Prebiotics from marine macroalgae for human and animal health applications. Mar Drugs. 2010;8:2038-2064. [PMID: 20714423 PMCID: PMC2920542 DOI: 10.3390/md8072038]

Local and Systemic Effects of Bioactive Food Ingredients: Is There a Role for Functional Foods to Prime the Gut for Resilience?

Scientific advancements in understanding the impact of bioactive components in foods on the gut microbiota and wider physiology create opportunities for designing targeted functional foods. The selection of bioactive ingredients with potential local or systemic effects holds promise for influencing overall well-being. An abundance of studies demonstrate that gut microbiota show compositional changes that correlate age and disease. However, navigating this field, especially for non-experts, remains challenging, given the abundance of bioactive ingredients with varying levels of scientific substantiation. This narrative review addresses the current knowledge on the potential impact of the gut microbiota on host health, emphasizing gut microbiota resilience. It explores evidence related to the extensive gut health benefits of popular dietary components and bioactive ingredients, such as phytochemicals, fermented greens, fibres, prebiotics, probiotics, and postbiotics. Importantly, this review distinguishes between the potential local and systemic effects of both popular and emerging ingredients. Additionally, it highlights how dietary hormesis promotes gut microbiota resilience, fostering better adaptation to stress-a hallmark of health. By integrating examples of bioactives, this review provides insights to guide the design of evidence-based functional foods aimed at priming the gut for resilience.

Metagenomic insights into the dynamic degradation of brown algal polysaccharides by kelp-associated microbiota

Marine bacteria play important roles in the degradation and cycling of algal polysaccharides. However, the dynamics of epiphytic bacterial communities and their roles in algal polysaccharide degradation during kelp decay are still unclear. Here, we performed metagenomic analyses to investigate the identities and predicted metabolic abilities of epiphytic bacterial communities during the early and late decay stages of the kelp Saccharina japonica. During kelp decay, the dominant epiphytic bacterial communities shifted from Gammaproteobacteria to Verrucomicrobia and Bacteroidetes. In the early decay stage of S. japonica, epiphytic bacteria primarily targeted kelp-derived labile alginate for degradation, among which the gammaproteobacterial Vibrionaceae (particularly Vibrio) and Psychromonadaceae (particularly Psychromonas), abundant in alginate lyases belonging to the polysaccharide lyase (PL) families PL6, PL7, and PL17, were key alginate degraders. More complex fucoidan was preferred to be degraded in the late decay stage of S. japonica by epiphytic bacteria, predominantly from Verrucomicrobia (particularly Lentimonas), Pirellulaceae of Planctomycetes (particularly Rhodopirellula), Pontiellaceae of Kiritimatiellota, and Flavobacteriaceae of Bacteroidetes, which depended on using glycoside hydrolases (GHs) from the GH29, GH95, and GH141 families and sulfatases from the S1_15, S1_16, S1_17, and S1_25 families to depolymerize fucoidan. The pathways for algal polysaccharide degradation in dominant epiphytic bacterial groups were reconstructed based on analyses of metagenome-assembled genomes. This study sheds light on the roles of different epiphytic bacteria in the degradation of brown algal polysaccharides.IMPORTANCEKelps are important primary producers in coastal marine ecosystems. Polysaccharides, as major components of brown algal biomass, constitute a large fraction of organic carbon in the ocean. However, knowledge of the identities and pathways of epiphytic bacteria involved in the degradation process of brown algal polysaccharides during kelp decay is still elusive. Here, based on metagenomic analyses, the succession of epiphytic bacterial communities and their metabolic potential were investigated during the early and late decay stages of Saccharina japonica. Our study revealed a transition in algal polysaccharide-degrading bacteria during kelp decay, shifting from alginate-degrading Gammaproteobacteria to fucoidan-degrading Verrucomicrobia, Planctomycetes, Kiritimatiellota, and Bacteroidetes. A model for the dynamic degradation of algal cell wall polysaccharides, a complex organic carbon, by epiphytic microbiota during kelp decay was proposed. This study deepens our understanding of the role of epiphytic bacteria in marine algal carbon cycling as well as pathogen control in algal culture.

From algae to advancements: laminarin in biomedicine

Laminarin, a complicated polysaccharide originating from brown algae, has emerged as a compelling candidate in the domain of biomedical research. This enigmatic molecule, composed of glucose units associated with both β-1,3 and β-1,6 glycosidic bonds, possesses an array of remarkable characteristics that render it auspicious for multifaceted biomedical applications. This review investigates the comprehensive potential of laminarin in the biomedical domain, emphasizing its remarkable biocompatibility, low cytotoxicity, and cell proliferation support. Laminarin's immunomodulatory attributes position it as an encouraging contender in immunotherapy and the development of vaccines. Moreover, its anti-inflammatory and antioxidant characteristics provide a promising avenue for combatting conditions associated with oxidative stress. In particular, laminarin excels as a drug delivery vehicle owing to its exceptional encapsulation capabilities emerging from its porous framework. Integrating pH and redox responsiveness in laminarin-based drug delivery systems is poised to redefine targeted therapies. Laminarin substantially contributes to tissue engineering by improving adhesion, migration of cells, and deposition of extracellular matrix. This augmentation magnifies the regenerative capability of tissue-engineered constructs, substantiated by the advancement of laminarin-based wound dressings and tissue scaffolds, marking considerable progress in the domain of wound healing and tissue regeneration. While laminarin exhibits substantial potential in biomedical applications, it remains in the initial phases of exploration. Comprehensive preclinical and clinical research is warranted to verify its effectiveness and safety across various applications. In essence, laminarin, a marine marvel, has the capability to remodel biomedical research, offering inventive solutions to complex difficulties.

Seaweed and Seaweed-Based Functional Metabolites as Potential Modulators of Growth, Immune and Antioxidant Responses, and Gut Microbiota in Fish

Seaweed, also known as macroalgae, represents a vast resource that can be categorized into three taxonomic groups: Rhodophyta (red), Chlorophyta (green), and Phaeophyceae (brown). They are a good source of essential nutrients such as proteins, minerals, vitamins, and omega-3 fatty acids. Seaweed also contains a wide range of functional metabolites, including polyphenols, polysaccharides, and pigments. This study comprehensively discusses seaweed and seaweed-derived metabolites and their potential as a functional feed ingredient in aquafeed for aquaculture production. Past research has discussed the nutritional role of seaweed in promoting the growth performance of fish, but their effects on immune response and gut health in fish have received considerably less attention in the published literature. Existing research, however, has demonstrated that dietary seaweed and seaweed-based metabolite supplementation positively impact the antioxidant status, disease resistance, and stress response in fish. Additionally, seaweed supplementation can promote the growth of beneficial bacteria and inhibit the proliferation of harmful bacteria, thereby improving gut health and nutrient absorption in fish. Nevertheless, an important balance remains between dietary seaweed inclusion level and the resultant metabolic alteration in fish. This review highlights the current state of knowledge and the associated importance of continued research endeavors regarding seaweed and seaweed-based functional metabolites as potential modulators of growth, immune and antioxidant response, and gut microbiota composition in fish.

Hyaluronic Acid-Alginate Homogeneous Structures with Polylactide Coating Applied in Controlled Antibiotic Release

The use of a controlled-release drug carrier is an innovative solution for the treatment of local infections, in particular in dentistry, skin diseases, and in open wounds. The biocompatibility, biodegradability, the possibility of a large amount of drug adsorbed (especially those with hydrophilic properties), and the ability to create structures of any shape and size are the reasons for hydrogels to be frequently studied. The main disadvantage of hydrogel carriers is the rapid rate of drug release; hence, in this study, an attempt was made to additionally chemically cross-link 1-ethyl-3-(3-dimethyl aminopropyl)-1-carbodiimide hydrochloride (EDC) with the hyaluronic acid-alginate (HA-SAL) structure. The answer to significantly reduce the mass flux typical for hydrogel structure was to surround it with a polymer layer using a dry cover. By coating the carriers with polylactide, the release time was increased by around forty times. As the carriers were designed to reduce local bacterial infections, among others in dentistry, the released antibiotics were amoxycillin, metronidazole, and doxycycline.

