Now showing 1 - 10 of 15
  • Publication
    Potential of a fucoidan-rich Ascophyllum nodosum extract to reduce Salmonella shedding and improve gastrointestinal health in weaned pigs naturally infected with Salmonella
    Background. Dietary supplementation with a fucoidan-rich Ascophyllum nodosum extract (ANE), possessing an in vitro anti-Salmonella Typhimurium activity could be a promising on-farm strategy to control Salmonella infection in pigs. The objectives of this study were to: 1) evaluate the anti-S. Typhimurium activity of ANE (containing 46.6% fucoidan, 18.6% laminarin, 10.7% mannitol, 4.6% alginate) in vitro, and; 2) compare the effects of dietary supplementation with ANE and Zinc oxide (ZnO) on growth performance, Salmonella shedding and selected gut parameters in naturally infected pigs. This was established post-weaning (newly weaned pig experiment) and following regrouping of post-weaned pigs and experimental re-infection with S. Typhimurium (challenge experiment). Results. In the in vitro assay, increasing ANE concentrations led to a linear reduction in S. Typhimurium counts (P <  0.05). In the newly weaned pig experiment (12 replicates/treatment), high ANE supplementation increased gain to feed ratio, similar to ZnO supplementation, and reduced faecal Salmonella counts on d 21 compared to the low ANE and control groups (P <  0.05). The challenge experiment included thirty-six pigs from the previous experiment that remained on their original dietary treatments (control and high ANE groups with the latter being renamed to ANE group) apart from the ZnO group which transitioned onto a control diet on d 21 (ZnO-residual group). These dietary treatments had no effect on performance, faecal scores, Salmonella shedding or colonic and caecal Salmonella counts (P > 0.05). ANE supplementation decreased the Enterobacteriaceae counts compared to the control. Enterobacteriaceae counts were also reduced in the ZnO-residual group compared to the control (P <  0.05). ANE supplementation decreased the expression of interleukin 22 and transforming growth factor beta 1 in the ileum compared to the control (P <  0.05).
      266Scopus© Citations 6
  • Publication
    Effect of seasons on the proximate composition of Laminaria hyperborea from Irish Atlantic coast
    This study aimed to analyze the seasonal variation in the proximate composition of Laminaria hyperborea collected in 2016 and 2017, off the west coast of Ireland.
  • Publication
    In vitro effects of seaweed extracts on intestinal commensals and pathogens of weaned piglets
    While the inclusion of certain seaweed extracts in weaner piglet diets leads to a beneficial gut microbial profile, the mode of action is not known. The aim of this study was to evaluate the prebiotic and antimicrobial potential of Laminaria digitata and Ascophylum nodosum extracts in vitro. Both extracts were two-fold diluted from 2 mg/ml to 0.25 mg/ml. The following strains were used at 106 -107 colonyforming unit(CFU)/ml concentrations: Lactobacillus plantarum, L. reuteri, Bifidobacterium thermophilum, Enterotoxigenic Escherichia coli O149 and Salmonella enterica ser Typhimurium PT12. Each concentration of each extract and controls (0 mg/ml) were incubated for 18 h at 37 °C aerobically or anaerobically (B. thermophilum). Final bacterial concentrations were determined by spread plating. All experiments were carried out with technical replicates on three independent occasions. All data were logarithmically transformed and analysed using the PROC GLM (SAS 9.4). The L. digitata extract increased B. thermophilum 0.7 LogCFU/ml at 0.25 mg/ml (P<0.05) and ≥1 LogCFU/ml from 0.5-2 mg/ml (P<0.05), with no effect on lactobacilli. The A. nodosum extract increased B. thermophilum up to 0.9 LogCFU/ml at all concentrations tested (P<0.05). Additionally, a 0.2 LogCFU/ml increase of L. reuteri and L. plantarum was observed at 2 mg/ml (P<0.05) and 1mg/ml (P<0.05), respectively. Both extracts displayed no antimicrobial activity against ETEC or S. Typhimurium. In conclusion, both extracts exhibited bifidogenic activity in vitro, with an additional slight increase of Lactobacillus spp. for A. nodosum, indicating a prebiotic potential.
