ivABSTRACTAlgae, includingseaweeds and microalgae, contribute nearly 30 percent of worldaquaculture production (measured inwetweight), primarily from seaweeds. Seaweeds andmicroalgae generate socio-economic benefits to tens of thousands of households, primarilyin coastal communities,includingnumerous women empowered by seaweed cultivation.Various human health contributions, environmental benefits and ecosystem servicesofseaweeds and microalgaehave drawn increasing attention to untapped potential of seaweedand microalgae cultivation. Highly imbalanced production and consumption acrossgeographic regions implies a great potential in the development of seaweed and microalgaecultivation.Yetjoint efforts of governments, the industry, the scientific community,internationalorganizations,civil societies,and other stakeholdersorexperts are needed torealize the potential. This documentexamines the status and trends of global algaeproduction with a focus on algae cultivation, recognizes the algae sector’s existing andpotential contributions and benefits, highlights a variety of constraints and challenges overthe sector’s sustainable development, and discusses lessons learned and way forward tounlock full potential in algae cultivation and FAO’s roles in the process. From a balancedperspective that recognizes not only the potential of algae but also constraints andchallenges upon the realization of the potential, information and knowledge provided bythis document can facilitate evidence-based policymaking and sector management in algaedevelopment at the global, regional and national levels
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SEAWEEDS AND MICROALGAE: AN OVERVIEW FOR UNLOCKING THEIR POTENTIAL IN GLOBAL AQUACULTURE DEVELOPMENT
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Seaweeds is the name implies to cover the macroscopic plants of the sea except the flowering plants. Most of the seaweeds are attached to rocks and also grow on other plants as epiphytes. Along the coast line of India, seaweeds are abundant where rocky or coral formations occur. This sort of substratum is found in the States of Tamil Nadu and Gujarat and in the vicinity of Bombay, Ratnagiri, Goa, Karwar, Vizhinjam, Varkala, Visakhapatnam and in the Lakshadweep and Andaman-Nicobar Islands. The seaweeds are classified into three important groups namely green, brown and red. Seaweeds contain different vitamins, minerals, trace-elements and proteins. Seaweeds are also a rich source of iodine.
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This article discusses seaweeds, their uses, and their potential uses. Includes tables with values and tonnage of important maricultured seaweeds.
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The total global demand for protein from both humans and livestock will rise substantially into the future due to the combined increase in population and per capita consumption of animal protein. Currently, net protein is primarily produced by agricultural crops. However, the future production of agricultural crops is limited by a finite supply of arable land, fresh water and synthetic fertilisers. Alternative crops such as seaweeds have the potential to help meet the protein demand without applying additional stress on traditional agricultural resources. This thesis investigates the potential of seaweeds as an alternative crop for the production of protein.
Chapter 1 provides a general introduction to the thesis. The chapter begins by introducing the current supply and future demand of protein globally, with a specific focus on the demands of mono-gastric livestock (poultry, swine and fish). This is followed by a summary of potential alternative protein sources that are currently being explored. Finally, seaweeds are introduced in the context of their potential as a biomass crop for the production of protein.
Many seaweed species have considerable plasticity in nitrogen content, yet the relationship between nitrogen content, protein concentration, protein quality and growth rate are poorly understood. Therefore, in Chapter 2, the plasticity in protein content in the green seaweed Ulva ohnoi was investigated. This was done by assessing the quantitative and qualitative changes in protein in Ulva ohnoi and relating these to changes in internal nitrogen content and growth rate. To do this water nitrogen concentrations and water renewal rates were varied simultaneously to manipulating the supply of nitrogen to outdoor cultures of U. ohnoi. Both internal nitrogen content and growth rate varied substantially, and the quantitative and qualitative changes in total amino acids were described in the context of three internal nitrogen states; nitrogenlimited, metabolic, and luxury. The nitrogen-limited state was defined by increases in all amino acids with increasing nitrogen content and growth rates up until 1.2 % internal nitrogen. The metabolic nitrogen state was defined by increases in all amino acids with increasing internal nitrogen content up to 2.6 % with no increases in growth rate. Luxury state was defined by internal nitrogen contents above 2.6 % which occurred only when nitrogen availability was high but growth rates were reduced. In this luxury circumstance, excess nitrogen was accumulated as free amino acids, in two phases. The first phase is distinguished by a small increase in the majority of amino acids up to ≈ 3.3 % internal nitrogen, and the second by a large increase in glutamic acid/glutamine and arginine up to 4.2 % internal nitrogen. This chapter demonstrates that the relationship between internal nitrogen content and amino acid quality is dynamic but predictable, and could be used for holding seaweeds in a desired nitrogen state during culture.
