COMPARISON BETWEEN PELLETED AND EXTRUDED AQUACULTURE FEEDS: PRODUCTION PROCESSES, FISH PREFERENCES, AND MARKET EXAMPLES IN AFRICA

By: Dr Eman Abo Shady. Researcher in Aquaculture / Sustainable Aquaculture Biology. Food Technology. Cairo, Egypt.

Aquaculture feeds play a crucial role in determining the growth, health, and overall productivity of fish farms. Pelleted and extruded feeds are the two main types used in the  industry,each with it sown production process, benefits, and drawbacks. Understanding the differences between these feeds, their production methods, and the fishs pecies that prefer the misses entail for making informed decisions, especially in the context of Africa’s growing aquaculture industry.

1. Pelleted Aquaculture Feeds

1. Production Process

The production of pelleted feeds involves several key steps:

• Ingredient Selection and Grinding: Raw materials, such as fishmeal, soybean meal, corn, and vitamins, are selected based on the nutritional needs of the target fish species. These ingredients are ground into a fine powder to ensure uniform mixing and pellet formation.
• Mixing: The ground ingredients are thoroughly mixed to create a homogenous blend. This step is crucial to ensure that every pellet contains a balanced composition of nutrients.
• Conditioning: The mixed feed is conditioned by adding steam and water to soften the ingredients. This makes it easier to form pellets and improves the binding of the feed particles.

• Pelleting: The conditioned feed is forced through a die using a pelleting machine. The die can vary in size depending on the desired pellet size, which is selected based on the fish species and their life stage. The feed is compressed under moderate pressure (typically70- 90°C), which helps to bind the ingredients together without fully gelatinizing the starch.
• Cooling and Drying: After pelleting ,the feed is hot and moist. It is passed through a cooler and dryer to reduce its moisture content and temperature. This step is essential to prevent mold growth and ensure the feed has a longer shelf life.
• Sieving and Packaging: The pellets are sieved to remove any fines or broken pieces, and then they are packaged for distribution.

• Fish Species That Prefer Pelleted Feeds

Pelleted feeds are suitable for a variety of fishs pecies, particularly those that are commonly farmed in Africa. These species typically do not require highly processed or floating feeds:

• Tilapia: Tilapia are often fed pelleted feeds, especially in smaller-scale operations. The yare highly adaptable and can thrive on a wide range of feed types, making pelleted feed an affordable option.

• Catfish: Like tilapia, catfish are commonly fed pelleted feeds.Their feeding habits make them less dependent on floating feed, allowing for the use of sinking pellets.

• Carp: Carp species are well-suited to pelleted feeds. They are bottom feeders and can efficiently consume sinking pellets.

• Market Examples of Pelleted Feeds in Africa

-Zambia’s Skretting Pelleted Feeds: These feeds are designed for tilapia and catfish and are popular among small-scale farmers for their affordability and local availability .

-Uganda’s Ugachick Pelleted Fish Feed: Ugachick produces arrange of pelleted feeds suitable for tilapia and catfish, targeting different growth stages.

1. ExtrudedAquacultureFeeds

        1. Production Process

The production of extruded feeds involves a more complex process, which includes the following steps:

• Ingredient Selection and Grinding: Similar to pelleted feed, raw materials are selected based on nutritional requirements and ground in to affine powder. The grinding processis more critical here, as the finer the grind, the better the extrusion quality.
• Preconditioning: The ground ingredients are mixed with steam and water in a preconditioner, which starts the cooking process. This step is essential for preparing the ingredients for extrusion.
• Extrusion: The preconditioned feed mixture is fed into an extruder, where it is subjected to high pressure and temperature (up to 150°C). The feed is cooked and the starches are gelatinized, making the nutrients more digestible. The extruder forces the feed through a die, and as it exits, the pressure drops rapidly, causing the feed to expand and often float.
• Shaping and Cutting: The extruded feed is cut to the desired length as it exits the die. The shape and size of the feed can be easily adjusted by changing the die configuration, allowing for the production of different pellet shapes and sizes.

