AQUA FARMING SYSTEM AND TREATMENT OF WATER MOULD, BACTERIAL COLDWATER DISEASE, RAINBOW TROUT FRY SYNDROME AND COLUMNARIS DISEASE

BACKGROUND

The invention relates to an aqua farming system.

The invention further relates to treatment of water mould, bacterial coldwater disease, rainbow trout fry syndrome and columnaris disease.

The demand for materials inhibiting of growth of harmful organisms, such as water mould (Saprolegniosis) in aqua farming systems is constantly growing. Additionally, bac- terial coldwater disease (BCWD) and rainbow trout fry syn drome (RTFS) , both caused by Flavobacterium psychrophilum, as well as columnaris disease caused by Flavobacterium co- lumnare are growing problems in aqua farming systems.

BRIEF DESCRIPTION

Viewed from a first aspect, there can be provided an aqua farming system comprising an active agent for inhibiting the growth of water mould Saprolegniosis and/or Flavobac- terium in said water system, wherein said active agent comprises coniferous resins acid(s) and/or alkali metal salt of coniferous rosin or alkaline-earth metal salt of coniferous rosin.

An advantage is that an aqua farming system for protecting farmed species and having ability to resist harmful organ isms may be achieved

The system and the use are characterised by what is stated in the independent claims. Some other embodiments are characterised by what is stated in the other claims. In ventive embodiments are also disclosed in the specifica tion and drawings of this patent application. The in ventive content of the patent application may also be de fined in other ways than defined in the following claims. The inventive content may also be formed of several sepa rate inventions, especially if the invention is examined in the light of expressed or implicit sub-tasks or in view of obtained benefits or benefit groups. Some of the defi nitions contained in the following claims may then be un necessary in view of the separate inventive ideas. Fea tures of the different embodiments of the invention may, within the scope of the basic inventive idea, be applied to other embodiments.

Coniferous resins acids are advantageously available in rosin, such as in spruce resin, and tall oil fraction ob tained as a by-product of a kraft pulping process of wood. Rosin primarily includes abietic acid type, e.g. abietic acid, dehydro abietic acid, and pimaric acid type, e.g. pimaric acid, isopimaric acid, resin acids.

Generally, coniferous resin acid(s) are available in a wide variety of sources. Coniferous resin acids are typi cally of spruce or pine origin. For example, coniferous resin acids are provided as "resin" or "rosin". According to a definition found in the literature, "resin" is a sol id or highly viscous substance of plant or synthetic origin. Resin is usually a mixture of organic compounds.

According to a definition, "rosin" is a solid form of res in produced by heating fresh liquid of resin to vaporize the volatile liquid terpene components. Rosin is also called colophony. The terms resin, rosin and colophony are also used synonymously in the literature. In the present invention, coniferous resin acids can be originated from any source. In an embodiment, the resin acids are provided in a highly viscous form of native res in found on the trunk, stub and branches of coniferous trees. This form of resin acids is called as "resin" in the present invention.

Rosinates, i.e. alkali metal salt of coniferous rosin or alkaline-earth metal salt of coniferous rosin are widely used as detergents in household cleaning purposes. They are available for example in Finland under brand names of Tolu Manty from Henkel and Mantysaippua from Foxtel, among others. These products are claimed to contain typically 15 - 30 wt.-% rosinate according to the manufacturers. The product used in example 5 (later in this description) con tained 13,2 wt.-% Sodium rosinate dissolved in water and alcohol .

The term "aqua farming system" (also known as aquaculture) means in this description farming of fish, fish eggs in hatcheries, crustaceans, molluscs, aquatic plants, algae in freshwater or saltwater and under controlled condi tions .

BRIEF DESCRIPTION OF FIGURES

Some embodiments illustrating the present disclosure are described in more detail in the attached drawings, in which

Figure 1 is a schematic view of an aqua farming system,

Figure 2 shows a cell-culture dish comprising Flavobacte- rium and coniferous resins acid(s) . DETAILED DESCRIPTION

In an embodiment, the coniferous resins acid(s) or rosinate(s) is/are incorporated in rosin, such as in pine or spruce resin.

In an embodiment, the coniferous resins acid(s) comprises tall oil rosin, and/or gum rosin, and/or wood rosin.

In an embodiment, the rosinate comprises alkali metal salt of tall oil rosin or alkaline-earth metal salt of tall oil rosin .

In an embodiment, the active agent as is arranged to be dispensed in form of particles, granulates or solid units in water.

In an embodiment, the active agent is arranged to be mixed with a polymeric substrate. In an embodiment, the polymeric substrate comprises poly amide, such as PA6 or PA66, or polyolefin, such as poly ethylene (PE) .

Figure 1 is a schematic view of an aqua farming system. In an embodiment, the active agent is arranged in a filtering element 1 arranged for filtering water in the aqua farming system 100. In an embodiment, the active agent is arranged in granulate form, as such or mixed with the polymeric substrate, in the filtering element 1.

