WEST BENGAL UNIVERSITY OF ANIMAL AND FISHERY SCIENCES

FACULTY OF FISHERY SCIENCES

A seminar on “ Use of Artificial Fish Feed: Merits & Demerits ”

Submitted to:Dr. T. K. GhoshDept. of FAQCourse: FAQ-225

Submitted by:Krishna Pada SinghaRoll No.- FS-11/13B. F. Sc-2nd Year

Introduction: Good nutrition in animal production systems is essential to

economically produce a healthy, high quality product. In ormental fish farming, nutrition is critical. Fish nutrition has advanced dramatically in recent years with the development of new, balanced commercial diets that promote optimal fish growth and health and also body colour.

The development of new species-specific diet formulations supports the aquarium culture industry as it expands to satisfy increasing demand for beautiful good quality ornamental fish.

Fish foods normally contain macro nutrients, trace elements and vitamins necessary to keep captive fish in good health. Approximately 80% of fish keeping hobbyists feed their fish exclusively prepared foods that most commonly are produced in flake, pellet or tablet form.

Types of feeds1. Natural fish feed- Live feed2. Artificial fish feed

Live feed: Live feed or fish food organisms are microscopic organisms naturally present in the aquatic environment as primary food for the larvae of fin fish and shell fish. Their size ranges from a micron to few millimetres. They are tiny forms which suits the mouth size of all kinds of fin fish and shell fish larvae.

• A few carnivores are notoriously difficult to wean off live food and may become stressed if they lack the chance to hunt. Live food includes various worms and insects, as well as fish, most often guppies, Mollies (sometimes in saltwater tanks) or goldfish. Aside from personal squeamishness, the biggest problem with live foods is the potential for introduction of fish disease.

• Many carnivores respond to live food in a way that they don't respond to any other food.

• Although Natural Food has minimal feed costs, ready availability, and good source of nutrients, it also has some disadvantages. These are

1. Lack of control (i.e. quality or quantity can impact on health of stock).

2. Unable to manipulate feed quality to ensure nutritional requirements are met.

3. Lower survival and growth rates compared to artificial feeds.

Contnd…

Artificial fish feed:• Prepared or artificial fish feeds may be

either complete or supplemental. Complete diets supply all the ingredients (protein, carbohydrates, fats, vitamins, and minerals) necessary for the optimal growth and health of the fish.

• In case of aquarium artificial fish feeds are essential. Unlike pond or other natural water bodies, aquarium does not able to produce required fish food organism in its closed system.

• Aquarium fishes mainly depend on the artificial food for their nutrition. As we no live feeds are not able to give all essential nutrients for fish nutrition so artificial food is required.

Classification of artificial feed according to preparatory methods:Dry feed - It is in dried form with 8-10% moisture. It is further classified into 5-subgroups:Pellets.Flakes- are flat in structure. Freeze-dried feed – they are in frozen form.Tablet form.Granular form – they are very small and round shape. They are similar to grains.Moist feed – It is prepared daily and fed to fishes – the moisture content is 35%.Paste feed – This is mainly prepared for young ones of all. The feed ingredients are made into paste and fed to the fishes squeezing through mesh.

Types Of Artificial foods:• The ‘manufactured’ foods can be broadly

classified as dried, freeze-dried & frozen diets.

Dried foods: Dried foods such as flakes, pellets,

sticks & tablets are widely available and are convenient to use. Many types of dried foods specially flaked foods, features special ‘growth, colour and vegetable’ diets.

Most dried foods have a limited shelf life and generally they should be used within a few months of purchase. Although they can still be used after this period, the vitamin levels decrease with time. Bulk buying of flaked foods, therefore, can sometimes be a false saving.

