Unpredictable soya prices and efforts to improve the livestock industry’s environmental footprint is driving creative thinking in the science of animal feeds, and there is currently a strong focus on the aquatic environment for breakthroughs.
Of the many options available, algae and similar plant-like organisms seem to present a wealth of opportunity, with higher digestibility and solubility than commonly used feed options.
Nutrient profile adds up
Research suggests that there is a wealth of nutrition available from microalgae, which are plankton invisible to the naked eye but can grow into large cultures of biomass. The challenge is to identify the right species to produce, and come up with ways to make useful products in an efficient way. These are issues that are not unique to algae, but often seen in novel feed development.
Research to date suggests its potential as an option to partially replace soybean meal and corn in livestock diets. Producing algae on a large scale also offers the added advantage of providing an environmental clean-up service for when water bodies have been tainted with phosphorus and nitrogen run-off from agriculture, with the algae using the excessive nutrients to multiply.
Work analysing the Picochlorum sp., for example, has revealed a diverse set of nutrients that could be of interest to the feed industry. But there are a range of microalgae species potentially on the menu.
“Which alga strain is best will depend of your main aim. The concentrations will differ but also grow rates and costs,” explained Dr Rommie van der Weide from Wageningen University and Research.
“Furthermore, the cell wall differs between species, making some easier to digest then others. For example, Euglena and Spirulina are easier to digest then Haematococcus, but that is an important source of astaxantine, which is costly ingredient used in some animal feeds.”
Pluses and minuses for prominent species
Spirulina is a name that often appears in scientific research. This blue-green algae is nutritious, high in antioxidants and is likely to have positive effects on creating a health gut microbiome — great starting points for an animal feed.
In tests with poultry, Spirulina has been linked to improved growth, hatchability and egg production, as well as positive impacts on disease resistance.
For this group of species, the route to mainstream acceptance may not be a smooth one, however. Choice tests have shown that chicken fed with Spirulina is generally rejected by consumers due to colour changes in the meat, with insect-fed chicken — never the easiest sell itself— preferred over it.
The idea of a colour-change is no mirage. When replacing a large proportion of soybean meal in bird diets, research has shown the meat to have reddish-yellow tones, and even at 15% inclusion a noticeable change is reported.
Macroalgae and beyond
And so to the macroalgae — multicellular species commonly known as seaweed. Species such as Asparagopsis taxiformis have emerged as a potential dietary option to reduce methane emissions from livestock, but despite positive results and optimistic noises from investors, mass production has yet to take off.
One solution may be to combine relatively low amounts of A. taxiformis with the microalgae Euglena gracilis, according to scientists based in Japan.
Their work involved creating a supplement using both the algal ingredients, which was then fed to Holstein cows. The combination performed better than either ingredient in isolation for reducing methane, while production was not affected.
A review led by Professor John O’Doherty at University College Dublin has suggested that the use of seaweed extracts, as opposed to whole seaweed, may be a better option for weaning pigs. Laminarin, fucoidan, and chitin derivatives should be key areas of focus as alternatives to the use of antibiotics and minerals in rearing the young animals, he noted, but work still needs to be done to establish the most effective ways of extracting these components.
The seas may not be the only source of aquatic feeds of the future. Species from the freshwater fern genus Azolla could have their place, particularly in developing countries due to potentially low production costs. Algae play a role in the potential here, as the plants have a symbiotic relationship with the blue-green alga Anabaena azollae, which concentrates the protein content — a quality always in demand for animal growth.
Questions over supply mechanisms
Whatever type of algae or related organisms rise to prominence in the coming years, establishing appropriate production and distribution networks will be vital in determining whether the products sink or swim in a bustling alternative feeds market.
Some countries may be more suited to a microalgae-as-feed industry than others. Researchers have made a case for Qatar as being one such place. With pressures on food supply, limited land for terrestrial farming but abundant access to the sea and sunshine, the conditions there could be ripe from using natural advantages to bring down production costs. The knowledge is very likely to already be in place in the country, with microalgae used for biofuels and waste water management.
Elsewhere, researchers at Birmingham City University in the UK are currently on a cost-effective production system for microalgae, optimised using mathematical modelling approaches.
In the Netherlands, there are ongoing pilot projects at the Application Centre for Renewable Resources, exploring how local networks for the production of algal products for use in agriculture, said Dr van der Weide. However, given there are very few farms with production facilities on site as yet, it is too early to make conclusions about how well this type of hyper-local supply might work, she added.
European support may bear fruit
Given the evidence to date, Dr van der Weide said there is some likelihood that livestock feed will, in the coming years, contain at least some algal products. The question remains as to just how big a contributor it is likely to be, though developments like €12 million of EU funding to develop algal products in the North Sea and Baltic areas are promising.
“Only a decade ago, the cultivation and use of algae in Europe was very much at the research stage,” said Angela Schultz-Zehden, MD of the funding’s recipients, the SUBMARINER Network.
“Today, many large-scale industry players are highly interested in algae as a new bio-resource to improve the environmental footprint of their products.”
Next stage: turning commercial interest into practical reality.
