Intraspecific variation in seaweeds: The application of new tools and approaches

Members of various algal lineages are known to be strong producers of atmospherically relevant halogen emissions, that is a consequence of their capability to store and metabolize halogens. This study uses a noninvasive, synchrotron-based technique, X-ray absorption spectroscopy, for addressing in vivo bromine speciation in the brown algae Ectocarpus siliculosus, Ascophyllum nodosum, and Fucus serratus, the red algae Gracilaria dura, G.gracilis, Chondrus crispus, Osmundea pinnatifida, Asparagopsis armata, Polysiphonia elongata, and Corallina officinalis, the diatom Thalassiosira rotula, the dinoflagellate Lingulodinium polyedrum and a natural phytoplankton sample. The results highlight a diversity of fundamentally different bromine storage modes: while most of the stramenopile representatives and the dinoflagellate store mostly bromide, there is evidence for Br incorporated in nonaromatic hydrocarbons in Thalassiosira. Red algae operate various organic bromine stores - including a possible precursor (by the haloform reaction) for bromoform in Asparagopsis and aromatically bound Br in Polysiphonia and Corallina. Large fractions of the bromine in the red algae G.dura and C.crispus and the brown alga F.serratus are present as Br(-) defects in solid KCl, similar to what was reported earlier for Laminaria parts. These results are discussed according to different defensive strategies that are used within algal taxa to cope with biotic or abiotic stresses.

Simple SummaryIn large-scale pig farming, alternative and safe antimicrobials are needed to enhance pig nutrition. Seaweed bioactives, and in particular phlorotannins, have been reported to have antimicrobial properties. However, their effect on the digestibility of pig feed is not well understood. This study investigates the effect of these phenolics on the in vitro dry matter digestibility of seaweed using an in vitro pig digestibility model. The effect of the phenolics when extracted into their purified phlorotannin form, and blended directly into pig feed, was also tested using the same model. The results found that, when added to the pig feed, purified phlorotannins had a more pronounced effect on digestibility than seaweeds containing phenolics. In addition, the results showed that given the seasonal variation within seaweeds, inclusion of whole seaweeds should be based on phenolic concentration as opposed to percentage inclusion of seaweeds.Phlorotannins have been reported to have positive effects on pig health, including improved gut health and digestibility. In this study, we investigate the effect of phenolics found in two brown seaweeds, Ascophyllum nodosum and Fucus serratus, on in vitro dry matter digestibility of seaweeds and commercial pig feed. Phlorotannin extracts and whole seaweeds were supplemented into pig feed to test their effect on digestibility. Solid-phase extraction was used to purify the phenolics to phlorotannins. The results showed a slight decrease in the digestibility of pig feed that was found to be significant when phlorotannin extracts were added from either seaweed. However, when whole A. nodosum was added to the pig feed, the effect on digestibility was less pronounced. Specifically, no significant difference in digestibility was observed at inclusion rates up to 5%, and thereafter results varied. A difference in digestibility was also observed in the same species at the same inclusion rate, collected from different seasons. This suggests that other compounds, e.g., polysaccharides, are having an effect on digestibility when whole seaweeds are supplemented to animal feed. This research has also highlighted the need to base supplementation on phenolic concentration as opposed to a standardised percentage inclusion of seaweeds to ensure that digestibility is not adversely affected.

Fucoxanthin is a xanthophyll pigment which occurs in marine brown algae (Phaeophyceae). The anti-diabetic, anti-obesity, anti-cancer, and antioxidant properties of fucoxanthin have been widely reported. Macroalgae, particularly brown seaweeds, grow prolifically around Irish coasts, representing a valuable resource of nutraceuticals such as fucoxanthin for functional food applications. The aim of this study was to maximise the solvent extraction yield from three anatomically discrete regions of the seaweed thallus: blade, stipe, and holdfast. Response surface methodology was applied to determine optimum parameters for extraction of fucoxanthin from the seaweed, Fucus vesiculosus, as a model species. A central composite design was applied with four extraction variables: time (30–70 min), temperature (30–70 °C), solvent pH (5.0–9.0), and percentage acetone (30–70 %). Fucoxanthin content of extracts was quantified by high-performance liquid chromatography. Percentage acetone was found to have the most significant (P = 0.0002) effect on fucoxanthin yield, followed by pH (P = 0.028) and temperature (P = 0.049). Multiple response optimisation determined that fucoxanthin yield from F. vesiculosus may be maximised by incubating at 30.0 °C for 36.5 min, pH 5.7, with 62.2 % acetone. Optimised responses were applied to a further nine brown seaweeds; Alaria esculenta, Ascophyllum nodosum, Fucus serratus, Himanthalia elongata, Laminaria digitata, Laminaria hyperborea, Pelvetia canaliculata, Saccharina latissima, and Saccorhiza polyschides. In all species, the blades contained significantly more fucoxanthin than stipes, while holdfasts contained the least. Alaria esculenta blade had the greatest yield (0.870 mg g−1 dry mass), followed by F. vesiculosus blade (0.699 mg g−1) and L. digitata blade (0.650 mg g−1).