Comparison of the Effects of Enzymolysis Seaweed Powder and Saccharomyces boulardii on Intestinal Health and Microbiota Composition in Kittens

Kittens are prone to intestinal health problems as their intestines are not completely developed. Seaweed is rich in plant polysaccharides and bioactive substances that are highly beneficial to gut health. However, the effects of seaweed on cat gut health have not been assessed. This study compared the effects of dietary supplementation with enzymolysis seaweed powder and Saccharomyces boulardii on the intestinal health of kittens. In total, 30 Ragdoll kittens (age: 6 months; weight: 1.50 ± 0.29 kg) were assigned to three treatment groups for a 4-week feeding trial. The dietary treatment given was as follows: (1) basal diet (CON); (2) CON + enzymolysis seaweed powder (20 g/kg of feed) mixed evenly with the diet (SE); and (3) CON + Saccharomyces boulardii (2 × 10¹⁰ CFU/kg of feed) mixed evenly with the diet (SB). Compared with the CON and SB groups, dietary supplementation with the enzymolysis seaweed powder improved the immune and antioxidant capacity and also reduced the intestinal permeability and inflammation levels of kittens. The relative abundance of Bacteroidetes, Lachnospiraceae, Prevotellaceae, and Faecalibacterium in the SE group was higher than those in the CON and SB groups (p ≤ 0.05), while the relative abundance of Desulfobacterota, Sutterellaceae, and Erysipelatoclostridium in the SB group was lower than that in the SE group (p ≤ 0.05). Moreover, enzymolysis seaweed powder did not alter the level of intestinal SCFAs in kittens. Conclusively, supplementing kitten diet with enzymolysis seaweed powder can promote intestinal health by enhancing the gut barrier function and optimizing the microbiota composition. Our findings provide new perspectives on the application of enzymolysis seaweed powder.

DNA barcoding of marine macroalgae as bioindicators of heavy metal pollution

Metal pollution in the marine coastal environment is an important topical issue. In this study, the water quality in five locations along the Alexandria coast (Eastern Harbor, El-Tabia pumping station, El Mex Bay, Sidi Bishir, and Abu Talat) was assessed by measuring physicochemical parameters from water samples. Depending on the morphological classification of macroalgae, the collected morphotypes were related to Ulva fasciata, Ulva compressa, Corallina officinalis, Corallina elongata, and Petrocladia capillaceae. Corallina officinalis and Corallina elongata demonstrated a high capacity for Cd, Pb, and Ni accumulation, and the highest values of Fe, Cu, and Mn were reported in Ulva fasciata and Ulva compressa. Two standard markers were applied, and results showed that the morphological classification matched the molecular data. Moreover, the analysis of algae can only reflect the accumulation of metals. The conclusion is that Ulva compressa and Corallina officinalis are potentially suitable indicators of localized short-term heavy metal pollution.

In Vitro Evaluation of Brown Seaweed Laminaria spp. as a Source of Antibacterial and Prebiotic Extracts That Could Modulate the Gastrointestinal Microbiota of Weaned Pigs

Laminaria spp. and their extracts have preventative potential as dietary supplements during weaning in pigs. The first objective of this study was to evaluate increasing concentrations of four whole seaweed biomass samples from two different Laminaria species harvested in two different months in a weaned pig faecal batch fermentation assay. Particularly, February and November whole seaweed biomass samples of L. hyperborea (LHWB-F and LHWB-N) and L. digitata (LDWB-F and LDWB-N) were used. In the next part of the study, the increasing concentrations of four extracts produced from L. hyperborea (LHE1-4) and L. digitata (LDE1-4) were evaluated in individual pure-culture growth assays using a panel of beneficial and pathogenic bacterial strains (second objective). The LHE1-4 and LDE1-4 were obtained using different combinations of temperature, incubation time and volume of solvent within a hydrothermal-assisted extraction methodology (E1-4). In the batch fermentation assay, the L. hyperborea biomass samples, LHWB-F and LHWB-N, lowered Bifidobacterium spp. counts compared to the L. digitata biomass samples, LDWB-F and LDWB-N (p < 0.05). LHWB-F and LDWB-N reduced Enterobacteriaceae counts (p < 0.05). LHWB-F and LDWB-F were selected as the most and least promising sources of antibacterial extracts from which to produce LHE1-4 and LDE1-4. In the pure-culture growth assays, E1- and E4-produced extracts were predominantly associated with antibacterial and bifidogenic activities, respectively. LHE1 reduced both Salmonella Typhimurium and Enterotoxigenic Escherichia coli with LDE1 having a similar effect on both of these pathogenic strains, albeit to a lesser extent (p < 0.05). Both LHE1 and LDE1 reduced B. thermophilum counts (p < 0.05). LDE4 exhibited strong bifidogenic activity (p < 0.05), whereas LHE4 increased Bifidobacterium thermophilum and Lactiplantibacillus plantarum counts (p < 0.05). In conclusion, antibacterial and bifidogenic extracts of Laminaria spp. were identified in vitro with the potential to alleviate gastrointestinal dysbiosis in newly weaned pigs.

Biomolecules from Macroalgae-Nutritional Profile and Bioactives for Novel Food Product Development

Seaweed is in the spotlight as a promising source of nutrition for humans as the search for sustainable food production systems continues. Seaweed has a well-documented rich nutritional profile containing compounds such as polyphenols, carotenoids and polysaccharides as well as proteins, fatty acids and minerals. Seaweed processing for the extraction of functional ingredients such as alginate, agar, and carrageenan is well-established. Novel pretreatments such as ultrasound assisted extraction or high-pressure processing can be incorporated to more efficiently extract these targeted ingredients. The scope of products that can be created using seaweed are wide ranging: from bread and noodles to yoghurt and milk and even as an ingredient to enhance the nutritional profile and stability of meat products. There are opportunities for food producers in this area to develop novel food products using seaweed. This review paper discusses the unique properties of seaweed as a food, the processes involved in seaweed aquaculture, and the products that can be developed from this marine biomass. Challenges facing the industry such as consumer hesitation around seaweed products, the safety of seaweed, and processing hurdles will also be discussed.

A comprehensive review on algal nutraceuticals as prospective therapeutic agent for different diseases

Ongoing research in the food supplement sector provides insightful information regarding algae as a new-generation nutritional supplement and is also referred to as a superfood. Due to the diverse nutritional components, algae have documented numerous health benefits like fighting microbial diseases, hypertension, obesity, and diabetes. Therefore, algae-derived nutraceuticals account for a rapidly expanding market in the food supplements sector. The concept of algal prebiotics and their role in modulating gut microbiota have also been a chief contributor to this. This review evaluates the use of possible algal species and their specific bioactive compounds for the management of several chronic diseases. Proteins, peptides, polysaccharides, phenolics, and vitamins give an insight into the significance of algae in boosting the immune system and improving the body's nutritional makeup. In addition, phyco-compounds such as polysaccharides and polyphenols are also receiving a lot more interest in cosmeceutical applications for protecting skin from photodamage. The incorporation of algae in the diet for the management and prevention of chronic diseases like cancer, lung, and heart disease has been discussed in this review along with their action mechanism. This review provides a brief overview of several bioactive compounds present in micro and macroalgae and their therapeutic effect on lifestyle diseases, gastrointestinal diseases as well as neurodegenerative diseases.

