offer protection against free radicals produced as a consequence of cisplatin use.     

绿原酸对凡纳滨对虾抗氧化系统及抗低盐度胁迫的影响

对绿原酸调节凡纳滨对虾(Litopenaeus vannamei)血淋巴抗氧化系统功能及抗低盐度胁迫的效果进行了评价。360尾凡纳滨对虾随机分为4组,分别投喂含有0、100、200和400 mg/kg绿原酸的饲料28 d,随后将对虾从盐度为32的天然海水直接转入至盐度为10的水中胁迫72 h。结果表明,在正常养殖条件下,绿原酸对凡纳滨对虾的成活率、血淋巴总抗氧化能力(Total antioxidative capacity, T-AOC)、超氧化物歧化酶(Superoxide dismutase, SOD)及过氧化氢酶(Catalase, CAT)活力均无明显影响,然而投喂含有绿原酸的饲料14 d,对虾血淋巴谷胱甘肽过氧化物酶(Glutathione peroxidase, GPx)活性和血淋巴细胞GPx和CAT基因表达水平均显著高于对照组(P<0.05);低盐度胁迫24 h,绿原酸组凡纳滨对虾的存活率较对照组提高10%,但各组之间无显著性差异(P>0.05);低盐度胁迫24 h,各组凡纳滨对虾血淋巴T-AOC、SOD和GPx活性与胁迫前相比均显著增加,说明低盐度胁迫条件下机体产生了抗氧化胁迫反应,同时绿原酸组对虾血淋巴GPx、CAT活性均显著高于对照组(P<0.05);低盐度胁迫72 h,绿原酸组对虾血淋巴T-AOC、GPx和CAT活性和血淋巴细胞GPx和CAT基因表达水平均明显高于对照组。上述结果表明绿原酸可有效调节凡纳滨对虾的抗氧化系统功能,增强对虾对于低盐度胁迫下的适应能力。     

Biology of the microsporidan parasite Pleistophora crangoni n. sp. in three species of crangonid sand shrimps

The microsporidium Pleistophora crangoni n. sp. is a common parasite of Crangon franciscorum, C. nigricauda, and C. stylirostris in the vicinity of Yaquina Bay, Oregon. Characteristics of the parasite are described. Skeletal muscle was the only host tissue infected. The seasonal prevalence and intensity of the parasite in crangonids are described, based on examination of 1556 C. franciscorum, 3877 C. nigricauda, and 1674 C. stylirostris collected at monthly intervals from June 1975 through June 1976. Prevalence in C. franciscorum and C. stylirostris increased through the autumn and reached winter peaks of 30.3 and 41.0%, respectively, then decreased in the spring. Prevalence in C. nigricauda remained below 8% through the year. Intensity increased with size of the shrimps in the three species. Infection experiments and field observations suggest that only very young shrimps are susceptible to infection during a relatively short period during the summer months. Following natural infection, the parasite spreads within the host, indicating repeated schizogonic cycles. Parasitic castration was indicated by the absence of gravid infected female shrimps and was confirmed by histological examination. Ovaries of infected shrimps did not develop beyond a very early stage. A shift in sex ratio toward females in infected shrimps indicates that the parasite may influence sex determination. Shrimps showed little cellular response to infection. Only rarely in heavily infected shrimps was encapsulation of parasite cysts observed; necrotic tissue was occasionally observed. Infected shrimps usually succumbed before uninfected shrimps when subjected to oxygen stress. The collection of infected shrimps that were unusually large may indicate that these individuals grew faster or lived longer than uninfected shrimps.     

