As nature’s “green gold”, microalgae address sustainability & environmental protection challenges.1 The use of microalgae in animal nutrition sector is attracting a fast-growing interest because of their unique properties and capabilities for health promotion and environmental protection.
Scientific Affairs Manager
AstaReal Sweden
WHAT ARE MICROALGAE?
Alga is defined as a simple, non-flowering, and typically aquatic plant that contains chlorophyll but has no true stems, roots, and leaves. More than 70,000 different algae species have been identified worldwide (European Algae Biomass Association, 2021), ranging from giant kelp (large seaweeds belong to multicellular macroalgae family) to unicellular microalgae.
Microalgae are microscopic organisms found in both seawater and freshwater. They can be classified as eukaryotic microorganisms or prokaryotic cyanobacteria (blue-green algae), with more than 25,000 species already isolated and identified.2
MICROALGAE IN NATURE
Microalgae play a vital role in aquatic ecosystems being the foundation of the food chain for all aquatic organisms. They perform photosynthesis, which is an important natural mechanism to reduce the atmospheric carbon dioxide concentration through converting sunlight, water and CO2 to algal biomass and oxygen. It is estimated that these single-celled microorganisms produce most of the oxygen we breathe. They are also able to lower the concentrations of nitrogen and phosphorus in wastewater and help tackling the environmental pollution and climate change.
AN UNTAPPED NATURAL RESOURCE FOR ANIMAL NUTRITION
Microalgae cultivation benefits from a short generation time as the microorganisms can multiply exponentially under favorable environmental conditions. However, of the several thousand microalgae species, only a few dozen are currently commercialized. Microalgae are considered as indispensable resources for food, bioactives, nutraceuticals, pigments, bioenergy molecules, biofertilizers, and agents for bioremediation.3 The main applications of microalgae are summarized in Figure 1.2
Future success of animal nutrition industry in sustainably safeguarding the animals’ food security depends on utilization of innovative feed resources which do not compete with human food.
Carole Anne Llewellyn, Professor in Applied Aquatic Bioscience at Swansea University believes that in order to meet our global climate change targets and achieve a sustainable equilibrium, we need to work towards a circular economy that eliminates waste and pollution, keeps materials in circulation and regenerates nature. This must replace our existing linear “use and discard” model which has led to unbalanced nutrient cycles.1 Food and feed industries are playing a significant role in this matter.
Given the negative impact of conventional animal feed sources, such as soy, on climate and forested lands, alternative solutions are highly sought-after. So, the use of microalgae in animal nutrition sector is attracting a fast-growing interest because of their unique properties and capabilities for health promotion and environmental protection.
The key factors driving today’s interest in microalgae and its derivatives include microalgae’s high yield of healthful macro- and micro-nutrients such as carotenoids, its rapid accumulation of biomass, and its non-competing nature with crops for arable land.3 Adding to those is the growing market demand for natural, sustainable, plant-based, environmental- and planet-friendly food and feed solutions.
MICROALGAE AS RICH SOURCE OF HEALTHFUL PHYTONUTRIENTS
Carotenoids are a class of bioactive natural molecules synthesized by plants and certain photosynthetic microorganisms, like microalgae. They are an essential component due to their eminent photoprotective and antioxidant properties.
Astaxanthin is a reddish pigment from the xanthophyll carotenoids family responsible for the red-orange color of a number of marine animals and microorganisms like salmon, crabs, krill, lobsters, and even flamingos. It has a potent antioxidant and anti-inflammatory activity, higher than most other commonly known antioxidants. For instance, it has been shown that natural astaxanthin is 110 times stronger than vitamin E and 6000 times stronger than vitamin C in quenching free radicals and so protecting the cells from oxidative stress.4 It is also shown that natural astaxanthin has a 20-fold higher antioxidant potency than synthetic astaxanthin.5
In marine environments, algae rich in astaxanthin is a food for zooplankton which in turn is ingested by fish (e.g. salmonids) and exoskeleton-bearing creatures (e.g. crabs, crayfish, lobsters, krill and shrimp).6
Natural astaxanthin´s color has physical and biological functions in the animal kingdom. It protects animals in the peak of their struggle against harsh environmental conditions. In salmon, for instance, astaxanthin is thought to play an important role during their exhaustive upstream migration.
The unicellular green microalgae Haematococcus pluvialis are known as the richest source of natural astaxanthin. They can be found in freshwater bodies that dry out periodically, like the rock pools in Stockholm (Sweden) archipelago. H. pluvialis accumulates high astaxanthin content under stress conditions such as high salinity, nitrogen deficiency, high temperature and light.7 In this situation, the green algae turn red. Astaxanthin protects the algae’s DNA, lipids and cell structure from UV radiation and other sources of free radicals during the whole dormant period. In this form the algae can survive for months or even years until the environment conditions improve again – this highlights the power of natural astaxanthin for increasing the chance of survival.
