Azolla – The best feed for cattle and poultry
Azolla is a free floating water fern that floats in water and fixes nitrogen in association with the nitrogen fixing blue green algae, Anabaena azollae. Azolla is considered to be a potential biofertilizer in terms of nitrogen contribution to rice. Long before its cultivation as a green manure, Azolla has been used as a fodder for domesticated animals such as pigs and ducks. In recent days, Azolla is very much used as a sustainable feed substitute for livestock especially dairy cattle, poultry, piggery and fish.
Azolla contains 25 – 35 per cent protein on dry weight basis and rich in essential amino acids, minerals, vitamins and carotenoids including the antioxidant b carotene. The rare combination of high nutritive value and rapid biomass production make Azolla a potential and effective feed substitute for live stocks.
Azolla fronds, Polythene sheet, Super phosphate and Cow dung.
The area selected for Azolla nursery should be partially shaded. The convenient size for Azolla is 10 feet length, 2 feet breadth and 1 feet depth. The nursery plot is spread with a polythene sheet at the bottom to prevent water loss. Soil is applied to a depth of 2 cm and a gram of super phosphate is applied along with 2 kg of vermicompost or cow dung in the nursery for quick growth. Azolla mother inoculum is introduced @ 5 kg/plot.
The contents in the plot are stirred daily so that the nutrients in the soil dissolve in water for easy uptake by Azolla. Azolla is harvested fifteen days after inoculation at the rate of 50-80 kg / plot. One third of Azolla should be left in the plot for further multiplication. Five kg cow dung slurry should be sprinkled in the Azolla nursery at ten days intervals. Neem oil can be sprayed over the Azolla at 0.5 5 level to avoid pest incidence.
Value of the technology
The egg yield is increased in layer birds due to Azolla feeding. The Azolla fed birds register an overall egg productivity of 89.0 per cent as against 83.7 per cent recorded by the birds fed with only concentrated feed. The average daily intake of concentrated feed is considerably low (106.0 g) for birds due to Azolla substitution as against 122.0 g in the control birds.
The Azolla feeding to layer birds increase egg weight, albumin, globulin and carotene contents. The total protein content of the eggs laid by the Azolla fed birds is high and the total carotene content of Azolla eggs (440 g 100 g-1 of edible portion) is also higher than the control. The rapid biomass production due to the high relative growth rate, increased protein and carotene contents and good digestability of the Azolla hybrid Rong ping favour its use as an effective feed supplement to poultry birds.
In Indian conditions, agriculture is very much coupled with poultry farming. Azolla is an important low cost input, which plays a vital role in improving soil quantity in sustainable rice farming. The twin potentials as biofertilizer and animal feed make the water fern Azolla as an effective input to both the vital components of integrated farming, agricultural and animal husbandry.
Azolla is a water fern and requires a growth temperature of 35-38º C. The multiplication of Azolla is affected under elevated temperature. Hence adopting this technology in dry zones where the temperature exceeds 40ºc is difficult.