Emerging prospects of macro- and microalgae as prebiotic

Bioprospecting of cellulases from marine fungi for macro-algal biomass degradation for biofuel application

The marine ecosystem, the largest on Earth, supports around 80 % of plant and animal species. Marine macroalgae, rich in polysaccharides like cellulose, remain underutilized despite their potential in a circular bioeconomy. Efficient valorization can promote sustainability, whereas mismanagement raises ecological concerns. Unlike lignocellulosic biomass, macroalgae lack lignin, making their processing unique. Global interest in macroalgae for biofuel applications is growing, particularly through polysaccharide-degrading biocatalysts like cellulases. Fungi, known for secreting extracellular cellulases and other enzymes, play a key role in biomass degradation. Marine fungi associated with macroalgae may possess enhanced enzymatic capabilities, enabling efficient algal polysaccharide breakdown. These fungi have immense potential in macroalgal biorefineries, facilitating the conversion of complex polysaccharides into oligosaccharides and monosaccharides for biofuels, pharmaceuticals, nutraceuticals, and cosmetics. Developing advanced bioprocessing technologies for marine fungi could provide robust cellulases that withstand industrial conditions, optimizing macroalgal biomass conversion. This review comprehensively examines cellulase production from marine fungi, their bioprocessing strategies, and their role in degrading macroalgal biomass. Additionally, other fungal enzymes and their industrial applications are briefly discussed. This study highlights the potential of marine fungi-derived cellulases in biofuel production, aligning with sustainable development goals and supporting global bioeconomic advancements.

Unveiling the Anti-Aging Potential of Marine Natural Bioproducts

Aging is a natural process resulting in the progressive impairment of multiple functions in the human body, leading to a decline in cellular functionality and the development of aging-related diseases. External stress factors, such as ultraviolet (UV) radiation, pollution, and toxin exposure, increase oxidative stress, damage cellular repair mechanisms, and speed up aging processes. With the rise in the world's aging population, there are enlarged demands for the use of sustainable natural products in food, nutrient supplements and cosmetics that can slow down aging and prolong healthy life and longevity. Algae, including both macroalgae and microalgae, have been recognised as a source of valuable proteins, amino acids, fatty acids, vitamins, and minerals useful for human consumption and medical applications. With increasing demands for nutraceutical and pharmaceutical bioproducts from environmentally friendly resources, the biotechnological industry, over recent decades, has had to provide new, advanced solutions using modern high-throughput omics technologies. The application of proteomics in the area of discoveries of natural products with anti-aging properties has become more popular for wide industry applications. New proteomics profiling provides a better understanding of changes occurring in protein and peptide content, their structure, function and interactions, as well as the regulatory processes and molecular pathways. Mass spectrometry-based proteomics has been used for a wide range of applications including protein identification, characterisation, as well as quantification of proteins within the proteome and sub-proteome. The application of chemical proteomics facilitated the identification of natural products approach and included the synthesis of probes and target fishing, allowing the advanced identification of proteins of interest. This review focuses on marine macro- and microalgal anti-aging compounds and novel proteomics approaches, providing recent experimental evidence of their involvement in anti-aging processes that should facilitate their use in innovative approaches and sustainable biotechnological applications.

Effects of Supplementation with Microalgae Extract from Tetradesmus obliquus Strain Mi175.B1.a on Gastrointestinal Symptoms and Mental Health in Healthy Adults: A Pilot Randomized, Double-Blind, Placebo-Controlled, Parallel-Arm Trial

Microalgae, a marine-derived natural ingredient, has emerged as a rich source of bioactive compounds with the potential to modulate gut-brain axis activities. The objective of this study was to investigate whether supplementation with a microalgae extract from Tetradesmus obliquus strain Mi175.B1.a (TOME) influences gut health and reduces stress and anxiety in healthy adults experiencing mild to moderate gastrointestinal (GI) distress. Methods: Fifty-six healthy adults (age: 31.9 ± 7.7 years; body weight: 71.8 ± 12.6 kg; BMI: 24.6 ± 2.8 kg/m2) were enrolled in a randomized, double-blind, placebo-controlled, parallel-arm clinical trial. Participants were randomly allocated to receive capsules containing either 250 mg/day of TOME or a placebo for four weeks. Primary outcomes included the assessment of GI symptoms using the Gastrointestinal Symptom Rating Scale (GSRS) and Bristol Stool Scale (BSS). Secondary outcomes focused on subjective evaluation of mood, stress, and anxiety, as well as blood pressure responses to sympathetic nervous system activation induced by the cold pressor test (CPT). In addition, stool, plasma, and saliva samples were collected to assess biomarkers associated with stress, sympathetic activation, intestinal permeability, and GI health. 16S rRNA sequencing was performed to analyze changes in gut microbial populations. Results: Daily supplementation for four weeks with TOME was safe and well tolerated in the study population. In addition, TOME significantly reduced GSRS global scores (p = 0.02), as well as constipation (p = 0.05) and indigestion (p = 0.03) subcomponent scores compared to Placebo. There was also a significant increase in Shannon's index before FDR correction (p = 0.05; FDR = 0.12) and stool butyrate level was significantly lower in the TOME group than in Placebo after 4 weeks of supplementation (p = 0.039). Both groups showed a significant reduction in perceived stress scores, but the TOME intervention group also had reduced Negative Affect scores (p < 0.001). In addition, plasma chromogranin A, a stress biomarker, was significantly reduced after TOME intervention (p = 0.03). There were no negative effects on blood lipids or other parameters related to sympathetic activation or cardiovascular health. Conclusions: Overall, these results suggest that 4-week supplementation with T. obliquus strain Mi175.B1.a improves GI symptoms, potentially through effects on the gut microbiota, and may promote positive effects on mental health. Additional research should follow up on mental health outcomes in populations with increased stress and anxiety and investigate mechanisms underlying improvements in GI health. This trial was registered at clinicaltrials.gov as NCT06425094.

Barros A, Miranda IM. The Role of Chlorella and Spirulina as Adjuvants of Cardiovascular Risk Factor Control: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Background/Objectives: Chlorella and Spirulina supplementation may reduce the risk of cardiometabolic diseases by better controlling blood cholesterol, triglycerides, glucose, weight, and blood pressure (BP). However, the available studies are limited in size and have used different outcomes. Methods: To gain power in assessing the impact of microalgae supplements on cardiovascular risk factors, we searched PubMed on 3 February 2023 for randomised controlled trials assessing the effects of Chlorella and Spirulina on modifiable cardiovascular risk factors. Results: We found 12 studies in Chlorella and 9 studies on Spirulina. Depending on the available outcomes, varying numbers of participants (Chlorella: 168 to 279; Spirulina: 101 to 299) were included. Our analysis showed that Chlorella supplementation had a neutral effect on BP and lipemia. On the other hand, Spirulina intake led to a significant reduction in diastolic BP (-0.42, 95% CI: -0.81 to -0.02, p = 0.04) but did not significantly affect lipemia indexes, despite a trend toward a reduction in total cholesterol (-0.17, 95% CI: -0.39 to 0.06, p = 0.15). This meta-analysis suggests Spirulina supplementation can be used as an adjuvant to control cardiometabolic risk factors, particularly for BP. However, the magnitude of this effect is small and of uncertain clinical significance. Conclusions: Further randomised trials are needed to better assess the potential of these supplements as adjuvants for the control of cardiovascular risk factors.

Effects of using microalgae in poultry diets on the production and quality of meat and eggs: a review

1. This review was conducted to examine the nutritional composition of microalgae and their effects as a feed ingredient in poultry diets, delving into their influence on the production and quality of meat and eggs. Data collection focused on peer-reviewed scientific articles, with no limitation on the temporal horizon.2. Regarding nutritional composition, the collected papers indicated that certain microalgae species have a rich nutritional composition, with approximately 50% of their biomass composed of proteins. They contain a high concentration of EPA and DHA, important fatty acids that are found in low concentrations in conventional feedstuffs, and the presence of carotenoids such as beta-carotene.3. Incorporating microalgae into the diet of poultry can improve performance variables, such as mortality, live weight and feed conversion rate. It promotes benefits in meat and egg quality, with reduced cholesterol, increased EPA and DHA, intensified colour and higher concentration of carotenoids.

