Ingredients and Manufacturing Process for Fish Feed (Shinking & Floating) Formulation
General Fish Feeding practice by the farmers:
Feed has got a significant impact on the quality, safety and nutritional value of farmed fish. The feed requirements of fish vary in quantity and quality according to the feeding habits, physiological stages of the species and environmental variations viz., temperature; amount and type of natural food availability in the culture system.
There are three factors to consider in the choice of feed ingredients for aquafeeds, (i) quality – nutrient composition and presence of any anti-nutrients (substances that interfere directly with the absorption of nutrients or contaminants); (ii) quantity – quantum of availability; and (iii) price of ingredients. Also, the other challenges of fish feed management are feed formulation, feed processing, storage, handling and transport.
Carps are omnivorous in feeding habit. Feeding practices for IMC can be divided into three parts. (i) The natural feed: Pond preparation by using Mohua oil cake and lime is very essential to fulfill the requirement of plankton production in pond. Mohua oil cake is essential as it eradicates the weed fishes first but after that it is used as pond manure which helps to produce plankton in fish pond. Apart from using as a fertilizer lime also provides calcium which is very important to fish. Apart from Mohua oil cake and lime there are so many other manures and fertilizers are added to the pond for the production of the natural food. For example, raw cow dung, poultry manure etc. are using as manure and single super phosphate, urea etc. are using as fertilizer.
Majority of the micronutrients get available from the pond. (ii) Farm-made feed: Farmers in our country uses farm-made feed by using ingredients that are available locally to feed IMC. The ingredients that are used by the farmers are discussed below. (iii) Supplementary feed: Along with the farm-made feed, farmers also provide supplementary feed to the ponds to fulfill the nutritional requirements of fishes. The ratio of far-made feed and supplementary feed is about 70:30. Usually, farm-made feeding is done in the morning and supplementary feeding is done in the evening.
Feed ingredients used in farm-made feed:
Feed ingredients sources that are used by the farmers in most of the farms are mustard oil cake, ground nut oil cake, soybean cake meal as protein source. Cereals like rice bran, wheat and its by-product, maize, boiled rice, broken rice and other millets are used as energy source. Some non-conventional feed ingredients used are meat meal, guar gum, poultry by-products etc. Some 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 used as feed ingredients that cater to dietary fat requirements. It is to be noted that, the proportion of ingredients in the feed changes with the changing environment and fish health condition. Hatchery owners also use chick-pea, jaggery, salt etc. as feed ingredients of brooder fishes.
Farm made feeds are an ad hoc concept for start-ups in aquaculture, where the volume of feed requirement is small and resources and funds are limiting. Farm-made feed is not only cost effective, but can also judiciously make use of available feed ingredients and generate employment and livelihoods. Through farm-made feed omega-3 enriched carps could be produced. The “Fish Feeds” outreach activity provided ample opportunities for research and extension activities towards improving fish production and sustainability by adopting multidisciplinary research in a network mode by the participating institutes with the cooperation of aqua-farmers and feed manufacturers.
Composition Of Fish Feeds:
Fish feeds, like other animal feeds, can be divided into six main compounds :(1) water, (2) protein, (3) fat, (4) ash, (5) crude fiber, and (6) nitrogen-free extract. The main features of fish feed are protein and fat content. The protein in the diet is mainly used for the accumulation of tissues, fat is the main source of energy and the increase of adipose tissue. The amount of carbohydrates in fish feed is usually low because fish, especially carnivorous fish, are less able to digest carbohydrates. Therefore, the energy in the diet must come from fats and fats have higher energy density than carbohydrates. As a result, fish feed is more concentrated than that of farm animals on land, so protein levels (up to about 40-45%) and energy density are higher. The digestible protein/digestible energy ratio is an important feature of a fish feed and, as a rule of thumb, should more or less resemble the protein/energy ratio of the growing fish itself. In this way, maximum retention of dietary protein (an expensive component of fish feed) is achieved.
Fish Feed Extruder Machine:
Fish feed extruder is a necessary equipment for small and medium-sized fish farms and fish feed processing plants.
Basic Ingredients For Fish Feed Formulation
Fish meal
Fish oil
Rice bran
Shrimp bran
Wheat bran
Soybeans cake
Cotton seed cake
Dried potatoes etc.
The Essential Nutrients Required For Fish Feed Formulation
Protein:
Protein is a very essential nutrient for fish feed formulation. This is because protein is the main source of energy for fish. Fish need two or three times as much protein as other animals for energy.
Minerals:
Minerals are another essential nutrient in fish feed formulations. This is a necessary condition for the development of fish bones. Therefore, the production of fish feed must include minerals such as zinc, copper, iodine, iron, manganese and calcium.
Vitamin:
Fish are very susceptible to bacteria. So fish need vitamins to build a strong immune system. It should be noted that the amount of vitamins contained in the fish feed formula should be minimal.
Other nutrients required for fish feed formulation include water, fat and carbohydrates.
Fish Feed Formulation Manufacturing Process
Grinding of Ingredients:
In a fish feed formulation, the first thing you do is measure all the necessary ingredients in specified proportions and grind them one by one.