Bioactive Compounds from Brown Algae Alleviate Nonalcoholic Fatty Liver Disease: An Extensive Review

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent chronic liver diseases. The increasing NAFLD incidences are associated with unhealthy lifestyles. Currently, there are no effective therapeutic options for NAFLD. Thus, there is a need to develop safe, efficient, and economic treatment options for NAFLD. Brown algae, which are edible, contain abundant bioactive compounds, including polysaccharides and phlorotannins. They have been shown to ameliorate insulin resistance, as well as hepatic steatosis, and all of these biological functions can potentially alleviate NAFLD. Accumulating reports have shown that increasing dietary consumption of brown algae reduces the risk for NAFLD development. In this review, we summarized the animal experiments and clinical proof of brown algae and their bioactive compounds for NAFLD treatment within the past decade. Our findings show possible avenues for further research into the pathophysiology of NAFLD and brown algae therapy.

Fortified milk-beverage with amphora algae and its functionality for aflatoxin inactivation in rats

Aflatoxins are considered a severe hazard, contaminate dietary products, and cause malignant alterations in liver tissues. Fermented milk (FM) is prepared using probiotic lactic acid strains. This investigation aimed to produce an integrated milk beverage, inactivating aflatoxins toxicity and biotransformation. The proximate analysis of the investigated materials and biochemical parameter changes of the in-vivo experiment were determined. Results reflected the extract’s valuable content of polysaccharides and antioxidants. Nine phenolics were identified predominantly with catechin (39.67 ± 1.5 µg/g). FM-fortification is reflected by enhancement in protein (49.5 ± 2.97 g/Kg) and fiber content (1.78 ± 0.54 g/Kg) compared to the FM content. Relative rats’ weight gain improved to 34.29% for the fortified-FM group close to the control; it was recorded at 16.47% for the AFM1 group. Alkaline phosphatase in AFM1 rats was 99.2 ± 1.86 U/L and decreased to 44.2 ± 0.71 U/L in the fortified-FM group (44.2 ± 0.71 U/L) to be close to the control group. Aflatoxin M1 rats exposure reflects tissue alterations and cell damage, which recorded lesser in rats treated by extract and beverage administrations. The beverage’s corrective action relied on two integrated mechanisms, aflatoxin-binding to bacterial and bioactivity interaction of extract substances. This beverage stopped tissue alterations that occurred due to aflatoxins. The result supports the future production of fortified-milk beverages as a bio-shield against aflatoxin toxicity, besides their nutritional and functional properties.

Immunomodulatory Effects of an Aqueous Extract of Black Radish on Mouse Macrophages via the TLR2/4-Mediated Signaling Pathway

Here, we determined the immunostimulatory effects of black radish (Raphanus sativus ver niger) hot water extract (BRHE) on a mouse macrophage cell line (RAW 264.7) and mouse peritoneal macrophages. We found that BRHE treatment increased cell proliferation, phagocytic activity, nitric oxide (NO) levels, cytokine production, and reactive oxygen species synthesis. Moreover, BRHE increased the expression of the following immunomodulators in RAW 264.7 cells and peritoneal macrophages: pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), iNOS, and COX-2. BRHE treatment significantly up-regulated the phosphorylation of components of the mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), Akt, and STAT3 signaling pathways. Further, the effects of BRHE on macrophages were significantly diminished after the cells were treated with the TLR2 antagonist C29 or the TLR4 antagonist TAK-242. Therefore, BRHE-induced immunostimulatory phenotypes in mouse macrophages were reversed by multiple inhibitors, such as TLR antagonist, MAPK inhibitor, and Akt inhibitor indicating that BRHE induced macrophage activation through the TLR2/4-MAPK-NFκB-Akt-STAT3 signaling pathway. These results indicate that BRHE may serve as a potential immunomodulatory factor or functional food and provide the scientific basis for the comprehensive utilization and evaluation of black radish in future applications.

Antrodia cinnamomea polysaccharide improves liver antioxidant, anti-inflammatory capacity, and cecal flora structure of slow-growing broiler breeds challenged with lipopolysaccharide

Lipopolysaccharides (LPS) induces liver inflammatory response by activating the TLR4/NF-κB signaling pathway. Antrodia cinnamomea polysaccharide (ACP) is a medicinal mushroom that can protect from intoxication, liver injury, and inflammation. Nevertheless, the effect of ACP on the liver antioxidant, anti-inflammatory capacity and cecal flora structure of LPS-challenged broilers remains unclear. The aim of this experiment was to investigate the effects of ACP on the anti-oxidative and anti-inflammatory capacities of the liver, and cecal microbiota in slow-growing broilers stimulated by LPS. A total of 750 slow-growing broilers (9-day-old) were assigned to five treatments with 6 replicates of 25 chicks per replicate: a control diet, the chicks were fed a control diet and challenged with LPS. Dietary treatments 3 to 5 were the control diet supplemented with 100, 200, 400 mg/kg ACP challenged with LPS, respectively. The groups of 100 mg/kg ACP supplementation significantly increased liver index, pancreas index, and bursa of Fabricius index (P < 0.05). The GSH-Px content of LPS-challenged broilers was lower than that of the control group (P < 0.001), but the content of MDA increased (P < 0.001). Feeding with 100 mg/kg ACP resulted in increased the activity of T-AOC, GSH-Px, and T-SOD, and decreased MDA content (P < 0.05). The activity of TNF-α, IL-1β, and IL-6 of the LPS group increased, but these indicators were decreased with supplemental 100 mg/kg ACP (P < 0.05). Dietary application of ACP up to 100 mg/kg down-regulated (P < 0.05) the expression of TLR4/NF-κB pathway in the liver induced by LPS. The results of 16S rRNA demonstrated that feeding with 100 mg/kg ACP can change the diversity and composition of the gut microbiota, and restrained the decline of beneficial cecal microbiota (typically Lactobacillus, Faecalibacterium, and Christensenellaceae R-7 group) in the challenged LPS group (P < 0.05). Conclusively, feeding a diet with 100 mg/kg ACP may have beneficial effects on liver damage and the bacterial microbiota diversity and composition in the ceca of LPS-stressed slow-growing broiler breeds, probably because of its combined favorable effects on antioxidants and cytokines contents, and restoration the decline of beneficial cecal microbiota.

Marine Macroalgae in Rabbit Nutrition—A Valuable Feed in Sustainable Farming

Simple Summary

Commercial rabbit farming has faced critical challenges in the last few years, during which the ban on the prophylactic use of antibiotics in animal feed has added to the weakness of the production system and a decrease in consumption of rabbit meat. Considering the potential role of macroalgae as an alternative to the use of antibiotics in animal nutrition, this review paper aims to evaluate the use of macroalgae in rabbit farming. It specifically focuses on how macroalgae can be used sustainably to improve rabbit health as an economically viable alternative that could help guarantee the future of this high-value sector.

Abstract

The rabbit meat industry has faced critical challenges in the last few years, during which the ban on the prophylactic use of antibiotics in animal feed has added to the weakness of the production system and a decrease in consumption of rabbit meat. This review paper highlights the potential value of macroalgae in the rabbit farming sector as an alternative to the use of antibiotics to improve rabbit health. In line with sustainable agriculture programmes, the use of seaweed in rabbit nutrition may improve gut health according to the One Health approach, whereby consumers and the environment could receive tangible benefits. The inclusion of algae in animal feed has experimentally proven to help to reduce intestinal dysbiosis. However, further studies evaluating the prebiotic effects of algal components on gut health and also identifying the compounds directly responsible for the antimicrobial, antiviral, antioxidative and anti-inflammatory properties of algae are still needed. Furthermore, the inclusion of marine algae in rabbit food could potentially become a commercial marketing strategy that could attract new consumers who are concerned about environmental sustainability and who are looking for different, high-quality foods.

