Fish Feed Ingredients and Their Classification with Respect to Indian Aquaculture Perspective

Fish Feed Ingredients and Their Classification with Respect to Indian Aquaculture Perspective

The aquaculture industry in India has witnessed substantial growth in recent years, making it an essential contributor to the nation’s food security and economy. A crucial aspect of successful aquaculture is the development of nutritious and cost-effective fish feeds. Fish feed ingredients play a pivotal role in formulating feeds that meet the nutritional requirements of diverse fish species. In this essay, we will explore the various fish feed ingredients used in Indian aquaculture, their classification, and their significance in promoting sustainable and profitable fish farming practices.

Indian aquaculture has demonstrated a six and half fold growth over the last two decades, with freshwater aquaculture contributing over 95 percent of the total aquaculture production. The production of carp in freshwater and shrimps in brackishwater form the major areas of activity. Aquaculture in India, in general, is practiced with the utilisation of low to moderate levels of inputs, especially organic-based fertilisers and feed but to increase the output successfully nutritional manipulations and better feeding managements have to be followed. As in any aquaculture venture, feed forms the major part of the operational cost so feed should be designed scientifically by judiciously formulating the feed composition so that best growth rate can be achieved at minimal possible feed cost. For this a sound knowledge of the nutritional requirements and feed ingredients should be possessed. In the culture systems producing more than 1 tonne/ha/yr feed interventions are usually required. Further, in semiintensive and intensive culture systems feed becomes more important as it is the major source of nutrition in semiintensive culture and the only nutritional source in intensive culture.

FEED INGREDIENT CLASSIFICATION

Feed ingredients can be classified on the basis of composition, function and source.

Classification on the basis of composition:

Here we look at the constituents of the ingredients and use them accordingly and in proper proportions in the feed. (i) Protein constituents: Certain ingredients are rich in proteins and are used as per their amino acid profiles. Fish meal, soyabean meals are some of the common ingredients used as the sources of proteins in fish feed. (ii) Lipid constituents: Ingredients like fish oil, coconut oil are used to increase the fatty acid or triacyglyceride content of the fish feed. (iii) Carbohydrate constituents: Ingredients such as Alginic acid, tapioca flour, are included in the feed as carbohydrate source. (iv) Vitamin constituents: Vitamins are required for effective metabolism of animals as they are indispensable part of many metabolic enzymes. Their deficiency leads to disorders diseases and cripples the organism. Vitamin mix solutions are added to fish feed to provide fish with a balanced diet. (v) Mineral constituents: Any organism would require minerals for ensuring proper functioning of the body. Requirement of any mineral above 100 milligrams a day is labeled mineral while trace minerals are required in very small quantities (in micrograms).There are about 21 recognised elements which perform essential functions in the body. Minerals provide rigidity to the endoskeleton in finfish and exoskeleton on shellfish. They are required in maintaining acid-base equilibrium and osmotic balance with the environment, they are involved in proper functioning of muscle fibers and neurons, they are involved in endocrine system, they are present as components of red blood cells, enzymes and organic compounds in tissues and cells.

Classification on the basis of function: On the basis of function, ingredients can be classified as (i) Energy supplements and (ii) Non energy yielding supplements. (i) Energy supplements: These ingredients have more than 20% protein level. They are also called protein supplements. Carbohydrates, fats and protein are included in this category (ii) Non energy yielding supplements: Ingredients that contain less than 20% protein and 18% fibres are classified as energy yielding supplements. These include vitamins, minerals which have physiological and biochemical roles and are important in deciding efficiency of the diet Classification on the basis of source: Feed ingredients can be of animal origin or can be derived from plants. (i) Ingredients of animal origin: Feed forms the most expensive production function in aquaculture and in feed, protein is the most expensive component that determines the cost of feed and hence, in turn, determines the cost of fish production. Ingredients of plant origin are generally protein contributors. Fish meal, slaughter house waste are widely used to increase the protein composition of fish feed. Fish meal is a very important ingredient in this regard as it is rich in lysine and methionine which are found in deficit quantities in plant derivatives. In addition to this, fish processing by-products, processing house waste can be procured cheaply for incorporating into feed. Certain fishing by-catch like Mantis shrimps (Squilla sp.) or market value fish like Anchovies can be used to prepare fish meal which can be added as a protein source in feeds. But, apart from being very good sources of proteins, animal derivatives have certain disadvantages like high bacterial load, low shelf life of raw material and of the product made from them, hygiene requirements in handling the animal derived raw material and processing it adds up the cost of feed production. (ii)Ingredients of plant origin: Agriculture forms the primary economic sector of India and this country has a wide variety of vegetative flora hence it would be wise to use plant derivatives in feed preparation for they will be abundantly available throughout the length and breadth of the country unlike fish meal which will be a scarce item in North-Indian states like Jammu and Kashmir, Himachal Pradesh, Haryana, Punjab etc. and in North-eastern states. As ingredients of plant origin will be available in almost all the seasons and in large quantities, they will be cheaper. Handling such raw materials is easy, their shelf life is more than that of the ingredients from animals. Health and hygiene problem in handling plant derivatives is less which in turn will reduce the cost of feed production. Rice Bran, wheat bran, oil cakes and soya bean meal have been widely used as traditional feed in Indian aquaculture. The problem with the ingredients of plant origin is that their nutrient composition, especially amino acid profile varies widely from plant to plant. This creates a restriction in their free usage in feed composition. Plant proteins are deficient in lysine and methionine. Digestibility of plant proteins is also less than fish proteins.