Mixing of Ingredients:
The next step is to mix all the dry ingredients that are already grounded. You need a fish feed mixer to make it. After mixing the dry ingredients, you should mix the vitamins and minerals together.
Add Water and Oil to the Mixture:
Warm the oil, add it to the mixture and mix everything together for at least five minutes. Then add a little water at a time. Mix it with the mixture until it forms a mash.
Process the Feed Mash in a Pellet Machine:
The fish feed mixture is put into the fish feed extruder so that it can be processed into pellets. The size of the pellets will depend on the size of the fish that wants to be feed.
Fish Feed Extruder
Dry the Fish Feed Pellets:
After granulated mash is formed, it is then dried in a fish feed dryer to reduce the moisture content. Pellets should be dried at a lower temperature than 60 degrees. This is because high temperatures can destroy micronutrients found in the feed.
Cooling technology:
The pellets are usually cooled in Counter-flow type feed cooler, where cool air takes away some heat and water. The pellets can be packaged at room temperature. If the pellets are cooled without drying, a large number of small cracks will appear on the surface and extend deep due to rapid cooling and dehydration inside the pellet. Even fine gelatinized powders may produce this phenomenon.
Classifying Screener:
After pelleting, drying and cooling, unfinished products should be screened by screening. Powder and debris leach from the bottom of the machine. Sieve out large particles and residues from the top of the machine. Finished materials are packed from the interlayer in the feed column.
Fishes are being fed with the extruded floating feeds replacing the traditional method of feeding with the raw materials .
Aquatic animals cannot digest starch effectively resulting in excessive excrement which causes physiological problems such as excessive gas, bloating diarrhoea and these apart, from affecting the growth of the fish also lead to water pollution.
Easy digestion
The extrusion which is a high temperature and short duration process cooks the materials killing the germs and pathogens and makes the feed easily digestible.
The response from farmers is encouraging as the use of extruded floating fish feed comes with a host of advantages in terms of digestion ,growth, water protection, zero water pollution , optimized labour usage and zero wastage of raw materials
In the traditional method of fish farming, a mixture of de-oiled cakes/ or rice bran is used for feeding the fishes.
The mixture normally settles down at the pond bottom causes water pollution. There is also a lot of wastage which otherwise could have been used for other applications
Since the raw materials are not formulated well, the growth of the fish takes longer duration of time involving higher feed conversion ratio.
Traditional feeding
For traditional feeding about 4-5 kgs of raw materials is required to produce 1 kg of fish. Whereas through extruded feed one requires about 1.2 kg to produce 1 kg of fish
Extruded feed is much more safe, because fed ingredients can be pasteurized or sterilized during feed extrusion operation, thus reducing the effects of feed on the health of aquatic animals and water quality.
The latest evolution of the aquaculture diet has been the introduction of extrusion. This production technique has brought two great benefits. The first is to be able to choose the degree of floatation of the food, by acting on the density of the extrudate. This allows today to have floating granules, or semi-floating. In fact, the behavior of food in the water column is a very important aspect to support the attitudes of different species of fish to food. The second advantage provided by the extrusion process concerns the possibility of considerably increasing the lipid percentage of the food, thanks to its porosity. This has led to the formulation of high energy diets containing up to 30 to 35% lipids.
The amount of fat contained in an aquaculture feed is of great importance for the use of nutrients by high aquatic organisms. Fish, especially carnivorous species (Salmonidae), have a low digestive capacity in carbohydrates. They prefer to use proteins and fats as a source of energy. A diet capable of providing the energy needed to metabolize fish through lipids allows for a large saving of proteins, which will then be used more for growth and flesh formation, instead of energy source.
Using less protein for energy purposes is important for both:
Have a cheaper diet, given the cost of fishmeal.
The use of amino acids as a source of energy encourages the release of pus of nitrogenous material by fish, which has a major impact on the pollution of aquatic environments.
Aquaculture is the fastest growing zootechnic sector in the world. Its annual growth rate has been 10% in recent years. The expansion of the sector has been very rapid in recent decades, leading to an ever-increasing demand for raw materials for the production of fish feed, particularly fish-derived meals and oils. These two ingredients come mainly from the processing of small pelagic fish caught and not intended for direct human consumption. Only a marginal part of the fishmeal and fish oils used in feed formulation comes from the processing of fish waste for human consumption.
Replacing fish oils and meal with other plant-based products was also needed to address the sustainability issue by looking at the relationship between the amount of fish used in food formulation and the amount of high fish. This relationship called “fish in fish”, was very unfavorable in the past, some fish production using up to 5 kg of fish caught to produce 1 kg of farmed fish. Now, thanks to progress in feeding, this ratio has been reduced for all species raised, even for strictly carnivorous species. For example, today a farmed salmon is able to grow faster, ingesting less fish for its nutrition than a specimen of the same wild species. Thanks to the genetic selection of farmed fish and the formulation of increasingly balanced feeds, the aquaculture sector is able to provide extremely efficient feed conversion indices, the best of all animals in the world. For some species, we have indices below 1, that is, less than 1 kg of food, which contains more than 95% dry matter, is required for the growth of one kg of fish.
Dr.BK Saha, Aquaculture consultant,Kolkata
Reference-On request