Modulatory effect of Gracilaria gracilis on European seabass gut microbiota community and its functionality

Seaweeds are an important source of nutrients and bioactive compounds and have a high potential as health boosters in aquaculture. This study evaluated the effect of dietary inclusion of Gracilaria gracilis biomass or its extract on the European seabass (Dicentrarchus labrax) gut microbial community. Juvenile fish were fed a commercial-like diet with 2.5% or 5% seaweed biomass or 0.35% seaweed extract for 47 days. The gut microbiome was assessed by 16S rRNA amplicon sequencing, and its diversity was not altered by the seaweed supplementation. However, a reduction in Proteobacteria abundance was observed. Random forest analysis highlighted the genera Photobacterium, Staphylococcus, Acinetobacter, Micrococcus and Sphingomonas, and their abundances were reduced when fish were fed diets with algae. SparCC correlation network analysis suggested several mutualistic and other antagonistic relationships that could be related to the predicted altered functions. These pathways were mainly related to the metabolism and biosynthesis of protective compounds such as ectoine and were upregulated in fish fed diets supplemented with algae. This study shows the beneficial potential of Gracilaria as a functional ingredient through the modulation of the complex microbial network towards fish health improvement.

Effect of sodium alginate supplementation on weight management and reproductive hormones in polycystic females

Dietary fiber is getting attention these days due to its tendency to improve the reproductive performance in human beings. Sodium alginate (SA) is one of the natural dietary fibers. The present study aimed to evaluate the effect of SA on serum insulin, blood sugar, lipid profile, estrogen and testosterone in polycystic (PCOS) females. A single in vivo trial was conducted on thirty adult PCOS females (25 ± 5 years old) with a body mass index (BMI) of 27.5 ± 3.5 kg m^-2. Blood samples of all PCOS females were drawn for the initial biochemical analysis and considered as the negative control (NC). A complete randomized design was used to divide the NC group into three equal subgroups (n = 9) i.e. SA3: with 0.03 g; SA6: with 0.06 g per kg body weight per day of sodium alginate; the positive control (PC): metformin 500 mg day^-1 for 60 days (two months). A significant reduction (p < 0.05) in the body weight, BMI, blood sugar, serum insulin, lipids and testosterone was observed, while a significant incremental effect (p < 0.05) was observed in the high-density lipoprotein level. The percentages of some physical parameters were also improved like obesity, menstrual cycle, physical activity, psychological issues and hirsutism. Therefore, the study concluded that SA exhibited therapeutic potential for weight management and the improvement of serum testosterone in PCOS females.

Unraveling the mechanism of raffinose utilization in Ligilactobacillus salivarius Ren by transcriptomic analysis

In the gastrointestinal tract, some dietary carbohydrates, such as xylose, raffinose and arabinose, are able to stimulate the growth of Lactobacillus and Bifidobacterium. In this study, the growth rate of Ligilactobacillus salivarius Ren in raffinose was 0.91 ± 0.03 h-1, which was higher than that in glucose (0.83 ± 0.01 h-1). However, limited information is available on specific transporters and glycoside hydrolases responsible for raffinose uptake and catabolism in L. salivarius. Transcriptomic analysis revealed the differential expression of 236 genes (∣log2FoldChange∣ > 0.8) in response to raffinose, which were mainly associated with raffinose transport, raffinose hydrolysis, galactose metabolism and pyruvate metabolism. Notably, gene rafP encoding lactose/raffinose permease was 101.86-fold up-regulated. Two α-galactosidase gene galA1 and galA2 were 117.82-fold and 2.66-fold up-regulated, respectively. To further investigate the role of these genes in raffinose utilization, insertional inactivation was performed using the pORI28-pTRK669 system. The growth assay of these mutants in modified MRS containing 2% (w/v) raffinose indicated that RafP played an important role in raffinose transport and GalA1 was the primary enzyme involved in raffinose hydrolysis. To our knowledge, this is the first report on the molecular mechanism of raffinose utilization in L. salivarius.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03280-6.

Blood Coral Polysaccharide Helps Prevent D-Gal/LPS-Induced Acute Liver Failure in Mice

Objective

The liver protection of blood coral polysaccharide (BCP) was investigated.

Materials and Methods

We evaluated the effect of BCP on liver pathology, liver function, oxidation and inflammation-related indicators of D-Gal/LPS-induced acute liver failure (ALF) mice in vivo.

Results

Liver index and liver pathology observation in mice showed that BCP could inhibit liver tissue swelling and hemorrhage, hepatocyte damage, and inflammatory infiltration in ALF. Serum liver function results showed that BCP effectively inhibits the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), total bilirubin (TBil), alkaline phosphatase (AKP), myeloperoxidase (MPO). High dose-blood coral polysaccharide (H-BCP) was better than silymarin. Serum antioxidant and immune results showed that BCP increased the levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GSH-Px), and inhibited the levels of malondialdehyde (MDA) and nitric oxide (NO). Also, BCP increased immunoglobulins G (IgG) and A (IgA) levels, thereby enhancing humoral immunity. Liver anti-inflammatory ELISA results showed that BCP reduced the levels of interleukin (IL)-6, IL-1β, IL-17, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ, and enhanced the level of anti-inflammatory factor IL-10. H-BCP was the most effective treatment. Real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR) of liver tissues confirmed that BCP increases the relative expression levels of antioxidant and anti-inflammatory-related cuprozinc superoxide dismutase (Cu/Zn-SOD, SOD1), manganese superoxide dismutase (Mn-SOD, SOD2), CAT, GSH, GSH-Px, and IL-10. In contrast, it inhibits inflammation-related genes IL-6, IL-1β, IL-17, TNF-α, IFN-γ, inducible nitric oxide synthase (iNOS, NOS2), and cyclooxygenase (COX)-2. In addition, BCP also inhibits the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and enhance B-cell inhibitor-α (IκB-α) gene relative expression in the liver, which may be related to NF-κB pathway inhibition.

Conclusion

BCP prevents D-Gal/LPS-induced ALF in mice, and its effect is concentration dependent.

Gut Microbiota of Individuals Could Be Balanced by a 14-Day Supplementation With Laminaria japonica and Differed in Metabolizing Alginate and Galactofucan

Laminaria japonica is rich in alginate (Alg) and galactofucan (GF) which have both been reported to regulate gut microbiota composition. To reveal the effect of L. japonica on human gut microbiota, the fecal microbiota of 12 volunteers before and after 14-day L. japonica intake was sequenced and compared, and the capabilities of the gut microbiota to utilize Alg and GF were also investigated. The 16S rRNA gene sequencing results demonstrated that Firmicutes/Bacteroidetes ratio could be balanced by L. japonica supplementation. The ability of gut microbiota to utilize Alg was significantly enhanced by L. japonica supplementation. Furthermore, the multiple linear regression analysis suggested that bacteria from Bacteroidaceae and Ruminococcaceae were positively correlated with Alg utilization while those from Erysipelotrichaceae, Bacteroidaceae, and Prevotellaceae participated in GF degradation. Moreover, the production of acetic acid and the total short-chain fatty acids (SCFAs) in fermentation were consistent with the consumption of Alg or GF, and propionic acid content was positively correlated with Alg consumption. In addition, the percentage of monosaccharides in the consumed GF after the fermentation suggested that gut microbiota from individuals could consume GF with different monosaccharide preferences. These findings shed a light on the impacts of dietary L. japonica on human health.