Isolation of Lactic Acid Bacteria from Kuruma Shrimp (Marsupenaeus japonicus) Intestine and Assessment of Immunomodulatory Role of a Selected Strain as Probiotic

Fifty-one lactic acid bacteria (LAB) strains were isolated and identified based on 16S ribosomal DNA sequence from the intestinal tracts of 142 kuruma shrimps (Marsupenaeus japonicus) collected from Kanmon Strait, Fukuoka and Tachibana Bay, Nagasaki, Japan. Cellular immunomodulatory function of 51 isolated LAB strains was assessed by measuring the level of interferon (IFN)-γ induction in mouse spleen cell culture. The strain Lactococcus lactis D1813 exhibited the highest amount of IFN-γ production and also bactericidal activity and was selected for testing its immunomodulatory role as a probiotic in kuruma shrimp. We also assessed the effect of dietary incorporation of this probiotic on resistance to Vibrio penaeicida infection in the kuruma shrimp. Our results demonstrate that probiotic L. lactis D1813-containing diet-fed (10⁵ cfu g^?1) shrimps displayed a significant up-regulation of lysozyme gene expressions in the intestine and hepatopancreas. However, insignificantly higher expression of anti-lipopolysaccharide factor, super oxide dismutase, prophenoloxidase, and toll-like receptor 1 was recorded in the intestine of shrimps fed the probiotic diet. Moreover, significantly increased (P?<?0.01) resistance to the bacterial pathogen in term of better post-infection survival (61.7 %) was observed in the shrimps fed with the probiotic-incorporated diet compared with the control diet-fed group (28.3 %). The present study indicates the immunomodulatory role of the LAB L. lactis D1813 on the kuruma shrimp immune system and supports its potential use as an effective probiotic in shrimp aquaculture.     

Effects of cold stress on juvenile Piaractus mesopotamicus and the mitigation by β-carotene

This study investigated the effects of cold stress on morphometrical and hematological biomarkers, energy metabolism, and oxidative stress in different tissues of P. mesopotamicus, and the protective role of β-carotene. Fish were fed with a control diet (CD) and the same diet supplemented with 105 mg/kg β-carotene (BD) for 60 days. After the feeding trial, fish fed CD or BD diets were exposed to control (24 °C) and low temperature (14 °C) for 24 h. Fish (CD and BD) exposed to thermal stress showed lower hepatosomatic index. The hemoglobin increased only in CD-fed fish exposed to 14 °C. Increased glycemia, plasmatic protein depletion, and decreased hepatic glycogen were observed in fish fed the CD, while only the lipid levels in liver were augmented in BD-fed fish exposed at 14 °C. Regarding the oxidative stress, increased antioxidant enzymes activity and lipid peroxidation were observed in CD-fed fish exposed to cold. The two-way ANOVA showed an interaction between dietary treatment and temperature for glucose and oxidative stress biomarkers, with the highest values recorded in 14 °C-exposed fish fed with the CD. Our study demonstrated that cold stress had the greatest impact on fish oxidative status, and β-carotene reduces harmful effects induced by cold in P. mesopotamicus.     

Effect of prebiotics on bacteriocin production and cholesterol lowering activity of <Emphasis Type="Italic">Pediococcus acidilactici</Emphasis> LAB 5

The in vitro influence of three prebiotics viz. mannitol, maltodextrin and sorbitol was evaluated on probiotic aspects like bile salt tolerance, cholesterol lowering efficiency and bacteriocin production of the strain, Pediococcus acidilactici LAB 5 which was isolated from vacuum packed fermented meat product. Optimum temperature for bacteriocin production in MRS medium was 37°C. The strain deconjugated bile salt (sodium taurocholate) to 607.66 ± 10.894 μg/ml from initial bile salt concentration 3 mg/ml. In vitro cholesterol removal capability of the strain P. acidilactici LAB 5 was 62 ± 2.742 μg/ml. Prebiotic sorbitol had a positive influence on the probiotic parameters like better cell growth, bacteriocin production and cholesterol removal capability. Anaerobic condition had influenced largely on bile salt deconjugation, cholesterol removal and bacteriocin production. Synbiotic treatment of P. acidilactici LAB 5 with sorbitol for 1 month lowered the plasma cholesterol level to 176.34 ± 12.66 μg/ml in comparison to untreated one (208.76 ± 20.27 μg/ml) in Swiss albino mice. Intestinal adherence of P. acidilactici LAB 5 was also more in synbiotic condition than only in probiotic and control treatments.     