However, the health benefits of astaxanthin are not limited to better survival rates. Its benefits have been scientifically proven for various bodily organs and systems, including muscles, eyes, brain, skin, immune and reproductive systems, etc.
With the increasing awareness about the potential health benefits and safety of natural astaxanthin, its commercial use in various industries, such as aquaculture, food and feed, cosmetics, nutraceuticals, and pharmaceuticals are expanding rapidly.
The most common use of commercially produced astaxanthin is in fish farming (aquaculture) where it imparts the natural, pink-red color to farmed salmonids and crustaceans. However, a wide range of animals, including pets and animals in competitive sports (e.g. race horses), and agriculture (livestock) can benefit from this potent natural ingredient.
HEALTH BENEFITS OF NATURAL ASTAXANTHIN
AstaReal as the global pioneer and expert in microalgae cultivation, natural astaxanthin production, R&D and clinical science is an authority in both animal and human food supplements. It is the only brand of natural astaxanthin backed by over 70 clinical studies. AstaReal AB (Sweden) offers its well-studied natural astaxanthin products for animal nutrition in different formats.
AstaReal’s H. pluvialis algal flour (biomass that is the crushed and spray-dried aplanospores of microalga) is not only rich in astaxanthin, but also contains valuable proteins, carbohydrates, and essential fatty acids, as well as other carotenoids including lutein, beta-carotene, and canthaxanthin that provide additional health values.
Health benefits of its natural astaxanthin has been studies in different animal categories.
In a study by Zanghi et al. on dogs, astaxanthin has shown a significant effect on muscle recovery through facilitating carbohydrate sparing and promoting lipid utilization in muscles during exercise.8
In another study on dogs suffering from an inflammatory eye condition, the dogs were fed an antioxidant/anti-inflammatory nutraceutical diet containing natural astaxanthin for 60 days. The diet appeared to significantly increase the eye’s tear production and to clinically ameliorate the inflammation status as well as the corneal keratinization, corneal pigment density and mucus discharge in these dogs that were initially poorly responsive or unresponsive to immune-suppressive therapy.9
In addition, Sato et al. studied the effects of dietary supplementation with astaxanthin (75 mg/day) and L-carnitine (3,000 mg/day) for eight weeks on serum markers and clinical incidence rate of exercise-induced muscle damage in training Thoroughbred horses.10 Markers of exercise-induces muscle damage (serum creatine kinase[CK] activity) and muscle fatigue (lactate dehydrogenase-5, LDH-5) were significantly lower in the supplemented group of horses. Exertional rhabdomyolysis (tying-up syndrome) is one of the most common muscle disorders occurring in horses either during or immediately after exercising. The clinical signs of this disease are variable, ranging from slight stiffness to immobility, signs of pain, and reluctance to move. These can limit and inhibit the performance of the horse.10 So, it is crucial to prevent or at least ameliorate the burden through safe dietary and non-invasive interventions such as natural astaxanthin supplementation.
Natural astaxanthin supplementation in dogs11 and cats12 could also enhance immune defense and improve immune response.
Moreover, astaxanthin supplementation has been associated with improved fertility13,14, and better growth performance15 in livestock, as well as optimum reproduction, growth, survival and immunocompetence in aquaculture.16,17,18
CURRENT MICROALGAE PRODUCTION AND FUTURE POTENTIAL
Microalgae production volume globally, and in Europe are estimated to be around 30 206, and 182 tons of dry weight per year, respectively. Food supplements and nutraceuticals (24%), cosmetics (24%), and feed (19%) are the main applications of microalgae biomass, contributing together to 67% of the total use.19,20
The scale of microalgal cultivation is currently not big enough to fully substitute the conventional livestock, and animal feed. Therefore, the focus is on the use of microalgae products as food supplements, to improve and maintain the health of variety of animals. The market for algae-based animal feed and ingredients is set to grow rapidly as the techno economic analyses have shown good potential for scale-up and cost reduction of microalgae cultivation.
Microalgae are cultivated by different production methods, such as open pond raceway systems and photobioreactors (PBR). The latter is the most commonly used method in Europe. The disadvantages of open cultivation systems are the increased risk of contamination, lower control of the environmental conditions and greater land and water requirements.20
AstaReal AB uses the indoor PBR technology, which allows for stricter control of the environmental factors and biomass quality with no environmental impurities.