Insights into Algal Polysaccharides: A Review of Their Structure, Depolymerases, and Metabolic Pathways

In recent years, marine macroalgae with extensive biomass have attracted the attention of researchers worldwide. Furthermore, algal polysaccharides have been widely studied in the food, pharmaceutical, and cosmetic fields because of their various kinds of bioactivities. However, there are immense barriers to their application as a result of their high molecular size, poor solubility, hydrocolloid nature, and low physiological activities. Unique polysaccharides, such as laminarin, alginate, fucoidan, agar, carrageenan, porphyran, ulvan, and other complex structural polysaccharides, can be digested by marine bacteria with many carbohydrate-active enzymes (CAZymes) by breaking down the limitation of glycosidic bonds. However, structural elucidation of algal polysaccharides, metabolic pathways, and identification of potential polysaccharide hydrolases that participate in different metabolic pathways remain major obstacles restricting the efficient utilization of algal oligosaccharides. This review focuses on the structure, hydrolase families, metabolic pathways, and potential applications of seven macroalgae polysaccharides. These results will contribute to progressing our understanding of the structure of algal polysaccharides and their metabolic pathways and will be valuable for clearing the way for the compelling utilization of bioactive oligosaccharides.

The Effect of Sargassum siliquastrum Supplementation on Growth Performance, Cecal Fermentation, Intestine Histomorphology, and Immune Response of Japanese Quails

This study aimed to investigate the dietary effects of Sargassum siliquastrum on the growth performance, nutrient digestibility, cecal fermentation, microbial populations, antioxidant status, immune response, and intestine histomorphology of Japanese quails. A total of 450 Japanese quails, aged 7 days, weighing 27.35 ± 0.23 g, were randomly distributed to three dietary groups in a 42-day feeding experiment. Five replicates were prepared per group, with each replicate consisting of 30 chicks in a cage. The three dietary groups consisted of a basal diet (0% supplementation, which was the control) and diets supplemented with 1% and 2% of S. siliquastrum. The results showed that the S. siliquastrum-supplemented groups and the control group had a similar final body weight (FBW), average body gain (ADG), and average feed intake (ADFI). However, the S. siliquastrum-supplemented groups had a better feed conversion ratio (FCR), as well as a lower mortality rate, compared to the control group. S. siliquastrum supplementation improved the nutrient digestibility of dry matter (DM), organic matter (OM), crude proteins (CP), and crude fibers (CF) (p < 0.05). The S. siliquastrum-supplemented groups exhibited the heaviest empty intestine and cecum weights, as well as the longest intestinal and cecal lengths. Furthermore, the total volatile fatty acids (TVFA) and the propionic acid concentrations increased significantly in quails fed S. siliquastrum-supplemented diets (p < 0.05), although the concentration of NH3-N decreased (p < 0.05). The dietary inclusion of S. siliquastrum had a beneficial effect on cecal microbial populations, where the Lactobacillus sp. counts increased, and the E. coli and Clostridium perfringens counts decreased. The histopathological examination of the duodenum confirmed that S. siliquastrum dietary supplementation enhanced the height and width of the villi. Quails fed S. siliquastrum-supplemented diet exhibited the highest total antioxidant capacity, superoxide dismutase, glutathione peroxidase, and glutathione reductase activities, but the thiobarbituric acid reactive substance was decreased (p < 0.05). Serum IgA, IgG, and IgM concentrations increased considerably (p < 0.05) in S. siliquastrum-supplemented groups. In conclusion, S. siliquastrum supplementation in the diet of Japanese quail can provide beneficial effects on performance, cecal fermentation, beneficial bacteria populations, and the immune response, and could be considered as an alternative feed additive in poultry production.

Recent Advances in Bioutilization of Marine Macroalgae Carbohydrates: Degradation, Metabolism, and Fermentation

Marine macroalgae are considered renewable natural resources due to their high carbohydrate content, which gives better utilization value in biorefineries and higher value conversion than first- and second-generation biomass. However, due to the diverse composition, complex structure, and rare metabolic pathways of macroalgae polysaccharides, their bioavailability needs to be improved. In recent years, enzymes and pathways related to the degradation and metabolism of macroalgae polysaccharides have been continuously developed, and new microbial fermentation platforms have emerged. Aiming at the bioutilization and transformation of macroalgae resources, this review describes the latest research results from the direction of green degradation, biorefining, and metabolic pathway design, including summarizing the the latest biorefining technology and the fermentation platform design of agarose, alginate, and other polysaccharides. This information will provide new research directions and solutions for the biotransformation and utilization of marine macroalgae.

Therapeutic Potential of Seaweed-Derived Bioactive Compounds for Cardiovascular Disease Treatment

Cardiovascular diseases are closely related to hypertension, type 2 diabetes mellitus, obesity, and hyperlipidemia. Many studies have reported that an unhealthy diet and sedentary lifestyle are critical factors that enhance these diseases. Recently, many bioactive compounds isolated from marine seaweeds have been studied for their benefits in improving human health. In particular, several unique bioactive metabolites such as polyphenols, polysaccharides, peptides, carotene, and sterol are the most effective components responsible for these activities. This review summarizes the current in vitro, in vivo, and clinical studies related to the protective effects of bioactive compounds isolated from seaweeds against cardiovascular disorders, including anti-diabetic, anti-hypertensive, anti-hyperlipidemia, and anti-obesity effects. Therefore, this present review summarizes these concepts and provides a basis for further in-depth research.

Potential Prebiotic and Anti-Obesity Effects of Codium fragile Extract

Polysaccharides from marine algae exhibit beneficial biological activities. In this study, we examined the effect of Codium fragile extract (CFE) on prebiotic and anti-obesity activity through in vitro experiments. CFE increases the growth of specific beneficial microbial populations with concomitant decrease in pathogenic microbes. Further, total phenolic content (TPC), total flavonoid content (TFC), and DPPH radical scavenging activity (DPPH activity) after fermentation with CFE as the carbon source were higher than for glucose as the control. Moreover, CFE inhibited adipocyte differentiation by inducing differentiation-related factors when the induction of 3T3-L1 preadipocytes into adipocytes was induced. Therefore, we suggest that CFE can be used as a prebiotic material with an anti-obesity effect for human health.

Evaluation of the Antibacterial and Prebiotic Potential of Ascophyllum nodosum and Its Extracts Using Selected Bacterial Members of the Pig Gastrointestinal Microbiota

Ascophyllum nodosum and its extracts are promising antibacterial and prebiotic dietary supplements for pigs. The objectives of this study were to evaluate the effects of the increasing concentrations of: (1) two whole biomass samples of A. nodosum with different harvest seasons, February (ANWB-F) and November (ANWB-N), in a weaned pig faecal batch fermentation assay, and (2) A. nodosum extracts produced using four different extraction conditions of a hydrothermal-assisted extraction methodology (ANE1-4) and conventional extraction methods with water (ANWE) and ethanol (ANEE) as solvent in individual pure culture growth assays using a panel of beneficial and pathogenic bacterial strains. In the batch fermentation assay, ANWB-F reduced Bifidobacterium spp. counts (p < 0.05) while ANWB-N increased total bacterial counts and reduced Bifidobacterium spp. and Enterobacteriaceae counts (p < 0.05). Of the ANE1-4, produced from ANWB-F, ANWE and ANEE that were evaluated in the pure culture growth assays, the most interesting extracts were the ANE1 that reduced Salmonella Typhimurium, enterotoxigenic Escherichia coli and B. thermophilum counts and the ANE4 that stimulated B. thermophilum growth (p < 0.05). In conclusion, the extraction method and conditions influenced the bioactivities of the A. nodosum extracts with ANE1 and ANE4 exhibiting distinct antibacterial and prebiotic properties in vitro, respectively, that merit further exploration.

