Here is evidence azolla is as good as any protein source

Victor Mwamuye

Victor Mwamuye on his azolla farm in Kilifi County. 

Photo credit: File | Nation Media Group

It looks like the story on azolla will not just fade away. This tells us livestock farmers are identifying with the plant’s potential as a cheap source of protein for animal feeds.

This is not surprising because protein is the most expensive component of animal feeds and also the most difficult to obtain.

Soybean is the most common source of protein for animal feeds around the world. The US produces the crop on a very large scale to supply its huge livestock production industry. Kenya grows very little soybean. Most of our supplies come from Uganda, Tanzania and Zambia.

The high cost of transport from these countries and the competition with other export markets makes the product very expensive to Kenyan feed manufacturers.

The high feed manufacturing price inevitably translates to very costly feeds, making livestock production unprofitable especially to the small-scale farmers.

Last week, I discussed the availability of azolla starter stock and how to establish the plant. Many readers have asked me whether there is data on the suitability of azolla as an animal feed.

Yes, the data is available for different species of animals. You may recall the plant is suitable as a feed for all species of livestock. In fact, there are ongoing studies to determine if the fern is suitable for human consumption.

From my knowledge of comparative digestion and animal bio-chemistry, I can bet the plant would be okay as human food. You see, none of the species of animals in which the plant has been tested has shown any adverse effects. Further, all the animals have shown beneficial outcomes when fed with azolla.

Two good indicators of possible suitability as human food are the pigs and fish. Pigs have a digestive system very close to the human one while fish are highly sensitive to poisons. However, no product is used in humans without being tested because despite similarities of humans and other animals, there are still some differences that could render a product unfit for human use.

To answer those farmers and readers who wanted to know if there is scientific data on the suitability of azolla as an animal feed substitute and supplement, I reviewed some publications on research done on the subject.

First, I pronounce a disclaimer that azolla cannot substitute other animal feed protein ingredients like soybean, sunflower and cottonseed cake. It is a supplement for these protein sources. This is because there is no one ingredient with all the required proteins and minerals.

Azolla is very rich in proteins, essential amino acids, vitamins (vitamin A, vitamin B12 and Beta carotene), growth promoter compounds and minerals. It has high levels of calcium, phosphorous, potassium, iron, copper and magnesium. The carbohydrates and fat content is low. The plant is highly digestible because it does not accumulate secondary plant materials such as the woody lignin.

Researchers led by Becerra in 1995, Lumpkin and Plucknett in 1982 and Van Hove and López in 1983 all concluded that azolla is the most-promising aquatic plant for livestock feed due to its ease of cultivation, productivity and nutritive value. Azolla’s use as a feed for fish, swine and poultry was tested and recommended by Alcantara and Querubin in 1985. Tran and Dao in 1979 reported that one hectare of azolla can produce 540-720kg of protein per month.

Poultry, particularly ducks and chickens, can be raised on a diet including fresh azolla. In 1966, Dao and Tran confirmed that azolla has long been recognised as a feed for wildfowl in the US, domesticated ducks in China and domestic fowl in Vietnam.

In 1978 in India, Subudhi and Singh concluded that fresh azolla could replace about 20 per cent of commercial feed in the diet of young chickens. They estimated that around 9kg of fresh azolla would be required daily for 100 chickens to make the replacement.

That amount could be produced in a shallow pond with an area of 60 square metres.

Some feeding trials have shown that 20–25 per cent of commercial chicken feeds could be replaced by supplementing it with fresh azolla. Birds with 75 per cent of the regular feed and 12.5 per cent azolla had an almost equal weight to birds with 100 per cent regular feed.

Furthermore, birds that received normal feed with 5 per cent extra in the form of azolla grew faster than the birds with 100 per cent f­eed alone. They also had a 10–12 per cent increase in the total body weight. The number of eggs laid and their quality was also higher in the azolla-fed birds.

Indian researchers led by Kamalasanana in 2002 found an increase in milk yield when azolla was combined with regular feed. They replaced 15-20 per cent of commercial feed with the same quantity of azolla on dry weight basis. This led to a 20-25 per cent saving on buying commercial feeds. Milk yield increased by between 10 and 15 per cent and went up to 20 per cent in the dry summer months.

The researchers noted that the increase in milk yield was higher than the quantity of azolla fed. They concluded there was need for more research to understand why azolla feeding caused an unexpected high increase in milk yield.

There is a lot of evidence on the benefits of azolla farming. However, farmers taking it up should be aware that water quality and availability are the most limiting challenges of its production.

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