Kelp preparations for enhancing the growth of seafood and algae Description The present invention relates to the use of a solid or liquid kelp preparation, preferably of a liquid kelp preparation, especially of Kelpak® (from Compo, Germany) for promoting the growth of seafood, in particular of crustaceans and especially of shrimps and prawns, and to a method for promoting the growth of seafood, which method comprises treating the seafood's habitat with a solid or liquid kelp preparation preferably with a liquid kelp preparation, especially with Kelpak®. Moreover, the invention relates to the use of a solid or liquid kelp preparation preferably of a liquid kelp preparation, especially of Kelpak®, for quantitatively and/or qualitatively enhancing the growth of algae and to a method for quantitatively and/or qualitatively enhancing the growth of algae, which method comprises treating the algae and/or their habitat with a solid or liquid kelp preparation preferably with a liquid kelp preparation, especially with Kelpak®.

The worldwide increasing demand for seafood and especially for shrimps and prawns cannot be satisfied by natural populations. Thus, industrial-scale breeding has become the main seafood source. In general, intensively and semi-intensively managed aqua- culture farms rely on artificial shrimp feeds (often based on cereals or soybeans), either exclusively or as a supplement to the organisms that naturally occur in a pond. Artificial feeds generally are used in the form of specially formulated, granulated pellets that disintegrate quickly. Up to 70% of such pellets are wasted, as they decay before the shrimps have eaten them. Waste from the artificial food pellets and excrements of the shrimps can however lead to the eutrophication of the ponds and can lead to an increased disease rate. In case that artificial feeds are used only as a supplement to the organisms that naturally occur in a pond, a food chain is established in the ponds, based on the growth of phytoplankton. Frequently, fertilizers and mineral conditioners are used to boost the growth of the phytoplankton to accelerate the growth of the shrimps. This fertilization, especially in case it is not carried out on a demand basis, can however also lead to the eutrophication of the ponds and also to an increased disease rate.

It was an object of the present invention to provide a method for promoting the growth of seafood (in particular of crustaceans and especially of shrimps and prawns), which avoids or at least reduces the negative effects of the prior art growth promoting methods. It was also an object of the present invention to provide a method for promoting the growth of seafood by quantitatively and/or qualitatively enhancing the growth of algae which serve as food for seafood (in particular for crustaceans and especially for shrimps and prawns),

The object is achieved by the use of a solid or liquid kelp preparation.

Thus, in a first aspect, the present invention relates to the use of a solid or liquid kelp preparation for promoting the growth of seafood, in particular of crustaceans and especially of shrimps and prawns. The invention also relates to a method for promoting the growth of seafood (in particular of crustaceans and especially of shrimps and prawns), which method comprises treating the seafood's habitat with a solid or liquid kelp preparation.

As already pointed out, the seafood is preferably selected from crustaceans and more preferably from shrimps and prawns. Shrimps are swimming, decapod crustaceans classified in the suborder Caridea, found widely around the world in both fresh and salt water. Prawns are also decapods, belonging however to the suborder Dendrobran- chiata. They are similar in appearance to shrimp, but can be distinguished by the gill structure which is branching in prawns, but is lamellar in shrimp. While in biological terms shrimps and prawns belong to different suborders of Decapoda, they are very similar in appearance. In commercial farming and fisheries, the terms shrimp and prawn are often used interchangeably. However, recent aquaculture literature increasingly uses the term "prawn" only for the freshwater forms of palaemonids and "shrimp" for the marine penaeids. In the terms of the present invention, no strict distinction is made.

Preferably, the shrimps and prawns are selected from those species typically used in aquaculture. Most aquacultured shrimps/ prawns are of the family Penaeidae. Examples are Penaeus vannamei (Pacific white shrimp), Penaeus monodon (giant tiger prawn), P. stylirostris (Western blue shrimp), P. chinensis (Chinese white shrimp, also known as the fleshy prawn), P. japonicus (Kuruma shrimp), P. indicus (Indian white shrimp), and P. merguiensis (Banana shrimp).

Kelp are large seaweeds belonging to the brown algae (class Phaeophyceae) and are classified as the order Laminariales. There are about 300 different genera. Some species can be very long and form kelp forests.