Fucoidans, a diverse group of sulphated polysaccharides from brown algae, are biopolymers with many documented activities in vitro. While several factors are known to influence these activities, the degree of sulphation of the polymer is often regarded as a key parameter. The degree of sulphation on a biopolymer may be seasonally dependent, which, in turn, may affect the bioactivities of fucoidans. In this study, the effect of season and geographical location on the fucoidan sulphur content (as a proxy for degree of sulphation), was investigated. Crude fucoidan extracts were obtained using microwave-assisted extraction on eight different brown algae species, which were then analysed using elemental analysis. A significant seasonal dependence on the sulphur content in fucoidan extracts from Fucus serratus was observed. The difference in sulphur content between the investigated Fucus species is likely due to their different reproduction strategies. Of the eight species used in this study, Ascophyllum nodosum and Fucus evanescens contained the most sulphated fucoidans, while the species Dictyosiphon foeniculaceus contained lightly sulphated fucoidans. This suggests that species which thrive in saline waters may contain more sulphated fucoidans as a means of mitigating osmotic stress. No significant effects on the sulphur content in fucoidans from Fucus vesiculosus was observed between the three investigated countries. From these findings, it is apparent that seasonality is an important parameter, which must be considered for large scale production of highly sulphated fucoidans.

The polyphenol content in the brown algae of the Barents, White Seas, as well as the water areas of the Northwest Atlantic (the Norwegian Sea, the Faxflow bay of the Atlantic Ocean) located in Russia, Norway, Greenland, and Iceland are compared. Algae of the following species were used for this study: Fucus vesiculosus, Fucus spiralis, Fucus serratus, Ascophyllum nodosum, Fucus evanescens. It was found that the most productive raw materials for the extraction of polyphenolic compounds are brown algae F. vesiculosus, growing in Zavalishin Bay of the Barents Sea (Russia): the highest polyphenol content (14.4%) in the summer of 2019 was noted here. Polyphenols detected in F. vesiculosus in the summer from the White Sea on about. Great burnt (13.3%) (Russia), as well as in the Norwegian Sea, Cape Sydspissen (11.6%) (Norway). The minimum content of polyphenols was found in F. spiralis (0.7% dry mass) on the coast of Iceland (Faxflow bay), a low content of polyphenols was characteristic of all types of algae from this location (0.7–2.4%). Three-way analysis of variance (MANOVA) on the example of three types of algae (F. vesiculosus, F. spiralis, A. nodosum) showed that all the studied factors (place of collection, type of algae, fertile phase) are significant. The most significant factor affecting the accumulation of polyphenols by brown algae is the location of algae growth. The high content of polyphenols in the types of algae we studied from Russian water areas allows us to recommend their use as food and medicinal raw materials, as well as raw materials for biologically active additives.

ABSTRACTSeaweed has been proposed as an ingredient that can increase the umami taste and saltiness of food items. However, seaweed is not regularly consumed in North America. This study aimed to evaluate how nonconsumers of seaweed (n = 103) perceive the sensory properties and acceptance of soup with brown seaweed (Ascophyllum nodosum) and red seaweed (Chondrus crispus) powder added. The samples include a control soup (without seaweed) and soup with 1.5% and 3% brown seaweed, as well as 1.5% and 3% red seaweed by weight. Furthermore, before evaluating the soup, they were asked to identify the flavors and textures they associate with seaweed. The brown and red seaweed increased the umami and saltiness intensity of the soup, but it also increased the bitterness and sourness. The red seaweed also decreased the sweetness, overall liking, and liking of the soup's flavor. The participants associated seaweed with fishy, salty, and umami flavors and undesirable textures (slimy, tough, chewy). Seaweed increased the umami and salty taste of soup when evaluated by nonconsumers, but it also introduced other tastes to the soup. This study also identified nonconsumers’ beliefs about seaweed and should help create novel food products using seaweed.