Combined or Individual Effects of Dietary Probiotic <Emphasis Type="Italic">Pedicoccus acidilactici</Emphasis> and Nucleotide on Growth Performance,Intestinal Microbiota,Hemato-biochemical Parameters,and Innate Immune Response in Goldfish (<Emphasis Type="Italic">Carassius auratus</Emphasis>)

This study investigated the effect of dietary supplementation of probiotic Pedicoccus acidilactici and nucleotide (separately or combined) on growth performance, intestinal microbiota, hemato-immunological parameters, and immunity response in goldfish (Carassius auratus). Fish (average weight 5–6 g) were acclimatized and divided into eight experimental diets supplemented with P. acidilactici of different concentrations (0.1, 0.2, and 0.3% diet) and nucleotides (0 and 0.5% diet) for 6 months. Fish fed with experimental diets showed significant differences in terms of final weight, weight gain, feed conversion ratio, daily growth rate, and condition factor when compared to control diet (P < 0.05). Fish fed with probiotic (0.3%) separately and combined with nucleotide (0.5%) had highest RBC and WBC when compared to other diets (P < 0.05), while the highest values for Hb and Hct as well as total protein, glucose, albumin, and globulin were observed in probiotic (0.2%) and nucleotide (0.5%) combined diet. Serum lysozyme and anti-protease activities were significantly higher in probiotic (0.1 and 0.2%) and nucleotide (0.5%) combined diets. Similarly, these two diets combined showed the highest colonization of P. acidilactici when compared to other diets. In conclusion, combined dietary probiotic and nucleotide improve the growth performance, hemato-biochemical parameters, and intestine growth in C. auratus.     

Dietary β-glucan stimulate complement and C-reactive protein acute phase responses in common carp (Cyprinus carpio) during an Aeromonas salmonicida infection

The effect of β-glucans as feed additive on the profile of C-reactive protein (CRP) and complement acute phase responses was studied in common carp Cyprinus carpio after exposition to a bacterial infection with Aeromonas salmonicida. Carp were orally administered with β-glucan (MacroGard^®) for 14 days with a daily β-glucan intake of 6 mg per kg body weight. Fish were then intraperitoneally injected with either PBS or 1 × 10⁸ bacteria per fish and sampled at time 0, 6, 12, 24, 48, 72, 96 and 120 h post-injection (p.i.) for serum and head kidney, liver and mid-gut tissues. CRP levels and complement activity were determined in the serum samples whilst the gene expression profiles of CRP and complement related genes (crp1, crp2, c1r/s, bf/c2, c3 and masp2) were analysed in the tissues by quantitative PCR. Results obtained showed that oral administration of β-glucan for 14 days significantly increased serum CRP levels up to 2 fold and serum alternative complement activity (ACP) up to 35 fold. The bacterial infection on its own (i.e. not combined with a β-glucan feeding) did have significant effects on complement response whilst CRP was not detectably induced during the carp acute phase reaction. However, the combination of the infection and the β-glucan feeding did show significant effects on both CRP and complement profiles with higher serum CRP levels and serum ACP activity in the β-glucan fed fish than in the control fed fish. In addition, a distinct organ and time dependent expression profile pattern was detected for all the selected genes: a peak of gene expression first occurred in the head kidney tissue (6 h p.i. or 12 h p.i.), then an up-regulation in the liver several hours later (24 h p.i.) and finally up- or down-regulations in the mid-gut at 24 h p.i. and 72 h p.i. In conclusion, the results of this study suggest that MacroGard^® stimulated CRP and complement responses to A. salmonicida infection in common carp.     

