5 key factors for the future of aquaculture nutrition

Global aquaculture has come a long way since people first began fish farming. Over the years, improvements in management systems and aquaculture feed mean that we can now produce more food than ever before. However, with the demand for food fish rising alongside a growing global population, the future will see further changes in this industry. Here are some of the current main developments that will define the next steps in aquaculture’s legacy.

Increased application of recirculating aquaculture systems (RAS)

Recirculating aquaculture systems (RAS) are not a new topic. This farming method has been around since the 1980s and used intensively in the Atlantic salmon industry for many years. However, it has taken the rest of the aquaculture industry almost 20 years to embrace it.

There are several reasons why RAS is the future, but the primary reasons are:

• Sustainability
• Efficiency

To operate a successful RAS, feed must be optimized to increase palatability, reduce water pollution and allow both the system and the fish perform at their best. As RAS facilities are land-based operations, there is reduced pressure on pond/sea stocks. Also, advancements have been made to recycle existing water in these facilities, preventing a further drain on resources.

Further developments in this area have seen the development of RAS systems for shrimp, revolutionizing shrimp farming by allowing more controlled environments and easing long-term environmental challenges. Furthermore, we are seeing a shift in governmental legislation and movement from cage farming for environmental reasons, such as maintaining freshwater quality and protecting wild fish populations, including aquatic plants and animals. This implies a very strong future for RAS.

Removing fishmeal and fish oil from aquaculture feed

Feed, essentially, provides energy and nutrients to support the development of each species, but the fish has no preference regarding how the energy and nutrients are sourced. The percentage of fishmeal in aquatic diets has significantly reduced since 2000, and the move from fishmeal and fish oil for many fish species is not very far away. Plant proteins and other ingredients can replace the fishmeal component in fish food. However, they are majorly constrained by issues of low digestibility. Formulations must be highly digestible, and each ingredient must add value and enrichment to the diet to impact performance. Utilizing enzymes in aquafeed can help fish and shrimp digest feed better to support a healthy digestive system and help increase cost-efficiency.

Choosing a feed that is right for your farm means you could potentially:

• Use less feed
• Improve production
• Improve output
• Reduce environmental impact

Unfortunately, there is a hidden risk when increasing the quantity of plant-based raw materials on aquaculture farms. Mycotoxin contamination is known as a silent enemy for producers as it is visibly difficult to detect. Long-term ingestion of feed with low/acute or high exposure levels can be a reason for poor growth and unexplained mortalities on fish farms. Correct management at all relevant production points is crucial in handling this threat. Feed supplements can also help negate the effects of mycotoxins in the digestive tract and prevent them from being absorbed by the body.

Additionally, logistics are increasing at an alarming rate. This provides an opportunity to improve sustainable practices and become less dependent on imports. The quality team at Alltech Coppens has focused on sourcing quality local ingredients and adapting the formulations to suit these conditions and provide the most benefit to the fish.

Advancements in feed formulation, a significant move to net energy formulations

Feed production must be efficient and cost-effective for the producer. To produce a feed that can provide the fish with optimal energy levels for production, understanding the digestibility parameters of each raw material is crucial.

The gross energy is the total energy is available in the feed to the animal. When the animal digests feed, it uses digestible energy. Further energy will be lost due to metabolic processes, and what remains becomes net energy.

The fish can use net energy to grow and maintain its health status. Micronutrients are key to maximizing this growth, but their efficiency can vary. Recent research in the Alltech Coppens Aqua Centre has shown that metabolic energy losses can range from 30–40% if the feed is not correctly formulated, impacting the growth of the fish. Comparing the net energy of different types of feed, as well as considering palatability and sustainability, can help producers choose the best feed for performance.

A healthy gut is the key to success

Achieving optimal health status in fish is one of the main goals for aquaculturists. Disease and/or significant growth reduction will increase costs for the producer. Poor health status can account for some of the biggest losses in the fish farming industry.

At Alltech, we believe that a healthy gut is the key to success. A healthy gut can digest and absorb the maximum amount of nutrients. The intestinal microflora, gut morphology, immune system and nutrient uptake — plus how each of these elements interacts — all play a role in the health and performance of fish and shrimp. Animals in farmed environments also require essential nutrients to meet their basic nutritional needs. A fish’s skin, gut and gills are the primary points of interaction with external environmental factors that can impact its health. These organs must be protected, both internally and externally.

The more robust the animal, the less vulnerable it will be to stress throughout the production cycle, ensuring the highest levels of efficiency.

Potential stress factors to look out for include:

• The rigors of production
• Age
• Quality of the feed
• Temperature
• Salinity
• pH

Each of these can cause an imbalance in the gut, leading to increased disease susceptibility. The subsequent adverse effects on growth rates and immunity can then have negative financial impacts. Protecting their health will provide the most benefit to the farmer.

Sustainability

Providing food security for future generations requires careful management of our present environment. Sustainable aquaculture is the solution; the FAO announced that by 2030, 60% of food fish will come from aquaculture. The environment needs to be considered in every aspect of production. If we truly understand the needs of fish, quantify the different necessary micronutrients and analyze the composition of feces, we can better understand how to improve water quality.

Poor water quality leads to environmental impacts and economic losses that can be avoided by carefully selecting a balanced selection of supplements that support a healthy culture system and environments for the future. RAS environments and the move from marine-based ingredients, as discussed above, have made positive impacts, and all of these will provide access to sustainable marine protein sources for future generations.

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