The Alternatives: Seaweed

Macroalgae, more generally identified as seaweed, refers to thousands of marine algae species essential for the ocean due to its importance as an aquatic habitat and nutrient source for other sea animals. The three main categories of algae are Green algae (Chlorophyceae), brown algae (Phaeophyceae), and red algae (Rhodophyceae). Green algae thrive in a rich environment, and some even have the potential to grow very fast; one of them is the algae Ulva sp., more commonly known as sea lettuce. Additionally, Ulva sp. has been gaining attention in the past decade due to its rich nutrient content.

This potential is what the founder of Living Seas Aquafeeds Pte. Ltd., Timothy Hromatka, saw and grew his interest in further developing this seaweed. It began during the Covid-19 pandemic when Timothy was stuck in Singapore, where he rented some land from a friend to build a small, intensive shrimp farm coupled with raceways. There he started to plant sea lettuce for water filtration in a recirculating, Integrated Multi-Trophic Aquaculture (IMTA) system and started learning more about shrimp and seaweed aquaculture.

“I would feed my shrimp the seaweed that I grew, and I noticed that they were actively seeking it out and preferred it over pellets: the shrimp were getting something from the seaweed that they wanted more than a “complete” commercial feed. So back here in Indonesia, I continued to dig deeper and became obsessed with using seaweeds in aquafeeds,” Timothy said.

Seaweed as a Feed Supplement

Timothy was wildly convinced of the benefits of incorporating seaweed into a modern shrimp diet. To reduce predation, according to him, seaweeds have several defensive mechanisms which need to be understood. But in general, green seaweeds like sea lettuce (Ulva sp.) try to grow faster than they can be eaten. In contrast, red and brown seaweeds contain high amounts of bioactive molecules for protection which research shows can have a positive immunostimulant effect on shrimp to reduce disease and stress challenges and increase overall vigor.

In Lombok, Timothy runs a laboratory and a small shrimp farm where they have developed (and continue to improve) their Living Sea’s Shrimp Supplement, which incorporates various types of seaweeds, volcanic, deep-earth minerals, and other marine ingredients that is in the process of patenting, so he cannot yet disclose. “We have three balanced goals in mind: improving shrimp stamina and growth, disease resistance, and pond water quality and stability, which are measured in Survival Rates (sampling and feeding), Feed Conversion Rates, and Average Daily Weight Gain. Currently, at our farm, we are getting a 6% improvement in ADG and a 13% reduction in FCR compared to the control with our Shrimp Supplement replacing 5% of the commercial shrimp feed,” he claimed.

“I would feed my shrimp the seaweed that I grew, and I noticed that they were actively seeking it out and preferred it over pellets”

He adds that many probiotics, prebiotics, and feed supplements are available to the modern shrimp farmer. Still, all of these are either top-dressed onto commercial feeds or added directly into the pond water as a powder or liquid, and none of these are introduced as feed replacements. This means that the costs of these supplements are on top of the feed cost and an additional expense to the farmer. “One of our key differences is that our product replaces 5% of the commercial compound feed at the same price, so there is no additional production cost to the farmer using our feed supplement,” he said.

Though algae meal shows promising results as an alternative feed supplement, Timothy admits there are still plenty of challenges he has faced in developing his product. According to him, one of the challenges for growth will be the availability of raw materials. The beneficial effects of seaweed inclusion in animal feeds are becoming known, and this is not just for aquaculture but for poultry, swine, and bovine as well; more and more people are eating seaweed products. So, there will be more and more competition for raw materials, which could slow the growth or affect the cost of this Shrimp Supplement. “I want to keep the price of my supplement the same as the price of shrimp feed so that when a farmer replaces 5% of their shrimp feed with my supplement, they have no increase in their production cost, and any improved SR and FCR are realized as an extra “bonus” for the farmer,” he hopes.

Seaweed as a Feed Ingredients

How about using seaweed in feed formulation?

The Shrimp Nutritionist of Gold Coin Group Inc., Alexandre Veille, said that as a feed mill, they are looking at consistency, as they are mandated to provide the same feed with the same performance. “We are, in a sense, like champagne makers, the opposite of winemakers, that offers each year a different product. Seaweed is a lot seasonal, hence not easily compatible with consistency,” he said. Another aspect to consider, Alex adds, is the wide variety of seaweed (from the macroalgae: Gracilaria to the microalgae: Spirulina). While some have great potential for aquafeed, others are less interesting, and it also significantly influences the cost of the product.

On one hand, he continued, macroalgae production is dominated by Gracilaria, Sargassum, and Eucheema, which are widely used for food texturants. They are a good candidate for fiber and micronutrient supply in aquafeed since fish and shrimp have more specialized enzymes to degrade marine polysaccharides than they have for terrestrial ones. However, the price will be the next challenge once seasonality and supply problems are solved, as feed mill prefers to use a low-moisture product. Seaweed is 80% water; hence after drying, someone will have to pay for this loss!

On the other hand, the use of microalgae known for their fatty acid (Spirulina) or astaxanthin content (Haematococcus) for animal feed competes with the human supplement market. Similar to some feed that uses fish meal with high fat (e.g. tuna by-product fish meal) and fish oil is usually very expensive or limited. Only if the end product can be marketed as such (e.g. “natural astaxanthin fed”), then those feed supplements can find their place. Otherwise, the cost will be too high both for the feed mill and the farmer.

Nevertheless, Alex admits that the company has done the research regarding the potential of seaweed as a feed ingredient for some time. Gold Coin, a part of the Aboitiz Group, has seen the potential of seaweed long ago and has started studying it in animal feed. The identified limitations were either inconsistency of the supply or cost of the product. At the same time, the main improvements found were related to feed intake, palatability, mineral composition of the meat, and of course, fillet/cooked color grade improvement. The best results for this trial were observed in shrimp grown in biofloc systems. It’s part of the natural diet of shrimp, and they can digest the fiber in seaweed better than they can digest terrestrial plants, providing better digestive health. “From our experience and trials, 2% is the ideal inclusion rate for seaweed meals to be included in shrimp and fish to balance the quality variation while seeing the benefit on feed intake and performance,” he explains.

According to Alex, anything can be a feed ingredient as long as we know its value. If we only consider protein, he said, the best way to evaluate is to compare the cost of the protein to the soybean meal (SBM) because SBM is a very consistent ingredient that can be digested pretty easily by any animal. “Today, SBM is priced around 600 USD/MT for 46% of protein. Hence the cost of protein will be around 13 USD/% of CP. Any ingredient with a protein cost that is lower or similar will be considered as a protein source. Seaweed protein is rarely higher than 10%, and the market selling price for it is rarely below 600 USD/MT, giving it a protein cost four times higher than SBM,” Alex explains.

Other than that, product consistency and availability is the most challenging aspect of using seaweed meal. While April till the end of August will create bountiful harvests, the end of the year or when the tide is too strong often create scarcity. This inconsistent supply is a real challenge for the feed mills to include seaweed meals in their formulation. Additionally, sometimes you have beach-harvested seaweed, with some lots containing up to 10% sand or salt concentration from 10 to 20%. Depending on the origin, the seaweed can be heavily loaded with heavy metals, which can be an issue for animal performance. In the end, mixing it all is very challenging for quality control of the end pellet. “Maybe in coming years, with the end product reflecting farmer practices and providing them fair support, there will be more room for seaweed usage in feed. That’s why with Reimagin Seaweed - the innovative start-up that aims to transform the seaweed industry in the Philippines by addressing some of the most significant challenges facing the industry today - we expect to have a better source and competitive price of algae to support our internal demand of seaweed meal,” Alex closed.