There is another general classification of fish feed ingredients, which is as follows:

1. Dry forages and roughages: This include hay, straw, hulls and other products with more than 18% crude fibre content. Rice Bran and seed coats are of special mention in this category. 2. Pastures, range plants and forages fed green: this includes ingredients that may be slightly cured on the stem, cut and fed fresh. E.g. Hydrilla, dried Azolla, Colocasia leaves etc. 3. Silages: this is a category where feed ingredients are reduced in size and then preserved by reducing their pH. The silage so obtained is added to the feed and not fed directly. Grasses, slaughter house waste, fish, grains, roots, tubers etc are generally preserved in this form. 4. Energy feeds: This includes ingredients with protein content below 20% and fibre content less than 18% (on dry weight basis). E.g. Vitamins and minerals mix. 5. Protein supplements: This includes ingredients containing protein level above 20% (on dry weight basis). E.g. oil cakes, soya bean meal etc. 6. Mineral supplements. 7. Vitamin supplements 8. Additives: The ingredients in this category are added in feed to make it more efficient by enhancing its pelletability, palatability, attractiveness. These are antibiotics, colouring materials, flavours, hormones, medicines, binders etc.

Conventional Feed Ingredients:

Aquaculture in India has been a traditional practice in the form of traditional brackishwater ‘capture-andculture’ systems like ‘Pokkali’ in Kerala, ‘Bhasabhada fisheries’ in West Bengal. This started as extensive type of culture system in India which required only fish seed and some manuring as inputs. But as the demand for the fish rose more fish had to be produced from the same area available. Stocking of the ponds or other suitable water bodies had to be done beyond their carrying capacities and for this feed had to be a new input. Aquaculture like any other traditional practice tends to utilize locally available inputs. In India, agricultural by-products and waste is abundantly available in one or the other form and our ancestors have learned to use them in aquaculture. These conventional inputs had been used to provide fish mainly with proteins and energy. Though these inputs have been successful in supplementing feed with some nutrient value and producing fish slightly above the natural carrying capacity of the water bodies they have some disadvantages also, the biggest being that their nutrient value is not sufficiently large to produce exceptionally high quantities of fish. Some of the conventionally used feed ingredients are discussed below: (i) Rice bran: This has been the most popular ingredient of the practical diets for fin fishes especially carps. It has crude protein value of 10- 12%, crude fibre 12-18%, total lipid 7-12%, ash 8-12%. It is a good source of energy and B group vitamins. Deoiled rice bran is better in terms of nutritional profile and this also keeps away the problem of rancidity. (ii) Wheat flour and wheat bran: This is a good source of energy having crude protein 10-14%, crude fibre 12-18%, ash 6-18%. It is a good source of phosphorous, potassium, magnesium and zinc. Amongst vitamins, niacin, pantothenic acid and biotin are in good amounts. For prawn feeds, ground whole wheat flour is widely used. Inclusion of this in feeds foments gelatinization hence improving the feed stability. (iii) Corn gluten: Crude protein 20- 30%; arginine and lysine levels are low; good source of iron and zinc, niacin and vitamin E. (iv) Sorghum and millet: Crude protein 8-12%; poor profile of amino acids, minerals and vitamins; can be used as an energy source. (v) Oil cakes and meal: In India oil cakes have been widely used as feed ingredients based upon the type of oil seeds in various regions. Some important ones are: (a) Soyabean oil cake: Among the plant sources soyabean oil cake is considered as the best source of protein, in terms of its protein content and amino acid profile. The energy content varies with the deoiling extent and deoiling process which will have an effect on the fibre content of the meal. Despite its high protein content, it lack in methionine, lysine and threonine levels are also less as compared to animal protein source. Supplementing it with the deficient amino acids it can be a very good feed ingredient. It also contains protease inhibitors, urease enzyme, haemagglutinins and glycosides like saponin, but all the antinutritional factors can be destroyed by heat treatment which may compromise some amino acids. Phytates, lipoxidase antivitamin A, antivitamin D are some other antinutritional factors present. About 50% of phosphoric acid is present as phytic acid which is rendered unavailable. Among vitamins, choline is found in relatively high amounts. Levels of incorporation in feeds for tilapia, carps, channel catfish is as high as 50%; sea bass, grouper, trout 10- 20%, prawns upto40%. Protein level is 46-48% in solvent extracted meals while it is 38-42% in mechanically extracted forms. (b) Cotton seed oil cake: Protein content varies from 29-42% depending upon the amount of hull removed. The content as well as availability of lysine, threonine, and methionine is lower than in soyabean oil meal. It is a good source of thiamine and vitamin E. Presence of phenolic pigment gossypol and cyclopropenoic fatty acids adversely affect the nutritional value value of cotton seed oil cake. (c) Groundnut oil cake: Crude protein ranges from 35-42%. It is lower in lysine, tryptophan, threonine and methionine in soyabean meal cake. It is a good source of magnesium, sulphur and potassium. Good source of vitamins, niacin, pantothenic acid, thiamine, while choline and vitamin E levels are low. Highly prone to fungal growth and mycotoxin (aflatoxin) in humid conditions. (d) Sunflower oil cake: Highly deficient in lysine. Methionine and cystine higher than soyabean. Vitamin B and carotenoids found in good quantities. (e) Mustard oil cake: used in carp diets. Non detoxified cakes contain erucic acid, glucosinolates. Some other oil seed cakes are Safflower oil cake, Rapeseed oil cake, gingely oil cake, linseed oil cake. Cereal products: Ground broken rice, wheat, soghum, millets and maize can be used considering their cost, availability and carbohydrate content Root Crop: Tapioca, sugar beet molasses and meals from potatoes Have been used. Hydrocyanic acid content should be checked in the tapioca before use.