Natural astaxanthin has a wide array of applications and the various ingredient formats that are available in the market, offers a huge possibility for formulating innovative animal food and feed.
References:
1Carole Anne Llewellyn. Microalgae is nature’s ‘green gold’: our pioneering project to feed the world more sustainably. 2022. Accessed on April 28th, 2022 at: https://theconversation.com/microalgae-is-natures-green-gold-our-pioneering-project-to-feed-the-world-more-sustainably-170158
2Vale M A, Ferreira A, Pires J C,Gonçalves A L(2020) CO2 capture using microalgae. In: Mohammad Reza Rahimpour, Mohammad Farsi, Mohammad Amin Makarem (Eds) In Advances in Carbon Capture. Woodhead Publishing, Duxford, pp 381 – 405. ISBN 9780128196571.
3Global Perspectives on Astaxanthin From Industrial Production to Food, Health, and Pharmaceutical Applications. Gokare A. Ravishankar, Ambati Ranga Rao. 2021, Elsevier Inc. ISBN: 978-0-12-823304-7. DOI: https://doi.org/10.1016/C2019-0-01800-6.
4Nishida et al. Quenching Activities of Common Hydrophilic and Lipophilic Antioxidants against Singlet Oxygen Using Chemiluminescence Detection System. Carotenoid Science (2007) Vol.11:16-20.
5Oslan, S.N.H. et al. Bioprocess Strategy of Haematococcus lacustris for Biomass and Astaxanthin Production
Keys to Commercialization: Perspective and Future Direction. Fermentation 2022, 8, 179. https://doi.org/10.3390/fermentation8040179.
6Lim KC et al. (2018), Astaxanthin as feed supplement in aquatic animals. Rev Aquacult, 10: 738-773. https://doi.org/10.1111/raq.12200
7Ambati RR et al. Astaxanthin: Sources, Extraction, Stability, Biological Activities and Its Commercial Applications—A Review. Mar. Drugs 2014, 12, 128-152; doi:10.3390/md12010128.
8Zanghi BM et al.: Effects of postexercise feeding of a supplemental carbohydrate and protein bar with or without astaxanthin from Haematococcus pluvialis to exercise-conditioned dogs. Am J Vet Res. 2015 Apr;76(4):338-50.
9Destefanis S et al.: Clinical evaluation of a nutraceutical diet as an adjuvant to pharmacological treatment in dogs affected by Keratoconjunctivitis sicca. BMC Vet Res. 2016 Sep 22;12(1):214.
10Sato F et al.: Effects of Daily Astaxanthin and L-Carnitine Supplementation for Exercise-Induced Muscle Damage in Training Thoroughbred Horses. Journal of Equine Veterinary Science. 35. 2015.
11Chew BP et al.: Dietary astaxanthin enhances immune response in dogs. Veterinary Immunology and Immunopathology. 2011;140(3-4):199-206.
12Park et al. Astaxanthin stimulates cell-mediated and humoral immune responses in cats. Veterinary Immunology and Immunopathology. 2011;144:455–461.
13Kamada H et al.: Astaxanthin increases progesterone production in cultured bovine luteal cells. J Vet Med Sci. 2017 Jun 29;79(6):1103-1109. Epub 2017 Apr 23.
14Wan FC et al.: Protective effects of astaxanthin on lipopolysaccharide-induced inflammation in bovine endometrial epithelial cells†. Biol Reprod. 2020 Feb 14;102(2):339-347.
15Hosseindoust et al. Muscle Antioxidant Activity and Meat Quality Are Altered by Supplementation of Astaxanthin in Broilers Exposed to High Temperature. Antioxidants 2020, 9, 1032.
16Daly B et al.: Dietary astaxanthin supplementation for hatchery-cultured red king crab, Paralithodes camtschaticus , juveniles. Aquacult Nutr. 2013 Jun;19(3):312–20.
17Li M et al.: Comparison effect of dietary astaxanthin and Haematococcus pluvialis on growth performance, antioxidant status and immune response of large yellow croaker Pseudosciaena crocea. Aquaculture. 2014 Oct;434:227–32.
18Cai M et al.: Dietary Haematococcus pluvialis promotes growth of red swamp crayfish Procambarus clarkii (Girard, 1852) via positive regulation of the gut microbial co-occurrence network. Aquaculture. 2022 Mar;551:737900.
19Janssen et al. Microalgae based production of single-cell protein. Current Opinion in Biotechnology 2022, 75:102705.
20Araújo et al. (2021) Current Status of the Algae Production Industry in Europe: An Emerging Sector of the Blue Bioeconomy. Front. Mar. Sci. 7:626389. doi: 10.3389/fmars.2020.626389.