Suitable kelp species to be used according to the present invention are for example Nereocystis luetkeana, Giant kelp (Macrocystis pyrifera), Kombu (Laminaria japonica or Saccharina japonica), Laminaria digitata, Laminaria hyperborea, Laminaria ochroleuca, Laminaria saccharina, Laminaria agardhii, Laminaria angustata, Laminaria bongardina, Laminaria cuneifolia, Laminaria dentigera, Laminaria digitata, Laminaria ephemera, Laminaria farlowii, Laminaria groenlandica, Laminaria longicruris, Laminaria nigripes, Laminaria ontermedia, Laminaria pallida, Laminaria platymeris, Laminaria setchellii, Laminaria sinclairii, Laminaria solidungula, Laminaria stenophylla, Alaria marginata, Costaria costata, Durvillea antarctica, Durvillea willana, Durvillaea potatorum, Ecklonia brevipes, Ecklonia maxima, Ecklonia radiata, Eisena arborea, Egregia menziesii, Hedophyllum sessile, Macrocystis angustifolia, Pleurophycus gardneri or Pterygophora californica. Among these, preference is given to Ecklonia maxima.

Thus, preferably a liquid or solid preparation of Ecklonia maxima (also called sea bamboo) is used.

The kelp preparation to be used according to the invention is preferably liquid. More preferably, the kelp preparation to be used according to the invention is a liquid preparation of Ecklonia maxima. The liquid preparation is preferably a kelp extract, especially an extract of Ecklonia maxima.

The kelp preparation used according to the invention preferably comprises phytohor- mones, in particular growth-promoting hormones. The phytohormones preferably comprise auxins, cytokinins and/or gibberellins. More preferably, they comprise auxins and optionally also cytokinins and/or gibberellins. Even more preferably, they comprise auxins, cytokinins, and optionally also gibberellins. Preferably, the auxin content overbalances the cytokinin content (on a weight basis), preferably by a rate of at least 2, e.g. by a rate of 2 to 2000, preferably by a rate of 2 to 1000 and more preferably by a rate of 2 to 500, more preferably by a rate of at least 10, e.g. by a rate of 10 to 2000, preferably by a rate of 10 to 1000 and more preferably by a rate of 10 to 500 (i.e. the weight ratio of auxins to cytokinins in the preparation is preferably at least 2:1 , e.g. 2:1 to 2000:1 , preferably 2:1 to 1000:1 and more preferably 2:1 to 500:1 , and is more pref- erably at least 10:1 , e.g. 10:1 to 2000:1 , preferably 10:1 to 1000:1 and more preferably 10:1 to 500:1 ).

Moreover, the kelp preparation used according to the invention preferably also contains amino acids, vitamins and/or mineral compounds. The amino acids preferably comprise glycine, alanine, valine, leucine, isoleucine, serine, threonine, tyrosine, lysine, aspar- agic acid and/or proline. The vitamins preferably comprise vitamin A, vitamins of the B group, vitamin C and/or vitamin E. The mineral compounds preferably comprise following elements: K, N, P, Mg, S, Ca, Fe, Mn, Cu, Zn and/or Mo. Without wishing to be bound by theory, it is believed that said phytohormones and possibly also said amino acids, vitamins and/or mineral compounds are responsible for the positive effect achieved by the use and method according to the invention, namely the promoted growth of the seafood and/or the quantitatively and/or qualitatively enhanced growth of algae.

The kelp preparation used according to the invention is of such a composition that, once in contact with water, it releases instantaneously, by degrees or deferredly components of the composition which promote the growth of the seafood and/or quantitatively and/or qualitatively enhance the growth of algae, such as said phytohormones and also amino acids, vitamins and mineral compounds.

The kelp preparation can be prepared by any known methods for extracting active compounds, such as said phytohormones, amino acids, vitamins and/or mineral compounds, from algae and plants. For instance, the harvested kelp or a part thereof, usu- ally after a purification step for removing salt water and impurities, may be extracted.

Extraction is preferably carried out under such conditions that the kelp's cells burst. Extraction may take place by using pressure or by using steam extraction, alcohol extraction, osmosis, ultrasound or other known methods. Pressure methods which lead to cell disruption are preferred. Suitable pressure methods include the use of mills, such as bead mills or ball mills, or homogenizers, such as rotor-stator homogenizers or high- pressure homogenizers. Preferably, extraction is carried out by using the "burst-cell- method" (also called "cold cell-burst process"), a method using high pressure at low temperatures.

The resulting extract may be used as such or may be further purified, e.g. by filtration.

