Laminaria digitata, or Kelp, is the most commonly known brown seaweed. Photo:

Laminaria digitata, or Kelp, is the most commonly known brown seaweed. Photo:

Emmy Koeleman writes in All About Feed & Dairy Global about a review in the Journal of Animal Feed Science and Technology that looked at the different seaweeds available and how they can be used for ruminants, pigs, poultry and rabbits.

Seaweeds are valuable alternative feeds for livestock, mostly as sources of important nutrients, notably chelated micro-minerals, the availability of which is higher than that of inorganic ones.

Seaweeds include brown algae (Phaeophyceae), red algae (Rhodophyceae) and green algae (Chlorophyceae). Due to their larger size and ease of harvesting, brown seaweeds have been studied and exploited more than other algae types for their use in animal feeding.

Brown algae are the largest seaweeds, up to 35–45 m in length for some species and extremely variable in shape. The most common genera include Ascophyllum, Laminaria, Saccharina, Macrocystis, Nereocystis, and Sargassum. Laminaria and Saccharina have a long history of use in animal feeding in Western and Northern Europe and are still of great economic importance.

Red algae have a characteristic bright pink color caused by biloprotein pigments (R-phycoerythrin and R-phycocyanin). Most marine red algae species occur from low tide marks to 100 m depth. Major red algae genera include Pyropia, Porphyra, Chondrus and Palmaria. In the 19th and early 20th centuries, Palmaria palmata was eaten by sheep and goats in Gotland (Sweden) and by cows in Brittany (France).

Green algae are typically green in color due to the presence of chlorophyll in their chloroplasts. Main genera include Ulva, Codium, Enteromorpha, Chaetomorpha and Cladophora. Ulva lactuca, also called water lettuce, is the most studied among Ulva species. All Ulva species are edible.

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