Shashi Pal, Hemant Kumar, T.K.S. Rao and Dhirendra Kumar
College of Veterinary and Animal Sciences, Kishanganj
Introduction
During the last two-three decades or more, there is phenomenal growth in poultry sector of India. Among the livestock sector, poultry production and farming system is the most profitable enterprises as well as entrepreneurship. This sector plays an important role in nutritional security supplying of quality animal proteins in the form of meat and eggs for human consumption. Due to the rapid growth of poultry farming sector in the country, the sector is facing severe challenges of poor availability and high price of feed ingredients for maintaining the pace of commercial poultry farming. Increase in price of feed for poultry has resulted in competition with food ingredients for human consumption; feed ingredients for pig feeding, feed ingredients for other livestock feed/ concentrate feed which has increased the cost of conventional feed ingredients. Feed is the major input in poultry production system and feed alone cost 70-75 percent of the total cost of poultry production. It is necessary to practice the efficient and low cost feed formulation strategy in order to sustain the poultry sector. Several unconventional feed ingredients are available which can be utilized for preparing low cost feed. Azolla is one of such nutritious and low cost ingredient which can be used for formulating low cost feed for poultry as an alternative to costly conventional feed resources.
Importance of Azolla
Azolla is an aquatic fern which flows on water surface, individually or in mats. Azolla plants are triangular or polygonal in shape. A variety of Azolla, Azolla pinnata is found in most of the Asian countries. It fixes atmospheric nitrogen in association with the nitrogen fixing blue green alga (Anabaena azollae).
| Nutrient Composition of Azolla | ||
| Nutrients in Azolla | Fresh/raw Azolla (on % basis) | Azolla meal (on %DM basis) |
| Moisture | 90 – 92 | 10-11 |
| Dry Matter | 7.75- 8.23 | 89-90 |
| Organic matter | 75-80 | 75-80 |
| Crude protein | 4 – 5 | 20-30 |
| Crude fat | 0.5 – 2 | 3.5-4.0 |
| Crude fibre | 14-15 | 14-15 |
| Carbohydrate | 0.2 – 1 | 4 |
| Ash | 2-2.5 | 24-25 |
Azolla is considered to be a potential bio-fertilizer for rice crop (Kannaiyan, 1992). Azolla contains 20-30% protein on dry weight basis which is higher than most green forage crops and rich in essential amino acids (notably lysine), minerals, vitamins and carotenoids favourable for animal nutrition (Ivan et al., 1989). Azolla is used as sustainable feed substitute and can be valuable protein supplement for livestock especially dairy cattle, fish, poultry and piggery. The combination of high nutritive value and rapid biomass production make Azolla a potential and effective feed substitute for livestock, particularly poultry birds. It can be used either in fresh Azolla or dried Azolla meal form. The nutritive composition of Azolla is given above.
Azolla Production
Azolla is distributed throughout the world, from temperate region to tropical region countries. Azolla production can be relatively inexpensive but it usually requires intensive labour with properly trained and skilled. Water is the basic requirement for the growth and multiplication of Azolla and is extremely sensitive to lack of water. Environmental constraints such as very high temperatures, low humidity and poor quality of water can restrict the propagation of azolla (Giridhar et al., 2013). Azolla requires optimum temperature of 20-30oC for proper growth and nitrogen fixation. Outside this range, growth of Azolla decreases and the plant begins to die at temperatures below 5°C and above 45°C. Some species of Azolla can withstand temperatures as low as -5°C without apparent harm. Azolla grows best in full to partial shade (25-50% of full sunlight). The optimum relative humidity for azolla growth is between 85 to 90%. If the relative humidity is lower than 60%, Azolla becomes dry and fragile (Hasan et al., 2009). Successful cultivation of azolla requires the application of a certain amount of phosphorus fertilizer (0.5 to 1.0 kg P/ha/week). Azolla doubles its biomass in 2-3 days, depending on the conditions. In India, some scientists have reported the yields of 37.8 ton fresh weight/ha (2.78 ton DM/ha) for Azolla pinnata.
Azolla cultivation for poultry feeding
Azolla is a highly productive plant. Azolla can be cultivated by an ordinary farmer and multiplied easily. For the small poultry farmer, Azolla cultivation in pits is very easy and economical. They should select a shaded area for pit construction close to the house (to ensure regular monitoring) and for easily available water source. A pit of the size 4-4.5 m² and 30 cm deep can produce about 2 kg/day of fresh azolla, enough to supplement 20 birds daily. Care must be taken that the floor of the pit is even. A plastic sheet/ Silpaulin sheet of proper size should be spread uniformly in the pit and properly confined. To initiate azolla cultivation, a thin layer of 10-12 cm soft fertile soil mixed with cow dung (3 kg) dissolved in 6-7 liters of water should be added as fertilizer and the pond should be inoculated with fresh azolla culture (about 400 g for a sq.m pond). For proper and continuous growth of Azolla, application of about 1 kg of cow dung and 80-100 grams of superphosphate after every 2 weeks is required. The first crop should be ready in 15-20 days and after that harvesting on daily basis. The pit needs to be emptied once in six months. Azolla produced in surplus amount can be dried in the shade and processed for later use.
Importance of Azolla in poultry feeding
- Feeding azolla to poultry improves the weight of broiler chickens and increases the egg production of layers.
- Azolla meal contains 20-30% protein.
- Azolla is an important low cost input, unconventional feed ingredients for poultry feed formulation. It may reduce the poultry feed cost.
- Azolla is a good source of protein and may be used upto 10% level in the broiler diet for better performance.
- It can be used directly to feed the birds as fresh form or dried form.
- Ad lib feeding of Azolla for poultry may be practiced.
- Fresh Azolla may replace 20 % of commercial poultry feed in the diet of young chicken birds (about 9 kg of fresh Azolla each day for 100 chickens).
Processing of Azolla
Azolla can be processed by manual and automatic method. Azolla can be offered to poultry birds either in fresh/ raw or dried form. It can be fed either directly or mixed with feed to poultry. Some times birds take a few days to acclimatize to the taste of azolla, therefore it is better to apply it slowly and mix with the poultry feed in the initial stages. Azolla should be washed thoroughly with fresh water in order to remove the foul odour of dung before feeding. Fresh azolla is highly perishable in nature and it is advisable to feed it to the birds. If it is in surplus amount, it can be dried immediately either in the shade or sun and stored for later use or use during lean period.
