Azolla has enormous potential as a livestock feed due to:

• Its high content in proteins, essential amino acids, vitamins (vitamin A, vitamin B12, Beta Carotene), growth promoter intermediaries and minerals.
• Its ability to proliferate without inorganic nitrogen fertilization.
• Its high rate of growth in water without the need to displace existing crops or natural ecological systems.

It has been used for many years throughout Asia and parts of Africa to feed pigs, ducks, chickens, cattle, fish, sheep and goats and rabbits.

Suitability of Azolla as a livestock feed

Green plants have long been recognized as the cheapest and most abundant potential source of proteins because of their ability to synthesize amino acids from a wide range of virtually unlimited and readily available primary materials (Fasuyi & Aletor, 2005)

Azolla is very rich in proteins, essential amino acids, vitamins (vitamin A, vitamin B12, Beta Carotene), growth promoter intermediaries and minerals including calcium, phosphorous, potassium, ferrous, copper, magnesium.  On a dry weight basis, azolla has 25-35% protein content, 10-15% mineral content, and 7-10% comprising a combination of amino acids, bio-active substances and biopolymers (Kamalasanana et al., 2002). Azolla’s carbohydrate and oil content is very low.

Azolla is also rich in iron (1000–8600 ppm dry weight), copper (3–210 ppm dry weight) manganese (120–2700 ppm dry weight), vitamin A (300–600 ppm dry weight.), vitamin A (300–600 ppm dry weigh), chlorophyll and carotenes. It contains 4.8–6.7% dry weight crude fat, with 6.1–7.7% and 12.8– 26.4% total fat for the polyunsaturated acids omega 3 and omega 6 (Paoletti et al., 1987).

Azolla meal contains 25.78% crude protein, 15.71% crude fiber, 3.47% ether extract, 15.76% ash and 30.08% nitrogen free extract on the air-dry basis (Basak et al., 2002).  In addition, aquatic plant species including azolla do not to accumulate secondary plant compounds and therefore has a greater potential than tree leaves to source protein for monogastric animals.

Becerra et al. (1995), Lumpkin & Plucknett (1982) and Van Hove & López (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 also tested and recommended by Alcantara & Querubin (1985) and Tran & Dao (1979) reported that one hectare of azolla can produce 540-720 kg of protein per month.

Azolla’s composition therefore makes it one of the most economic and efficient feed substitutes for livestock, particularly as can be easily digested by livestock due to its high protein and low lignin content.

Here are some examples.

Poultry

Poultry and in particular ducks and chickens can be raised on a diet including fresh azolla. It has long been recognized as a feed for wildfowl in the USA and for domesticated ducks in China and it has been used as a feed to domestic fowl in Vietnam (Dao & Tran, 1966).

The poultry industry has traditionally been one of the most profitable businesses in Bangladesh’sagriculture, providing nutritious meats and eggs for human consumption within the shortest possible time.

However, the industry is now threatened by higher prices and the non-availability of feed ingredients, reflecting feed costs comprising 60-65% of the total cost of poultry production.

In India, Subudhi & Singh (1978) concluded that fresh azolla could replace about 20% of commercial feed in the diet of young chickens.  They estimated that to replace this much commercial feed would require about 9 kg of fresh azolla each day for 100 chickens and that this amount could be produced in a shallow pond 60 m² in area.

Alcantara & Querubin (1985) and Querubin et al. (1986) found that the nutrient digestibility of crude protein, crude fat, and crude fiber were not affected by the level of azolla in the ration, and that broilers can readily digest the crude fiber in azolla, but not that in rice bran, so that digestibility is not a limiting factor when azolla is used.  Kamalasanana et al. (2002) and Prabu (2007) also found that the nutrient constitution of azolla is almost identical to that of commercial poultry feed, except that azolla’s protein content is high and calcium content is slightly low.

Their feeding trials showed that 20–25% of commercial feed could be replaced by supplementing it with fresh azolla, with the addition of azolla feed also having a variety of benefits:

• Birds with 75% of the regular feed and 12.5% in the form of azolla had an almost equal weight to birds with 100% regular feed.
• Furthermore, birds receiving normal feed with 5% extra in the form of azolla grew faster than the birds with 100% feed alone and had a 10–12% increase in the total body weight.
• The number of eggs laid per bird and the quality of eggs (the yellow yolk portion of egg being more prominent and yellowish) was better than in birds not fed on azolla.

Basak et al. (2002) investigated the use of Azolla pinnata meal as a 5% supplementary feed for commercial broiler chicks in Bangladesh.  Based on their investigations, they concluded that:

• Live weight, production number and protein efficiency were significantly improved.
• Feed conversion ratio and energy efficiency were significantly improved.
• The total broiler was cost significantly lower with the azolla meal.
• Dressing and giblet percentages was significantly increased on diet with 5% azolla meal.
• Azolla meal had no deleterious effect on the palatability of the broiler diets.
• The addition of azolla meal has no deleterious effect on palatability of the diets.

Egg-type chicks

As in Bangladesh and India, the poultry industry as one of the most profitable business of agriculture in Nigeria, providing nutritious meats and eggs for human consumption within the shortest possible time, but the availability of quality feed at a reasonable cost is a key to successful poultry operation.