Chlorella and vegetable oil inclusion in diets for growing rabbits: effects on growth, digestibility, plasma metabolites, and caecal fermentations and microbiota

The inclusion of microalgae in livestock diets has been shown to enhance animal productivity, immune response, and meat quality. However, the role of chlorella (Chlorella vulgaris) in growing rabbit nutrition has been scarcely explored, with available studies focusing on low inclusion levels (<1%) and their effects on rabbit growth and immune response. This study evaluated the growth performance, nutrient digestibility, plasma metabolites, caecal fermentative activity, and caecal microbiota composition of growing rabbits fed diets with different inclusion levels of chlorella and crude fat. A total of 648 mixed-sex Grimaud crossbred rabbits (33 d of age; 841 ± 140 g live weight) were fed six experimental diets (96 rabbits per diet for the growth trial) based on a bifactorial design with three dietary inclusion levels of chlorella (0, 1, and 2%) and two levels of crude fat (3 and 5%) obtained by the inclusion of soybean oil (1 and 3%, respectively). The trial lasted 38 days until slaughter. From 47 to 51 days of age, 72 rabbits (12 per diet) were submitted to a digestibility trial. At 51 days of age, samples of plasma and caecal content were collected from 36 rabbits (six rabbits per diet) to analyse plasma metabolites, caecal fermentations, and caecal microbiota. Rabbit live weight at 71 days of age (2 700 g, on average), weight gain (48.8 g/d) and feed conversion ratio (3.27) were unaffected by chlorella inclusion, while feed conversion ratio improved (-5%; P < 0.001) with an increase of crude fat from 3 to 5%. The digestibility of ADF (23.2 vs 20.9%; P < 0.05) and crude fat (83.8 vs 85.6%; P < 0.01) improved with the inclusion of chlorella at 2%, as well as the digestibility of crude fat (82.4 vs 86.9%; P < 0.001) and gross energy (57.3 vs 58.7%; P < 0.001) with crude fat inclusion at 5%. Plasma non-esterified fatty acids decreased (-19%; P < 0.05) in diets with 5% crude fat. Neither chlorella nor crude fat inclusion levels affected other plasma metabolites, caecal fermentations, or caecal microbiota. Overall, the inclusion of chlorella up to 2% in diets for growing rabbits did not significantly affect diet nutritional value, animal performance, or caecal activity. On the other hand, increasing crude fat to 5% improved the overall feed efficiency.

Marine microalgae and their industrial biotechnological applications: A review

BACKGROUND

For use in specialized programs in the food, pharmaceutical, nutraceutical, cosmetic, and animal feed sectors, micro-algal biomass has been generated industrially. They can be grown in closed buildings, such as photobioreactors, or open structures. The utilization of biomass from microalgae for energy production is another crucial topic. Because of the world's diminishing petroleum sources and the greenhouse gas emissions from gasoline lines, it is now obvious that fuels generated from petroleum are not sustainable.

RESULTS

Microalgae can produce a variety of unique, sustainable biofuels. These include biodiesel made from trans-esterification of microalgal lipids, bioethanol from fermentation of carbohydrates, methane created by anaerobic digestion of algal biomass, and biohydrogen produced by photobiological processes. The idea of using microalgae as a fuel source is not entirely novel.

CONCLUSION

This analysis emphasizes the significance of recent and noteworthy advancements in the industrial usage of microalgae, with an emphasis on their biotechnological applications.

Improving Undernutrition with Microalgae

Undernutrition is an important global health problem, especially in children and older adults. Both reversal of maternal and child undernutrition and heathy ageing have become United Nations-supported global initiatives, leading to increased attention to nutritional interventions targeting undernutrition. One feasible option is microalgae, the precursor of all terrestrial plants. Most commercially farmed microalgae are photosynthetic single-celled organisms producing organic carbon compounds and oxygen. This review will discuss commercial opportunities to grow microalgae. Microalgae produce lipids (including omega-3 fatty acids), proteins, carbohydrates, pigments and micronutrients and so can provide a suitable and underutilised alternative for addressing undernutrition. The health benefits of nutrients derived from microalgae have been identified, and thus they are suitable candidates for addressing nutritional issues globally. This review will discuss the potential benefits of microalgae-derived nutrients and opportunities for microalgae to be converted into food products. The advantages of microalgae cultivation include that it does not need arable land or pesticides. Additionally, most species of microalgae are still unexplored, presenting options for further development. Further, the usefulness of microalgae for other purposes such as bioremediation and biofuels will increase the knowledge of these microorganisms, allowing the development of more efficient production of these microalgae as nutritional interventions.

Seaweed-based biopolymers for food packaging: A sustainable approach for a cleaner tomorrow

With the increasing environmental and health consequences of uncontrolled plastic use, the scientific community is progressively gravitating toward biodegradable and ecofriendly packaging alternatives. Seaweed polysaccharides have attracted attention recently because of their biodegradability, nontoxicity, antioxidant properties, and superior film-forming ability. However, it has some limitations for packaging applications, such as low tensile strength, water solubility, and only modest antimicrobial properties. The incorporation of biopolymers, nanoparticles, or organic active ingredients enhances these characteristics. This review encapsulates the contemporary research landscape pivoting around the role of seaweed polysaccharides in the development of bioplastics, active packaging solutions, edible films, and protective coatings. A meticulous collation of existing literature dissects the myriad food application avenues for these marine biopolymers, emphasizing their multifaceted physical, mechanical, thermal, and functional attributes, including antimicrobial and antioxidant. A key facet of this review spotlights environmental ramifications by focusing on their biodegradability, reinforcing their potential as a beacon of sustainable innovation. This article delves into the prevalent challenges that stymie large-scale adoption and commercialization of seaweed-centric packaging, offering a comprehensive perspective on this burgeoning domain.

In vitro evaluation of antioxidant potential of polysaccharides and oligosaccharides extracted from three different seaweeds

Bioactive polysaccharides and oligosaccharides were successfully extracted from three distinct seaweeds: Sargassum sp., Graciallaria sp., and Ulva sp. utilizing various extraction techniques. The obtained polysaccharides and oligosaccharides were subjected to comprehensive characterization, and their potential antioxidant properties were assessed using a Hep G2 cell model. Analysis via FTIR spectroscopy unveiled the presence of sulfate groups in the polysaccharides and oligosaccharides derived from Sargassum sp. The antioxidant capabilities were assessed through various assays (DPPH, ABTS, Fe-ion chelation, and reducing power), revealing that SAR-OSC exhibited superior antioxidant activity than others. This was attributed to its higher phenolic content (24.6 μg/mg), FRAP value (36 μM Vitamin C/g of extract), and relatively low molecular weight (5.17 kDa). The study also investigated the protective effects of these polysaccharides and oligosaccharides against oxidative stress-induced damage in Hep G2 cells by measuring ROS production and intracellular antioxidant enzyme expressions (SOD, GPx, and CAT). Remarkably, SAR-OSC demonstrated the highest efficacy in protecting Hep G2 cells reducing ROS production and downregulating SOD, GPx, and CAT expressions. Current findings have confirmed that the oligosaccharides extracted by the chemical method show higher antioxidant activity, particularly SAR-OSC, and robust protective abilities in the Hep G2 cells.

Engineered Chlorella vulgaris improves bioethanol production and promises prebiotic application

Microalgal biomass for biofuel production, integration into functional food, and feed supplementation has generated substantial interest worldwide due to its high growth rate, non-competitiveness for agronomic land, ease of cultivation in containments, and presence of several bioactive molecules. In this study, genetic engineering tools were employed to develop transgenic lines of freshwater microalga Chlorella vulgaris with a higher starch content, by up-regulating ADP-glucose pyrophosphorylase (AGPase), which is a rate-limiting enzyme in starch biosynthesis. Expression of the Escherichia coli glgC (AGPase homolog) gene in C. vulgaris led to an increase in total carbohydrate content up to 45.1% (dry cell weight, DCW) in the transgenic line as compared to 34.2% (DCW) in the untransformed control. The starch content improved up to 16% (DCW) in the transgenic alga compared to 10% (DCW) in the control. However, the content of total lipid, carotenoid, and chlorophyll decreased differentially in the transgenic lines. The carbohydrate-rich biomass from the transgenic algal line was used to produce bioethanol via yeast fermentation, which resulted in a higher ethanol yield of 82.82 mg/L as compared to 54.41 mg/L from the untransformed control. The in vitro digestibility of the transgenic algal starch revealed a resistant starch content of up to 7% of total starch. Faster growth of four probiotic bacterial species along with a lowering of the pH of the growth medium indicated transgenic alga to exert a positive prebiotic effect. Taken together, the study documents the utilization of genetically engineered C. vulgaris with enriched carbohydrates as bioethanol feedstock and functional food ingredients.