In Chapter 3, I assessed the relative importance of direct and indirect effects of salinity on protein in seaweed. Indirect effects, through altering growth rates, and direct effects, through altering the synthesis of specific amino acids and osmolytes, were examined in the context of the concentration and quality of protein in Ulva ohnoi. To do this, U. ohnoi was cultured under a range of salinities without nutrient limitation. Both the concentration and quality of protein varied across the salinity treatments. Protein concentration was strongly related to the growth rate of the seaweed and was highest in the slowest growing seaweed. In contrast, the quality of protein (individual amino acids as a proportion of total amino acid content) was strongly related to salinity for all amino acids, although this varied substantially amongst individual amino acids. Increases in salinity were positively correlated with the proportion of proline (46 % increase), tyrosine (36 % increase) and histidine (26 % increase), whereas there was a negative correlation with alanine (29 % decrease). The proportion of methionine, with strong links to the synthesis of the osmolyte dimethylsulphonioproprionate (DMSP), did not correlate linearly with salinity and instead was moderately higher at the optimal salinities for growth. This chapter demonstrates that salinity simultaneously affects the concentration and quality of protein in seaweed through both indirect and direct mechanisms, with growth rates playing the overarching role in determining the concentration of protein.
During my investigations into the protein physiology and nutrition of seaweeds, it became evident that there were many inconsistencies and potential inaccuracies with the way protein concentrations are reported. Therefore, in Chapter 4, I assessed these issues on a broad scale by systematically analysing the literature to assess the way that people measure and report protein in seaweeds with the aim to provide an evidence-based conversion factor for nitrogen to protein that is specific to seaweeds. Almost 95 % of studies on seaweeds determined protein either by direct extraction procedures (42 % of all studies) or by applying an indirect nitrogen-to-protein conversion factor of 6.25 (52 % of all studies), with the latter the most widely used method in the last 6 years. Metaanalysis of the true protein content, defined as the sum of the proteomic amino acids, demonstrated that direct extraction procedures under-estimated protein content by 33 %, while the most commonly used indirect nitrogen-to-protein conversion factor of 6.25 overestimated protein content by 43 %. I then questioned whether a single nitrogen-toprotein conversion factor could be used for seaweeds and evaluated how robust this would be by analysing the variation in N-to-protein conversion factors for 103 species across 44 studies that span three taxonomic groups, multiple geographic regions and a range of nitrogen contents. This resulted in an overall median nitrogen-to-protein conversion factor of 4.97 and a mean nitrogen-to-protein conversion factor of 4.76. Based on these results I proposed that the value of 5 be adopted as the universal seaweed nitrogen-to-protein (SNP) conversion factor. This chapter highlighted that most of the quantitative data on the protein contents of seaweeds have been under- or overestimated and was in need of review in regards to the potential applications of seaweed protein.
Therefore, in Chapter 5, seaweeds were quantitatively assessed as a protein source in livestock feeds using the dataset established in Chapter 4 as a platform to compare the quality and concentration of protein to traditional protein sources (soybean meal and fishmeal) and then benchmarking the seaweeds against the amino acid requirements of mono-gastric livestock (chicken, swine and fish). The quality of seaweed protein (% of essential amino acids in total amino acids) is similar to, if not better than, traditional protein sources. However, seaweeds without exception have substantially lower concentrations of essential amino acids, including methionine and lysine, than traditional protein sources (on a whole biomass basis, % dw). Correspondingly, seaweeds in their whole form contain insufficient protein, and specifically insufficient essential amino acids, to meet the requirements of most mono-gastric livestock. This chapter highlights that the protein from seaweeds must be concentrated or extracted, and these techniques are the most important goals for developing seaweeds as alternative source of protein for mono-gastric livestock.