Virulence of an emerging pathogenic lineage of Vibrio nigripulchritudo is dependent on two plasmids

Vibrioses are the predominant bacterial infections in marine shrimp farms. Vibrio nigripulchritudo is an emerging pathogen of the cultured shrimp Litopenaeus stylirostris in New Caledonia and other regions in the Indo‐Pacific. The molecular determinants of V. nigripulchritudo pathogenicity are unknown; however, molecular epidemiological studies have revealed that recent pathogenic V. nigripulchritudo isolates from New Caledonia all cluster into a monophyletic clade and contain a small plasmid, pB1067. Here, we report that a large plasmid, pA1066 (247 kb), can also serve as a marker for virulent V. nigripulchritudo, and that an ancestral version of this plasmid was likely acquired prior to other virulence‐linked markers. Additionally, we demonstrate that pA1066 is critical for the full virulence of V. nigripulchritudo in several newly developed experimental models of infection. Plasmid pB1067 also contributes to virulence; only strains containing both plasmids induced the highest level of shrimp mortality. Thus, it appears that these plasmids, which are absent from non‐pathogenic isolates, may be driving forces, as well as markers, for the emergence of a pathogenic lineage of V. nigripulchritudo.     

The Effects of Alpha-Tocopherol on Hippocampal Oxidative Stress Prior to in Pilocarpine-Induced Seizures

Reactive oxygen species have been implicated in seizure-induced neurodegeneration, and there is a correlation between free radical level and scavenger enzymatic activity in the epilepsy. It has been suggested that pilocarpine-induced seizures is mediated by an increase in oxidative stress. Current research has found that antioxidant may provide, in a certain degree, neuroprotection against the neurotoxicity of seizures at the cellular level. Alpha-tocopherol has numerous nonenzymatic actions and is a powerful liposoluble antioxidant. The objective of the present study was to evaluate the neuroprotective effects of alpha-tocopherol (TP) in rats, against oxidative stress caused by pilocarpine-induced seizures. 30 min prior to behavioral observation, Wistar rats were treated with, 0.9% saline (i.p., control group), TP (200 mg/kg, i.p., TP group), pilocarpine (400 mg/kg, i.p., P400 group), or the combination of TP (200 mg/kg, i.p.) and pilocarpine (400 mg/kg, i.p.). After the treatments all groups were observed for 6 h. The enzymatic activities, lipid peroxidation and nitrite concentrations were measured using speccitrophotometric methods and these data were assayed. In P400 group mice there was a significant increase in lipid peroxidation and nitrite levels. However, no alteration was observed in superoxide dismutase (SOD) and catalase activities. In the TP and pilocarpine co-administered mice, antioxidant treatment significantly reduced the lipid peroxidation level and nitrite content, as well as increased the SOD and catalase activities in rat hippocampus after seizures. Our findings strongly support the hypothesis that oxidative stress occurs in hippocampus during pilocarpine-induced seizures, indicate that brain damage induced by the oxidative process plays a crucial role in seizures pathogenic consequences, and imply that strong protective effect could be achieved using alpha-tocopherol.     

Oxidative effects of inorganic and organic contaminants on haemolymph of mussels

We applied a newly-established method in haemolymph of mussels, Mytilus galloprovincialis, exposed to different concentrations of heavy metals, such as zinc and cadmium and organic pollutants, such as PAHs and lindane, for the detection of total antioxidant capacity (TAC). The susceptibility of exposed mussels was increased in relation to oxidative stress induced by contaminants tested. Oxidative modifications of proteins were estimated by measuring protein carbonyl content (PCC) and malondialdehyde levels (MDA). For PCC measurement, a highly sensitive and accurate ELISA method, which requires only 5 µg of protein, was used. The significant increase of PCC and MDA in haemolymph of exposed mussels reinforces its role as biomarkers of oxidative stress. Significant correlation of TAC assay, PCC and MDA was conducted in order to evaluate the utility of PCC and TAC assay, used in the present study, as tools for determining oxidative effects of pollutants in mussels. The results reinforce the application of PCC method as useful tool for the determination of PCC alterations in haemolymph of mussels exposed to different levels of contaminants. In addition, the TAC method gives encouraging results, concerning its ability to predict antioxidant efficiency in haemolymph of mussels exposed to inorganic and organic contaminants.     

