Protein in aquafeeds, a major cost and how to handle it

Protein is a major cost in aquafeed as aquatic animals have high protein needs compared to terrestrial animals. Furthermore, fishmeal is very often used in fish and shrimp diets. Its price increases faster than other ingredients. Over a 25 years period, fishmeal price increased by 350%, while soybean increased only by 150% (Source: Indexmundi).

In this situation, feed producers need to be careful when using protein sources to fulfill the needs of the animals. First from an economic point of view, but also regarding the quality of this protein. Indeed, protein itself doesn’t mean a lot, protein could have a low digestibility (because of intrinsic composition of an ingredient, or suffer from processing for eg), it could also be unbalanced. This could result in lower growth of the animal. This brief article will help you save some cost on your feed while safeguarding its quality.

The quality of feed relies on the quality of its ingredients

“Quality inputs lead to quality outputs”, this saying is also true for feed. If one doesn’t watch out what they buy or don’t handle it properly; even fish meal could be lower quality than vegetable ingredients. It depends on the raw material quality, is it processed fresh, how is it cooked and dried, extracted, protected and finally stored. These key points are similar for quite a lot of ingredients. Therefore, analysis can give a good overview of the quality of ingredients. Specific criteria exist for each raw material.

Some important analysis to ensure the quality of several ingredients

For example fishmeal quality could be impacted before processing if the fish are not stored properly; this will be evaluated by the biogenic amines values which are the result of degradation of specific amino acids. Processing could also have an impact on the quality of the product by overcooking; this could be evaluated by oxidative parameters. Overall quality of the proteins of fishmeal is often evaluated by pepsin digestibility. Similar parameters could be analysed on animal meals such as poultry meal, meat and bone meal. For soybean meal, different tests exist such as the urease test and anti-trypsic factors. They will analyse if the process well-cooked protein, making it digestible, but without overcooking which may result in lower digestibility of certain sensitive amino acids such as lysine. Free lysine could also be an indicator of the quality of DDGS. The main risk with these products is overcooking which reduces the overall digestibility. The table above summarizes some important analysis to ensure the quality of several ingredients, it is important to follow these parameters according to importance and risk.

Beyond Protein: digestibility and amino acid profile to fulfill each species needs

Once your raw materials are sourced, analysed and validated, the second step is to know if they are digestible by the targeted animals. Digestibility of protein depends on several factors but mainly depends upon the type of raw material. Indeed, the form of protein, amino acid chain, branching with other compounds like carbohydrates affect the way fish or shrimp enzymes are able to digest it.

As an example, fishmeal digestibility is affected by ash content, the more ash there is, the less digestible it will be (but this is not the only parameter to take into consideration). Within the various vegetable protein sources existing in the world some are more digestible than others. Some of the most digestible ones will be soybean, peas and beans whereas coprah, alfalfa or linseed will be among the least digestible ones.

Another parameter to consider is what part of the initial raw material is in the final product. Indeed, when extracting different parts of a seed, protein digestibility may change. For example, wheat grain or wheat flour, which are roughly the whole grain, almost have the same digestibility. But when considering wheat bran, digestibility will be reduced as this part of the grain contains more fiber affecting the overall protein quality.

On the other hand, with the process concentrating the protein in the product, digestibility will increase. Wheat gluten meal (80% protein) is more digestible than wheat gluten feed (20% protein) which is more digestible than wheat grain. Similar patterns will also occur in other plant products, or in animal proteins.

AQUANEO, the aquaculture brand of TECHNA, has been acquiring this knowledge over several years of experience and integrated this specific information in its own formulation matrix. In the end, it will be used to ensure feed quality while formulating at the lowest cost for our customers.

Another aspect to take into consideration is amino acid profile. This is usually quite stable on vegetable products but it could fluctuate a lot in fishmeal or animal proteins depending on the species and part of the animal being processed (whole, trimmings, feather, blood, meat, bones…). Amino acid profile analysis should be performed on these fluctuating ingredients. In the graphic below, we can see that amino acid profiles are very different according to raw material. For example, using wheat and corn products as protein replacers may create lysine deficiency as their Lysine/Protein ratio is around 2% compared to fishmeal which is usually above 6% of total protein. Once again all these information are part of AQUANEO’s formulation matrix and will be used to prepare the feed recipe. Furthermore, AQUANEO’s lab offers the analysis of amino acid profile of raw materials.

All the above mentioned will give a very good overview of the quality of different raw materials available. Now the formulation can fulfil the requirements of the targeted animal. Not only by adding a certain amount of nitrogen, but also including quality, digestibility of protein, plus its amino acid profile.

Economix: an interesting solution to reduce costs and improve protein utilisation

As mentioned at the beginning, protein is the major cost for most feeds for aquaculture, but ways exist to reduce this cost. Like acting on the overall digestibility of feed. Indeed, specific additives like Economix, developed by AQUANEO, can help the animal’s digestive system to increase the digestibility of protein and therefore the performance of the animal.

Results of a trial done in SPAROS Portugal on seabream (115g) showed an increase of protein digestibility from 93,8% up to 94,3% with the use of Economix. It also showed an important increase in methionine digestibility from 87,9% to 91,7%. In the Economix formula, crude protein level was reduced by 1%, but keeping the same digestible protein (38,5% in AQUANEO’s formulation matrix) and same amino acid profile. Composition of the feeds was very similar, but we replaced 2% fishmeal from the control formula. Fish meal was replaced mainly by wheat, monocalcium phosphate and Economix. The use of this additive allowed a cost reduction of 12,4€/MT on a typical Mediterranean fish feed while improving the digestibility and keeping the same performances.

Another trial was done on 90g trout with a top coating of the Economix on a standard commercial feed and a vegetable feed (no fish meal or oil). Results showed an increased weight gain and decreased FCR at the end of the trial. But also a lower abdominal fat notation, probably coming from the fact that protein was better utilised and less energy was deposited in the viscera. In this last case using Economix could save on the feeding cost up to 3€/MT of fish. (Extra cost - Better performances = Gain).
 

Economix solution reduces the cost of feed while keeping feed quality and fish performance. It could be used with simple ingredient substitution (-2% Fishmeal => +1% Soybean +0,8% Cereal + 0,2% Economix) or with a reformulation through its valorisation matrix.
 

Shall you require more information on AQUANEO’s support regarding analysis, formulation or Economix, please contact us.