Therefore, in Chapter 6, I examined multiple techniques to isolate and concentrate protein in a seaweed, returning to the model organism the green seaweed Ulva ohnoi. The aim of this chapter was to compare the protein isolation and concentration efficiency of a mechanical-based method (as applied to leaves) to the solvent based method (as applied to seed crops). Protein isolate yields ranged from 12.28 ± 1.32 % to 21.57 ± 0.57 % and were higher using the methods established for leaves compared to those for seeds. Protein isolates from all treatment combinations were ~ 250 – 400 % higher in the concentration of protein and essential amino acids compared to the original whole biomass, reaching a maximum concentration of 56.04 ± 2.35 % and 27.56 ± 1.16 % for protein and total essential amino acids, respectively. In contrast, protein and essential amino acid concentrations were only ~ 30 – 50 % higher in protein concentrates compared to the original whole seaweed, reaching a maximum of 19.65 ± 0.21 % and 9.52 ± 0.11 % for protein and total essential amino acids, respectively. This chapter demonstrated that the methodologies used for the isolation of protein in leaves are more suited to seaweeds than those that are based on seed crops, which have traditionally been applied to seaweeds. This chapter also demonstrated that protein isolation methods are more suited to seaweeds with low concentrations of protein, such as Ulva ohnoi, compared to protein concentration methods.
In summary, the research presented throughout this thesis establishes that seaweeds, irrespective of cultivation conditions and species, are not viable as a protein source for mono-gastric livestock in a whole form and will need to be processed post-harvest to concentrate their protein. Therefore, it is proposed that the most important strategy for developing seaweeds as a protein crop is the development of protein isolates and concentrates from seaweeds produced under intensive cultivation.
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Powdered seaweed or seaweed flour is already used as an ingredient in terrestrial and aquatic feeds. The seaweed is usually a single species and publications over the years have demonstrated a range of benefits - for instance improved resistance to viral and bacterial pathogens.
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Throughout human history, seaweeds have been used as food, folk remedies, dyes, and mineral-rich fertilisers. Seaweeds as nutraceuticals or functional foods with dietary benefits beyond their fundamental macronutrient content, are now a major research and industrial development concept. The occurrence of dietary and lifestyle-related diseases, notably type 2 diabetes, obesity, cancer, and metabolic syndrome has become a health epidemic in developed countries. Global epidemiological studies have shown that countries where seaweed is consumed on a regular basis have significantly fewer instances of obesity and dietary-related disease. This review outlines recent developments in seaweed applications for human health from an epidemiological perspective and as a functional food ingredient.
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Seaweeds are macroalgae, which generally reside in the littoral zone and can be of many different shapes, sizes, colours and composition. They include brown algae (Phaeophyceae), red algae (Rhodophyceae) and green algae (Chlorophyceae). Seaweeds have a long history of use as livestock feed. They have a highly variable composition, depending on the species, time of collection and habitat, and on external conditions such as water temperature, light intensity and nutrient concentration in water. They may contain non-protein nitrogen, resulting in an overestimation of their protein content, and nitrogen-to-protein conversion factors lower than 6.25, normally used for feed ingredients, have been advocated. They contain considerable amount of water. Most essential amino acids are deficient in seaweeds except the sulphur containing amino acids. Seaweeds concentrate minerals from seawater and contain 10-20 times the minerals of land plants. They contain only small amounts of lipids (1-5%), but majority of those lipids are polyunsaturated n-3 and n-6 fatty acids. Brown seaweeds have been more studied and are more exploited than other algae types for their use in animal feeding because of their large size and ease of harvesting. Brown algae are of lesser nutritional value than red and green algae, due to their lower protein content (up to approx. 14%) and higher mineral content; however brown algae contain a number of bioactive compounds. Red seaweeds are rich in crude protein (up to 50%) and green seaweeds also contain good protein content (up to 30%). Seaweeds contain a number of complex carbohydrates and polysaccharides. Brown algae contain alginates, sulphated fucose-containing polymers and laminarin; red algae contain agars, carrageenans, xylans, sulphated galactans and porphyrans; and green algae contain xylans and sulphated galactans. In ruminants, step-wise increase in the levels of seaweeds in the diet may enable rumen microbes to adapt and thus enhance energy availability from these complex carbohydrates. In monogastrics, those polysaccharides may impact the nutritional value but the addition of enzyme cocktails might help. In vivo studies on ruminants, pigs, poultry and rabbits reveal that some seaweeds have the potential to contribute to the protein and energy requirements of livestock, while others contain a number of bioactive compounds, which could be used as prebiotic for enhancing production and health status of both monogastric and ruminant livestock. Seaweeds tend to accumulate heavy metals (arsenic), iodine and other minerals, and feeding such seaweeds could deteriorate animal and human health. Regular monitoring of minerals in seaweeds would prevent toxic and other undesirable situations. © 2015 Food and Agriculture Organization of the United Nations.