Breaking barriers: bacterial-microalgae symbiotic systems as a probiotic delivery system

The gut microbiota is one of the essential contributors of the pathogenesis and progress of inflammatory bowel disease (IBD). Compared with first-line drug therapy, probiotic supplementation has emerged as a viable and secure therapeutic approach for managing IBD through the regulation of both the immune system and gut microbiota. Nevertheless, the efficacy of oral probiotic supplements is hindered by their susceptibility to the gastrointestinal barrier, leading to diminished bioavailability and restricted intestinal colonization. Here, we developed a bacteria-microalgae symbiosis system (EcN-SP) for targeted intestinal delivery of probiotics and highly effective treatment of colitis. The utilization of mircroalge Spirulina platensis (SP) as a natural carrier for the probiotic Escherichia coli Nissle 1917 (EcN) demonstrated potential benefits in promoting EcN proliferation, facilitating effective intestinal delivery and colonization. The alterations in the binding affinity of EcN-SP within the gastrointestinal environment, coupled with the distinctive structural properties of the SP carrier, served to overcome gastrointestinal barriers, minimizing transgastric EcN loss and enabling sustained intestinal retention and colonization. The oral administration of EcN-SP could effectively treat IBD by reducing the expression of intestinal inflammatory factors, maintaining the intestinal barrier and regulating the balance of gut microbiota. This probiotic delivery approach is inspired by symbiotic interactions found in nature and offers advantages in terms of feasibility, safety, and efficacy, thus holding significant promise for the management of gastrointestinal disorders.

Potential Prebiotic Effect of Inulin-Enriched Pasta after In Vitro Gastrointestinal Digestion and Simulated Gut Fermentation

In the current study, the prebiotic potential of an innovative functional pasta enriched with 12% (w/w) inulin was investigated. To this aim, pasta was subjected to in vitro gastrointestinal digestion followed by simulated gut fermentation compared to the control pasta (CTRL) not containing inulin. The incorporation of inulin positively (p < 0.05) affected some organoleptic traits and the cooking quality of the final product, giving an overall score significantly higher than CTRL. The resultant essential amino acid content was similar in both pasta samples while the total protein content was lower in inulin-enriched pasta for the polymer substitution to durum wheat flour. The prebiotic potential of chicory inulin was preliminarily tested in in vitro experiments using seven probiotic strains and among them Lacticaseibacillus paracasei IMPC2.1 was selected for the simulated gut fermentation studies. The positive prebiotic activity score registered with the probiotic strain suggested the suitability of the inulin-enriched pasta with respect to acting as a prebiotic source favoring the growth of the probiotic strain and short chain fatty acid (SCFA) production. The present study contributes to broadening knowledge on the prebiotic efficacy of inulin when incorporated into a complex food matrix.

Extraction, Characterisation and Evaluation of Antioxidant and Probiotic Growth Potential of Water-Soluble Polysaccharides from Ulva rigida Macroalgae

Ulva rigida green macroalgae contain a variety of polysaccharides. A recent study investigated the optimum concentration and yield of polysaccharide extraction from oven-dried U. rigida biomass using a water-soluble polysaccharide extraction method that adhered to safety standards. This study utilised complete factorial experiments to examine the effects of varying factors on polysaccharide extraction. Results showed a positive correlation between increased levels of all factors and higher polysaccharide extraction yield. This study also found that the main factors and their interaction had a significant impact on the extracted polysaccharides from U. rigida. The highest polysaccharide content and yield were 9.5 mg/mL and 189 mg/g, respectively. Water-soluble polysaccharides demonstrated the presence of reducing sugar (8 mg/g), phenolics (0.69 mg/g) and flavonoids (1.42 mg/g) and exhibited antioxidant properties. Results revealed that freeze-dried polysaccharide powders were primarily composed of the monosaccharide rhamnose. Preliminary results on the effect of these powders on probiotics demonstrated that supplementation of polysaccharides from U. rigida promoted viable Lactobacillus rhamnosus ATCC 53103 growth during cultivation. This discovery has the potential to revolutionise the human food industry and promote the development of functional ingredients for novel and future food products, with numerous applications in the nutraceutical and pharmaceutical industries.

Emerging microalgal feed additives for ruminant production and sustainability

The global demand for animal-derived foods has led to a substantial expansion in ruminant production, which has raised concerns regarding methane emissions. To address these challenges, microalgal species that are nutritionally-rich and contain bioactive compounds in their biomass have been explored as attractive feed additives for ruminant livestock production. In this review, we discuss the different microalgal species used for this purpose in recent studies, and review the effects of microalgal feed supplements on ruminant growth, performance, health, and product quality, as well as their potential contributions in reducing methane emissions. We also examine the potential complexities of adopting microalgae as feed additives in the ruminant industry.

Protein hydrolysate and oil from fish waste reveal potential as dog food ingredients

The increased fish consumption by the growing human population in the world translates into an increase in fish waste. The reintroduction of these fish by-products into food and feed chains presents economic benefits and contributes to counteracting their negative environmental impact. Under this context, the present study aimed to evaluate the effects of the dietary inclusion of fish hydrolysate and oil obtained from fish waste (experimental diet) in substitution of shrimp hydrolysate and salmon oil (control diet) mainly imported from third countries on palatability, apparent total tract digestibility, fecal characteristics and metabolites, blood fatty acid profile, flatulence, and coat quality of adult dogs. A two-bowl test was performed to evaluate palatability by the pairwise comparison between the two diets. A feeding trial was conducted according to a crossover design with two diets (control and experimental diets), six adult Beagle dogs per diet, and two periods of 6 weeks each. The replacement of shrimp hydrolysate and salmon oil with fish hydrolysate and oil did not affect the first diet approach and taste, as well as the intake ratio. Generally, the digestibility of dry matter, nutrients, and energy was not affected by diet, but the intake of digestible crude protein (CP) and ether extract was higher, respectively, with the control and the experimental diet. The higher intake of eicosapentaenoic acid and docosahexaenoic acid with the experimental diet was reflected in a higher content of these long-chain polyunsaturated fatty acids and the omega-3 index of red blood cells, but it did not affect coat quality. The significantly higher intake of digestible CP with the control diet might have contributed to the higher fecal ammonia-N and valerate concentrations. Daily fecal output and characteristics were similar between diets. Overall, results suggest that fish hydrolysate and oil from the agrifood industry might constitute sustainable functional ingredients for dog feeding while adding value for wild fisheries, aquaculture, and fish farming under a circular economy approach and reducing dependence on imports from third countries with a high carbon footprint.

Exploring the modulatory effects of brown seaweed meal and extracts on intestinal microbiota and morphology of broiler chickens challenged with heat stress

Brown seaweed (Ascophyllum nodosum) is known for its prebiotic roles and can improve animal intestinal health by enhancing the growth of beneficial microbes and inhibiting pathogenic ones. However, the gut health-modulatory roles of brown seaweed on chickens challenged with heat stress (HS) are rarely studied. The current study examined the effects of brown seaweed meal (SWM) and extract (SWE) on the ceca microbiota and small intestinal morphology of chickens challenged or unchallenged with HS. Three hundred and thirty-six 1-day-old Ross 308 broiler chicks were randomly assigned to either a thermoneutral (TN; 24 ± 1°C); or HS room (HS; 32-34°C, 8 h/d from d 21 to 27). All birds in each room were randomly allotted to 4 treatments - control (CON), CON + 1 mL/L seaweed extract (SWE) in drinking water, CON + 2 mL/L SWE in drinking water, and CON + 2% seaweed meal (SWM) in feed and raised for 28 d. On d 14 and 28, 12 and 24 birds per treatment group, respectively, were euthanized to collect the ceca content for gut microbiota analysis and small intestinal tissues for morphological examination. On d 14, 2% SWM increased (P = 0.047) the relative abundance of cecal Fecalibacterium and all brown seaweed treatments improved jejunal villus height (VH) and VH:CD compared to the CON diet. On d 28, HS significantly reduced (P < 0.05) ileal VH, VW, and VH:CD, and duodenal VH and VH:CD. Among the HS group, 2% SWM and 2 mL/L SWE significantly increased (P < 0.05) the relative abundance of Lactobacillus, Sellimonas, and Fournierella, compared to the CON diet. HS birds fed with 2% SWM had higher ileal VH and VH:CD compared to other treatments. In summary, SWM and SWE enhanced the abundance of beneficial microbes and improved small intestinal morphology among HS chickens. This implies that seaweed could potentially alleviate HS-induced intestinal impairment in chickens.