NON CONVENTIONAL FISH FEED INGREDIENTS: Non-conventional feed resources refer to all those feed ingredients that are not traditionally used in animal feeding and are not normally used in commercially produced rations for livestock. Characteristics of Non conventional feed resources: i) They are end products of production and consumption that not have been used, recycled or salvaged. ii) They are mainly organic and can be in solid, slurry or liquid form. iii) Their economic value is often less than the cost of their collection and transformation for use and consequently they are discharged as wastes. 1) Fisheries by-products: Waste from fish processing industries have found a good use in formulating fish feed. The are procured everyday from the processing industries in bulk and either used immediately after short storage time or can be preserved by ensilage for future use. Some of the by-products are: i) Fish meal: this is perhaps the most abundant animal protein source commercially produced and marketed in several countries. In fact this fish meal industry is sustaining the worlds largest single fish species exploited by man; Peruvian Anchovy (Engraulis ringens). Best fish meals are manufactured by steam cooking. In India, fish meal marketed is pulverized fish meal. Though very high in protein levels its cost makes its use sparingly in feed for carp but it can be used in good quantities in shrimp and trout feeds. Protein content is 60-75%, fat ranges from 4-20%, ash content depends on the processing level and varies highly ranging from 11-12% in anchovies to over 23% in white fish meal. ii) Fish solubles: This is the water remaining after the oil is removed from the liquid pressed out during the manufacture of fish meal. The condensed and dried fish solubles when included in small quantities an aqua feed serve as an attractant. It is high in B group vitamin and contains an unidentified growth factor iii) Fish silage: It is prepared from trash fish, waste fish head, vicera prawn waste small crabs and mixed with a mixture of acids to bring down the pH to 4. This causes liquefaction and prevents bacterial decomposition. Biological fish silage is prepared by introducing lactic acid bacteria into ground fish carbohydrate mixture. The lactic acid bacteria produce the acid necessary to preserve the fish. The resulting liquid product can be used as an ingredient mainly in fish feeds. iv) Crustacean meals: Meals obtained form small prawns, prawn heads, mantis shrimp, crabs and krill are important ingredient for prawn feeds. Fresh crustacean meals are good attractants for prawn. Crude protein level varies between 30- 50% depending upon size and species. Ash content ranges from 25- 40% and chitin is as high as 16%. It is good source of cholesterol, carotenoid pigments, chitin, calcium, iron, manganese, choline, niacin, pantothenic acid and cyanocobalamine. Fresh material should be used always. In prawn feeds inclusion rates range from 5- 15% and meals from small prawns up to 25% 2) Meat meal and meat and bone meal: These are dried mammalian tissue exclusive of hair, hooves, horns, hide trimmings, manure and stomach content. Protein content is about 51% for meat meal and 50% for meat and bone meal. Fat is about 9.1-9.7% in both. Meat has phosphorus content less than 4.4% while it is above 4.4% in meat and bone meal. Calcium content of meat and bone meal is 8.8-12% and in meat meal is less 3%. Both have ash content of 27-31% 3) Blood meal: It is a dry product made from clean fresh animal blood, exclusive of all extraneous matter. It can be prepared by spray drying, flash drying and conventional drying. Its protein content is 85%, lysine is 9-11% with lysine over 80%. 