Specifically, the kelp preparation used according to the invention is Kelpak®, a seaweed extract commercially available from Compo, Germany. This algae extract pre- pared from Ecklonia maxima contains, inter alia, auxins, cytokinins, amino acids, vitamins and mineral compounds. Its composition is said to be as follows:

- nitrogen: ca. 3.6 g/l

- phosphor: ca. 1 g/l

- potassium: ca. 7.2 g/l

- auxins: ca. 1 1 mg/l

- cytokinins: ca. 0.031 mg/l

- amino acids: ca. 2.478 mg/l

- carbohydrates: ca. 16.9 g/l

- proteins: ca. 3 g/l - vitamins: ca. 21.7 g/l.

Kelpak® is said to be produced by first removing salt water and impurities from the freshly harvested kelp Ecklonia maxima and then subjecting its fronds and stipes to the "burst-cell-method" (also called "cold cell-burst process"), a method using high pressure at low temperatures (see D.V. Robertson-Andersson et al., J. Appl. Phycol. 2006, 18, 315-321 ; W.A. Stirk et al., J. Appl. Phycol. 2004, 16, 31 -39; W.A. Stirk et al., J. Appl. Phycol. 1996, 8, 503-508; W.A. Stirk et al., S. Afr. J. Bot, 2004, 70, 145-151 ; F.N. Verkleij, Biol. Ag. Hort. 1992, 8, 309-324). Only the pure filtered cell sap is then used for Kelpak®.

In general, the habitat of the seafood, e.g. the pond where it is growing or living, is treated with the kelp preparation, e.g. by adding the preparation to the water in the pond. The preparation may be added as such or diluted (ordinarily with water) or may be mixed with feeds used as an additional nutrient for the seafood growing in the pond.

The kelp preparation is added to the habitat of the seafood in such a quantity that the amount of phytohormones added via the kelp preparation is preferably in a range of from 1 mg to 50 mg, more preferably from 3 mg to 20 mg and in particular from 3 mg to 15 mg per hectare of the habitat. If Kelpak® is used, this is added in an amount of preferably 100 ml to 2 I, more preferably from 200 ml to 1.5 I and specifically from 0.5 I to 1 I of the commercial formulation per hectare.

The addition is preferably carried out 1 to 20 times, more preferably 3 to 15 times and specifically 5 to 12 times during the life cycle of the seafood nourishing on the algae to be treated.

It is believed that the growth promotion of the seafood may be partly due to an enhanced growth of algae growing in the ponds where the seafood lives, which in turn is caused by the treatment of the ponds with the kelp preparation. Thus, the invention also relates to the use of a solid or liquid kelp preparation for quantitatively and/or qualitatively enhancing the growth of algae.

As regards suitable and preferred kelp preparations, reference is made to what has been said above.

"Quantitatively enhancing the growth" means that the dry biomass of the algae is enhanced, as compared to algae not treated with the kelp preparation or not growing in a medium which is/has been treated with the kelp preparation. The biomass increase is either due to a numeric increase (i.e. the number of algae in a specific volume of the medium in which they grow/live is increased) or by an increase in weight (i.e. the dry biomass of the single organisms increases) or a combination of the two aspects. More frequently, the biomass increase via a numeric increase (i.e. the number of algae in a specific volume of the medium in which they grow/live is increased) predominates.

"Qualitatively enhancing the growth" means that the algae have a higher quality with respect to their nutritional value and/or their content in vitamins, minerals and/or other nutritional factors and thus are healthier and/or more nutritive for the seafood for which they serve as food, as compared to algae not treated with the kelp preparation or not growing in a medium which is/has been treated with the kelp preparation. "Healthier" means that the seafood nourishing on thusly treated algae show a decreased disease level and/or a decreased mortality. Additionally or alternatively, "qualitatively enhancing the growth" also means that the algae treated with the kelp preparation and/or growing in a medium which is/has been treated with the kelp preparation have a prolongated lifetime.

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. In water, algae form the phytoplankton and a big part of the phytobenthos. The largest and most complex benthic marine forms are called seaweeds. Algae are photosynthetic, like plants, and "simple" because they lack various structures that characterize land plants, such as phyllids and rhizoids in nonvascular plants, or leaves, roots, and other organs that are found in tracheophytes. For that reason they are currently excluded from being considered plants. Many are photoautotrophic, although some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular species rely entirely on external energy sources and have limited or no photosynthetic apparatus. Despite the fact that modern sources restrict the term "algae" to eukaryotic organisms, in the pre- sent invention, the prokaryotic Cyanobacteria (commonly referred to as blue-green algae), which were traditionally included as "algae" in older textbooks, are also encompassed by this term.