Advances in oligosaccharides production from brown seaweeds: extraction, characterization, antimetabolic syndrome, and other potential applications

Brown seaweeds are a promising source of bioactive substances, particularly oligosaccharides. This group has recently gained considerable attention due to its diverse cell wall composition, structure, and wide-spectrum bioactivities. This review article provides a comprehensive update on advances in oligosaccharides (OSs) production from brown seaweeds and their potential health applications. It focuses on advances in feedstock pretreatment, extraction, characterization, and purification prior to OS use for potential health applications. Brown seaweed oligosaccharides (BSOSs) are extracted using various methods. Among these, enzymatic hydrolysis is the most preferred, with high specificity, mild reaction conditions, and low energy consumption. However, the enzyme selection and hydrolysis conditions need to be optimized for desirable yield and oligosaccharides composition. Characterization of oligosaccharides is essential to determine their structure and properties related to bioactivities and to predict their most suitable application. This is well covered in this review. Analytical techniques such as high-performance liquid chromatography (HPLC), gas chromatography (GC), and nuclear magnetic resonance (NMR) spectroscopy are commonly applied to analyze oligosaccharides. BSOSs exhibit a range of biological properties, mainly antimicrobial, anti-inflammatory, and prebiotic properties among others. Importantly, BSOSs have been linked to possible health advantages, including metabolic syndrome management. Metabolic syndrome is a cluster of conditions, such as obesity, hypertension, and dyslipidemia, which increase the risk of cardiovascular disease and type 2 diabetes. Furthermore, oligosaccharides have potential applications in the food and pharmaceutical industries. Future research should focus on improving industrial-scale oligosaccharide extraction and purification, as well as researching their potential utility in the treatment of various health disorders.[Figure: see text].

Evaluating the Prebiotic Properties of Agar Oligosaccharides Obtained from the Red Alga Gracilaria fisheri via Enzymatic Hydrolysis

Currently, the demand in the food market for oligosaccharides with biological activities is rapidly increasing. In this study, agar polysaccharides from Gracilaria fisheri were treated with β-agarases and hydrolyzed to agar oligosaccharides (AOSs). High-performance anion-exchange chromatography/pulsed amperometric detection (HPAEC-PAD), Fourier-transform infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC), were employed to analyze the chemical characteristics of AOSs. The FT-IR spectra revealed that the enzymatic hydrolysis had no effect on specific functional groups in the AOS molecule. To investigate the prebiotic and pathogen inhibitory effects of AOSs, the influence of AOSs on the growth of three probiotic and two pathogenic bacteria was examined. The gastrointestinal tolerance of probiotics in the presence of AOSs was also investigated. AOSs enhanced the growth of Lactobacillus plantarum by 254%, and inhibited the growth of Bacillus cereus by 32.80%, and Escherichia coli by 58.94%. The highest survival rates of L. plantarum and L. acidophilus were maintained by AOSs in the presence of α-amylase and HCl under simulated gastrointestinal conditions. This study demonstrates that AOSs from G. fisheri exhibit potential as a prebiotic additive in foods.

Effects of microalgae, with or without xylanase supplementation, on growth performance, organs development, and gut health parameters of broiler chickens

Microalgae are becoming potential sustainable feed ingredients, whereas terrestrial feedstuffs are becoming scarce and costly. They are rich in nutritional and functional values but have lower digestibility. This study evaluated the effects of microalgae with or without xylanase supplementation on growth performance and gut health of broiler chickens. A total of 162-day-old Cobb 500 chicks were raised for 35 d. Birds were fed with either 1 of the 3 dietary treatments: 1) corn-soybean meal-based diet (CON), 2) CON + 3% microalgae (MAG), and 3) MAG + xylanase (MAG+XYN) in 2 phases (starter: d 0-21 and finisher: d 22-35) in mash form. Each dietary treatment had 6 replicates, with 9 birds in each replicate. The level of significance was considered at the P value <0.05. The BW, ADG, and ADFI were significantly higher in MAG by 50%, 52.5%, and 42.4%, respectively, and MAG+XYN by 44.1%, 49.7%, and 38.6%, respectively, compared to the CON group. No significant difference was observed for FCR; however, FCR was reduced by 6.3% in both MAG and MAG+XYN groups compared to the CON group. The carcass and organ weight relative to the total body weight were not significantly different among the treatments. The expressions of Zonula occludens 1 (ZO1), Cluster of differentiation 56 (CD56), and Solute carrier family 7 member 7 (SLC7A7) were significantly modulated, for example, by 3.7, 3.9, and 3.3 folds, respectively, in the MAG group compared to CON and 0.8, 0.6, and 1.1 folds, respectively, in the MAG group compared to MAG+XYN groups on d 35. Villi surface area (VSA) of ileum tended to increase on d 3 (P = 0.0725) and d 35 (P = 0.0785) in the MAG and MAG+XYN groups, compared to the CON group. The results suggest that adding microalgae with or without xylanase to broiler's diet could promote growth performance and show a tendency to improve gut health parameters. The nutrient profile and its functional properties make microalgae a valuable resource to the poultry industry as a part substitution of corn and soybean meal and a functional feed supplement to modulate the gut health of broilers.

Sustainable mixotrophic microalgae refinery of astaxanthin and lipid from Chlorella zofingiensis

Microalgal astaxanthin possesses numerous bioactivities and has several health applications. The current research focuses on designing and optimizing the two-stage mixotrophic bioprocess by Chlorella zofingiensis for astaxanthin production. Gradual increase in light intensity (4-8k-lux) and 3x micronutrient concentration were the key parameters for maximizing biomass yield of 2.5 g/L during 15 days of stage I. Furthermore, stress conditions (excessive CO2, light, salinity, etc.) enhanced astaxanthin yield at stage II. 20k lux light, 3x nutrients, and 5% CO2 were the best ranges for maximum astaxanthin production. Maximum biomass yield and astaxanthin content were 3.3 g/L and 16.7 mg/g, respectively, after 29 days of bioprocess. Astaxanthin biosynthesis was also affected by salinity, but less than other parameters. Astaxanthin bioprocess resulted in enhanced lipid yields of 35-37%, which could be used for biodiesel. This study shows promising scale-up potential with attractive sustainability features of Chlorella zofingiensis model for commercial astaxanthin-lipid biorefinery.

Effects of microalgae as dietary supplement on palatability, digestibility, fecal metabolites, and microbiota in healthy dogs

The current trend of dog owners increasingly favoring the functional value of food to assure preventive health and wellbeing of their pets has been raising the interest in microalgae as natural additives with bioactive properties. However, scientific studies addressing the effects of microalgae supplementation in diets for dogs are scarce. This study aimed to evaluate the effects of dietary supplementation with three microalgae species (Chlorella vulgaris, Nannochloropsis oceanica, and Tetradesmus obliquus) on diet palatability, total tract digestibility, metabolizable energy content, fecal metabolites and microbiota of dogs. Twelve adult Beagle dogs were used in three two-bowl tests to compare the palatability of a commercial complete diet for adult dogs without (reference diet) and with 1.5% supplementation of each microalgae. From the results obtained, three digestibility trials were performed according to a replicated Latin square 3 × 3, with six adult Beagle dogs, three experimental periods of 10 days each, and three dietary supplementation levels of microalgae (0.5, 1.0, and 1.5%). In each trial, effects of microalgae supplementation levels on total tract digestibility, metabolizable energy content, fecal metabolites and microbiota of dogs were evaluated. First diet approached or tasted was not significantly affected by microalgae inclusion, but dogs showed a preference for the reference diet over the diets with 1.5% inclusion of C. vulgaris and N. oceanica, no difference being observed with 1.5% T. obliquus. In all digestibility trials, dietary supplementation with microalgae up to 1.5% did not greatly affected the dietary chemical composition and kept unaffected food intake, fecal output and metabolites, and digestibility of nutrients and energy. Compared with the reference diet, supplementation with C. vulgaris increased protein digestibility. Fecal characteristics and metabolites were affected by microalgae supplementation, being the effects dependent on the species. Fecal microbiota composition of dogs fed with microalgae-supplemented diets was modified by promoting the beneficial Turicibacter and Peptococcus genera associated with gut health and activation of the immune system. Overall, the results support C. vulgaris, N. oceanica, and T. obliquus as sustainable functional supplements that potentially enhance gastrointestinal health of dogs through the selective stimulation of microbiota without detrimental effects on food intake and digestibility.