Lipoic acid prevents fructose-induced changes in liver carbohydrate metabolism: Role of oxidative stress

Background

Fructose administration rapidly induces oxidative stress that triggers compensatory hepatic metabolic changes. We evaluated the effect of an antioxidant, R/S-α-lipoic acid on fructose-induced oxidative stress and carbohydrate metabolism changes.

Methods

Wistar rats were fed a standard commercial diet, the same diet plus 10% fructose in drinking water, or injected with R/S-α-lipoic acid (35 mg/kg, i.p.) (control + L and fructose + L). Three weeks thereafter, blood samples were drawn to measure glucose, triglycerides, insulin, and the homeostasis model assessment-insulin resistance (HOMA-IR) and Matsuda indices. In the liver, we measured gene expression, protein content and activity of several enzymes, and metabolite concentration.

Results

Comparable body weight changes and calorie intake were recorded in all groups after the treatments. Fructose fed rats had hyperinsulinemia, hypertriglyceridemia, higher HOMA-IR and lower Matsuda indices compared to control animals. Fructose fed rats showed increased fructokinase gene expression, protein content and activity, glucokinase and glucose-6-phosphatase gene expression and activity, glycogen storage, glucose-6-phosphate dehydrogenase mRNA and enzyme activity, NAD(P)H oxidase subunits (gp91^phox and p22^phox) gene expression and protein concentration and phosphofructokinase-2 protein content than control rats. All these changes were prevented by R/S-α-lipoic acid co-administration.

Conclusions

Fructose induces hepatic metabolic changes that presumably begin with increased fructose phosphorylation by fructokinase, followed by adaptive changes that attempt to switch the substrate flow from mitochondrial metabolism to energy storage. These changes can be effectively prevented by R/S-α-lipoic acid co-administration.

General significance

Control of oxidative stress could be a useful strategy to prevent the transition from impaired glucose tolerance to type 2 diabetes.     

Protection of blue shrimp (Litopenaeus stylirostris) against the White Spot Syndrome Virus (WSSV) when injected with shrimp lysozyme

In this study we found that a blue shrimp (Litopenaeus stylirostris) lysozyme gene (Lslzm) was up-regulated in WSSV-infected shrimp, suggesting that lysozyme is involved in the innate response of shrimp to this virus. Shrimp were intramuscularly injected with Lslzm protein to identify how this recombinant protein protects L. stylirostris from WSSV infection and to determine how this protein influences nonspecific cellular and humoral defense mechanisms. Higher survival rates and a lower viral load (compared with controls) were reported for shrimps that were first injected with the Lslzm protein and then infected with WSSV. In addition, the Lslzm expression level and the immunological parameters (including THC, phagocytic activity, respiratory burst activity, phenoloxidase activity and lysozyme activity) were all significantly higher in the WSSV-infected shrimp treated with the Lslzm protein, compared with the controls. These results indicate that lysozyme is effective at blocking WSSV infection in L. stylirostris and that lysozyme modulates the cellular and humoral defense mechanisms after they are suppressed by the WSSV virus.     

Role of soy isoflavone in preventing aging changes in rat testis: Biochemical and histological studies

Testicular function and structure harmed by ageing. Goal of this research was to assess preventive actions of soy isoflavone oral administration for 8 weeks on testes of old male albino rats, and potential mechanisms of action. Adult control (N = 10) and elderly control (N = 10) rats were fed usual diet, while aged treatment group (N = 10) gave oral 100 mg/kg soy isoflavone daily for 8 weeks. ELISA kits were used to measure testosterone levels and oxidative stress indicators [malonaldehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD)] in serum. Aging produced functional and structural testicular changes and decreased ki67 proliferative marker immunoexpression versus adult control rats due to enhancement of oxidative stress. Soy isoflavone exerted protective effect on testicular function and structure as assessed by increase serum levels of testosterone and preserved histological structure and immune-expression features. These protected effects due to isoflavone antioxidant properties proved by decrease in serum values of MDA, while GSH and SOD were elevated after treatment. These data demonstrated protective effects of isoflavone against age changes in rat testes, by reducing oxidative stress and increasing antioxidants and testicular ki67 proliferative marker immunoexpression.     

