Omega-3 fatty acids constitute a family whose primary element is alpha-linolenic acid (ALA, 18/3(n-3)), a fatty acid that is essential to the organism’s functioning. The other members, derived from ALA, are constituted of longer and more unsaturated carbon chains. The main ones are EPA acid (eicosapentaenoic acid), DHA acid (docosahexaenoic acid) and, more recently discovered, DPA acid (docosapentaenoic acid).
The nutritional importance of omega-3s is broadly documented in human nutrition (Ponnanpalam et al. 2021). They enable optimal physiological functioning and are beneficial to health (Shahidi et al., 2018). Omega-3s have a potential effect in the prevention and treatment of cardiovascular diseases, certain auto-immune diseases, diabetes and certain types of cancers and play an important role in neuronal development (Gonzalez-Esquerra and Leeson., 2001). These elements have aroused great interest in the development of functional foods that have omega-3s in their composition. These advancements have led to improved omega-3 content in products of animal origin via the diet of production animals with the intake of adapted lipids (Bourre et al., 2004). The marketing of animal products enriched with polyunsaturated fatty acids via the animal diet is therefore a way to increase the consumption of omega-3s in humans.
The quality of fats present in the animal feed fundamentally determines the nutritional value for humans of the foods derived from it. The (qualitative and quantitative) consequences of changes to the composition of animals’ diets on this nutritional value are more extensive in monogastrics than polygastrics. It has been proven that by feeding animals with fish or seaweed extract in the form of oils, the quantity of DHA is multiplied by 20 in fish (salmon), 7 in chicken, 3 to 6 in eggs and 2 in beef (Bourre et al., 2005).
However, the quantity of omega-3 fatty acids in the milk fat of ruminants is very low (Gomez-Cortés et al., 2018). These low rates coupled with a non-negligible saturated and trans fatty acid content have led certain nutritionists to advise against consuming milk fats and whole milk products. But the omega-3 content in milk fat may naturally be improved by supplementing ruminants’ diet with a lipid source enriched in polyunsaturated fatty acids. Nevertheless, the percentage of polyunsaturated fatty acid in milk fat rarely exceeds 1% (Papadopoulos et al., 2002).
In parallel, it is important to specify that the consumption of omega-3 fatty acids by animals helps improve their health and performance.
Seaweed could therefore be a circular and sustainable food ingredient that is promising for animal nutrition. This aquatic organism could therefore be a source of protein as well as fats (Madeira et al., 2017). Certain specific photosynthetic micro-algae contain high quantities of DHA and EPA. They could therefore constitute beneficial supplements to animal feed. In additional to these nutritional aspects, seaweed has multiple properties: antibacterial, anti-inflammatory and antioxidant (Furbeyre et al., 2017, Jesus Raposo et al., 2013) properties that are beneficial to animal health.
Following this literature, it is important to determine to what extent seaweed-based products can provide digestible nutrients, to find out their impact on production performance and animal health as well as their impact on the omega-3 content of animal products consumed in human diets.
An initial study relating to the effects of micro-algae (Nannochloropsis limnetica) on the retention of nutrients and performance, the characteristics of eggs and the health parameters in egg-laying hens enables us to identify an improved laying rate with micro-algae intake (1 to 3% of the ration), a lower rate of blood haptoglobin (inflammation marker) as well as a significant effect of the inclusion of seaweed on EPA and in particular the DHA content in the egg yolk. Consequently, the total omega-3 content of the egg is positively affected by the micro-algae inclusion rate. The DHA and EPA levels in eggs obtained in this study are respectively 20.5 – 53.9 and 0.7 – 5.3 mg/egg. Based on the average consumption of feed and the number of eggs produced per period, the estimated assimilation of EPA and DHA in eggs is approximately 35% for the different seaweed incorporation levels. Although there are not yet any official guidelines for the intake of long-chain omega-3 fatty acids in humans, a minimum of 160 to 250 mg and a maximum of 3,000 mg of EPA and DHA combined are appropriate for daily consumption. The consumption of omega-3 enriched eggs with these micro-algae can contribute to this intake. (Mens et al., 2022).
The aim of a second study is to assess the in vivo effects of iso-energetic diets providing the same quantity of fats but with different sources of omega-3 fatty acids (palm oil, linseed oil and seaweed oil) on the performance and composition of milk fat. In dairy ewes, replacing a fat enriched with 2.3% saturated fatty acids with the fat from seaweed oil containing omega-3 fatty acids is an effective strategy to enrich milk with DPA, EPA and DHA and reduce the n6/n3 ratio. However, ‘protected’ forms of seaweed oil must be envisaged to prevent the potential negative effects on animals’ ingestion of dry matter, the milk yield and the quality of the milk (Manso et al., 2022).