Variability in Macro- and Micronutrients of 15 Rarely Researched Microalgae

Microalgae have enormous potential for human nutrition, yet the European Commission has authorized the consumption of only eleven species. Strains of fifteen rarely researched microalgae from two kingdoms were screened regarding their nutritional profile and value for human health in two cultivation phases. Contents of protein, fiber, lipids, fatty acids, minerals, trace elements and heavy metals were determined. In the growth phase, microalgae accumulated more arginine, histidine, ornithine, pure and crude protein, Mg, Mn, Fe and Zn and less Ni, Mo and I₂ compared to the stationary phase. Higher contents of total fat, C14:0, C14:1_n5, C16:1_n7, C20:4_n6, C20:5_n3 and also As were observed in microalgae from the chromista kingdom in comparison to microalgae from the plantae kingdom (p < 0.05). Conversely, the latter had higher contents of C20:0, C20:1_n9 and C18:3_n3 as well as Ca and Pb (p < 0.05). More precisely, Chrysotila carterae appeared to have great potential for human nutrition because of its high nutrient contents such as fibers, carotenoids, C20:6_n3, Mg, Ca, Mn, Fe, Se, Zn, Ni, Mo and I₂. In summary, microalgae may contribute to a large variety of nutrients, yet the contents differ between kingdoms, cultivation phases and also species.

Xanthophyll-Rich Extract of Phaeodactylum tricornutum Bohlin as New Photoprotective Cosmeceutical Agent: Safety and Efficacy Assessment on In Vitro Reconstructed Human Epidermis Model

The nutritional and health properties of algae make them perfect functional ingredients for nutraceutical and cosmeceutical applications. In this study, the Phaeodactylum tricornutum Bohlin (Phaeodactylaceae), a pleiomorphic diatom commonly found in marine ecosystems, was investigated. The in vitro culture conditions used favoured the fusiform morphotype, characterized by a high accumulation of neutral lipids, as detected by fluorescence microscopy after BODIPY staining. These data were confirmed by HPLC-DAD-APCI-MS/MS analyses carried out on the ethanolic extract (PTE), which showed a high content of xanthophylls (98.99%), and in particular of fucoxanthin (Fx, 6.67 g/100 g PTE). The antioxidant activity (ORAC, FRAP, TEAC and β-carotene bleaching) and photostability of PTE and Fx against UVA and UVB rays were firstly evaluated by in vitro cell-free assays. After this, phototoxicity and photoprotective studies were carried out on in vitro reconstructed human epidermidis models. Results demonstrated that PTE (0.1% Fx) and 0.1% Fx, both photostable, significantly (p < 0.05) reduce oxidative and inflammatory stress markers (ROS, NO and IL-1α), as well as cytotoxicity and sunburn cells induced by UVA and UVB doses simulating the solar radiation, with an excellent safety profile. However, PTE proved to be more effective than Fx, suggesting its effective and safe use in broad-spectrum sunscreens.

A sustainable vanadium bioremediation strategy from aqueous media by two potential green microalgae

Globally, environmental concerns are rapidly growing due to increasing pollution levels. Vanadium is a hazardous heavy metal that poses health issues with an exposure concentration of about 2 ppm. It is regularly discharged by some industries and poses an environmental challenge. There are no sustainable green treatment methods for discharged effluents to mitigate vanadium threats to humans and the environment. In this study, the goal was to develop a green, sustainable method for removing vanadium and to utilize the produced biomass for biofuels, thus offsetting the treatment cost. Microalgae Chlorella sorokiniana SU1 and Picochlorum oklahomensis were employed for vanadium (III) treatment. The maximum removal was 25.5 mg L^-1 with biomass and lipid yields of 3.0 g L^-1 and 884.4 mg L^-1 respectively after 14 days of treatment. The vanadium removal capacity by microalgae was further enhanced up to 2-2.7 folds while optimizing the key parameters, pH, and temperature before removing biomass from the liquid phase. FTIR is used to analyse the reactive groups in algal cell walls to confirm vanadium adsorption and to understand the dominant and quantitative interactions. Zeta potential analysis helps to find out the most suitable pH range to facilitate the ionic bonding of biomass and thus maximum vanadium adsorption. This study addresses regulating external factors for enhancing the removal performance during microalgal biomass harvesting, which significantly enhances the removal of vanadium (III) from the aqueous phase. This strategy aims to improve the removal efficiency of microalgal treatment at an industrial scale for the bioremediation of vanadium and other inorganic pollutants.

Coffee by-products: An underexplored source of prebiotic ingredients

Consumers' demand for foods with high nutritional value and health benefits has fueled the development of prebiotic foods. In coffee industry, cherries transformation into roasted beans generates a large amount of waste/by-products (pulp/husks, mucilage, parchment, defective beans, silverskin and spent coffee grounds) that usually end up in landfills. The possibility to use coffee by-products as relevant sources of prebiotic ingredients is herein ascertained. As a prelude to this discussion, an overview of pertinent literature on prebiotic action was conducted, including on biotransformation of prebiotics, gut microbiota, and metabolites. Existing research indicates that coffee by-products contain significant levels of dietary fiber and other components that can improve gut health by stimulating beneficial bacteria in the colon, making them excellent candidates for prebiotic ingredients. Oligosaccharides from coffee by-products have lower digestibility than inulin and can be fermented by gut microbiota into functional metabolites, such as short-chain fatty acids. Depending on the concentration, melanoidins and chlorogenic acids may also have prebiotic action. Nevertheless, there is still a lack of in vivo studies to validate such findings in vitro. This review shows how coffee by-products can be interesting for the development of functional foods, contributing to sustainability, circular economy, food security, and health.

Bioprocess development to enhance biomass and lutein production from Chlorella sorokiniana Kh12

Present study focused on optimizing bioprocess condition for microalgal lutein production. From previous baseline yields of biomass (3.46 g/L) and lutein (13.7 mg/g), this study examined few key parameters. The 3X:3X ratio macro- and micronutrients was the most affecting parameter with highest biomass and lutein yields of 4.61 g/L and 14.3 mg/g. Temperature 30 °C enhanced the lutein up to 17.3 mg/g but reduced the biomass to 3 g/L. The light effects study showed 10 k lux was most effective for lutein up to 14 mg/g, and effect of increasing salinity (25-75 %) was detrimental. All the above parameters' optimization resulted in a lipid content of 22.5-26.5 %. A maximum lutein productivity and yield of 0.451 mg/L/d and 65.74 mg/L with a 3X:3X macro- and micronutrient ratio was achieved. The Chlorella sorokiniana Kh12 strain exhibited one of the highest yields among recent reports; hence it could be a source for commercial lutein production.

Carbon nanomaterial-treated cell cultures of Nostoc flagelliforme produce exopolysaccharides with ameliorative physio-chemical properties

The feasibility and efficiency of carbon nanomaterials (CNMs) in algal biotechnology are less known. In this study, the influences of four CNMs, graphene (G), graphene oxide (GO), multiwalled carbon nanotube (MWCNT), and aminated multiwalled carbon nanotube (MWCNT-NH₂), on cell growth and exopolysaccharide (EPS) production, as well as the physiochemical properties of EPS, were investigated in cell culture of Nostoc flagelliforme. A proper concentration (15 mg L^-1) of four CNMs was chosen for use after a preliminary test. Upon GO treatment, the biomass was improved by 11.1 % and the EPS production was increased by 36.1 % on day 16 compared to the nontreated control. Four CNM treatments significantly improved cellular O₂·^- and H₂O₂ levels as well as superoxide dismutase and catalase activities. The monosaccharide compositions and functional groups of the EPSs were obviously altered by the CNM treatments. Particularly, the GO treatment-resulting EPS showed obviously improved flocculating ability, water absorption ability, and reactive oxygen species scavenging ability. In general, four CNMs exerted distinct influences on the production and physio-chemical property alteration of the EPS in N. flagelliforme culture. This work expands our understanding of the application of CNMs in the induced production and functional modification of polysaccharides during algal cultivation.

