Fish Feed Extrusion Blog – Fish Feed Formulation and Production (Catfish)

About Sunpring fish feed formulation and production. The importance of offering fish a complete natural feed cannot be understated. From increasing feed efficiency to ensuring rapid weight gain, it goes a long way in enhancing the right growth and development of fish for sale. A complete fish feed contains all the elements and nutrients required by fish for growth. However, the cost of feed stuffs can be very high. Hence farmers should factor in feed selection and use, especially when rearing catfish.

The common idea is to process fish feeds instead of buying them. But the process is complicated, requiring an exceptional composition of proteins, fats, and other nutrients. Fish feeds are typically prepared via food extrusion, producing pellets which easily float in water thus making it easy to feed the fish. 

Feed formulation and ingredients

Because catfish are unique, no single constituent can provide all the nutrients and energy needed for proper growth and development. Most commercial catfish feeds contain a mixture of vitamins, foodstuffs and other mineral contents that offer the necessary nutrients and energy required by the catfish. When designing the feed, the type and quantity of each feed depend on several factors which include ingredient cost, nutritional requirements, and availability of each ingredient as well as the processing characteristics. 

Protein supplements

Feed-stuffs with twenty percent or more crude protein content are known as protein supplements. These supplements can be obtained from plant or animal sources. Animal protein supplements are often derived from inedible tissues such as marine sources, milk products, and bones. Examples of these feeds prepared from animal sources include catfish offal meal, blood/bone meal, marine fish meals and poultry byproduct meal. 

Unlike plant proteins, animal proteins such as fish meal are higher in quality and are often considered an essential nutrient for fry and small fingerling catfish. These animal proteins can also be supplemented by other animal and plant proteins to enhance growth and feed efficiency. Animal proteins can be replaced or supplemented by plant sources such as cottonseed meal, peanut meal, and soybean oil. 

Energy supplements

On the other hand, energy supplements refer to feed-stuffs that contain below 20% crude protein content. Examples of these supplements include vegetable oil, animal fats as well as grain and grain by-products. Apart from providing energy to the catfish, energy supplements are essential in preventing the dietary protein from being used for energy purposes. Conventional energy sources used in commercial feed production include fish oil, corn, wheat grain, Milo, rice bran and animal fats.

Catfish feed formulation

Most commercially prepared catfish feeds are prepared based on a fixed formula with little or no use of computer-aided programs. In most cases, a least-cost computer program is used to prepare feed formula. However, when using a least-cost computer program to create the feeds, the manufacturer must know the nutrient concentrations in the feeds, nutrient requirements, the cost of feed ingredients, as well as nutrient availability from the feed-stuffs and nutritional restrictions. 

Today, the use of the least-cost approach to preparing the feeds is limited because little is known about the nutrient levels that increase the profit margin about levels that can result in maximum weight gain in catfish. Moreover, preparing a multitude of feed-stuffs on a timely basis is not easy. Even so, most manufacturers use a simplified approach of the least-cost method to prepare fish feeds. Below are some examples of processes involved in the preparation of fish feeds.

Premixing

At this stage, nutrients, vitamins, and other mineral complexes are added and mixed with the grains. These nutrients are usually added in excesses to make for the losses that may occur during production and storage. 

In commercial preparation of feed-stuffs, mixing is done mechanically in a mixing chamber until a high-quality nutritional feed is obtained. 

Processing of fish feed

The main aim of this preparation is to increase the profit margin in fish production by enhancing the nutritional value of the feeds mixture. In typical cases, the main processes in feed preparation include, mixing, grinding and extrusion. In other cases, steam pelleting can be used in place of extrusion although extrusion is widely recommended. 

The extrusion process is widely preferred because of many reasons. For instance, it ensures that the feeds are pelleted and water stable, so they float easily on the water surface.  

Therefore, extrusion is an important process in the commercial production of catfish feeds. If a particular nutrient or feed additive cannot withstand extrusion, the feed-stuff can be processed via steam pelleting into a sinking pellet. To reduce the formation of fine particles, fats and oils are sprayed on the pellets after extrusion. 

Why extrusion is essential in fish feed production

Here are more reasons why extrusion is essential in fish feed production:

• High-fat pellets.

  Extruded aqua pellets can take in more fats compared to pelleted feeds. Different coating systems such as atmospheric and vacuum approaches can be applied to add fats to the pellets. Today, it is possible to produce aquatic feeds with up to 50 percent fats, thanks to the food extrusion technology.

• Varying the size of pellets.

  It is feasible to produce different sizes and shapes of aquatic feeds using extrusion technique. These sizes may range from 0.6mm to about 60mm. The size of the pellets is important because small fish cannot feed on large pellets. Thus each fish can find its appropriate feed.

• Production of soft aquatic pellets.

  Extrusion processing allows production of very soft pellets with up to 30 percent or higher moisture content. These soft pellets are suitable for feeding fish species such as blue tuna.

• Mechanical resistance of pellets.

  Feeds manufactured via food extrusion are more resistant to mechanical durability and produce less fine particles in the finished feed.

• Water absorption of the feeds.

  The moisture content of the extruded pellet can be regulated over a wide range during the extrusion process. This phenomenon is important in enhancing water stability of the finished product. In essence, extruded pellets absorb more water thus retain their shape for a long time, reducing the loss of vital nutrients.

• Enhanced storage.

  Unlike fresh feeds, extruded feeds can be stored for a long time because they are free from disease and virus transmission. Most importantly, feeding extruded pellets in large ponds is less labor intensive unlike when using fresh trash feeds.

• Hygienic qualify feed produced.

• Use of wet materials in the pellet.

  After extrusion, the pellets are taken into a dryer that helps to lower high moisture and temperature. Here, low temperatures of less than 80ºC are commonly used.

Conclusion

Extruded fish feeds provide all the essential nutrients needed by the catfish. Since most commercial feeds are almost similar in quality, composition and are efficient for faster growth of fish, farmers should consider making their feeds using the extrusion technology.