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- PublicationEffects of extraction method on the prebiotic potential of Ascophylum nodosum extractsSeaweed-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.
- PublicationExploring ultrasound-assisted extraction to recover high valuable polysaccharides from brown macroalgae and its related antioxidant activitiesThis 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).
- PublicationEffect of seasons on the proximate composition of Laminaria hyperborea from Irish Atlantic coastThis 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.
- PublicationIn vitro effects of seaweed extracts on intestinal commensals and pathogens of weaned pigletsWhile 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.
- PublicationUltrasonic extractionFound 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.
- PublicationExtraction and yield optimisation of fucose, glucans and associated antioxidant activities from laminaria digitata by applying response surface methodology to high intensity ultrasound-assisted extractionThe 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.
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- PublicationThe influence of duration of feeding dietary vitamin D enriched mushroom powder to finisher pigs on growth performance and meat quality parametersNovel feed additives that replace the use of synthetic additives while enhancing pig performance and pork quality are continuously being explored. A complete randomised block design experiment was conducted to examine the effects of the duration of feeding of vitamin D2 enriched mushrooms to finisher pigs and its effect on pig performance and pork quality. Sixty pigs were assigned to one of three dietary treatments for a 69-day feeding period. The dietary treatments were as follows: (T1) basal diet; (T2) basal diet + 1 g/kg of feed vitamin D2 enriched mushroom powder for 48 days prior to slaughter (MPVD-48); and (T3) basal diet + 1 g/kg of feed vitamin D2 enriched mushroom powder for 26 days prior to slaughter (MPVD-26). The mushroom vitamin D content was naturally enriched using synthetic ultraviolet B exposure to obtain a vitamin D2 level of 50 µg/kg of feed. Dietary supplementation of vitamin D2 enriched mushroom powder, irrespective of feeding duration, caused a reduction (P < 0.05) in feed intake, whilst improving (P < 0.05) gain-to-feed ratio. Supplementation of vitamin D2 enriched mushroom powder for 26 days prior to slaughter caused pork lightness (L*) values to remain stable over the 21-day storage time-period compared with all other dietary groups. Supplementation for 26 days also caused a reduction in lipid peroxidation on day 4 of storage compared with supplementation for 48 days. Irrespective of feeding duration, vitamin D2 enriched mushroom powder supplementation improved FRAP (ferric reducing antioxidant power) values of pork compared with the basal. In conclusion, vitamin D2 enriched mushroom supplementation, irrespective of feeding duration, caused a reduction in feed intake but improved feed efficiency. The supplementation of vitamin D2 enriched mushrooms for the shorter duration of 26 days prior to slaughter improved pork quality in relation to colour and antioxidant status.
- PublicationPotential of a fucoidan-rich Ascophyllum nodosum extract to reduce Salmonella shedding and improve gastrointestinal health in weaned pigs naturally infected with SalmonellaBackground. 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).
- PublicationEffect of β-glucanase and β-xylanase enzyme supplemented barley diets on nutrient digestibility, growth performance and expression of intestinal nutrient transporter genes in finisher pigsThe study investigated the effect of dietary supplementation of an enzyme mix (β-glucanase and β-xylanase) to barley based diets that had different chemical compositions achieved through different agronomical conditions on growth performance, nutrient digestibility and intestinal nutrient transporters. Ninety-six pigs (44.7 kg (SD 4.88)) were assigned to one of four dietary treatments. The treatments were as follows: (T1) low quality barley diet, (T2) low quality barley diet supplemented with β-glucanase and β-xylanase enzyme supplement, (T3) high quality barley diet and (T4) high quality barley diet supplemented with β-glucanase and β-xylanase enzyme supplement. The inclusion of barley was 500 g/kg. There was an interaction between barley type and enzyme supplementation on average daily gain (ADG) and average daily feed intake (ADFI) (P < 0.05). Pigs offered the low quality barley diet supplemented with enzymes had an increase in both ADG and ADFI compared to the low quality barley diet only. However, there was no response to enzyme inclusion in the high quality barley diet. Pigs offered the low quality barley diet with enzymes had a higher coefficient of apparent total tract digestibility (CATTD) of gross energy (GE) compared to the low quality barley diet only (P < 0.05). However, the increase in the high quality barley diet with enzyme supplementation was not as great as with the low quality barley diet. Pigs offered the low quality barley had an upregulation in the expression of the ghrelin gene (GHRL) in the jejunum compared to pigs offered the high quality barley diet (P < 0.05). There was a barley × enzyme interaction observed for the expression of the cluster of differentiation gene (CD36) in the duodenum and the peptide transporter 1 gene (PEPT1/SLC15A1) and sodium-glucose linked transporter 1 gene (SGLT1/SLC5A1) in the ileum (P < 0.01). Pigs offered the high quality barley diet with enzymes had increased expression of CD36, PEPT1/SLC15A1 and SGLT1/SLC5A1 compared to the high quality barley diet alone. However the low quality barley diet with enzymes down regulated the expression of CD36, PEPT1/SLC15A1 and SGLT1/SLC5A1 compared to the low quality barley diet alone. In conclusion, offering a low quality barley diet supplemented with an enzyme mix improved ADG, ADFI and nutrient digestibility as well as modifying the expression of CD36, PEPT1/SLC15A1 and SGLT1/SLC5A1. The inclusion of an enzyme mix to the high quality barley diet improved nutrient digestibility and caused an upregulation in the expression of CD36, PEPT1/SLC15A1 and SGLT1/SLC5A1 but it did not improve animal performance.
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- PublicationSeasonal Variation of the Proximate Composition, Mineral Content, Fatty Acid Profiles and Other Phytochemical Constituents of Selected Brown MacroalgaeThe 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.
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