4) Feather meal: It is made from poultry feathers, hydrolyzed under pressure in the pressure of Ca (OH)2 and dried. Its protein content is 80- 85% and not less than 75% of protein must be digestible by the pepsin digesting method. Its use in fish feed is restricted due to its poor digestibility by fish. 5) Milk by-products: Dried whey, dried whey products, casein and dried skim milk. Dried whey is obtained when lactose has been removed. Protein content is relatively low (13-17%), yet are classified a protein supplements. Dried skim milk forms a part of larval diet as it digestibility is high and has good amino acid profile. It has about 34% protein. Casein is the residue obtained by acid or rennet coagulation of defatted milk. It has 80%protein. 6) Gelatin: it is obtained by partial hydrolysis of collagen from animal skin, tendons and ligaments. It is hard and brittle when solid but dissolve in hot water and forms gel when cooled. It is 88-92% protein and contains no tryptophan. Used as protein source and binding agent. 7) Silkworm pupae: used in feeds at low level. Has high levels of chitin, and lipid which is prone to rancidity, Solvent extraction of lipids may improve the quality. 8) Chicken eggs: without shell have crude protein level of about 46% and has 43% lipid content. Ash contributes to 4%. It is a good source of amino acids, pantothenic acid, cyanocobalamine, riboflavin, iron and zinc. Particularly beneficial in hatcheries and nurseries. 9) Concentrates: A concentrate is usually described as a feed or feed mixture which supplies primary nutrients (protein, carbohydrate and fat) at higher level but contains less than 18% crude fibre with low moisture and total ammonia nitrogen over 60% on air dry basis. Miscellaneous ingredients: Fruit processing waste as from citrus fruits can be incorporated in the diets which act as a source of carotenoids and vitamins. Single cell protein: This term applies to a wide range of products of microbial origin (Tuse’ 1884, Taco & Jacson 1985). The microbes may be of algal (Spirulina maxima, Scenedesmus obliques, Chlorella vulgaris), fungal or bacterial origin (Methamonas methanica) resulting from fermentation process. Yeast and breweries, sewage, processing waste, wood pulp operation, and petroleum cracking products are some of the substrates which are harmful to the environment but can be utilized to produce single cell protein. Yeast, Spirulina are some of the examples of SCP having lot of potential in the fish feed manufacture. Yeast may not be used as such but is fed to Artemia in which lipid content is seen to rise. Feeding this Artemia provides fish fry with essential fatty acids in the diet (E. H. Lim, T. J. Lam and J. L. Ding 2005). Spirulina has crude protein level of 55- 65% with good levels of essential amino acids, calcium, and phosphorus.

Azolla as feed ingredient

Recently, the utilization of aquatic plants having high food value are used to supplement fish food has taken a new dimension for producing the much required animal protein at low cost (Lakshmanan et al., 1967). Azolla, which grows in association with the blue green algae Anabaena azollae, is perhaps the most promising from the point of view of ease of cultivation productivity and nutritive value (Lumpkin and Plucknett 1982;Van Hove and Lopez 1983). Azolla contains 20- 25.5% protein, 3.1%fat, 34.9%carbohydrate, 8.5-11.7% cellulose and essential aminoacids. Grass carp and common carp recorded a weight gain of 174 and 35.8g / fish respectively and utilized Azolla nitrogen to the extent of 30% (Ayyappan, 1992).