The Faculty of Agriculture and Forestry, University of Ibadan, Ibadan in Nigeria conducted a program to increase the feed base production systems to locally available feed resources in developing countries.  Alalade & Iyayi’s (2006) study at the Faculty determined the chemical composition of azolla meal and assessed its feeding value for egg-type chicks. They reached the same conclusions that supported those of Basak et al. (2002):

• The chemical score index showed the potential of azolla meal to be a good source of protein. Leucine, lysine, arginine and valine were the predominant essential amino acids while tryptophan and the sulphur-containing amino acids were deficient.
• Azolla meal has a potential as a feed for chicks. The inclusion of azolla meal up to 10% improved performance of chicks.

Rice-Duck-Azolla-Loach cultivation

The Japanese farmer Dr Takao Furuno has developed rice-duck-azolla-loach cultivation as an integrated biosystem which eliminates the need for fertilizers, herbicides and pesticides by incorporating duck-raising into organic rice cultivation.  The approach is now being replicated with substantial success all over south-east Asia as an effective way to boost farmers’ incomes, reduce environmental impact and improve food security.

Read more about the excellent and sustainable methods developed by Dr Furono here.

Azolla as a feed for Mallards

Azolla’s potential as a feed for Mallard (egg production) and Muscovy (meat production) ducks has also been investigated in Vietnam. Becerra et al. (1995) conducted feeding trials to determine the effect of feeding Azolla microphylla as partial replacement of the protein in boiled soya bean in diets based on sugar cane juice for meat ducks.

Fresh azolla was offered ad libitum three, four or five times per day, at a rate of 1 kg fresh weight per pen at each feeding and the times increased with the age of the birds to minimize losses. The rations were fed from the age of one month to 70 days old.

Daily boiled soya bean allowances were calculated so that azolla offered ad libitum would supply approximately 0 (control), 15, 30, 45 or 60% of the daily crude protein intake. A vitamin-mineral premix (0.5% of the diet) and common salt (0.25% of the diet) were mixed with the whole boiled soybeans.  The results showed no significant differences between the dietary treatments containing 0, 20, 30 and 40% azolla replacing corresponding levels of PSS, both for Mallard (egg production) and Muscovy (meat production) ducks.

Becerra et al. (1995) concluded that fresh azolla can partially replace whole soya beans up to a level of about 20% of the total crude protein in diets of fattening ducks based on sugar cane juice, without any problems or no adverse effects to growth rate or health. Cost of feed per kg gain was the lowest, and net profit per bird highest for this treatment.

Cattle and milk production

Fodder is an important requirement for cattle. Even if the animals are fed with commercial feeds from the market, fresh green grass or dry straw is essential as fodder availability greatly reduces the expenditure on commercial feeds.  The success of a dairy plant depends largely on increasing milk production without escalation in feeding cost. Growing fodder grass is a good option. Another is azolla  cultivation.

Although the demand for milk and meat has increased in countries such as India, there has also been a substantial decline in fodder production owing to the decreasing forest and grassland areas.  The fodder availability from various crops has also decreased largely due to the introduction of high yielding dwarf varieties.  Shortages of fodder are therefore being compensated with commercial feed, resulting in increased cost of meat and milk production. Moreover, as commercial feed is mixed with urea and other artificial milk boosters, it has a deleterious effect on the quality of milk produced and the longevity of the livestock, which in turn leads to degenerative diseases like cancer and coronary ailments in human beings.

Dr. Kamalasanan Pillai and his colleagues at the Natural Resources Development Project (NARDEP) in Vivekananda Kendra therefore conducted trials using azolla as a feed substitute for dairy animals.

Kamalasanana et al. (2002) found an increase in milk yield when azolla was combined with regular feed, and that 15-20% of commercial feed could be replaced with the same quantity of azolla  on dry weight basis without affecting milk production, providing a 20-25% savings on buying commercial feeds:

“The increase in the milk yield was to the tune of 10–15%, which went up to 20%, during summer months from February to May. It is found that the increase in the quantity of the milk produced on the base of nutrient was higher than the quantity of azolla fed. Hence, it is assumed that more than the carbohydrate, protein content and other components, like carotinoids, biopolymers, probiotics etc., may be contributing to the over all increase in the production of milk.”

They also concluded that feeding with azolla improved the quality of milk and the health and longevity of livestock.

Another example of azolla successful use as a feed for dairy cattle was Akhilesh Kumar’s study in the Patna district of Bihar, India. His results were so successful that he published a newspaper article followed by lectures to agricultural officers and veterenary surgeons at the BAIF State head office.  After hearing the lectures and seeing the results, the BAIF Programme co-ordinator, Dr. K. K. Singh,  recommended azolla’s use in the district by 100 farmers in the first month, followed by 10,000 farmers in the following six months.

The ICRISAT Initiative

Similar results were reported in an ICRISAT Initiative in India called Bhoochetana (‘Land Rejuvenation’):

“Many of these farmers told us that Bhoochetana has rejuvenated their thinking about agriculture, filling them with enthusiasm and hope for the future”.