Seasonal Nutritional Profile of Gelidium corneum (Rhodophyta, Gelidiaceae) from the Center of Portugal

Gelidium corneum is a well-known agarophyte, harvested worldwide for its high agar quality. However, the species also exhibits an interesting nutritional profile, but with seasonal variations. Therefore, to evaluate the nutritional value of G. corneum, ash, crude protein, total lipids, and carbohydrates were analyzed at different times of the year. The heavy metals mercury, arsenic, lead, cadmium, and tin, as well as iodine were also measured. Finally, the seasonal antioxidant capacity of G. corneum extracts was evaluated. Our results indicate that the biomass is rich in protein (up to 16.25 ± 0.33%) and carbohydrates (up to 39.5 ± 3.29%), and low in lipids (up to 2.75 ± 0.28%), and especially in the summer, the AI, TI indexes, n-6/n-3 and h/H ratios (0.93, 0.6, 0.88 and 1.08, respectively) are very interesting. None of the contaminants exceeded the legally established limits, and the iodine values were adequate for a healthy diet. Finally, the antioxidant capacity is fair, with the DPPH ≤ 10.89 ± 1.46%, and ABTS ≤ 13.90 ± 1.54% inhibition, FRAP ≤ 0.91 ± 0.22 AAE.g⁻¹, and TPC ≤ 6.82 ± 0.26 GAE.g⁻¹. The results show that G. corneum is an attractive resource, with potential use as food or as a food supplement.

In vitro simulated digestion and fermentation characteristics of polysaccharide from oyster (Crassostrea gigas), and its effects on the gut microbiota

Oyster is a kind of nutritious shellfish widely consumed globally, and its polysaccharide (OPS) has been verified to have strong functional activity. However, it is still unclear about the specific digestion and prebiotic properties of OPS. In the present study, the digestion and fermentation properties of OPS and its effect on gut microbiota were evaluated using simulated digestion (saliva, stomach, and small intestine) and fermentation models in vitro. The results showed that the molecular weight (Mw) of OPS decreased from 5.73 × 10⁶ to 4.35 × 10⁶ Da, and the reducing sugar content increased from 0.043 to 0.096 mg/mL, indicating that OPS was partially degraded during the saliva-gastrointestinal digestion. During fermentation, the Mw and carbohydrate residue of indigestible OPS (OPSI) decreased, and free monosaccharides were released, suggesting that OPSI could be further degraded and utilized by gut microbiota. Notably, OPSI could regulate the composition and diversity of the microbial community, especially increase the abundance of beneficial bacteria such as Bacteroides, Prevotella, and Faecalibacterium. Additionally, after fermentation for 24 h, OPSI promoted the production of short-chain fatty acids (SCFAs), and acetic acid, propionic acid, and n-butyric acid were the main metabolites. These results provided a reference for the digestive characteristics of OPS and revealed that OPS might be a potential prebiotic to prevent diseases by improving intestinal health.

Marine bioactives: from energy to nutrition

Microalgae have been evaluated as promising resource for biodiesel production, but algal biofuel production is not yet commercially viable, which reflects the high energy costs linked with cultivation, harvesting, and dewatering of algae. As crude oil processing declines, microalgae biorefineries are being considered for producing bioactives such as enzymes, proteins, omega-3 oils, pigments, recombinant products, and vitamins, to offset the costs of biofuel production. We believe that producing algal bioactives through advanced manufacturing pathways, encompassing a biorefinery approach, would be effective, profitable, and economical.

Seaweed Supplementation Failed to Affect Fecal Microbiota and Metabolome as Well as Fecal IgA and Apparent Nutrient Digestibility in Adult Dogs

The present study investigated in dogs the dietary effects of intact seaweeds on some fecal bacterial populations and metabolites, fecal IgA and apparent total tract digestibility (ATTD). Ten healthy adult dogs were enrolled in a 5 × 5 replicated Latin square design to evaluate five dietary treatments: control diet (CD); CD + Ascophyllum nodosum; CD + Undaria pinnatifida; CD + Saccharina japonica; CD + Palmaria palmata (n replicates per treatment = 10). Seaweeds were added to food at a daily dose of 15 g/kg. The CD contained silica as a digestion marker. Each feeding period lasted 28 d, with a 7 d wash-out in between. Feces were collected at days 21 and 28 of each period for chemical and microbiological analyses. Fecal samples were collected during the last five days of each period for ATTD assessment. Dogs showed good health conditions throughout the study. The fecal chemical parameters, fecal IgA and nutrient ATTD were not influenced by algal supplementation. Similarly, microbiological analyses did not reveal any effect by seaweed ingestion. In conclusion, algal supplementation at a dose of 15 g/kg of diet failed to exert noticeable effects on the canine fecal parameters evaluated in the present study.

Lipidomics of the Edible Brown Alga Wakame (Undaria pinnatifida) by Liquid Chromatography Coupled to Electrospray Ionization and Tandem Mass Spectrometry

The lipidome of a brown seaweed commonly known as wakame (Undaria pinnatifida), which is grown and consumed around the world, including Western countries, as a healthy nutraceutical food or supplement, was here extensively examined. The study was focused on the characterization of phospholipids (PL) and glycolipids (GL) by liquid chromatography (LC), either hydrophilic interaction LC (HILIC) or reversed-phase LC (RPLC), coupled to electrospray ionization (ESI) and mass spectrometry (MS), operated both in high and in low-resolution mode. Through the acquisition of single (MS) and tandem (MS/MS) mass spectra more than 200 PL and GL of U. pinnatifida extracts were characterized in terms of lipid class, fatty acyl (FA) chain composition (length and number of unsaturations), and regiochemistry, namely 16 SQDG, 6 SQMG, 12 DGDG, 5 DGMG, 29 PG, 8 LPG, 19 PI, 14 PA, 19 PE, 8 PE, 38 PC, and 27 LPC. The FA (C16:0) was the most abundant saturated acyl chain, whereas the monounsaturated C18:1 and the polyunsaturated C18:2 and C20:4 chains were the prevailing ones. Odd-numbered acyl chains, iJ., C15:0, C17:0, C19:0, and C19:1, were also recognized. While SQDG exhibited the longest and most unsaturated acyl chains, C18:1, C18:2, and C18:3, in the sn-1 position of glycerol, they were preferentially located in the sn-2 position in the case of PL. The developed analytical approach might pave the way to extend lipidomic investigations also for other edible marine algae, thus emphasizing their potential role as a source of bioactive lipids.

Marine Algae of the Genus Gracilaria as Multi Products Source for Different Biotechnological and Medical Applications

BACKGROUND

Gracilaria has been shown to be an important source of marine bioactive natural biomaterials and compounds. Although there are no enough patents used Gracilaria worldwide, the current study tries to put the Gracilaria on the spot for further important patents in the future.

OBJECTIVE

The current study investigates the pharmaceuticals and biochemical activity of Gracilaria because no previous studies have been carried out to examine the biochemical and pharmaceutical activates of Gracilaria from the Suez Canal of Egypt as an excellent source for bioactive compounds.

METHODS

Different advanced experimental models and analytical techniques, such as cytotoxicity, total antioxidant capacity, anticancer, and anti-inflammatory profiling were applied. The phytochemical analysis of different constituents was also carried out.

RESULTS

The mineral analysis revealed the presence of copper (188.3 ppm) and iron (10.07 ppm) in addition to a remarkable wealth of selenium and sulfur contents giving up to 36% of its dry mass. The elemental analysis showed high contents of sulfur and nitrogen compounds. The GCMS profiling showed varieties of different bioactive compounds, such as fatty acids, different types of carotenoids in addition to pigments, alkaloids, steroids. Many other compounds, such as carbohydrates and amino acids having antioxidant, anti-inflammatory, and antiviral activities, etc. were identified. The cytotoxicity activity of Gracilaria marine extract was very effective against cancerous cell lines and showed high ability as a potent antitumor due to their bioactive constituents. Specialized screening assays using two anticancer experimental models, i.e., PTK and SKH1 revealed 77.88% and 84.50% inhibition anticancer activity; respectively. The anti-inflammatory activities investigated using four different experimental models, i.e., COX1, COX2, IL6, and TNF resulted in 68%, 81.76%, 56.02% and 78.43% inhibition; respectively. Moreover, Gracilaria extracts showed potent anti-Alzheimer with all concentrations.