Frozen Fish Food: This is simply whatever ingredients are frozen. Often, it's frozen into little blocks that are more easily cut apart. This food is full of the ingredients 'original nutrients’, with nearly nothing lost in the minimal processing. There have been reports of disease being introduced via frozen foods. Many bacteria and viruses are capable of surviving freezing, allowing this to happen. In a healthy tank, such an introduction is unlikely to cause harm, but it is still a possibility.

Freeze-dried Foods: Includes tubifex, mosquito larvae, blood worms, daphnia (water fleas) and brine shrimp, krill and a large number of other terrestrial and aquatic invertebrates. These foods are excellent treats for many fish, and are good base food for some carnivores. Freeze-dried foods are almost guaranteed to be free of contaminants that are sometimes a concern with live and frozen foods.

Vacation food:Vacation foods, also known as "food blocks" (or "weekend blocks" for smaller versions), are designed to be placed inside the aquarium to forego feeding while the owner is absent. These blocks release small amounts of food as they dissolve. Food blocks can be a good choice for smaller tropical fish, but can pollute the water if the tank is neglected for too long.

Another two types:

Medicated fish foodMedicated fish food is a safe and effective method to deliver medication to fish. One advantage is that medicated food does not contaminate the aquatic environment and also, unlike bath treatments, does not negatively affect fish, filtration and algae growth in the aquarium. The parasites will get treated on spot by medicated food, because the fish is ingesting it.

Sources of fish food Fish meal: Fish meal (protein source) have two basic types: (a) those produced from fishery wastes and,(b) those from specific fish (such as herring) which

are harvested solely for the purpose of producing fish meal.

Squid meal: It is a highly digestible protein source for fish which provides a full range of amino acids, vitamins, minerals and cholesterol (1.0–1.5%) of cholesterol suitable for fish fry and young fish.

Shrimp meal: It is a source of pigments that enhances the desirable colour in the tissues of fish. It is also a secondary supplemental protein source for fish.

Soybean meal: It is a high protein source for fish and has become a substitute for traditionally-used marine animal meals.

Whole wheat: Whole wheat (carbohydrates) is not the best source of energy in fish but is an excellent source of roughage for fish such as Goldfish and Koi. It is also a natural source of vitamin E which promotes growth and enhances coloration.

Brine shrimp: Brine shrimp (Artemia) is a source of protein, carotene (a colour enhancer) and acts as a natural laxative in fish digestive systems. Brine shrimps can also supply the fish with vegetable matter due to their consumption of algae.

Spirulina: Spirulina is a blue-green plant plankton rich in raw protein, vitamins A, B1, B2, B6, B12, C and E, beta-carotene, colour enhancing pigments, a whole range of minerals, essential fatty acids and eight amino acids required for complete nutrition.

Components of artificial feed:• Ornamental fish require a high-quality, nutritionally

complete, balanced diet to grow rapidly and remain healthy.

• Artificial fish feed has essential nutrients, pigments, binding agents, preservatives and also attractants.

1. Proteins: Because protein is the most expensive part of fish

feed, it is important to accurately determine the protein requirements for each species. Protein helps to build up muscle and tissue. Sources include fish meal, soyabean meal, fish hydrolysate, skin milk powder, legumes and wheat gluten. Pearson Square method is generally followed to estimate protein level.

2. Lipids – Lipids (fats) are high-energy nutrients that can be utilized to

partially spare (substitute for) protein in aquaculture feeds. Lipids supply about twice the energy as proteins and carbohydrates. Lipids typically comprise about 15% of fish diets, supply essential fatty acids (EFA) and serve as transporters for fat-soluble vitamins.

Oils from marine fish, such as sardines and vegetable oils from canola, sunflower and linseed are common sources of lipids in fish feeds.

3. Carbohydrates – Carbohydrates (starches and sugars) are the most

economical and inexpensive sources of energy for fish diets. Although not essential, carbohydrates are included in aquaculture diets to reduce feed costs and for their binding activity during feed manufacturing. Dietary starches are useful in the extrusion manufacture of floating feeds.