The effect of bitter almond (Amygdalus communis L. var. Amara) gum as a functional food on metabolic profile, inflammatory markers, and mental health in type 2 diabetes women: a blinded randomized controlled trial protocol

BACKGROUND

Using functional foods in the prevention and treatment of type 2 diabetes mellitus (T2DM) has increased across the world owing to their availability, cultural acceptability, and lower side effects. The present study will aim to examine the impact of bitter almond (Amygdalus communis L. var. Amara) gum as a functional food on metabolic profile, inflammatory markers, and mental health in women with T2DM.

METHODS

We will conduct a randomized, triple-blind, placebo-controlled trial. A total of 44 women with T2DM will be randomly allocated into two groups: an intervention group (n = 20) and a placebo group (n = 20). Patients will receive either 5 g/d of bitter melon gum or a placebo for 8 weeks. Clinical and biochemical outcome parameters which include glycemic indices, lipid profile, inflammatory markers, oxidative stress indices, tryptophan (Trp), kynurenine (KYN), cortisol, glucagon-like peptide 1 (GLP-1), leptin, adiponectin, ghrelin, peroxisome proliferator-activated receptor (PPAR) gene expression, brain-derived neurotrophic factor (BDNF), endothelial cell adhesion molecules, plasminogen, cluster deference 4 (CD4), cluster deference 8 (CD8), anthropometric indices, blood pressure, dietary intake, and mental health will be measured at the baseline and end of the study. Statistical analysis will be conducted using the SPSS software (version 24), and P value less than 0.05 will be considered statistically significant.

DISCUSSION

The present randomized controlled trial will aim to investigate any beneficial effects of bitter almond gum supplementation on the cardio-metabolic, immune-inflammatory, and oxidative stress biomarkers, as well as mental health in women with T2DM.

ETHICS AND DISSEMINATION

The study protocol was approved by the Ethical Committee of the Tabriz University of Medical Sciences (IR.TBZMED.REC.1399.726).

TRIAL REGISTRATION

Iranian Registry of Clinical Trials ( www.irct.ir/IRCT20150205020965N7 ).

Advancement in algal bioremediation for organic, inorganic, and emerging pollutants

Rapidly changing bioremediation prospects are key drive to develop sustainable options that can offer extra benefits rather than only environmental remediation. Algal remediating is gaining utmost attention due to its mesmerising sustainable features, removing odour and toxicity, co-remediating numerous common and emerging inorganic and organic pollutants from gaseous and aqueous environments, and yielding biomass for a range of valuable products refining. Moreover, it also improves carbon footprint via carbon-capturing offers a better option than any other non-algal process for several high CO₂-emitting industries. Bio-uptake, bioadsorption, photodegradation, and biodegradation are the main mechanisms to remediate a range of common and emerging pollutants by various algae species. Bioadsorption was a dominant remediation mechanism among others implicating surface properties of pollutants and algal cell walls. Photodegradable pollutants were photodegraded by microalgae by adsorbing photons on the surface and intracellularly via stepwise photodissociation and breakdown. Biodegradation involves the transportation of selective pollutants intracellularly, and enzymes help to convert them into simpler non-toxic forms. Robust models are from the green microalgae group and are dominated by Chlorella species. This article compiles the advancements in microalgae-assisted pollutants remediation and value-addition under sustainable biorefinery prospects. Moreover, filling the knowledge gaps, and recommendations for developing an effective platform for emerging pollutants remediation and realization of commercial-scale algal bioremediation.

Algal biomass to biohydrogen: Pretreatment, influencing factors, and conversion strategies

Hydrogen has gained attention as an alternative source of energy because of its non-polluting nature as on combustion it produces only water. Biological methods are eco-friendly and have benefits in waste management and hydrogen production simultaneously. The use of algal biomass as feedstock in dark fermentation is advantageous because of its low lignin content, high growth rate, and carbon-fixation ability. The major bottlenecks in biohydrogen production are its low productivity and high production costs. To overcome these issues, many advances in the area of biomass pretreatment to increase sugar release, understanding of algal biomass composition, and development of fermentation strategies for the complete recovery of nutrients are ongoing. Recently, mixed substrate fermentation, multistep fermentation, and the use of nanocatalysts to improve hydrogen production have increased. This review article evaluates the current progress in algal biomass pretreatment, key factors, and possible solutions for increasing hydrogen production.

A commercial blend of macroalgae and microalgae promotes digestibility, growth performance, and muscle nutritional value of European seabass (Dicentrarchus labrax L.) juveniles

Algae can leverage aquaculture sustainability and improve the nutritional and functional value of fish for human consumption, but may pose challenges to carnivorous fish. This study aimed to evaluate the potential of a commercial blend of macroalgae (Ulva sp. and Gracilaria gracilis) and microalgae (Chlorella vulgaris and Nannochloropsis oceanica) in a plant-based diet up to 6% (dry matter basis) on digestibility, gut integrity, nutrient utilization, growth performance, and muscle nutritional value of European seabass juveniles. Fish (11.3 ± 2.70 g) were fed with isoproteic, isolipidic, and isoenergetic diets: (i) a commercial-type plant-based diet with moderate fishmeal (125 g kg^-1 DM basis) and without algae blend (control diet; Algae0), (ii) the control diet with 2% algae blend (Algae2), (iii) the control diet with 4% algae blend (Algae4), and (iv) the control diet with 6% algae blend (Algae6) for 12 weeks. The digestibility of experimental diets was assessed in a parallel study after 20 days. Results showed that most nutrients and energy apparent digestibility coefficients were promoted by algae blend supplementation, with a concomitant increase in lipid and energy retention efficiencies. Growth performance was significantly promoted by the algae blend, the final body weight of fish fed Algae6 being 70% higher than that of fish fed Algae0 after 12 weeks, reflecting up to 20% higher feed intake of algae-fed fish and the enhanced anterior intestinal absorption area (up to 45%). Whole-body and muscle lipid contents were increased with dietary algae supplementation levels by up to 1.79 and 1.74 folds in Algae 6 compared to Algae0, respectively. Even though the proportion of polyunsaturated fatty acids was reduced, the content of EPA and DHA in the muscle of algae-fed fish increased by nearly 43% compared to Algae0. The skin and filet color of juvenile European seabass were significantly affected by the dietary inclusion of the algae blend, but changes were small in the case of muscle, meeting the preference of consumers. Overall results highlight the beneficial effects of the commercial algae blend (Algaessence^®) supplementation in plant-based diets for European seabass juveniles, but feeding trials up to commercial-size fish are needed to fully assess its potential.

Microalgae in Terms of Biomedical Technology: Probiotics, Prebiotics, and Metabiotics

Green, red, brown, and diatomic algae, as well as cyanobacteria, have been in the focus of attention of scientists and technologists for over 5 decades. This is due to their importance as efficient and economical producers of food additives, cosmetics, pharmaceuticals, biofertilizers, biofuels, and wastewater bioremediation agents. Recently, the role of microalgae has increasingly been considered in terms of their probiotic function, i.e., of their ability to normalize the functioning of the microbiota of humans and agricultural animals and to produce biologically active substances, including hormones, neurotransmitters, and immunostimulators. A separate brief subsection of the review deals with the potential functions of microalgae with respect to the brain and psyche, i.e., as psychobiotics. Moreover, algal polysaccharides and some other compounds can be broken down to short fragments that will stimulate the development of useful intestinal microorganisms, i.e., function as efficient prebiotics. Finally, many components of microalgal cells and chemical agents produced by them can exert important health-promoting effects per se, which indicates that they are as potentially valuable metabiotics (the term preferred by late Prof. B.A. Shenderov), which are alternatively denoted as postbiotics in the literature.

