Wednesday, November 5, 2008
Azolla species
Azolla spp.
6 tropical and warm species (A. filiculoides, A. pinnata, etc.). The aquatic fern Azolla contains a symbiotic, heterocystous, blue-green alga, Anabaena azollae within cavities in its leaves. By the process of nitrogen-fixation the alga is capable of fulfilling the N requirements of the association.
An Azolla plant consists of a short, branched, floating stem, bearing roots which hang down in the water. Each leaf is bi-lobed, the upper lobe containing green chlorophyll while the lower lobe is colourless. Under certain conditions, an anthocyanin pigment, also occurs giving the fern a reddish-brown colour. This is particularly associated with over-fertilization of ponds, pollution and excess sunlight. Shaded conditions are preferred to full exposure to tropical sunlight.
The plant is highly productive with the ability to double its weight in 7 days. It can produce 9 tonnes of protein per hectare of pond per year. It is used as green manure (in rice paddies), stock feed and for controlling mosquitoes by blocking water-surface. Because the fern can form dense mats on water surfaces, it is classified as a water weed in many areas.
Azolla has reportedly been used as a feed for pigs and ducks in SE Asia; for cattle, fish and poultry in Vietnam; and for pigs in Singapore and Taiwan. It is described as an excellent substitute for green forage for cattle in Vietnam and may replace up to 50% of the rice bran used as feed for pigs in that country.
Although very low in DM, it contains a high level of protein (24% CP). The amino acid composition of Azolla compared well with reference protein sources. Methionine is low, as with many leaf proteins, but the value for lysine is more than twice that of corn.
As a supplement for growing pigs, performance was reduced compared to controls in the growing phase but the animals compensated and grew faster in the period from 24-89 kg. It has been used as a sole feed for lactating sows which have a higher intake to deal with the low DM content.
Ducks (650-1800g LW) consumed 350g Azolla when given free-choice with sugarcane juice and soya (about 5% of the diet). It is also used for grazing ducks and geese in paddy fields where the Azolla is used as a fertilizer.
6 tropical and warm species (A. filiculoides, A. pinnata, etc.). The aquatic fern Azolla contains a symbiotic, heterocystous, blue-green alga, Anabaena azollae within cavities in its leaves. By the process of nitrogen-fixation the alga is capable of fulfilling the N requirements of the association.
An Azolla plant consists of a short, branched, floating stem, bearing roots which hang down in the water. Each leaf is bi-lobed, the upper lobe containing green chlorophyll while the lower lobe is colourless. Under certain conditions, an anthocyanin pigment, also occurs giving the fern a reddish-brown colour. This is particularly associated with over-fertilization of ponds, pollution and excess sunlight. Shaded conditions are preferred to full exposure to tropical sunlight.
The plant is highly productive with the ability to double its weight in 7 days. It can produce 9 tonnes of protein per hectare of pond per year. It is used as green manure (in rice paddies), stock feed and for controlling mosquitoes by blocking water-surface. Because the fern can form dense mats on water surfaces, it is classified as a water weed in many areas.
Azolla has reportedly been used as a feed for pigs and ducks in SE Asia; for cattle, fish and poultry in Vietnam; and for pigs in Singapore and Taiwan. It is described as an excellent substitute for green forage for cattle in Vietnam and may replace up to 50% of the rice bran used as feed for pigs in that country.
Although very low in DM, it contains a high level of protein (24% CP). The amino acid composition of Azolla compared well with reference protein sources. Methionine is low, as with many leaf proteins, but the value for lysine is more than twice that of corn.
As a supplement for growing pigs, performance was reduced compared to controls in the growing phase but the animals compensated and grew faster in the period from 24-89 kg. It has been used as a sole feed for lactating sows which have a higher intake to deal with the low DM content.
Ducks (650-1800g LW) consumed 350g Azolla when given free-choice with sugarcane juice and soya (about 5% of the diet). It is also used for grazing ducks and geese in paddy fields where the Azolla is used as a fertilizer.
Azolla Farming _ Alternative Fodder
The demand for milk and meat in India is creating new potential in the profitability of animal husbandry as an occupation. Yet, at the same time, there is a substantial decline in fodder availability. The area under forest and grasslands is decreasing as is the amount of various crop residues available for feed, largely due to the introduction of high yielding dwarf varieties. The shortage of fodder is therefore compensated with commercial feed, resulting in increased costs in meat and milk production. Moreover, as commercial feed is mixed with urea and other artificial milk boosters, it has a negative effect on the quality of milk and the health of the livestock.
The search for alternatives to concentrates led us to a wonderful plant azolla, which holds the promise of providing a sustainable feed for livestock. Azolla is a floating fern and belongs to the family of Azollaceae. Azolla hosts a symbiotic blue green algae, Anabaena azollae, which is responsible for the fixation and assimilation of atmospheric nitrogen. Azolla, in turn, provides the carbon source and favourable environment for the growth and development of the algae. It is this unique symbiotic relationship that makes azolla, a wonderful plant with high protein content.
Nutrient content and its impact on growthAzolla is very rich in proteins, essential amino acids, vitamins (vitamin A, vitamin B12 and Beta- Carotene), growth promoter intermediaries and minerals like calcium, phosphorous, potassium, ferrous, copper, magnesium etc. On a dry weight basis, it contains 25 - 35 percent protein, 10 - 15 percent minerals and 7 - 10 percent of amino acids, bio-active substances and bio-polymers. The carbohydrate and fat content of azolla is very low. Its nutrient composition makes it a highly efficient and effective feed for livestock (see Table 1). Livestock easily digest it, owing to its high protein and low lignin content, and they quickly grow accustomed to it. Moreover it is easy and economic to grow.