Inhibition of monoterpene biosynthesis accelerates oxidative stress and leads to enhancement of antioxidant defenses in leaves of rubber tree (Hevea brasiliensis)

This paper mainly studies the possible antioxidant of monoterpene and effects of its absence on other antioxidant defense. The leaves of rubber tree (Hevea brasiliensis) were fed with fosmidomycin through transpiration stream, in the dark, at room temperature for 2 h, and were then exposed to bright illumination (1,500 μmol m⁻² s⁻¹) and moderately high temperature (30°C) for 1 h. The results showed that monoterpene biosynthesis in leaves was considerably inhibited by fosmidomycin, and the elevated levels of both hydrogen peroxide and malondialdehyde were observed in the leaves fed with fosmidomycin (LFF). Compared to the control leaves (CK), ∆F/F _m′ in the LFF was markedly lower during the first 20 min; however, there were no significant differences in non-photochemical quenching and photosynthetic pigments (chlorophylls and carotenoids). In contrast, the activities of antioxidant enzymes (superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase) were enhanced in the LFF. Meanwhile, the contents of antioxidant metabolites (ascorbate and glutathione) were also elevated in the LFF, when compared with the CK. The results obtained here suggest that monoterpene may be very effective molecule in protecting plants against oxidative stress, the absence of monoterpene leads to the increased responses of the enzymatic and non-enzymatic antioxidant defenses to oxidative stress, and the enhancement of the enzymatic and non-enzymatic antioxidant defenses may, in part, compensate for the loss of antioxidant conferred by monoterpene.     

Eradication of <Emphasis Type="Italic">Salmonella</Emphasis> Typhimurium infection in a murine model of typhoid fever with the combination of probiotic <Emphasis Type="Italic">Lactobacillus fermentum</Emphasis> ME-3 and ofloxacin

Background  

The aim of the study was to detect whether in experimental Salmonella enterica Typhimurium infection the probiotic Lactobacillus fermentum ME-3 in combination with fluoroquinolone therapy would eradicate S. Typhimurium, prevent the development of liver and spleen granulomas and improve the indices of oxidative stress in the ileum mucosa.     

Study of the physicochemical and biological stability of pediocin PA‐1 in the upper gastrointestinal tract conditions using a dynamic in vitro model

Aims: To evaluate the survival of Pediococcus acidilactici UL5 and its ability to produce pediocin PA‐1 during transit in an artificial gastrointestinal tract (GIT). To investigate the physicochemical and biological stability of purified pediocin PA‐1 under GIT conditions. Methods and Results: Skim milk culture of Ped. acidilactici UL5 was fed to a dynamic gastrointestinal (GI) model known as TIM‐1, comprising four compartments connected by computer‐controlled peristaltic valves and simulating the human stomach, duodenum, jejunum and ileum. This strain tolerated a pH of 2·7 in the gastric compartment, while lower pH reduced its viability. Bile salts in the duodenal compartment brought a further 4‐log reduction after 180 min of digestion, while high viable counts (up to 5 × 10⁷ CFU ml^?1 fermented milk) of Ped. acidilactici were found in both the jejunal and ileal compartments. Pediococcus acidilactici recovered from all four compartments was able to produce pediocin at the same level as unstressed cells. The activity of the purified pediocin in the gastric compartment was slightly reduced after 90 min of gastric digestion, while no detectable activity was found in the duodenal, jejunal and ileal compartments during 5 h of digestion. HPLC analysis showed partial degradation of the pediocin peptide in the duodenal compartment and massive breakdown in the jejunal and ileal compartments. Conclusions: Pediococcus acidilactici UL5 showed high resistance to GIT conditions, and its ability to produce pediocin was not affected, suggesting its potential as a probiotic candidate. The physicochemical and biological stability of pediocin was significantly poor under GIT conditions. Significance and Impact of the Study: Pediococcus acidilactici UL5 appears to be a potential probiotic candidate because its capacity to produce pediocin PA‐1 is not affected by the GI conditions as well as the strain shows an acceptable survival rate. Meanwhile, purified pediocin PA‐1 losses activity during GIT transit; microcapsules could be used to deliver it to the target site.     