• Drying and Cooling: The extruded pellets are dried to reduce moisture content and then cooled to prevent spoilage. This step also ensures that the feed retains its expanded shape and texture.
• Coating: In some cases, the extruded pellets are coated with oils, vitamins, or other nutrients after drying. This process can enhance the nutritional profile and palatability of the feed.

• Sieving and Packaging: The final product is sieved to remove fines and then packaged for distribution.

• Fish SpeciesThat PreferExtruded Feeds

Extruded feeds are particularly beneficial for species that require floating feed or have specific dietary needs that are better met by the extrusion process:

• Tilapia: While tilapia can consume pelleted feeds, they also benefit greatly from extruded feeds, especially in intensive farming systems where feed conversion efficiency is critical. Floating extruded feeds are easier to monitor and reduce feed waste.
• Catfish: In commercial operations, catfish are often fed extruded feeds, particularly floating pellets, which are easier to monitor and manage in large ponds or tanks.
• Trout: Trout are carnivorous fish that require a high-protein diet. Extruded feeds, which can include higher levels of protein and fat, are ideal for meeting the nutritiona lneeds of trout .
• Shrimp and Marine Fish: Although less common in Africa, shrimp and marine fish species, such as seabass and seabream, also prefer extruded feeds due to their higher digestibility and specific nutrient requirements.

• Market Examples of Extruded Feeds in Africa

-Egypt’s Aller Aqua Extruded Feeds: Aller Aqua provides arrange of extruded feeds for tilapia and catfish, tailored to different growth stages. Their floating feeds are widely used in commercial aquaculture operations in Egypt .

-South Africa’s Nova Feeds: Nova Feeds produces high-quality extruded feeds for trout, tilapia, and catfish. These feeds are formulated to provide optimal growth and feed conversion ratios, particularly in intensive farming systems .

-Nigeria’s *Coppens (DeHeus): Coppens is known forits floating extruded feeds,which are popular in Nigeria’s aquaculture sector. These feeds are designed to maximize growth rates and minimize environmental impact.

1. Comparative Analysis in the African Context

1. EconomicConsiderations

Pelleted feeds are generally more affordable and accessible to smallholder farmers, who dominate the aquaculturel and scape in many African countries. However, extruded feeds, with their higher nutritional efficiency and reduced environmental impact, are becoming more popular among commercial operations, where the higher initialcosts are offset by improved feed conversion ratios and better fish growth.

• Environmental Impact

The use of extruded feeds, which have higher digestibility and result in less waste, is particularly important in regions where water quality is a concern. However, the higher energy consumption in the extrusion process must be considered, especially in areas with limited access to affordable energy sources.

• Technological and Infrastructural Factors

The availability of technology for producing extruded feeds is still limited in many parts of Africa. Countries with more developed aquaculture sectors, such as Egypt,  ,and Nigeria, have adopted extruded feed technology, while other regions rely more heavily on pelleted feeds due to the lower technological and capital requirements.

• Feed Supply Chain

The supply chain for aquaculture feeds in Africa varies widely. Pelleted feeds, which can be produced with simpler equipment and are often locally available, dominate in regions with less developed infrastructure. Extruded feeds, which require more sophisticated production facilities, are generally produced in centralized locations and distributed through more complex supply chains.

1. Conclusion

The choice between pelleted and extruded aquaculture feeds in Africa depends on various factors, including the species being farmed, the scale of the operation, economic considerations, and environmental impact. While pelleted feeds offer an affordable and flexible option for many African farmers, extruded feeds provide superior nutritional efficiency and environmental benefits, making them increasingly popular in commercial aquaculture. Understanding the specific needs of the fish species being farmed and the local context is essential for selecting the most appropriate feed type.

Source: Aquaculture Feed Magazine Africa. Issue 3, Volume 2; 2024.