This encouraging data demonstrates a relationship between seaweed intake in animals’ feed rations and the omega-3 content of products of animal origin. Seaweed can therefore be a beneficial strategy to improve the nutritional values of products of animal origin.
References :
« 75_Bourre_2004_Medecine_et_Nutrition_Pertinence_de_l_enr.pdf ». Consulté le 28 février 2023. http://www.bourre.fr/pdf/Articles_generaux_revues_syntheses/75_Bourre_2004_Medecine_et_Nutrition_Pertinence_de_l_enr.pdf.
« Bourre – 2003 – Alimentation animale et valeur nutritionnelle indu.pdf ». Consulté le 28 février 2023. https://www.ocl-journal.org/articles/ocl/pdf/2003/05/ocl2003105-6p405.pdf
Bourre, Jean-Marie. « Alimentation Animale et Valeur Nutritionnelle Induite Sur Les Produits Dérivés Consommés Par l’homme : Les Lipides Sont-Ils Principalement Concernés ? » Oléagineux, Corps Gras, Lipides 10, no 5‑6 (septembre 2003): 405‑24. https://doi.org/10.1051/ocl.2003.0405.
Furbeyre, H., J. van Milgen, T. Mener, M. Gloaguen, et E. Labussière. « Effects of Dietary Supplementation with Freshwater Microalgae on Growth Performance, Nutrient Digestibility and Gut Health in Weaned Piglets ». Animal 11, no 2 (février 2017): 183‑92. https://doi.org/10.1017/S1751731116001543.
Gómez-Cortés, Pilar, Manuela Juárez, et Miguel Angel de la Fuente. « Milk Fatty Acids and Potential Health Benefits: An Updated Vision ». Trends in Food Science & Technology 81 (1 novembre 2018): 1‑9. https://doi.org/10.1016/j.tifs.2018.08.014.
« González-Esquerra et Leeson – 2001 – Alternatives for enrichment of eggs and chicken me.pdf ». Consulté le 28 février 2023. https://cdnsciencepub.com/doi/pdf/10.4141/A00-092.
González-Esquerra, R., et S. Leeson. « Alternatives for Enrichment of Eggs and Chicken Meat with Omega-3 Fatty Acids ». Canadian Journal of Animal Science 81, no 3 (1 septembre 2001): 295‑305. https://doi.org/10.4141/A00-092.
Jesus Raposo, Maria Filomena de, Rui Manuel Santos Costa de Morais, et Alcina Maria Miranda Bernardo de Morais. « Health Applications of Bioactive Compounds from Marine Microalgae ». Life Sciences 93, no 15 (10 octobre 2013): 479‑86. https://doi.org/10.1016/j.lfs.2013.08.002.
Madeira, Marta S., Carlos Cardoso, Paula A. Lopes, Diogo Coelho, Cláudia Afonso, Narcisa M. Bandarra, et José A. M. Prates. « Microalgae as Feed Ingredients for Livestock Production and Meat Quality: A Review ». Livestock Science 205 (1 novembre 2017): 111‑21. https://doi.org/10.1016/j.livsci.2017.09.020.
Manso, Teresa, Beatriz Gallardo, Paz Lavín, Ángel Ruiz Mantecón, Carmen Cejudo, Pilar Gómez-Cortés, et Miguel Ángel de la Fuente. « Enrichment of Ewe’s Milk with Dietary n-3 Fatty Acids from Palm, Linseed and Algae Oils in Isoenergetic Rations ». Animals 12, no 13 (janvier 2022): 1716. https://doi.org/10.3390/ani12131716.
Mens, A. J. W., M. M. van Krimpen, S. K. Kar, F. J. Guiscafre, et L. Sijtsma. « Enriching Table Eggs with N-3 Polyunsaturated Fatty Acids through Dietary Supplementation with the Phototrophically Grown Green Algae Nannochloropsis Limnetica: Effects of Microalgae on Nutrient Retention, Performance, Egg Characteristics and Health Parameters ». Poultry Science 101, no 6 (1 juin 2022): 101869. https://doi.org/10.1016/j.psj.2022.101869.
Papadopoulos, George, Christos Goulas, Eleni Apostolaki, et Ruben Abril. « Effects of Dietary Supplements of Algae, Containing Polyunsaturated Fatty Acids, on Milk Yield and the Composition of Milk Products in Dairy Ewes ». Journal of Dairy Research 69, no 3 (août 2002): 357‑65. https://doi.org/10.1017/S0022029902005599.
Shahidi, Fereidoon, et Priyatharini Ambigaipalan. « Omega-3 Polyunsaturated Fatty Acids and Their Health Benefits ». Annual Review of Food Science and Technology 9, no 1 (2018): 345‑81. https://doi.org/10.1146/annurev-food-111317-095850.
