Seaweed and Man - Seaweed Biology - page 471

the soil and crops to various applications, e.g., different concentrations of extracts
that can decide between inhibition and promotion of germination and growth. Table
12 (in Craigie 2011 ) summarizes the bioactive properties reported for seaweed
extracts in plants and animals. As for plants the choice of algal species and extract
concerning its nature and proportion in the feed of the respective livestock has to be
carefully tested to avoid detrimental effects and improve overall health and benefit
reproduction (Craigie 2011 ). Addition of 4% Sargassum meal to the feed of shrimp
cultures reduced cholesterol contents of their muscle tissue by 29%, quite desirable
for shrimp grown for human consumption (Casas-Valdez et al. 2006 ). In the case of
cattle there can even be an advantage elicited in the shelf life of steaks, since a
short-term feed addition of 2% Ascophyllum meal (Tasco) prior to slaughter not
only results in a better marbling of steaks but also retains the red color over a longer
period. The latter is due to a higher proportion of oxymyoglobin compared to
conventionally fed cattle (Braden et al. 2007 ).
Of the 10 larger and 17 smaller producers of commercial seaweed extracts for
agriculture that Craigie mentions, only three are presently located in Asia, that is in
China, even though Asia is producing

98% of all seaweeds. The indisputable
benefits of seaweed utilization in plant and animal farming excite expectations
toward a more extended production and use in the future.

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22.3.4 Other Applications of Seaweeds

The phycocolloids agar, carrageen and alginates have long been used for their water
binding and thickening properties: While agar is not only known as a neutrally
flavored thickener of stews, sauces, desserts etc., it is also indispensable as a solid
culture medium in medical bacteriology and microbiological research. Alginates
from brown seaweeds are used in printing dyes and for better adsorptivity of
textiles. They are together with other seaweed components valued ingredients of
cosmetics. Extracts typically found in cosmetics are made from Ulva lactuca,
Ascophyllum nodosum, Laminaria longicruris, Saccharina latissima, Laminaria
digitata, Alaria esculenta, various Porphyra species, Chondrus crispus , and
Mastocarpus stellatus (Cosmetic Ingredient Dictionary 2002 -2011).
The latest innovation is a textile fiber named SeaCell

. It is a cellulose-based
fiber produced from seaweeds like Ascophyllum nodosum and used as a yarn for
clothing or for filling duvets (Smartfiber 2010 ).
Another field of high interest and great demand is the partial replacement of fish
meal by seaweeds. Only a small selection of seaweed species will probably be
suited. Experiments by Walker et al. ( 2009 ) showed positive results with up to 30%
Porphyra spp. in the diet of juvenile Atlantic cod. If Porphyra (“nori”) was
introduced into the commercial aquaculture of fish, demand and price of the already
valuable seaweed would probably rise enormously.
Due to their high carbohydrate content seaweeds can be fermented to methane
(biogas) and in many places (mainly beach cast) seaweeds are considered a

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