The algae the growth of which is to be enhanced according to the present invention are aquatic, preferably marine, and represent a food source for seafood, in particular for crustaceans and especially for shrimps and prawns. Examples of suitable algae groups are haptophyta, cryptista, dinozoa, chlorarachinphyta, bacillariophyta (diatoms), phae- ophyta (brown algae), rhodophyta (red algae), chlorophyta (green algae), picobiliphyta and cyanobacteria (blue-green algae). Preferably, the algae the growth of which is to be enhanced according to the present invention are selected from bacillariophyta (diatoms) and cyanobacteria (blue-green algae).

In a further aspect, the present invention relates to a method for quantitatively and/or qualitatively enhancing the growth of algae, which method comprises treating the algae and/or their habitat with a solid or liquid kelp preparation.

As regards the terms "quantitatively and/or qualitatively enhancing the growth of algae" as well as suitable and preferred algae and kelp, reference is made to what has been said above.

In general, the habitat of the algae, e.g. the pond where they are growing or living, is treated with the kelp preparation, e.g. by adding the preparation to the water in the pond. The preparation may be added as such or diluted (ordinarily with water) or may be mixed with feeds used as an additional nutrient for the seafood growing in the pond.

The kelp preparation is added to the habitat of the algae in such an amount that the amount of phytohormones added via the kelp preparation is preferably in a range of from 1 mg to 50 mg, more preferably from 3 mg to 20 mg and in particular from 3 mg to 15 mg per hectare of the habitat. If Kelpak® is used, this is added in an amount of preferably 100 ml to 2 I, more preferably from 200 ml to 1.5 I and specifically from 0.5 I to 1 I of the commercial formulation per hectare.

The addition is preferably carried out 1 to 20 times, more preferably 3 to 15 times and specifically 5 to 12 times during the life cycle of the seafood nourishing on the algae to be treated.

The use and the method according to the invention lead to a quantitatively and/or qualitatively enhanced growth of algae, as represented by an enhanced dry biomass and/or a higher quality of the algae, e.g. a higher nutritional value and/or a higher content in vitamins, minerals and other nutritional factors.

The quantitatively and/or qualitatively enhanced growth of algae can in turn lead to a promoted growth of seafood, in particular of crustaceans and especially of shrimps and prawns nourishing on these algae. However, the enhanced growth of algae does not seem to be the only reason for the promoted growth of seafood.

The promoted growth of seafood is reflected in a diminished mortality of the seafood larvae, in a faster weight increase and/or in a lower disease level. The faster weight increase in turn means that less supplementary artificial feeds are necessary for obtaining seafood with the same or a comparable weight. This in turn implies a reduced pollution with decaying, wasted artificial feeds of the habitat, e.g. the pond, where the seafood is grown. If the amount of supplementary feeds is not reduced, this is never- theless advantageous for the seafood farmer as he can harvest the seafood earlier and thus has the possibility of having more life cycles of the seafood per year.

The invention is now further illustrated by the following non-limiting examples. Examples

1 . Effect of Kelpak® treatment on the growth of shrimps

Between January and June 2008, seawater shrimp ponds containing diatoms and blue- green algae were treated with Kelpak®, Fitobloom® (a fertilizer on a microalgae basis) and Cal P-24.

The respective treatments were carried out on the days and in the quantities compiled in Table 2:

Table 2

Fitobloom 7-1

Fitobloom 4-1

Fitobloom 2-1 In parallel, the same number of ponds containing a comparable initial number of diatoms and blue-green algae was treated analogously, but without the use of Kelpak®. While the shrimps growing in the ponds treated with Kelpak® had reached maturity (= at least 25 g per shrimp) in 149 days (actually, after 149 days, the shrimps had a mean weight of 27.3 g), the shrimps growing in the ponds without Kelpak® treatment had reached maturity only after 170 days (with a mean weight of 25.9 g). The survival rate was 40% in the Kelpak®-treated ponds and 39% in the ponds without Kelpak® treat- ment. The ponds treated with Kelpak® yielded 24,052 pounds of shrimps, as compared to 22,191 pounds of shrimps of the ponds without Kelpak® treatment. The shrimps in ponds treated with Kelpak® had consumed 16,700 pounds of artificial food, as compared to 22,191 pounds consumed in the ponds without Kelpak® treatment.