Press release ILVO conducts algae feeding trials on broilers and laying hens for the first time

Do hens and their meat or eggs benefit from adding algae to their feed? Although the ValgOrize project focuses on on sustainably and qualitatively produced tasty algae for human consumption, researchers from Flanders Research Institute for Agriculture, Fisheries and Food (ILVO) are also looking at how the residual flows from algae production can be valorized in chicken feed as part of a zero-waste approach.

The nutritional added value of algae

The application seems promising; not only do many algae species have a high protein content, they can also be beneficial for the fatty acid and amino acid composition of the eggs, and can even influence the color of the yolk. "But the amino acid and fatty acid composition, the digestibility of the feed and the taste of the end product, among other things, are all things we should certainly study before we introduce this as standard practice," says Johan De Boever, feed evaluation expert at ILVO. "We do this with the residual products from the ValgOrize food-related studies.

Residual flows from European algae production

The ValgOrize project was created to promote algae as food for humans in Europe. Within the project several studies are taking place, with an emphasis on taste, sustainability, market research and cultivation. But these studies also produce residual flows. Some product remains after extracting the nutrients from microalgae, and after centrifuging macroalgae (seaweed) to dry it. This remaining biomass still contains valuable nutrients and has interesting amino and fatty acid compositions for animal production. Therefore, the ValgOrize project has included the valorization of these residual flows as part of the research. Johan De Boever (ILVO): "It is important to investigate how the addition of this residual product could affect chickens (and other animals) and their production. When algae cultivation in Europe becomes more mainstream, which is the goal of this project, we need to know if this can and should become a valuable solution for the residual flows, and more importantly, how we can best achieve this valorization".

Feeding trials

The ILVO feeding trials will run throughout the duration of the project. So far, 3 species of algae have been tested in 3 different trials, in both laying hens and broilers, but concrete results are still awaiting completion of all analyses. The main question of the research is how to efficiently add algae-residual products to animal feed in order to make the practice interesting and beneficial for the animals and their final products. The answer to this question will largely depend on the composition of the different types of algae and, based on this, the final composition of the feed itself (certain studies recommend a maximum share of 10% algae in the feed. ILVO is now researching those optimal proportions). Making the addition of algae to feed "favorable" will primarily entail ensuring that the feed is digestible for the animals and has a positive effect on the amino acid and fatty acid proportions of the final products and on the color of the egg yolks, and either a non-obtrusive or positive effect on the taste and smell of the eggs and meat.

The researchers are convinced of the potential of the algae feed. Johan Robbens (ILVO), coordinator of the ValgOrize project, points out that "if you look at the composition of certain types of microalgae, compared to other, more conventional European food and feed sources (Table 1, see below), you can see that the protein, carbohydrate and fat content of the algae is just as good or even better, which makes the algae solid candidates as alternative protein sources". In addition, previous research has shown that algae can also have antibacterial, antiviral and/or anti-oxidative effects. Some algae are also rich in omega 3 fatty acids and may contain vitamins and/or pigments such as chlorophyll and carotenoids, which can help influence the color of egg yolks.

Bron	Ruw eiwit	Koolhydraten	Vetten
Sojabonen	37	30	20
Maïs	10	85	4
Tarwe	14	84	2
Anabaena cylindrica	43-56	25-30	4-7
Arthrospira maxima (Spirulina)	60-71	13-16	6-7
Chlorella vulgaris	51-58	12-16	14-22
Spirogyra sp.	6-20	33-64	11-21
Synechococcus sp.	73	15	11

Not all residual flows are created equal

What is already clear from the ongoing feed trials is that the residual flows cannot be added to the chicken feed without further processing. It is necessary to process these algae residues in a way that reduces the salt and mineral content to less than 10%, by washing them with fresh water and drying them. "Without this treatment, the chickens' digestion could be disrupted," says Marta Lourenço, poultry researcher at ILVO, "resulting in a decreasing efficiency of protein and energy utilisation. Further research should show whether other processing techniques are needed.

Other animal species

The focus of the feeding trials within the ValgOrize project is on poultry, due to the small amounts of residual flows available and the fact that chickens react quickly to changes in feed composition. Previous studies have also shown potential for pigs and dairy cattle. However, these results were not always unequivocal. In pigs, for example, the algae were used as alternative sources of protein, but the results in terms of growth of the pigs and fertility of the boars varied. In some studies in dairy cattle, an increase in milk production and an altered amino acid composition were observed. These results are promising, but require further research.

European algae production for food is almost non-existent

Currently, algae cultivation in Europe is still in its infancy. Of the more than 30 million tons of algae produced globally, Europe only contributes 1%. In addition, only 9% of these algae are used for food applications, in contrast to 90% worldwide. Another problem in European algae production is that it consists almost exclusively of wild harvesting, and not the sustainable alternative of renewable cultivation. Wild harvesting over-exploits natural resources and can also be a very damaging practice for the surrounding nature, while the direct effect of algae cultivation on most local ecosystems is much lower. A transition to this sustainable way of algae production is one of the goals of the ValgOrize project, together with the promotion of algae for food. This Interreg project brings together 11 partners from Belgium, the Netherlands, France and the United Kingdom to achieve these goals.