Classification of Fish Feed Ingredients

Fish feed ingredients in India are typically classified into several categories based on their nutritional content, origin, and role in fish nutrition:

1. Macro-ingredients: These are the primary ingredients that provide essential macronutrients, including proteins, carbohydrates, and lipids. Macro-ingredients are the main energy sources for fish.
2. Micro-ingredients: Micro-ingredients are the secondary components that contribute to the overall nutritional value of fish feeds. These include vitamins, minerals, and amino acids.
3. By-Products: By-products are derived from various industries, such as agriculture, fisheries, and agro-processing. These can include rice bran, wheat bran, oilseed cakes, and marine by-products like fishmeal.
4. Supplementary Ingredients: Supplementary ingredients are used in small quantities to enhance the palatability, texture, and overall quality of fish feeds. These may include flavors, binders, and preservatives.
5. Additives: Additives, such as enzymes and probiotics, are incorporated to improve feed digestibility and enhance fish health.

Common Fish Feed Ingredients in India

1. Fishmeal: Fishmeal is a highly digestible source of protein obtained from fish processing by-products. It is a staple ingredient in fish feeds, providing essential amino acids for fish growth.
2. Soybean Meal: Soybean meal is a rich source of plant-based protein and is often used in aquafeeds as a cost-effective alternative to fishmeal.
3. Groundnut Cake: Groundnut cake, a by-product of the oil extraction process, is another valuable protein source used in fish feeds.
4. Rice Bran: Rice bran, a by-product of rice milling, is a source of carbohydrates, lipids, and fiber that contributes to the energy content of fish feeds.
5. Wheat Bran: Wheat bran, similarly, adds carbohydrates, fiber, and some protein to fish feeds.
6. Maize: Maize and other grains are included in feeds to provide energy and are particularly suitable for species with omnivorous feeding habits.
7. Oilseed Meals: Meals derived from oilseeds like sunflower and safflower provide proteins and oils for energy and essential fatty acids.
8. Vitamins and Minerals: These micronutrients are added to ensure the balanced nutrition of fish. They include vitamins (A, D, E, K, and B-complex) and minerals (calcium, phosphorus, iron, and others).

III. Significance of Fish Feed Ingredients

1. Balanced Nutrition: A diverse range of ingredients ensures that fish receive balanced and complete nutrition, supporting healthy growth and development.
2. Economic Viability: Utilizing locally available and cost-effective ingredients makes fish farming economically viable and sustainable.
3. Reduced Reliance on Marine Resources: The use of alternative protein sources like soybean meal and oilseed cakes reduces the pressure on marine resources, helping to combat overfishing and promote sustainability.
4. Customized Feeding: Feed formulations can be tailored to the specific nutritional requirements of different fish species, growth stages, and environmental conditions.
5. Improved Feed Conversion Ratios: Properly formulated feeds maximize feed conversion ratios, ensuring efficient nutrient utilization and minimal waste.

Challenges and Future Considerations

1. Quality Control: Ensuring the quality and safety of feed ingredients is essential to prevent contamination and adverse effects on fish health.
2. Sustainability: The aquaculture industry must continue to explore sustainable alternatives to traditional fishmeal and other finite resources to ensure long-term viability.
3. Research and Development: Ongoing research into novel ingredients and feed formulations is critical to meet the evolving nutritional needs of diverse fish species and environmental conditions.

Conclusion

Fish feed ingredients are the building blocks of successful aquaculture in India. Their proper classification, utilization, and formulation are crucial for meeting the nutritional requirements of different fish species and promoting sustainable and profitable fish farming practices. As the aquaculture industry continues to grow, the responsible use of ingredients and a focus on research and innovation will be paramount to meet the increasing demand for safe, nutritious, and environmentally friendly fish feeds in the Indian perspective.With the ever increasing demand of fish it has become very important to turn the fish production from aquaculture for which feed inputs would be required to sustain stocks at higher densities. Traditionally used feeds are cheaper but not nutritionally balanced hence would fail to support high stocking densities. Knowledge about feed formulation has to be spread with a thought towards the acceptance pattern of the Indian farmers. Cost factor is a major deterrent that keeps farmers away from the formulated feeds so techniques should be developed to effectively utilize locally available ingredients.

Compiled  & Shared by- This paper is a compilation of groupwork provided by the

Team, LITD (Livestock Institute of Training & Development)

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 Reference-On Request.

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