  • Publication
    Polysaccharides from macroalgae: Recent advances, innovative technologies and challenges in extraction and purification
    Polysaccharides obtained from macroalgae have promising prospects and could contribute greatly to the future of a marine based bio-economy. Specifically, laminarin and fucoidan from brown macroalgae have a wide variety of potential industrial applications including functional foods and nutraceuticals, due to their broad range of biological activities. These beneficial biological activities are related to the chemical composition and structure of the macroalgal polysaccharides. The molecular weight, monosaccharide composition and sulphate content of these polysaccharides could be influenced by both macroalgal biology (i.e. variations in polysaccharide composition due to macroalgae species and their biological cycle) and different extraction/purification techniques employed to obtain polysaccharide enriched products (i.e. de-sulphation or fragmentation of sulphated polysaccharides). This review focuses on the extraction and purification methods for the macroalgal polysaccharides laminarin and fucoidan used in the recent literature. The application of innovative extraction technologies (such as ultrasound, microwave and enzyme-assisted extractions), as well as new purification techniques (i.e. membrane separation), are also discussed together with the challenges concerning molecule structure-function relationship and macroalgal variability.
      3523Scopus© Citations 252
  • Publication
    Seasonal Variation of the Proximate Composition, Mineral Content, Fatty Acid Profiles and Other Phytochemical Constituents of Selected Brown Macroalgae
    The main objective was to determine the chemical, phytochemical, fatty acid and mineral profiles of three commercially relevant brown macroalgae (Laminaria digitata, Laminaria hyperborea and Ascophyllum nodosum) collected each season for two years off the west coast of Ireland. All the chemical, phytochemical, fatty acid and minerals analysed varied significantly depending on the macroalgal species, season and year of collection. Overall, the protein contents of macroalgae were negatively correlated with carbohydrate content. Protein (2–11%) was at its highest during winter and/or spring, decreasing to a minimum during summer and/or autumn. The three macroalgal species analysed in this study had clearly differentiated fatty acid profiles. The concentration of fatty acids was higher in A. nodosum compared with both Laminaria species. The mineral profile of the three macroalgal species was rich in essential metals, particularly Ca, Mg and P, while the levels of I were approximately 9- to 10-fold higher in both Laminaria spp. compared with A. nodosum. The levels of toxic metals (Cd, Hg and Pb) in all the macroalgal species studied were low in the current study; while the levels of total As were high (49–64 mg/kg DW macroalgae) compared with previous reports.
      318Scopus© Citations 37
  • Publication
    Enhancing the extraction of polysaccharides and antioxidants from macroalgae using sequential hydrothermal-assisted extraction followed by ultrasound and thermal technologies
    Fucose sulphated polysaccharides (FSPs) and glucans have recently attracted the attention of the scientific community due to their wide range of biological activities. Both polysaccharides should ideally be selectively extracted using innovative technologies with high extraction efficiency. This study aims to: (1) Optimise the extraction variables used in hydrothermal-assisted extraction (HAE) to obtain high yields of FSPs, total glucans, and antioxidants from Laminaria hyperborea; (2) to apply these optimised protocols to other brown macroalgae; and (3) to explore the application of ultrasound and thermal technologies to increase the recovery of polysaccharides from the residual biomass. Box-Behnken design (three-factor, four-levels) was employed to optimise the HAE variables, and principal component analysis was used to evaluate the recovery of polysaccharides from the residual biomass. The optimal HAE conditions were 120 ◦C, 80.9 min, and 12.02 mL/g macroalgae from L. hyperborea. The best sequential application of ultrasound and thermal treatment achieved an additional 2971.7 ± 61.9 mg fucose/100 g dried macroalgal residue (dmr) from Ascophyllum nodosum and 908.0 ± 51.4 mg total glucans/100 g dmr from L. hyperborea macroalgal residues.