Effect of phlorotannin-rich extracts of Ascophyllum nodosum and Himanthalia elongata (Phaeophyceae) on cellular oxidative markers in human HepG2 cells

Phlorotannins have received much attention due to their ecophysiological importance and potential applications in the biotechnology and food industries. Antioxidant activity studies in seaweeds have mainly focused on in vitro assays; however, there is a paucity of data regarding the effect of brown algal phlorotannins on living cultured cells. The aim of the present study was to investigate both direct and protective effects of phlorotannin-rich extracts on cell viability and the cellular oxidative status of cultured liver cells HepG2 against oxidative stress induced by tert-butyl hydroperoxide (t-BOOH). Extracts of the Phaeophyceae Ascophyllum nodosum (Fucaceae) and Himanthalia elongata (Himanthaliaceae) were submitted to gastrointestinal digestion prior to incubation for 20 h in a HepG2 culture at physiological concentrations (0.5–50 μg mL^?1). Various markers of cellular oxidative stress were then assessed, such as the generation of reactive oxygen species (ROS), antioxidant defences (concentration of reduced glutathione and activities of glutathione peroxidase, reductase and glutathione-S-transferase) and the levels of malondialdehyde as a marker for lipid peroxidation. The direct effect on cellular markers was assessed immediately after the incubation period, whereas for the protective effect, the incubation period was followed by a 3-h treatment with t-BOOH. The results indicated no effect on cell viability, and both extracts showed reduced levels of ROS and increased antioxidant defences in the direct treatment. Moreover, the extracts showed a significant protective effect against chemically induced oxidative stress in HepG2 cells by reducing ROS generation and enhancing antioxidant defences, hence supporting the utility of including brown algal extracts in functional food products.     

Studies on the immunomodulatory effect of polysaccharide gel extracted from Durio zibethinus in Penaeus monodon shrimp against Vibrio harveyi and WSSV

Oral administration of polysaccharide gel (PG) in shrimp diets revealed immunostimulating potential and disease resistance in Penaeus monodon (black tiger shrimp). PG from the fruit-rind of Durio zibethinus has been characterized to be a pectic polysaccharide with immunomodulating and antibacterial activities. PG inhibited growth of the shrimp bacterial pathogen, Vibrio harveyi 1526, by agar diffusion and broth microdilution tests. Clear inhibition zones on agar plates were observed at the lowest PG concentration of 3.1 mg/ml, where minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for PG were 6.3 and 12.5 mg/ml, respectively. Each group of juvenile shrimps, initial mean body weight 0.29 ± 0.04 g, was housed in a closed-recirculating treated water system and was fed with PG-supplemented diets containing 1, 2 and 3% PG or shrimp basal diet in the control group for 8 and 12 weeks. PG-supplemented diets did not contribute to the overall growth of black tiger shrimp. The immune response was evaluated by analysis of prophenoloxidase activity and total hemocyte count in the shrimp fed PG-supplemented diets for 12 weeks. Prophenoloxidase activity in shrimp fed the 1, 2 and 3% PG-supplemented diet and total hemocyte count in shrimp fed the 1 and 2% PG-supplemented diet were higher (P < 0.05) than those of the control group. The percent survival was higher in groups fed the 1–3% PG-supplemented diets in challenge tests with either white spot syndrome virus (WSSV) or the bacterium V. harveyi 1526 than that of the control group. Relative percent survival (RPS) values in groups fed the 2% PG-supplemented diet showed the highest RPS value for disease resistance of 100% (at Day 6) and 36% (at Day 4) in treated shrimp against viral and bacterial infection, respectively. Mortality of PG-supplemented diets in treated shrimps against WSSV infection was also found to be much lower (P < 0.05) than that of the control group.