Limited research suggests the effect of brown seaweed in animal nutrition for improving gut health and performance, but there isn't any research suggests the effect of oral liquid seaweeds brown algae in broiler nutrition. So, this study was aimed to evaluate the effect of liquid brown seaweed algae (Ascophyllum nodosum) supplementation on broiler chick's performance and their intestine histology. The experimental chicks (total number of 120, one - day old, Indian River chicks) were used and fed the same diets during the experimental period (1–35 days). Brown seaweed algae were added in fresh water at the concentrations of 0 and 1 ml/ liter fresh water. Results indicated that chicks received 1 ml liquid brown algae/1 liter of drinking fresh water had the greatest body weight gain, better feed conversion ratio, significant increases in total protein, albumin, and globulin and significantly decreases in total lipids and total cholesterol than that in the control chicks. On the other hands, water consumption and relative weight of carcass were not significantly affected by the algae supplementation. Histological observations concluded that birds, which received brown algae in drinking fresh water, had better intestinal health in terms of well-developed villi with their columnar epithelial lining, which indicative of an increase of the digestive and absorptive surface area leading to better nutrient utilization. These results suggested that liquid brown algae have a beneficial effects on the growth performance, intestinal development without any side effects and we can replace it with powder brown algae in broiler chicks, but we need more researches to confirm this item.

Brown algae such as Ascophyllum nodosum (AN) and Fucus vesiculosus (FV) are gaining considerable attention as functional feed additives due to their health-beneficial properties. This study evaluated the antioxidant potential of AN and FV extracts in intestinal epithelial cells and the in vivo model Caenorhabditis elegans (C. elegans). Aqueous AN and FV extracts were characterized for total phenolic content (TPC), antioxidant capacity (TEAC, FRAP), and phlorotannin composition using LC-HRMS/MS. Antioxidant effects were assessed in vitro, measuring AAPH-induced ROS production in Caco-2 and IPEC-J2 cells via H2DCF-DA, and in vivo, evaluating the effects of paraquat-induced oxidative stress and AN or FV treatment on worm motility, GST-4::GFP reporter expression, and gene expression in C. elegans. FV exhibited higher total phenolic content, antioxidant capacity (TEAC, FRAP), and a broader phlorotannin profile (degree of polymerization [DP] 2–9) than AN (DP 2–7), as determined by LC-HRMS/MS. Both extracts attenuated AAPH-induced oxidative stress in epithelial cells, with FV showing greater efficacy. In C. elegans, pre-treatment with AN and FV significantly mitigated a paraquat-induced motility decline by 22% and 11%, respectively, compared to PQ-stressed controls. Under unstressed conditions, both extracts enhanced nematode healthspan, with significant effects observed at 400 µg/g for AN and starting at 100 µg/g for FV. Gene expression analysis indicated that both extracts modulated antioxidant pathways in unstressed worms. Under oxidative stress, pre-treatment with AN and FV significantly reduced GST-4::GFP expression. In the nematode, AN was more protective under acute stress, whereas FV better supported physiological function in the absence of stressors. These findings demonstrate that AN and FV counteract oxidative stress in intestinal epithelial cells and in C. elegans, highlighting their potential as stress-reducing agents in animal feed.

Bioactive compound-rich brown seaweeds are demonstrated to have numerous health benefits including anti-microbial and immunomodulatory bioactivities in the pig intestine. In this study, the immunomodulating effects of extracts of brown seaweed (Ascophyllum nodosum and Fucus serratus) were evaluated on the porcine colon using a bacterial lipopolysaccharide (LPS) ex vivo model. Approximately 1.5 × 1.5 cm of pig colon (n = 6) was stripped of its overlying muscle layer and incubated in 1 mL Dulbecco's Modified Eagle Medium containing bacterial LPS (10 μg) and seaweed extracts (1 mg). Gene expression of interleukin-8 (IL-8) and interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFA) were measured using quantitative real time PCR. In contrast to the low level of expression of IL-8, IL-6, and TNFA genes in the colonic tissue at 0 h, LPS treatment increased (P < 0.05) the expression of IL-8, IL-6, and TNFA genes to 2.38 ± 0.86, 1.90 ± 0.66, and 1.90 ± 0.57 fold, respectively. This pro-inflammatory response induced by the LPS was suppressed by the extracts of Ascophyllum. Ascophyllum extract reduced (P < 0.05) the expression of IL-8, IL-6, and TNFA genes to 0.99 ± 0.53, 0.75 ± 0.33, and 1.01 ± 0.17 fold, and Fucus extract reduced (P < 0.05) the expression of the corresponding genes to 0.70 ± 0.32, 0.69 ± 0.38, and 1.15 ± 0.25 fold, respectively. It is concluded that the extracts of Ascophyllum and Fucus seaweeds have potential to suppress the pro-inflammatory response induced by the bacterial LPS in the pig colon.