4. Vitamins: Vitamins are organic compounds necessary in the diet for

normal fish growth and health. They often are not synthesized by fish, and must be supplied in the diet.

5. Minerals: Minerals are inorganic elements necessary in the diet for

normal body functions. They can be divided into two groups (macro-minerals and micro-minerals) based on the quantity required in the diet and the amount present in fish.

6. Pigments – Mainly carotenoids are added to improve the colour of the fish. Astaxanthin is the commonly used additive (100-400 mg/kg). Natural sources includes Cyanobacteria (Spirulina), dried shrimp meal, shrimp & palm oils and extracts from marigold.

7. Binding Agents – Apart from these, binders like Guargum or Carboxy Methyl cellulose is added at 0.2% -1% level to increase the water stability of feed.

8. Preservatives - Preservatives, such as antimicrobials and antioxidants, are often added to extend the shelf life of fish diets and reduce the rancidity of the fats. Vitamin E is an effective antioxidant. Commonly available commercial anti-oxidants are butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and ethoxyquine. Sodium and potassium salts of propionic, benzoic or sorbic acids, are commonly available anti-microbials added at less than 0.1% in the manufacture of fish feeds.

9. Attractants - Other common additives incorporated in the fish feeds are chemo attractants and flavourings, such as fish hydrolysates and condensed fish soluble (typically added at 5% of the diet). Basically, attractants enhance fish pallatibility and its intake.

Storage Procedure of Fish Feed:

Freezer bags serve to store the prepared feeds, and using a bag vacuum sealer will greatly extend the shelf-life of both ingredients and the feed. The feed can be stored double bagged in the freezer but should be discarded after 6 months. Ideally, dried larval feeds are not frozen but stored in the refrigerator for no longer than 3 months.

How to feed the Fish? Feeding should be done at regular time everyday. It is vital that fishes are offered a relatively small amount of food, which should be consumed within 5 – 10 min of being placed in the tank. Overfeeding and under-feeding should be avoided. Overfeeding results in polluting water quality(ammonia concentration) due to accumulation of uneaten feed and faecal matter. Under feeding results reduced growth rate of fishes due to insufficient feed. Amount of Feed given:Per day = Biomass × Percentage of body weight of feed per dayBiomass can be calculated using the following formula.Biomass = Stocking density (in nos.) × Survival rate × Average body weight.

Protein Fat CarbohydrateSmall fishes 40-50% 4-6% 40-50%Large fishes 30-35% 6-8% 50%

Table : Nutritional requirements of small and adult fishes

Merits and Demerits of Artificial Fish Feed: Merits:• Specifically formulated for aquacultural use. These are properly

balanced with different types of nutrients.• Contains essential nutrients to meet the requirements of different

species. • Can be manipulated to suit developmental stages for a range of

species. • Consistent quality. • Readily available. • Wide variety and types. Demerits:• Expensive to purchase .• Requires refrigerated storage.• Overfeeding with artificial feed may cause water pollution.• Improper storage may cause contamination.

Conclusion: Aquarium fishes are dependent upon the aquarist to provide

them with a correct balanced diet, the overall effects of which will be seen in their colouration, growth, resistance to disease and their willingness to breed.

Today, using the high-quality flaked and similar prepared diets that are available from pet and aquatic dealers most easily and conveniently provide a balanced diet for aquarium fish. Such foods have now largely replaced the old fashioned, inconvenient and often potentially dangerous to made and live foods were so popular.

Furthermore, research on influence of nutrition on ornamental fish is hampered by a lack of suitable measurement other than growth. Whereas the measurement of skin colour is possible through well-established subjective and objective techniques, this would evaluate the influence of only carotenoids as dietary component.

References:• www.google.com• www.wikipedia.com• “ornamental fish culture & aquarium management” by Dr. A. D. Dholakia.• “Aquarium Fish: Survival Manual” by Brian Ward.

• Thank you……

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