The Natural Resources Development Project (NARDEP), Vivekananda Kendra, carried out trials in Tamil Nadu and Kerala using azolla as a feed substitute. The trials on dairy animals showed an overall increase of milk yield of about 15 percent when 1.5 - 2 kg of azolla per day was combined with regular feed. The increase in the quantity of the milk produced was higher than could be expected based on the nutrient content of azolla alone. Hence, it is assumed that it is not only the nutrients, but also other components, like carotinoids, bio-polymers, probiotics etc., that contribute to the overall increase in the production of milk. Feeding azolla to poultry improves the weight of broiler chickens and increases the egg production of layers. Azolla can also be fed to sheep, goats, pigs and rabbits. In China, cultivation of azolla along with paddy and fish is said to have increased the rice production by 20 percent and fish production by 30 percent.
Azolla productionNARDEP has been working on azolla for the last three to four years, studying its potential as a feed and exploring cost effective methods for the mass multiplication of azolla in farmers’ homesteads.
Close-up view of an azolla plant. The size of the plants are 1 - 3 cm.In our method, a water body is made, preferably under the shade of a tree, with the help of a silpauline sheet. Silpauline is a polythene tarpaulin which is resistant to the ultra violet radiation in sunlight. A pit of 2 x 2 x 0.2 m is dug as a first step. All corners of the pit should be at the same level so that a uniform water level can be maintained. The pit is covered with plastic gunnies to prevent the roots of the nearby trees piercing the silpauline sheet, which is spread over the plastic gunnies. About 10 - 15 kg of sieved fertile soil is uniformly spread over the silpauline sheet. Slurry made of 2 kg cow dung and 30 g of Super Phosphate mixed in 10 litres of water, is poured onto the sheet. More water is poured on to raise the water level to about 10 cm. About 0.5 - 1 kg of fresh and pure culture of azolla is placed in the water. This will grow rapidly and fill the pit within 10 - 15 days. From then on, 500 - 600 g of azolla can be harvested daily. A mixture of 20 g of Super Phosphate and about 1 kg of cow dung should be added once every 5 days in order to maintain rapid multiplication of the azolla and to maintain the daily yield of 500 g. A micronutrient mix containing magnesium, iron, copper, sulphur etc., can also be added at weekly intervals to enhance the mineral content of azolla.
The search for alternatives to concentrates led us to a wonderful plant azolla, which holds the promise of providing a sustainable feed for livestock. Azolla is a floating fern and belongs to the family of Azollaceae. Azolla hosts a symbiotic blue green algae, Anabaena azollae, which is responsible for the fixation and assimilation of atmospheric nitrogen. Azolla, in turn, provides the carbon source and favourable environment for the growth and development of the algae. It is this unique symbiotic relationship that makes azolla, a wonderful plant with high protein content.
Nutrient content and its impact on growthAzolla is very rich in proteins, essential amino acids, vitamins (vitamin A, vitamin B12 and Beta- Carotene), growth promoter intermediaries and minerals like calcium, phosphorous, potassium, ferrous, copper, magnesium etc. On a dry weight basis, it contains 25 - 35 percent protein, 10 - 15 percent minerals and 7 - 10 percent of amino acids, bio-active substances and bio-polymers. The carbohydrate and fat content of azolla is very low. Its nutrient composition makes it a highly efficient and effective feed for livestock (see Table 1). Livestock easily digest it, owing to its high protein and low lignin content, and they quickly grow accustomed to it. Moreover it is easy and economic to grow.
The Natural Resources Development Project (NARDEP), Vivekananda Kendra, carried out trials in Tamil Nadu and Kerala using azolla as a feed substitute. The trials on dairy animals showed an overall increase of milk yield of about 15 percent when 1.5 - 2 kg of azolla per day was combined with regular feed. The increase in the quantity of the milk produced was higher than could be expected based on the nutrient content of azolla alone. Hence, it is assumed that it is not only the nutrients, but also other components, like carotinoids, bio-polymers, probiotics etc., that contribute to the overall increase in the production of milk. Feeding azolla to poultry improves the weight of broiler chickens and increases the egg production of layers. Azolla can also be fed to sheep, goats, pigs and rabbits. In China, cultivation of azolla along with paddy and fish is said to have increased the rice production by 20 percent and fish production by 30 percent.
Azolla productionNARDEP has been working on azolla for the last three to four years, studying its potential as a feed and exploring cost effective methods for the mass multiplication of azolla in farmers’ homesteads.
Close-up view of an azolla plant. The size of the plants are 1 - 3 cm.In our method, a water body is made, preferably under the shade of a tree, with the help of a silpauline sheet. Silpauline is a polythene tarpaulin which is resistant to the ultra violet radiation in sunlight. A pit of 2 x 2 x 0.2 m is dug as a first step. All corners of the pit should be at the same level so that a uniform water level can be maintained. The pit is covered with plastic gunnies to prevent the roots of the nearby trees piercing the silpauline sheet, which is spread over the plastic gunnies. About 10 - 15 kg of sieved fertile soil is uniformly spread over the silpauline sheet. Slurry made of 2 kg cow dung and 30 g of Super Phosphate mixed in 10 litres of water, is poured onto the sheet. More water is poured on to raise the water level to about 10 cm. About 0.5 - 1 kg of fresh and pure culture of azolla is placed in the water. This will grow rapidly and fill the pit within 10 - 15 days. From then on, 500 - 600 g of azolla can be harvested daily. A mixture of 20 g of Super Phosphate and about 1 kg of cow dung should be added once every 5 days in order to maintain rapid multiplication of the azolla and to maintain the daily yield of 500 g. A micronutrient mix containing magnesium, iron, copper, sulphur etc., can also be added at weekly intervals to enhance the mineral content of azolla.
Saturday, November 1, 2008
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