CONCLUSION

Gracilaria proved to be a multi-product source of marine natural products for different biotechnological applications. Our recommendation is to investigate the Gracilaria bioactive secondary metabolites in order to create and innovate in more patents from current important seaweeds (Gracilaria).

Seaweed Components as Potential Modulators of the Gut Microbiota

Macroalgae, or seaweeds, are a rich source of components which may exert beneficial effects on the mammalian gut microbiota through the enhancement of bacterial diversity and abundance. An imbalance of gut bacteria has been linked to the development of disorders such as inflammatory bowel disease, immunodeficiency, hypertension, type-2-diabetes, obesity, and cancer. This review outlines current knowledge from in vitro and in vivo studies concerning the potential therapeutic application of seaweed-derived polysaccharides, polyphenols and peptides to modulate the gut microbiota through diet. Polysaccharides such as fucoidan, laminarin, alginate, ulvan and porphyran are unique to seaweeds. Several studies have shown their potential to act as prebiotics and to positively modulate the gut microbiota. Prebiotics enhance bacterial populations and often their production of short chain fatty acids, which are the energy source for gastrointestinal epithelial cells, provide protection against pathogens, influence immunomodulation, and induce apoptosis of colon cancer cells. The oral bioaccessibility and bioavailability of seaweed components is also discussed, including the advantages and limitations of static and dynamic in vitro gastrointestinal models versus ex vivo and in vivo methods. Seaweed bioactives show potential for use in prevention and, in some instances, treatment of human disease. However, it is also necessary to confirm these potential, therapeutic effects in large-scale clinical trials. Where possible, we have cited information concerning these trials.

Effects of red macroalgae Asparagopsis taxiformis supplementation on the shelf life of fresh whole muscle beef

This study was conducted to evaluate the effect of red macroalgae Asparagopsis taxiformis supplementation for cattle on the shelf life of fresh beef steaks (longissimus dorsi). Three treatment groups (seven steers per treatment) included: 1) Control diet, 2) Control diet + 0.25% of macroalgae inclusion (low dose, LD), and 3) Control + 0.5% of macroalgae inclusion (high dose, HD). After the animals were harvested, the strip loins from all animals were collected and aged for 14 days at the meat lab of the University of California, Davis. Then the strip loins were cut into steaks, packaged, and placed on a retail display case for 6 days. During a retail display, instrumental color (L*, a*, and b*) of lean muscle and external fat surfaces were measured every 12 h. Bacterial counts for total aerobic mesophilic bacteria (AMB), aerobic psychrotrophic bacteria (APB), and lactic acid bacteria (LAB) were assessed on days 0, 3, and 6 of retail display. The thiobarbituric acid reactive substances (TBARS) analysis was conducted to measure the lipid oxidation and the pH was also assessed on days 0, 3, and 6. No interactive effect between treatments and time on the shelf life of steaks was observed. The HD red macroalgae supplement decreased (P < 0.05) the lightness (L*) of the surface muscle of the steaks, while the lightness of the external fat was not affected (P < 0.05) by treatments throughout the retail display. The external fat yellowness of the steaks was lower (P < 0.05) in LD and HD treatment groups compared with the control group. An increase (P < 0.05) in counts of AMB, APB, and LAB was observed on the steaks from the steers in the HD treatment group while steaks in Control and LD group had similar bacterial numbers throughout the retail display. The results indicated that the shelf life of steaks from cattle in LD group remained the same as that of the Control group, but the HD of A. taxiformis caused a darker color of steaks with higher microbial counts, which may lead to a shortened shelf life due to undesirable appearance and faster microbial spoilage.

Prebiotic Effects of Seaweed Polysaccharides in Pigs

To ensure environmental sustainability, according to the European Green Deal and to boost the One Health concept, it is essential to improve animals' health and adopt sustainable and natural feed ingredients. Over the past decade, prebiotics have been used as an alternative approach in order to reduce the use of antimicrobials, by positively affecting the gut microbiota and decreasing the onset of several enteric diseases in pig. However, dietary supplementation with seaweed polysaccharides as prebiotics has gained attention in recent years. Seaweeds or marine macroalgae contain several polysaccharides: laminarin, fucoidan, and alginates are found in brown seaweeds, carrageenan in red seaweeds, and ulvan in green seaweeds. The present review focuses on studies evaluating dietary seaweed polysaccharide supplementation in pig used as prebiotics to positively modulate gut health and microbiota composition.

Effects of dietary supplementation with a laminarin-rich extract on the growth performance and gastrointestinal health in broilers

Restriction in antimicrobial use in broiler chicken production is driving the exploration of alternative feed additives that will support growth through the promotion of gastrointestinal health and development. The objective of this study was to determine the effects of dietary inclusion of laminarin on growth performance, the expression of nutrient transporters, markers of inflammation and intestinal integrity in the small intestine and composition of the caecal microbiota in broiler chickens. Two-hundred-and-forty day-old male Ross 308 broiler chicks (40.64 (3.43 SD) g) were randomly assigned to: (T1) basal diet (control); (T2) basal diet + 150 ppm laminarin; (T3) basal diet + 300 ppm laminarin (5 bird/pen; 16 pens/treatment). The basal diet was supplemented with a laminarin-rich Laminaria spp. extract (65% laminarin) to achieve the two laminarin inclusion levels (150 and 300 ppm). Chick weights and feed intake was recorded weekly. After 35 days of supplementation, one bird per pen from the control and best performing (300 ppm) laminarin groups were euthanized. Duodenal, jejunal and ileal tissues were collected for gene expression analysis. Caecal digesta was collected for microbiota analysis (high-throughput sequencing and QPCR). Dietary supplementation with 300 ppm laminarin increased both final body weight (2033 vs. 1906 ± 30.4, P < 0.05) and average daily gain (62.3 vs. 58.2 ± 0.95, P < 0.05) compared to the control group and average daily feed intake (114.1 vs. 106.0 and 104.5 ± 1.77, P < 0.05) compared to all other groups. Laminarin supplementation at 300 ppm increased the relative and absolute abundance of Bifidobacterium (P < 0.05) in the caecum. Laminarin supplementation increased the expression of interleukin 17A (IL17A) in the duodenum, claudin 1 (CLDN1) and toll-like receptor 2 (TLR2) in the jejunum and IL17A, CLDN1 and SLC15A1/peptide transporter 1 (SLC15A1/PepT1) in the ileum (P < 0.05). In conclusion, supplementation with laminarin is a promising dietary strategy to enhance growth performance and 300 ppm was the optimal inclusion level with which to promote a beneficial profile of the gastrointestinal microbiota in broiler chickens.

Whole Alga, Algal Extracts, and Compounds as Ingredients of Functional Foods: Composition and Action Mechanism Relationships in the Prevention and Treatment of Type-2 Diabetes Mellitus

Type-2 diabetes mellitus (T2DM) is a major systemic disease which involves impaired pancreatic function and currently affects half a billion people worldwide. Diet is considered the cornerstone to reduce incidence and prevalence of this disease. Algae contains fiber, polyphenols, ω-3 PUFAs, and bioactive molecules with potential antidiabetic activity. This review delves into the applications of algae and their components in T2DM, as well as to ascertain the mechanism involved (e.g., glucose absorption, lipids metabolism, antioxidant properties, etc.). PubMed, and Google Scholar databases were used. Papers in which whole alga, algal extracts, or their isolated compounds were studied in in vitro conditions, T2DM experimental models, and humans were selected and discussed. This review also focuses on meat matrices or protein concentrate-based products in which different types of alga were included, aimed to modulate carbohydrate digestion and absorption, blood glucose, gastrointestinal neurohormones secretion, glycosylation products, and insulin resistance. As microbiota dysbiosis in T2DM and metabolic alterations in different organs are related, the review also delves on the effects of several bioactive algal compounds on the colon/microbiota-liver-pancreas-brain axis. As the responses to therapeutic diets vary dramatically among individuals due to genetic components, it seems a priority to identify major gene polymorphisms affecting potential positive effects of algal compounds on T2DM treatment.