Nano magnetite assisted flocculation for efficient harvesting of lutein and lipid producing microalgae biomass

For commercial scale algal biorefining, harvesting cost is a major bottleneck. Thus, a cost-effective, less-energy intensive, and efficient harvesting method is being investigated. Among several harvesting methods, magnetic flocculation offers the benefits of modest operation, energy savings and quick separation. This study aims to develop novel magnetite-(Fe₃O₄) nanoparticles (MNPs) of 20 nm average size and their high reusability potential to reduce the harvesting cost of microalgae biomass. The MNPs were synthesized and characterized using FTIR, Zeta analyzer, and SEM before performing on Chlorella sorokiniana Kh12 and Tu5. For maximum harvesting efficiency >99%, the optimal culture pH, MNPs concentration, and agitation speed were 3, 200 mg/L, and 450 rpm, respectively. Subsequently, MNPs were recovered via alkaline treatment and reused up to 5 cycles as they retained their reactivity and harvesting efficiency. The studied MNPs-based harvesting method could be adopted at a commercial scale for cost-effective algae biorefinery in the future.

Impact of dietary Chlorella vulgaris and feed enzymes on health status, immune response and liver metabolites in weaned piglets

In this study, we analysed the impact of dietary inclusion of Chlorella vulgaris and carbohydrases on general health, redox status, immune response, liver lipids and metabolites in weaned piglets. Forty-four male piglets were allocated into four diets: control (n = 11), CH (control diet with 5% CH, n = 10), CH+R (control diet with 5% CH plus 0.005% Rovabio Excel AP, n = 10), and CH+M (control diet with 5% CH plus 0.01% of a pre-selected four-CAZyme mixture, n = 11). After 15 days of trial, animals were slaughtered and samples of blood and liver collected. Spectrophotometry methods and commercial kits were used to determine blood parameters and gas and liquid chromatography for hepatic fatty acid and chlorophylls profiles, respectively. While total, LDL- and VLDL-cholesterol were increased by CH, the opposite was recorded for HDL-cholesterol (p < 0.001). Piglets fed CH-based diets presented an increase of IgG and a decrease of IgM (p < 0.001) which along with lymphocytes exacerbation contributed for piglets' survival after weaning. n-6 PUFA were reduced in piglets fed CH and the opposite occurred for n-3 PUFA (p < 0.001), thus benefiting n-6/n-3 ratio in the liver. Chlorophylls amount was not changed by the use of Rovabio or enzymatic mixture. The discriminant analysis applied to hepatic parameters revealed a clear separation between control and CH-based diets but failed to discriminate feed enzymes. Our findings indicate health promoting effects of CH as feed ingredient in piglets' nutrition at weaning, without negatively impacting on animals' performance.

Biofilm-based delivery approaches and specific enrichment strategies of probiotics in the human gut

The use of probiotics has been one of the effective strategies to restructure perturbed human gut microbiota following a disease or metabolic disorder. One of the biggest challenges associated with the use of probiotic-based gut modulation strategies is to keep the probiotic cells viable and stable during the gastrointestinal transit. Biofilm-based probiotics delivery approaches have emerged as fascinating modes of probiotic delivery in which probiotics show significantly greater tolerance and biotherapeutic potential, and interestingly probiotic biofilms can be developed on food-grade surfaces too, which is ideal for the growth and proliferation of bacterial cells for incorporation into food matrices. In addition, biofilms can be further encapsulated with food-grade materials or with bacterial self-produced biofilms. This review presents a newly emerging and unprecedently discussed techniques for the safe delivery of probiotics based on biofilms and further discusses newly emerging prebiotic materials which target specific gut microbiota groups for growth and proliferation.

Emerging prospects of microbial production of omega fatty acids: Recent updates

Healthy foods containing omega-3/omega-6 polyunsaturated fatty acids (PUFAs) have been in great demand because of their unique dietary and health properties. Reduction in chronic inflammatory and autoimmune diseases has shown their therapeutic and health-promoting effects when consumed under recommended ratio 1:1-1:4, however imbalanced ratios (>1:4, high omega-6) enhance these risks. The importance of omega-6 is apparent however microbial production favors larger production of omega-3. Current research focus is prerequisite to designing omega-6 production strategies for better application prospects, for which thraustochytrids could be promising due to higher lipid productivity. This review provides recent updates on essential fatty acids production from potential microbes and their application, especially major insights on omega research, also discussed the novel possible strategies to promote omega-3 and omega-6 accumulation via engineering and omics approaches. It covers strategies to block the conversion of omega-6 into omega-3 by enzyme inhibition, nanoparticle-mediated regulation and/or metabolic flux regulation, etc.

Assessment of the Effects of Edible Microalgae in a Canine Gut Model

Microalgae are a source of bioactive compounds having recently been studied for their possible application as health-promoting ingredients. The aim of the study was to evaluate in an in vitro canine gut model the effects of four microalgae, Arthrospira platensis (AP), Haematococcus pluvialis (HP), Phaeodactylum tricornutum (PT) and Chlorella vulgaris (CV), on some fecal microbial populations and metabolites. The four microalgae were subjected to an in vitro digestion procedure, and subsequently, the digested biomass underwent colonic in vitro fermentation. After 6 h of incubation, PT increased propionate (+36%) and butyrate (+24%), and decreased total BCFA (−47%), isobutyrate (−52%) and isovalerate (−43%) and C. hiranonis (−0.46 log10 copies/75 ng DNA). After 24 h, PT increased propionate (+21%) and isovalerate (+10%), and decreased the abundance of Turicibacter spp. (7.18 vs. 6.69 and 6.56 log10 copies/75 ng DNA for CTRL vs. PT, respectively); moreover, after 24 h, CV decreased C. coccoides (−1.12 log10 copies/75 ng DNA) and Enterococcus spp. (−0.37 log10 copies/75 ng DNA). In conclusion, the microbial saccharolytic activities and the shift in fecal bacterial composition were less pronounced than expected, based on current literature. This study should be considered as a preliminary assessment, and future investigations are required to better understand the role of microalgae in canine nutrition.

Modulation of rumen bacterial community and feed utilization in camel and sheep using combined supplementation of live yeast and microalgae

The combination of live yeast and microalgae as feed supplementation could improve rumen fermentation and animal productivity. This study aimed to investigate the impact of a mixture of (YA) yeast (Saccharomyces cerevisiae) and microalgae (Spirulina platensis and Chlorella vulgaris) as feed supplementation on feed intake, rumen disappearance of barley straw, bacteria, and fermentation, blood parameters of camels and sheep. Three fistulated camels and three fistulated rams were fed a concentrates mixture and ad libitum barley straw as a basal diet alone or supplemented with YA mixture. The dietary supplementation improved the feed intake, rumen disappearance of barley straw nutrients, and the blood immunity parameters. The YA supplementation affected rumen fermentation as well as the composition and diversity of rumen bacteria; however, the response to the supplementation varied according to animal species. Principle Coordinate Analysis (PCoA) separated bacterial communities based on animal species and feeding treatment. Phylum Bacteroidetes and Firmicutes dominated the bacterial community; and the dominant genera were Prevotella, RC9_gut_group, Butyrivibrio, Ruminococcus, Saccharofermentans, Christensenellaceae_R-7_group, and Succiniclasticum. Our results suggest positive impacts of YA supplementation in rumen fermentation and animal performance.

Euglena gracilis Promotes Lactobacillus Growth and Antioxidants Accumulation as a Potential Next-Generation Prebiotic

Euglena gracilis, a single-celled microalga with various trophic growth styles under different cultivation conditions, contains nutrients, such as ß-1,3-glucans, essential amino acids, fatty acids, vitamins, and minerals. It has recently attracted attention as a new health food. Among them, ß-1,3-glucans, paramylon of Euglena, is an insoluble dietary fiber and is well known as an immune booster, attenuator of obesity and diabetes, reducer of acute liver injury, and suppressor of atopic dermatitis, and other chronic inflammatory disorders. Recently, evidence has appeared for the positive health effects of foods, food ingredients, or biochemical compounds derived from several other microalgae, such as Chlorella, Spirulina, Dunaliella, Phaeodactylum, and Pavlova. Until most recently, the prebiotic activity of Euglena and paramylon was reported. Emerging prospects of microalgae as prebiotics were well summarized, but the mechanisms behind the bacterial growth promotion by microalgae are not elucidated yet. Thus, we evaluated the prebiotic prospects of both autotrophic and heterotrophic Euglena on six different Lactobacillus. What’s more, the stimulated mechanism was revealed by bacterial culture medium metabolomic analysis. This study could widen the knowledge about the prebiotic activity of Euglena as a next-generation prebiotic and other microalgae-derived compounds as potential health foods.

