The total installed capacity of feed mills for shrimp feed production in India is about 1.6 million metric tonnes from 30 manufacturing plants. About 0.75 million tonnes of shrimp feed was produced during 2016, with roughly equal quantities of freshwater fish feed produced during the same period. Actual production capacity is around 2 to 2.3 million tonnes per annum and expanding as unfed or mash-fed carp farms shift to use of pelleted feeds, and as area under culture increases.
Although shrimp farming is fully dependent on formulated feeds, freshwater finfish farming is still in the process of transitioning to use of pelleted feeds, from use of raw agricultural by-products, farm-made feeds and organic fertilisers. High value coastal carnivorous fin fish continues to be produced via a combination of trash fish and formulated feeds, both imported and produced locally.
Our preliminary studies on farming of Asian seabass and cobia using locally manufactured feeds suggest that there is real potential for cost savings from the use of nutritionally balanced, modern formulated feeds. Increasing feed prices are a major challenge for the industry, not only as a consequence of increasing ingredient prices, but also due to the increasing cost of energy, marketing networks and logistics.
Marine protein sources
Fishmeal inclusion in shrimp feed formulations has fallen substantially. The establishment of sophisticated fishmeal plants in recent years enables quality fishmeal to be produced locally from available fishery resources and processing plant trimmings, which would otherwise be used as fertiliser in agriculture. The installed fish meal production capacity in the country is estimated to be 150,000 tonnes, out of which 100,000 tonnes was actually produced in 2016.
Fishmeal production in India may be divided into production of high quality sterile fishmeal (60-65% protein) from pelagic fishes such as sardines, wherein fish oil is also extracted as a high value by-product; and fishmeal prepared from processing waste (50-60% protein), in which fish oil separation is not practiced. Other ingredients available for feed production include sun-dried trash fish (176,000 tonnes), mantis shrimp(57,940 tonnes), steam sterilised shrimp heads and sergistid shrimp (48,000 tonnes) and squid waste meal (60,000 tonnes). Squid waste largely consists of the head, fin and viscera along with unclaimed mantles and tentacles. The protein content of the waste is high enough for proteolytic hydrolysis (enzymatic digestion) to generate large amounts of peptides and free amino acids that serve as feed attractants growth stimulants. This waste is collected and steam sterilised and converted into squid meal.
In a pilot scale project conducted at the ICAR - Central Institute of Brackishwater Aquaculture (CIBA), in collaboration with a firm M/S. Jass ventures Private Limited, squid waste was converted into squid silage using organic acid and has been used as an attractant in organic shrimp feed for tiger shrimp with highly encouraging results.
Plant protein sources
Soybean meal is the major plant protein source used in shrimp feeds. About 10 million tonnes of soybean seed was produced in 2016 but the annual availability of soybean meal for feed use has ranged from around 6-8 million tonnes during the preceding six years. Soybean meal for feed use is available in three grades with highest grade containing a minimum of 49 % protein mainly used in shrimp feed formulation. Soybean meal is extensively used as a feed ingredient due to its high protein content and consistency in nutrient concentration. The better solvent extraction process adopted during meal manufacture destroys most of the anti-nutritional factors present in the meal and the heat process adopted during the pelleting and extrusion also inactivates them.
Other important locally produced plant protein sources include ground nut cake (1.3 million tonnes, cottonseed meal (4 million tonnes), sesame cake (0.1 million tonnes), mustard/rape seed cake (3.4 million tonnes), sunflower cake meal (1.8 million tonnes), coconut cake, corn gluten meal and rice gluten. The major constraints in using these plant protein sources are the presence of anti-nutritional factors, imbalanced amino acid profiles and variability in nutrient content. Plant proteins are mainly used in freshwater fish feeds and their use is very limited in shrimp feed formulations.
Cereals such as wheat, rice, maize, sorghum, other millets and cassava are cultivated extensively in India. Wheat and its by-products and broken rice are the main energy sources used in shrimp feed while maize, broken rice, cassava and other millets are used in fish feeds. Rice bran and wheat bran are conventionally used in aquaculture feeds.
Non-conventional aquaculture feed ingredients such as blood meal, meat meal, bone meal, poultry feather meal, poultry by-product meal, guar gum, gram chunies and by-products from lentil processing industries and silkworm pupae. Vegetable oils such as groundnut oil, coconut oil, sunflower oil, sesame oil, mustard oil, soybean oil, soy lecithin, palm oil and, of late, rice bran oil are also produced and cater to dietary fat requirements.
Recently, Indian, aqua feed sector is exploring the opportunity to utilize abundantly available spent residues ,dried distillery grains with solubles (DDGS) as a potential ingredient in fish and shrimp feeds. DDGS available in two grades with 40-45% protein and 55-60% protein. In addition, de-fatted marine micro algal biomass generated from the potential biofuel production could be a potential ingredients due to their high levels of protein, relatively well-balanced amino acid profiles, and rich contents of minerals and vitamins, along with unique bioactive compounds. Indian aquafeed sector also started trialling some of the potential and novel ingredients such as insect meal, macro algal meal from freshwater, micro algal biomass, dry seaweed biomass, single cell protein etc.
CIBA initiative in cost effective feed for shrimp
CIBA as nodal agency in research and development of coastal aquaculture is at the forefront of developing local aquaculture feed technologies and products for different life stages of finfish and shellfish including shrimp. After extensive field evaluation, locally-developed cost effective feed technologies are commercialised and made available to farmers. Recent commercialisation of indigenous shrimp feed for Penaeus vannamei, branded as VannameiPlus, paved the way for availability of cost effective shrimp feed for small and marginal farmers, providing a cost reduction of 8 to 10%. As an approach to reduce the feed cost, we suggest establishment of small and medium feed manufacturing units, with a capacity of 1-2 tonnes/hour, which can cater to the requirements of local clusters of shrimp and fish farms, tapping locally available ingredients and resources. This model has been successful and more such small and medium scale feed mills need to be established across farming areas.
Farm made feed
Farm made feeds are an ad hoc concept we propose for start-ups in aquaculture, where the volume of feed requirement is small and resources and funds are limiting. This is not only cost effective, but can also judiciously make use of available feed ingredients and generate employment and livelihoods.
Larval feeds for shrimp and fin fish are not manufactured commercially in India and are imported. However, CIBA has developed broodstock feeds for milkfish and mullet and larval feeds for shrimp and marine finfish, which are in the process of commercialisation.
Traditional mash feeding is still the dominant feeding practice in fresh water fish farming wherein farmers use rice bran with any one of the locally available plant protein sources (groundnut cake, mustard cake, sesame cake) in the ratio of 3 to 4:1 The mixed feed, about 20 kg per station, is packed in polythene bags which have perforations at the bottom and the bags are then suspended on poles in the water column at a rate of around 25 bags per hectare of pond surface area. This feeding method was developed by farmers in Andhra Pradesh and is essentially a demand feeder resulting in higher growth rates, improved feed ingestion rates, and higher growth rate with minimal feed loss compared to broadcasting. Currently there is a steady shift in feeding practice from the mash feeding to pelleted and extruded feed which will result in further improvements in feed efficiency with proper feed management.
In the case of shrimp culture, nutritionally complete formulated feeds are used with check tray observations for feed management. The majority of the feeds used are pelleted shrimp feeds but recently extruded shrimp feeds have also been introduced by some commercial firms with a reasonable success rate. Manual hand feeding is the normal practice in shrimp farming but auto feeders are used by some of the corporate farms and innovative farmers with appreciable improvement in FCR.
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