by Mark Edwards
lgae provide a sustainable protein source for animal feed, but is it good enough protein? Comprehensive medical and nutritional studies have demonstrated that many different types of algae produce high quality proteins that are comparable to alternative protein sources.
All proteins are not created equal. Proteins are composed of different amino acids. The nutritional quality of a protein is determined by the content, proportion and availability of its amino acids. A good measure, the protein efficiency ratio (PER), is expressed in terms of weight gain per unit of protein consumed by test animals in feeding trials. Another metric, the biological value, (BV), is a measure of nitrogen retained in an animal’s tissues for growth or maintenance.
Digestibility also reflects the quality of a protein, which is measured by the digestibility coefficient (DC). Finally, the net protein utilization (NPU) – equivalent to the calculation BV × DC – is a measure both of the digestibility of the protein and the biological value of the amino acids absorbed from the food.
E.W. Becker’s excellent review article presents these values for popular algae species. E.W. Becker concluded that the average quality of the algae protein was equal, and in many cases superior to conventional plant proteins, including soy.
Algae provide far more than just good protein. Algae deliver a superior breadth of high-quality nutritional compounds, including peptides, carbohydrates, lipids, vitamins, pigments, minerals and trace elements.
Before a new food item is declared safe for human consumption, it must undergo a series of detailed toxicological tests to prove the harmlessness of the product. No serious anomalies have been reported in short-term or long-term feeding experiments, or in studies on acute or chronic toxicity.
Many algae producers in the US have acquired GRAS status, the FDA recognition that the material is Generally Regarded as Safe. The list of food authorized under the provisions of the European Union includes algae as feed material. No commercial GMO algae biofeeds are available today. GMO’s foods or feeds are not allowed in the European Union.
The nutritional contents of algae are rapidly gaining traction as valuable components in animal feed. Algae biofeeds provide a renewable source to substitute the conventional ingredients in animal feed for meat, dairy, poultry and fish.
Algae contain all the vitamins, minerals and micronutrients needed for healthy biofeeds, including Vitamins A, B1, B2, B6, B complex, C, D, and E. Algae are rich in niacin, iodine, potassium, iron, magnesium and calcium. Each cell contains polysaccharides, sugar and starch, as well as iron, sodium, phosphorus, magnesium, copper and calcium. Algae biofeeds deliver nutritional benefits not available from land plants, strong antioxidants such as omega-3 fatty acids. Productivity metrics for algae are extraordinary.
Algae biofeed already grows with substantially more productivity than food grains. Biofeed productivity will probably increase 10x in the next ten years due to innovations in biotechnologies.
Algae biofeeds provide a rich source of high-quality protein, vitamins, micronutrients (trace elements), and carotenoids. Algae also deliver polyunsaturated fatty acids (PUFAs), especially of n-3 and n-6 series such as eicosapentaenoic (EPA), docosahexaenoic (DHA), and arachidonic (AA), which are considered pharmacologically important for animal and human dietetics and therapeutics. Algae produce valuable biomolecules including astaxanthin, lutein, beta carotene, chlorophyll, phycobiliprotein, and beta-1,3-glucan. Several studies explain how each biomolecule enhances animal health.
Most of these valuable algae biomolecules are not synthesized in the animal, (or human) body, but are considered essential for healthy body and brain growth and development. Therefore, animals must get them through their diet. Algae provide both an ideal nutrient package and the delivery system. The algae package is so small it becomes immediately bioavailable to the animal. The algae delivery system provides higher nutralence than conventional animal feed, with significantly higher nutrient quality, density, diversity and bioavailability.
A few limitations are key to understanding why algae biofeeds do not yet dominate the feed market, except in aquaculture. Most of the investment in algae production has gone into biofuel. This has helped algae as nutrition indirectly, because the non-lipid portion of the algae biomass is often considered as biofertilizer or biofeed.
The current cost of conventional animal feeds, food grains, is lower than algae, thanks largely to the substantial subsidies to crops and Big Oil. If those subsidies were removed, and a price put on carbon and ecological degradation, algae biofeed production would be substantially lower cost than conventional feeds. If the true cost of irrigation water were charged to farmers, farmers would immediately switch to algae biofeed.
No books on algae biofeed are available yet, although several excellent review articles on both micro and macroalgae as biofeed have been published. Considerable knowledge has been accumulated for aquaculture, and fish biofeed serve as the primary example here.
Cellular metabolism across animal species enjoys more similarities than differences. However, as with any discipline, the devil is in the details. Different animal life stages, herbivore or carnivore, type of mouth, number of stomachs, gut microbes, digestive and excrement systems, make each animal species idiosyncratic to some degree.
Demand limits algae production today. Without demand for algae biofeeds yet, there are simply no commercial producers. Algae scientists are making substantial progress on producing more and higher quality biomass at lower cost. Demand for algae bioproducts will expand quickly as production costs fall. Feed formulations also limit algae biofeeds. Considerable research suggests algae may provide the best nutritional solution as a supplement rather than replacement to conventional feeds. Certain animals may need time to adapt their digestive system microbes by starting with a partial algae diet. Feed formulations will advance quickly as more food scientists explore the largely unexplored, but rich nutritive value of algae biofeed.
Algae biofeeds will make the biggest impact with omega-3 fatty acids. Algae are the “whole foods” of the ocean, and serve as a natural nutritional source for most fish. Salmon are carnivores, but also eat lots of algae. Their beautiful pink color comes from the astaxanthin that they cannot synthesize themselves, but get from their algae diet. Algae provide similar color and fish oil for krill, shrimp, crabs and lobsters.
Algae biofeeds have already penetrated the aquaculture market. About one-third of the algae produced in 2017 goes to feed fish. Fish farming needs algae biofeed solutions because fish farming puts tremendous strain on wild fish.