Alternative Proteins for Fish Diets: Implications beyond Growth

Aquaculture has been challenged to find alternative ingredients to develop innovative feed formulations that foster a sustainable future growth. Given the most recent trends in fish feed formulation on the use of alternative protein sources to decrease the dependency of fishmeal, it is fundamental to evaluate the implications of this new paradigm for fish health and welfare. This work intends to comprehensively review the impacts of alternative and novel dietary protein sources on fish gut microbiota and health, stress and immune responses, disease resistance, and antioxidant capacity. The research results indicate that alternative protein sources, such as terrestrial plant proteins, rendered animal by-products, insect meals, micro- and macroalgae, and single cell proteins (e.g., yeasts), may negatively impact gut microbiota and health, thus affecting immune and stress responses. Nevertheless, some of the novel protein sources, such as insects and algae meals, have functional properties and may exert an immunostimulatory activity. Further research on the effects of novel protein sources, beyond growth, is clearly needed. The information gathered here is of utmost importance, in order to develop innovative diets that guarantee the production of healthy fish with high quality standards and optimised welfare conditions, thus contributing to a sustainable growth of the aquaculture industry.

Emerging trends of microbial technology for the production of oligosaccharides from biowaste and their potential application as prebiotic

Oligosaccharides are the sugars made up of 3-10 saccharides units and one of the classes of prebiotics obtained from various biowastes. These biowastes could include rice straw, husk, spent coffee grounds, sugarcane bagasse, spent tea leaves, fruits and vegetables peel, corn stalk, corn stover, deoiled meals and brewer's spent grains etc., which can be used as a resource for oligosaccharides production. This review aims to provide a comprehensive overview of the suitability of different biowaste resources for oligosaccharide production followed by critical analysis of the recent updates and production methods. The review also discusses the tremendous prebiotic potential of oligosaccharides in food applications with prospects for further advancements in the field.

Algae as an emerging source of bioactive pigments

Algae have been identified as natural producer of bioactive commercial pigments. To perform photosynthesis, algae use pigments to harvest sunlight energy. The pigments found in algae are categorized in chlorophylls, phycobilins, and carotenoids. Popular carotenoids include astaxanthin, lutein,fucoxanthin, canthaxanthin, zeaxanthin, β-cryptoxanthin and finds application as antioxidant, anti-inflammatory, immunoprophylactic, antitumor activities among others. Due to double-bonds in their structure, they exhibit broad health applications while protecting other molecules from oxidative stress induced by active radicals using various mechanisms. These carotenoids are synthesized by certain species as major products however they also present as byproducts in several species based on the pathway and genetic capability. Haematococcus pluvialis and Chlorella zofingiensis are ideal strains for commercial astaxanthin production. This review provides recent updates on microalgal pigment production, extraction, and purification processes to standardize and analyze for commercial production. Also, discussed the factors affecting its production, application, market potential, bottlenecks, and future prospects.

Bioprospecting of marine microalgae from Kaohsiung Seacoast for lutein and lipid production

A bioprospecting study was conducted from Seawater samples collected at Kaohsiung Seacoast, Taiwan. The current research was aimed to isolate potential lutein-producing strain, evaluate and optimize the best cultivation mode, lutein accumulation stage, lutein-extraction method, and condition to recover maximum lutein (main product) and lipid (byproduct). Biorefinery is the latest approach worldwide to extract multi-products for cost-effectiveness. Selected isolate among several isolates, identified as Chlorella sorokiniana Kh12 and exploited under biorefinery concept for lutein and lipid extraction. Kh12 cultivated under mixotrophy: 2X-(HT)-9k yielded maximum biomass (3.46 g L^-1) and lutein (13.69 mg g^-1) which is among the higher yields reported so far. Among various tested solvents, methanol was the best extractor. Bead milling was most effective to disrupt algal cell walls, seven minutes of milling was best for maximum lutein (7.56 mg g^-1) extraction. Kh12 could be a promising candidate for commercial lutein and lipid co-production based on the outcome.

Assessment of the Resource Potential of Baltic Sea Macroalgae

The excess biomass of drifting algae and their casting to the Baltic Sea coast imposes a significant environmental burden. The analysis of beach-cast algae showed that the dominant species are macroalgae Ulva sp., Furcellaria lumbricalis, Cladophora sp., and Polysiphonia fucoides. The biomass of Furcellaria and Polysiphonia algae, containing 25.6% and 19.98% sugars, respectively, has the greatest resource potential in terms of obtaining carbohydrates. Fucose, glucose, and galactose were found to be the most common carbohydrates. The lipid content did not exceed 4.3% (2.3–4.3%), while the fatty acid composition was represented by saturated fatty acids (palmitic, stearic, methyloleic, behenic, etc.). The highest content of crude protein was found in samples of macroalgae of the genus Polysiphonia and amounted to 28.2%. A study of the elemental composition of drifting algae revealed that they have a high carbon content (31.3–37.5%) and a low hydrogen (4.96–5.82%), and sulfur (1.75–3.00%) content. Red algal biomass has the most resource potential in terms of biofuel generation, as it has a high number of lipids and proteins that can produce melanoidins during hydrothermal liquefaction, enhancing the fuel yield. The study noted the feasibility of using the biomass of the studied algae taxa to produce polysaccharides and biofuels. The analyses of antioxidant properties, fat content, and fat composition do not provide convincing evidence of the viability of using the aforementioned macroalgae for their production.

Microalgae Bioactive Carbohydrates as a Novel Sustainable and Eco-Friendly Source of Prebiotics: Emerging Health Functionality and Recent Technologies for Extraction and Detection

There is a global interest in the novel consumption, nutritional trends, and the market of new prebiotic sources and their potential functional impacts. Commercially available nutritional supplements based on microalgae that are approved to be edible by FDA, like Arthrospira platensis (Cyanobacteria) and Chlorella vulgaris (Chlorophyta) become widely attractive. Microalgae are rich in carbohydrates, proteins, and polyunsaturated fatty acids that have high bioactivity. Recently, scientists are studying the microalgae polysaccharides (PS) or their derivatives (as dietary fibers) for their potential action as a novel prebiotic source for functional foods. Besides, the microalgae prebiotic polysaccharides are used for medication due to their antioxidant, anticancer, and antihypertensive bioactivities. This review provides an overview of microalgae prebiotics and other macromolecules' health benefits. The phytochemistry of various species as alternative future sources of novel polysaccharides were mentioned. The application as well as the production constraints and multidisciplinary approaches for evaluating microalgae phytochemistry were discussed. Additionally, the association between this potential of combining techniques like spectroscopic, chromatographic, and electrochemical analyses for microalgae sensation and analysis novelty compared to the chemical methods was emphasized.

Evaluation of Nutraceutical Properties of Eleven Microalgal Strains Isolated from Different Freshwater Aquatic Environments: Perspectives for Their Application as Nutraceuticals

The increasing global population and the simultaneous growing attention to natural, sustainable, and healthier products are driving the food industry towards research on alternative food sources. In this scenario, microalgae are gaining worldwide attention as "functional feedstocks" for foods, feeds, supplements, and nutraceutical formulations, being a source of high-value metabolites including polyphenols and other antioxidant compounds. In this work, eleven microalgal strains from freshwater environments were evaluated for their nutraceutical properties, focusing on photosynthetic pigments, total polyphenols, and flavonoid content, as well as in vitro antioxidant activities. Data helped to select those strains showing the most promising features for simultaneous massive growth and bioactive compound production. Results highlighted that the microalgae have variable values for both biochemical parameters and antioxidant activities, mainly depending on the solvents and applied treatment rather than on the isolation sources or the phylogenetic attribution. According to our results, the putative best candidates for massive cultivation under laboratory conditions for the simultaneous extraction of different molecules with nutraceutical potential are strains F1 (Scenedesmaceae), F3 (Chlamydomonas debariana), R1 (Chlorella sorokiniana), and C2 (Chlorella-like).