In vitro and cellular antioxidant activities of seaweed extracts prepared from five brown seaweeds harvested in spring from the west coast of Ireland

Brown seaweeds are a rich source of carotenoids, particularly fucoxanthin, which has a wide range of potential health applications. Fucoxanthin fluctuates within and among seaweeds over time, frustrating efforts to utilise this resource. Thus, we require comprehensive analyses of long- and short-term concentrations across species in field conditions. Here, we used High Performance Liquid Chromatography to compare fucoxanthin content in four brown macroalgae, Ascophyllum nodosum, Fucus serratus, Fucus vesiculosus and Saccharina latissima, monthly for 1 year. F. serratus and F. vesiculosus had significantly higher fucoxanthin content (mg/g), which was highest in Spring (0.39 ± 0.04) and Autumn (0.45 ± 0.04) [mean (± SE)]. Two species, A. nodosum and F. serratus, were collected monthly at the same location for a further two non-consecutive years. For both A. nodosum and F. serratus, a significant interaction effect of seasons and years was identified, highlighting that there is variation in fucoxanthin content among and within species over time. We also show that fucoxanthin content differs significantly among months even within seasons. Therefore, it is not sufficient to assess fucoxanthin in single months to represent seasonality. We discuss how weather, nutrients and reproduction may have driven the seasonal variation, and reveal patterns of fucoxanthin concentration that can provide information concerning its availability for many important medical functions.

BackgroundIn this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated.MethodsThe fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (Caulerpa taxifolia, Sargassum natans) was determined using GCMS. Four independent replicates were taken from each seaweed species.ResultsOmega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs), were in the concentration range of 2-14 mg/g dry matter (DM), while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6) and/or eicosapentaenoic acids (EPA, C20:5, n-3), the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3) at ≈ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed.ConclusionMarine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6) FA: (n-3) FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3), while in S. natans also docosahexaenoic acid (DHA, C22:6, n-3) was detected.

Total phenolic contents, radical scavenging and cyclic voltammetry of seaweeds from Brittany

This study aimed to compare the anti-inflammatory effects of fucoidans from brown seaweeds (Saccharina japonica (SJ), Fucus vesiculosus (FV), Fucus distichus (FD), Fucus serratus (FS), and Ascophyllum nodosum (AN)), and determine the relationship between composition and biological activity. The anti-inflammatory activity was tested in vitro. It is believed that inflammation could be triggered by free radicals. Fucoidans from F. vesiculosus (FV1 and FV3) showed the strongest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity with an IC50 = 0.05 mg/mL. In the total antioxidant capacity (TAC) test, the activity was concentration-dependent. Notable, the TAC of fucoidans except samples of FV2 and SJ (which have a lower phenolic content) was higher than that of phloroglucinol. The TAC of fucoidans strongly and positively correlated with polyphenol content. A weak correlation was associated with xylose content. The synergistic effect for fucoidans was calculated for the first time using carbohydrates and polyphenols as model mixtures. The synergy in the DPPH test was found only for FV1 and FV3 (mixture effect ME = 2.68 and 2.04, respectively). The ME strongly positively correlated with polyphenols. The relationship of ME with fucose content was positive but moderate. It was first established that the anti-inflammatory effects of fucoidan could be mediated via the inhibition of protein denaturation. The inhibition was concentration-dependent and strongly correlated with the fucose content and moderate with sulfate content. The purified fucoidan FV2 showed the most promising activity (IC50 = 0.20 mg/mL vs. IC50 = 0.37 mg/mL for diclofenac sodium). Similar relations were also observed in the membrane protection model. Fucoidans were able to stabilize the cell membrane integrity of human red blood corpuscles (HRBC). The results of our study support the rationality of fucoidan use as a promising agent for the treatment of inflammatory-related diseases via mechanisms of radical scavenging, antioxidant activity, inhibition of protein denaturation, and HRBC membrane stabilization.

24(R, S)-Saringosterol - From artefact to a biological medical agent