Functional foods and bioactive ingredients harnessed from the ocean: current status and future perspectives

With an increase in life expectancy and decrease of quality-of-life couple with the high prevalence of diseases, diet is expected to play a key function in sustaining human health. Nutritionists, food technologists and medical experts are working in synergy to cater for the increasing demand of food with associated therapeutic benefits, commonly known as functional food, that may improve well-being and reduce the risk of diseases. Interestingly, the marine ecosystem, due to its abundant and phenomenal biodiversity of marine organisms, constitutes a vital source of a panoply of healthy foods supply for the thriving functional food industry. Marine organisms such as seaweeds, sea cucumbers, sponges, and mollusks amongst others are sources of thousands of biologically active metabolites with antioxidant, anti-parasitic, antiviral, anti-inflammatory and anticancer properties. Given the growing number of research and interest to probe into the therapeutic roles of marine products, this review was designed to provide a comprehensive summary of the therapeutic properties of marine organisms (macroalgae, sea cucumbers and fish among others) which are consumed worldwide, in addition to their potentials and as sources of functional ingredients for developing novel food and fostering wellness. The gap between research development and actual commercialization, and future prospects of marine-based products also summarized to some extent.

Insoluble dietary fiber derived from brown seaweed Laminaria japonica ameliorate obesity-related features via modulating gut microbiota dysbiosis in high-fat diet-fed mice

Gut microbiota (GM) is considered to play an important role in obesity. Additionally, the impact of dietary fiber (DF) consumption on GM has been well established. Brown seaweeds are known to be a rich source of DF. However, the effect of insoluble DFs (IDFs) alone from brown seaweed on obesity and GM remains to be determined. This study investigated the effect of IDFs prepared from Laminaria japonica Aresch on high-fat diet (HFD)-induced obesity and GM dysbiosis in mice. Although HFD-induced body weight gain was not significantly attenuated by the IDF treatment, HFD-induced liver injury was ameliorated, and the HFD-elevated serum cholesterol concentration and glucose level of obese mice were significantly lowered. IDF treatment significantly modulated the GM composition disturbed by the HFD. It was found that 5% IDFs restored the GM to a very similar composition to that in the normal mice. The relative abundance of Akkermansia genus was decreased by >300-fold in HFD-fed mice, and it was fully restored by 5% IDF administration. Akkermansia muciniphila, a short-chain fatty acid producer, was identified as a marker species in both control and high-dose IDF groups. Furthermore, IDFs significantly restored the HFD-reduced acetate and propionate levels in the cecal content. In conclusion, the beneficial effect of IDFs derived from L. japonica on obesity was confirmed in mice, and the underlying mechanism may be associated with the modulation of GM composition, possibly through the enrichment of Akkermansia.

Caulerpa lentillifera (Sea Grapes) Improves Cardiovascular and Metabolic Health of Rats with Diet-Induced Metabolic Syndrome

Caulerpa lentillifera (sea grapes) is widely consumed in South-East Asia as a low-energy food with high contents of vitamins and minerals. This study investigated dried sea grapes containing 16.6% insoluble fibre commercially produced in Vietnam as an intervention. We hypothesised that insoluble fibre is the primary metabolite that will reverse diet-induced metabolic syndrome. Male Wistar rats (n = 48) were randomly allocated to four groups in a 16 week protocol. Two groups were fed either corn starch (C) or high-carbohydrate, high-fat (H) diets for the full 16 weeks. The other two groups received C and H diets for eight weeks and then received C. lentillifera added to these diets for the final eight weeks (CCL and HCL, respectively). High-carbohydrate, high-fat diet-fed rats developed obesity, hypertension, dyslipidaemia, fatty liver disease and increased left ventricular collagen deposition. C. lentillifera supplementation in HCL rats decreased body weight, systolic blood pressure, plasma concentrations of total cholesterol and non-esterified fatty acids, inflammatory cells in heart and liver, and visceral adiposity. The Firmicutes to Bacteroidetes ratio decreased in the gut microbiota of HCL rats. Therefore, C. lentillifera attenuated cardiovascular and metabolic symptoms of metabolic syndrome in rats, possibly by preventing infiltration of inflammatory cells together with modulating gut microbiota.

Proximate Analysis of Selected Macroalgal Species from the Persian Gulf as a Nutritional Resource

Nowadays the exploration and utilisation of food and feed from marine origin is becoming more important with the increase of human population. Macroalgae are rich in nutritious compounds, which can directly be used in human and animal feed industries. The current study presents the screening of chemical components of eight macroalgae species, Sargassum boveanum, Sirophysalis trinodis, Hypnea caroides, Palisda perforata, Galaxaura rugosa, Caulerpa racemose, Caulerpa sertularioides and Bryopsis corticolans from the Persian Gulf. The results revealed that the eight studied algal species possess high protein (14.46% to 38.20%), lipid (1.27% to 9.13%) and ash (15.50% to 49.14%) contents. The fatty acids and amino acids profile showed the presence of essential fatty acids and amino acids with high nutritional value. Phaeophyta species, S. boveanum and S. trinodis, showed the highest value of ash content and polyunsaturated fatty acids while Chlorophyta species, C. racemose, C. sertularioides and B. corticolans, showed the highest level of lipid and protein contents. Rhodophyta species, G. rugosa and P. perforata, showed the highest essential amino acid content. In conclusion, this study demonstrates the potential of the studied marine species as a nutritional source for human and animal uses.

Effects of dietary kelp (Ascophylum nodosum) supplementation on survival rate and reproductive performance of mink challenged with Aleutian mink disease virus

Infection with Aleutian mink disease virus (AMDV) has negative effects on reproductive performance and survival rate of American mink (Neovison vison). The objectives of this study were to assess the effects of kelp (Ascophylum nodosum) supplementation on survival, growth rate, and reproductive performance of mink challenged with AMDV. AMDV-free female black mink (n = 75) were intranasally inoculated with a local AMDV strain. Mink were fed a commercial pellet supplemented with 1.5% or 0.75% kelp or were kept as controls (received no kelp) for 451 d. Body weight and rectal temperature were recorded on days 0, 31, 56, 99, 155, 366, and 451 post inoculation (PI). Annual mortality rates were 13.6%, 20.0%, and 31.8% for mink fed 1.5%, 0.75%, or 0.0% kelp, respectively (P = 0.29). Mink which were fed 1.5% kelp had a significantly (P < 0.01) greater daily weight loss during breeding and post-breeding periods (days 155–366 PI), and outperformed (P < 0.01) the other groups in regard to litter sizes at birth and weaning. Differences among treatments were not significant for the number of females mated, or whelped of those exposed to males, kit survival from birth to weaning, or rectal temperature. It was concluded that 1.5% kelp supplementation had beneficial effects on survival rate of adult mink and litter size.

Seaweed Potential in the Animal Feed: A Review

Seaweed (known as marine algae) has a tradition of being part of the animal feed in the coastal areas, from ancient times. Seaweeds, are mixed with animal feed, because when consumed alone can have negative impact on animals. Thus, seaweeds are very rich in useful metabolites (pigments, carotenoids, phlorotannins, polyunsaturated fatty acids, agar, alginate and carrageenan) and minerals (iodine, zinc, sodium, calcium, manganese, iron, selenium), being considered as a natural source of additives that can substitute the antibiotic usage in various animals. In this review, we describe the nutritional values of seaweeds and the seaweed effects in the seaweed-based animal feed/supplements.