Extruded Aqua Feeds vs Pelleted Aqua Feeds

Extruded Aqua Feeds vs Pelleted Aqua Feeds

In recent years, the rapid development of aquaculture industry, but also caused a wide range of applications in the aquaculture feed industry. Aquatic feed is designed for aquatic animal breeding, according to the type of feed can be divided into fish feed, shrimp feed and crab feed, according to the production process can be divided into pellet feed and extruder feed, and divided into mixed feed, concentrated feed and premix feed according to fodder features.

The raw materials of aquatic feed mainly consist of fish meal, cereal raw materials and oil, among which the first two always account for more than 50% of the cost of feed. Due to the small intestine of fish, lack of good digestion and absorption capacity, the fish feed processing technology requirements are far higher than the requirements of livestock feed, so the choice of appropriate fish feed manufacturing machine and technology is particularly important.

Machines for Making Extruded Aqua Feeds

Through the fish feed extruder we can use cheap local raw materials to produce high-quality aquatic feed, which may save your feed costs.

Difference Between Pellets and Extruded Feed

Today, the two most widely used techniques for producing aquatic feed are pelleting and extrusion. The feed produced by these processes is denser, has a lower moisture content and can be better preserved.

Pelletisation consists of compressing small particles to create larger ones called pellets, and during this process, moisture, temperature and pressure come into play. One of the main advantages of pellet feed is that compared with extrusion technology, the manufacturing cost is lower; However, it has many disadvantages that can be solved by extrusion technology. One of the biggest disadvantages of pelleting is its rapid sedimentation (estimated to result in a 10 to 15 per cent loss of granular feed), which means higher feed costs, less profitable products and greater environmental impact from pollution. In addition, the nutrients in the pellets dissolve faster in the water, so the quality of the fish feed is lower than that of the extruded feed.

The extrusion process is widespread today, as it can be used to manufacture all kinds of feeds, whether buoyant, fast or slow sinking, depending on the needs of each species.

Extrusion is a process involving high temperatures and short times, which minimises nutrient loss while improving the digestibility of starches and proteins compared to pelleted food. Extrusion is the process by which food is not only pressed into pellets but also “aged”, which is why it requires higher levels of water, temperature and pressure than granulation. When leaving the extruder, all these requirements must be met to achieve the desired degree of expansion. In addition, as mentioned above, its other benefits include lower pollution, longer water stability (from 12 to 36 hours) while maintaining all nutrients, higher digestibility, high efficiency and high conversion. Therefore, extruded feed is a high quality product that can improve the profit of fish farms.

How to Choose the Suitable Fish Feed Pellet

Fish feed cost accounts a large proportion of production coasts for fish farmers. Feed pellet is widely used in fish farming. Only choosing the high quality and right fish feed pellet can improve the feed utilization rate, the growth rate and the immune system to prevent diseases. So fish farmers have to learn how to choose the suitable fish feed pellet.

First, the nutrition of fish feed. The basic nutritional requirements of fish are protein, fat, carbohydrates, vitamins and minerals, etc. Therefore, fish feed must contain these substances. Some breeders believe that the higher the protein content, the better the feed particles. In fact, it is wrong that the quality of feed particles should consider not only the protein content, but also the proportion of other nutrients. Feed with balanced nutrients is an ideal choice for normal fish growth. Feed pellets use a variety of grains such as wheat, corn, and beans as feed components and can be added with protein, fish meal, minerals, and other liquid nutrients. So it can meet the nutritional needs of fish.

Second, the appearance of feed pellet. High quality feed pellets have a smooth surface and the same pellet diameter. The grain size of the fish feed should take into account the diameter of the fish and should not be too large or too small. Feed pellets should be twice the length of their diameter to increase feed intake and reduce feed waste.

Third, the stability in water. Fish eat slowly, so the feed pellets must remain in shape in the water for a long time. Fish farmers can buy samples and put them in water to test their stability before buying fish feed pellets.

Processing Differences

This brings us to the actual process differences. The feeding system is similar because both systems even require raw material feeding and volume or weight transfer control. Weight transfer or gravimetric analysis is common in extrusion cooking because it allows for more precise control of process additives such as water and steam as well as other liquids or solids. Why higher accuracy is required for extruding when more accurate particle properties can be obtained by adding additives by weight?

Precise diameter, density, oil absorption expansion rate, sinking rate, etc. are all controlled by process and addition. It has been shown that the above adjustment system is usually more advanced on extrusion cookers. The rotation speed, retention time and mixing effect are controllable to accurately contain and go to the uniformity of the pretreated material of the extruder. This is necessary because higher levels of liquid are used in the extrusion. It is not uncommon to add water in the 30% medium water range when extruding certain types of aquatic feeds. Pelleting is limited to liquid or percentage water content of about 17-18%.

Pellet Machinery for Making Aquatic Feed?

The most commonly used machinery for fish feed pellet making is fish feed extruder, which is used to produce extruded fish feed pellets. According to the different extrusion technology, there are two types of fish feed extruders: dry fish feed extruder and wet fish feed extruder. By using different types of screw to control the density of finished fish feed pellets, the fish feed extruder can produce floating, sinking and slowly sinking fish feed according to the feeding characteristics and habits of fish; Extruding fish feed particles can produce aquatic feeds of different sizes and shapes. Extruding fish feed pellets remain stable in water for a long time, thus reducing nutrient loss. Extruding pellet machinery can make aquatic feed more resistant to mechanical durability and less fines during transportation.