Mahadevappa and Gauramma (pictured with azolla), who farm two hectares of land, adopted a range of sustainable agricultural practices recommended by ICRISAT. These included the addition of azolla that they harvested from ponds, which increased the yield and enriched the fat content of their cows’ milk. They also learned to make compost from worms (vermiculture or vermicomposting) and combine it with manure and fertilizer to further raise crop yields.

Bhoochetana is a success. Since it started in 2008, agricultural production has risen by almost 6 percent. In 2011, 3 million farm families experienced yield gains of 35-66 % and, despite poor rains, the project resulted in economic growth of $130 million through increased food production.

Azolla and Fish

Azolla is a potential food for freshwater fish farming for two reasons:

• The primary limiting factor for productivity of tropical aquatic ecosystems is often the bioavailability of nitrogen, which can be supplied by azolla-anabaena.
• Approximately 95% of the cost of formulating an average production diet is related to meeting protein and energy needs of the fish,

It has been used for centuries in China to increase rice production by the incorporation of atmospheric nitrogen into the water used to grow rice. azolla-rice cultivation is now also being used in conjunction with fish farming, and result in increased rice production of 20% and fish production of 30% according to Kamalasanana et al. (2002).

Fiogbe et al. (2004) have also investigated the use of azolla  as a supplementary food for fish, because:

“In many developing countries people lack sufficient animal protein. In Benin, the main protein source is fish; however, consumption thereof is very low (7 kg year) compared to the adult requirement of fish or animal meat per year (30 kg year).”

Fish culture could be a means to increase animal protein consumption not only in Benin but also in most of the developing countries that lack sufficient animal protein. However, in a project financed by the European Union from 1978 to 1990, fish production in Benin fell due mainly to the high cost of the feed.”

They investigated Azolla microphylla’s potential to produce low-cost feeds for the omnivorous–phytoplanktonophagous tilapia, Oreochromis niloticus with diets ranging from zero to 45% diet dry weight of azolla.

Fiogbe et al. (2004) found that all diet levels with incorporated azolla meal exhibited weight gain, indicating that azolla can be used with local products to promote fish culture development.  They. concluded that the least expensive diet, which comprised 45% azolla , could be used as a complementary diet for tilapia raised in fertilized ponds and recommended azolla’s use for fish culture in rural areas, and mainly wetlands.

Other trials have focused on azolla’s use as a feed for the grass carp Ctenopharyngodon idell. This species has a short, inefficient digestive system and, at suitable water temperatures, will consume daily more than their own weight of aquatic weeds.  The fish showed a marked preference for azolla, duckweed, and other small floating weeds (Edwards, 1975; Varghese et al., 1976).

Azolla feed for the shellfish Abalone

Abalone are a group of marine gastropod mollusks that have a worldwide distribution along the coastal waters of every continent, except the Atlantic coast of South America, the Caribbean, and the east coast of the United States. Most abalone species are found in cold waters off the Southern Hemisphere coasts of New Zealand, South Africa, Australia, and western North America and Japan in the Northern Hemisphere.

Farming of abalone began in the late 1950s in Japan and China. Since the mid-1990s, there have been many increasingly successful endeavors to commercially farm abalone for food. Over-fishing and poaching have reduced wild populations to such an extent that farmed abalone now supplies most of the abalone eaten by people. The principal abalone farming regions are China, Taiwan, Japan, and Korea, and abalone is also farmed in Australia, Canada, Chile, France, Iceland, Ireland, Mexico, Namibia, New Zealand, South Africa, Thailand and the United States.

Abalone are herbivores and feed in the wild on seaweeds such as Gracilaria and Graciliariopsis, and one of the main concerns in abalone farming is the high cost of feed.  A study conducted by Ofelia Reyes and Armando Fermin at The Philippines’ SEAFDEC/AQD was therefore undertaken to determine if their diet could be supplemented or replaced by terrestrial plants such as Carica papaya, Leucaena leucocephala, Moringa oleifera, locally known as papaya, ipil-ipil and malunggay, respectively, plus Azolla pinnata.

Formulated diets in the study consisting of [1] M. oliefera and A. pinnata, and [2] L. leucocephala were fed daily to juvenile abalones at 2-3% of their body weights, whilst a control feed consisting of fresh Graciliariopsis bailinae was given daily at 30% of the total body weight.

After 120 days, the results showed that:

• Growth rates of abalone fed M. oliefera and A. pinnata were significantly higher than those fed L. leucocephala, and approximated the same as those fed fresh G. bailinae.
• Abalone fed on M. oleifera, A. pinnata and fresh G. bailinae showed greater weight gains compared with fed the L. leucocephala-based diet.
• Abalone fed M. oleifera and A. pinnata had a significantly higher protein productive value (PPV) of 79.9, compared to a value of 12.3 for those fed  G. bailinae.

The study concluded that M. oleifera and A. pinnata could be used as to supplement the diets for abalone because they are available year-round and contain essential nutrients to support the growth of H. asinina.

For more details see the SEAFDEC/AQD website.