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Seaweed is characterized by its nutritional composition. They contain protein and dietary fiber in high concentration, along with low fat and calorie intake. They also include bioactive compounds that are beneficial to health. For these reasons, it is incorporation in processed foods is interesting. In bakery and farinaceous foods, seaweed is incorporated as finely ground powder. The foods in which they have been incorporated are bread, noodles, cake, cookies, biscuits, and others. Thus, in general, foods with seaweeds incorporated, increase their content of protein, dietary fiber, total polyphenols, and antioxidant capacity.
Stable mixtures and emulsions are formed between the dough and the seaweed, furthermore, the functional properties improve in the products. Adding seaweeds into a bakery and farinaceous products decreases lightness, redness, and yellowness color parameters.
The sensorial quality is affected by the high concentration of seaweed, mainly flavor. It is being taken very carefully because sensory aspects are the most important for determining acceptability for consumers.
According to studies, the incorporation of seaweed in products should be a maximum of 10% for noodles, 4% for bread, 5% for biscuits, 5% for cookies, less than 10% for cake, and 3.55% in extruded maize.
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Seaweeds are macroalgae, with different sizes, colors and composition. They consist of brown algae, red algae and green algae, which all have a different chemical composition and bioactive molecule content. The polysaccharides, laminarin and fucoidan are commonly present in brown seaweeds, ulvans are found in green seaweeds and, red algae contain a large amount of carrageenans. These bioactive compounds may have several positive effects on health in livestock. In order to reduce the antimicrobials used in livestock, research has recently focused on finding natural and sustainable molecules that boost animal performance and health. The present study thus summarizes research on the dietary integration of seaweeds in swine. In particular the influence on growth performance, nutrients digestibility, prebiotic, antioxidant, anti-inflammatory, and immunomodulatory activities were considered. The review highlights that brown seaweeds seem to be a promising dietary intervention in pigs in order to boost the immune system, antioxidant status and gut health. Data on the use of green seaweeds as a dietary supplementation seems to be lacking at present and merit further investigation.
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There is a truly amazing variery of seaweed, known to scientists as macroalgae, in the waters of Long Island Sound. Unfortunately, many shoreline visitors know seaweed only as "slimy stuff" and never experience the natural symmetry and innate beauty of the large algae. Nor do rhey appreciate the ecological and economic importance of these organisms. Until now, there have nor been many publications available to help the public appreciate and learn about the seaweeds. This guide is intended for the curious beachcomber, rather than rhe biologist, and hopefully will improve the reputation of seaweed in our region.
The Sound has such a rich variety of algae because its variety of habitats, large temperature range, shallow depth, and relatively sheltered geographic location make it an ideal environment for growth. Like the garden plants more familiar to many people, not all of them bloom at the same time. There are some, however, that thrive year-round or nearly so, such as kelp, rockweed, bladder wrack, and Irish moss. Others may appear for days, weeks, or months. About 250 species have been documented in Long Island SOlLl1dby diligent collectors over the years. Some are found in hardto-access places-for example, inside a blade of eelgrass. or within a mollusk shell. The species included here are generally common ones that you may readily encounter, plus a few that have unusual or noteworthy fearures.
Biologists put the large seaweeds into three groups according to their dominanr pigments-Chlorophyta, Phaeophyra, and Rhodophyta-or simply, green, brown, and red. All contain chlorophyll, and carry out photosynthesis, but the green color is masked in orher species by the additional brown or red pigments. These pigments absorb various frequencies of light. The limited light available at various depths in coastal waters determines the depth, or zone, in which the algae can be found. In general. greens are closest to shore, and thus highest in elevation, browns are in the intertidal (=littoral) zone and subtidal zone, and reds both farthest down and farthest from shore. There is of course some overlap.
Most seaweeds attach to rocks or other hard surfaces by means of a structure called a holdfasr, but some float freely or form mats. Seaweeds provide habitat, food, and shelter for a number of aquatic animals. In the process of photosynthesis, they produce oxygen as a byproduct, and thus help to aerate the waters.
The algae are Structurally much more simple than land plants; they do not have true roots, stems, or leaves. They are thouglu to represent the evolutionary ancestors of all the terrestrial plants, however. Despite this simplicity, many seaweeds, particularly the reds, have complex and fascinating life histories and reproductive structures. This guide will not go inro detail on that topic, but the bibiography at the end will assist those who would like ro delve further into rhe subject.
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