      261Scopus© Citations 60
  • Publication
    Effects of extraction method on the prebiotic potential of Ascophylum nodosum extracts
    Seaweed-derived bioactive compounds exhibit various beneficial activities in humans and animals. A factor influencing their concentrations, and subsequent bioactivity, is the extraction method. Our aim was to evaluate the in vitro prebiotic potential of three differently-extracted Ascophylum nodosum samples. The samples were produced using either solid-liquid extraction with water (AN-W), or ethanol (AN-EtOH) as solvent or high pressure-assisted extraction with water as solvent (AN-HPW). All extracts were two-fold diluted from 2 mg/ml to 0.25 mg/ml. Lactobacillus plantarum (LP), L. reuteri (LR) and Bifidobacterium thermophilum (BT) were used at 106 -107 colony-forming unit(CFU)/ml. Each concentration of each extract and controls (0 mg/ml) were incubated for 18 h at 37 °C aerobically or anaerobically (BT). Final bacterial concentrations were determined by spread plating. All experiments were carried out in triplicate with technical replicates. All data were logarithmically transformed and analysed using PROC GLM (SAS 9.4). AN-HPW increased BT (≤0.9 LogCFU/ml, P<0.05) at all concentrations and LR and LP (0.2 LogCFU/ml, P<0.05) at 2 mg/ml and 1mg/ml, respectively. AN-W increased BT (≤0.6 LogCFU/ml, P<0.05) at 1-2mg/ml, but decreased both lactobacilli; LP ≤0.7 LogCFU/ml and LR ≤5.4 LogCFU/ml at all concentrations (P<0.05). AN-EtOH increased LP (≤0.7 LogCFU/ml, P<0.05), but reduced LR (≤5.7 LogCFU/ml, P<0.05) at all concentrations and BT (≤4 LogCFU/ml, P<0.05) at 1-2 mg/ml. In conclusion, the extraction method influenced the prebiotic potential of the A. nodosum extracts in vitro with AN-HPW being the most promising.
  • Publication
    Exploring ultrasound-assisted extraction to recover high valuable polysaccharides from brown macroalgae and its related antioxidant activities
    This study aimed to optimize the ultrasound-assisted extraction (UAE) parameters of temperature, time and amplitude on the yields of fucose and glucans and their antioxidant activities (FRAP and DPPH) of extracts from Laminaria digitata and to evaluate the application of these optimum UAE parameters in other brown macroalgae (L. hyperborea and Ascophyllum nodosum).
  • Publication
    Ultrasonic extraction
    Found in seaweed, fucoidans have many beneficial properties, but extracting them from the plant has proved difficult. UCD and TEAGASC researchers looked at one promising technology.
  • Publication
    Extraction and yield optimisation of fucose, glucans and associated antioxidant activities from laminaria digitata by applying response surface methodology to high intensity ultrasound-assisted extraction
    The objectives of this study were to employ response surface methodology (RSM) to investigate and optimize the effect of ultrasound-assisted extraction (UAE) variables, temperature, time and amplitude on the yields of polysaccharides (fucose and total glucans) and antioxidant activities (ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity (DPPH)) from Laminaria digitata, and to explore the suitability of applying the optimum UAE conditions for L. digitata to other brown macroalgae (L. hyperborea and Ascophyllum nodosum). The RSM with three-factor, four-level Box-Behnken Design (BBD) was used to study and optimize the extraction variables. A second order polynomial model fitted well to the experimental data with R2 values of 0.79, 0.66, 0.64, 0.73 for fucose, total glucans, FRAP and DPPH, respectively. The UAE parameters studied had a significant influence on the levels of fucose, FRAP and DPPH. The optimised UAE conditions (temperature = 76 ◦C, time = 10 min and amplitude = 100%) achieved yields of fucose (1060.7 ± 70.6 mg/100 g dried seaweed (ds)), total glucans (968.6 ± 13.3 mg/100 g ds), FRAP (8.7 ± 0.5 µM trolox/mg freeze-dried extract (fde)) and DPPH (11.0 ± 0.2%) in L. digitata. Polysaccharide rich extracts were also attained from L. hyperborea and A. nodosum with variable results when utilizing the optimum UAE conditions for L. digitata.
      282Scopus© Citations 70