In an embodiment, the aqua farming system 100 is a system for growing edible fish or shellfish products.

In an embodiment, the active agent is arranged in a struc- tural element 2 of the aqua farming system 100. In an embodiment, the structural element is a water pipe, such as a pipe 3 feeding recirculated water in a basin 6, a pipe 4 feeding water from the basin to the filtering el ement, and/or a pipe 5 feeding fresh water in the aqua farming system 100 from outside thereof.

In an embodiment, the aqua farming system 100 comprises a water basin 6, and the structural element 2 is a part of surface of said water basin.

According to an aspect, the farmed species is contacted a short residence time with the active agent. In an embodi ment, the residence time of the active agent in the aqua farming system is not more than 24 hours, and the concen tration of the active agent is in range of at least 0,1 ppm, preferably 0,2 ppm - 600 ppm, more preferably 0,3 ppm

- 500 ppm in water of said aqua farming system.

According to an aspect, the farmed species is contacted a long residence time with the active agent. In an embodi ment, the residence time of the active agent in the aqua farming system is at least 24 hours, and the concentration of the active agent in range of at least 0,1 ppm, prefera bly 0,2 ppm - 5 ppm, more preferably 0,3 ppm - 5 ppm in water of said aqua farming system.

In an embodiment, the concentration of the alkali metal salt of coniferous rosin or alkaline-earth metal salt of coniferous rosin in water is arranged in range of 100 ppm

- 4 %, preferably 1000 ppm - 2000 ppm. This is especially preferable embodiment for use in the treatment of water mould, even more preferable against water mould Sapro- legniosis diclina.

In an embodiment, coniferous resins acid(s) is/are used for the treatment of water mould ( Saprolegniosis) . In an embodiment, coniferous resins acid(s) is/are used for treatment of water mould ( Saprolegniosis Parasitica) . In an embodiment, coniferous resins acid(s) is/are used for treatment of water mould (Saprolegniosis Diclina) .

In an embodiment, coniferous resins acid(s) is/are used for treatment of water mould (Saprolegniosis) in land locked salmon ( Salmo salar m. Sebago) .

In an embodiment, coniferous resins acid(s) is/are used for treatment of bacterial coldwater disease (BCWD) . In an embodiment, coniferous resins acid(s) is/are used for treatment of rainbow trout fry syndrome (RTFS) .

In an embodiment, coniferous resins acid(s) is/are used for treatment of columnaris disease.

In an embodiment, alkali metal or alkaline-earth metal salt of coniferous rosin is used for treatment of water mould Saprolegniosis . In an embodiment, alkali metal or alkaline-earth metal salt of coniferous rosin is used for treatment of water mould Saprolegniosis parasitica .

In an embodiment, alkali metal or alkaline-earth metal salt of coniferous rosin is used for treatment of water mould Saprolegniosis diclina.

In an embodiment, alkali metal or alkaline-earth metal salt of coniferous rosin is used for treatment of water mould Saprolegniosis in land locked salmon Salmo salar m. Sebago . In an embodiment, alkali metal or alkaline-earth metal salt of coniferous rosin is used for treatment of bacteri al coldwater disease (BCWD) .

In an embodiment, alkali metal or alkaline-earth metal salt of coniferous rosin is used for treatment of rainbow trout fry syndrome (RTFS) . In an embodiment, alkali metal or alkaline-earth metal salt of coniferous rosin is used for treatment of colum- naris disease.

EXAMPLE 1

A land locked salmon ( Salmo salar m. sebago) got water mould ( Saprolegniosis) was arranged in a fish tank, the wolume of which were 10 liters. Furthermore, four healthy land locked salmons were arranged in the fish tank. Water was chanced in a continuous way in the fish tank by feeding water through a filter-bed at a rate 30 li ters/hour. Water temperature was 12 - 16 °C.

The filter bed comprises pellets that were made of compo- sition of 300 grams polyamide 6 (PA6) and 200 grams of tall oil rosin.

The ill salmon recovered in five days. The ill salmon did not infect the healthy salmons. Two weeks after the recov- ery of ill salmon, all five salmons were visually healthy.

EXAMPLE 2

A land locked salmon ( Salmo salar m. sebago) got water mould (Saprolegniosis) was arranged in a circulating water aquarium comprising filter bed having pellets that were made of composition of 300 grams polyamide 6 (PA6) and 200 grams of tall oil rosin.

The fish was kept in the aquarium for three hours, after which it was transferred to a fish tank, the volume of which were 10 liters. Water was chanced in a continuous way in the fish tank by feeding water through a filter-bed at a rate 30 liters/hour. Water temperature was 12 - 16 °C. The fish tank did not comprise active agent, and in the water therein was not added active agent.

The fish recovered visually from the water mould and stayed healthy to the end of the experiment (one week) . There were also four healthy land locked salmons in the fish tank. They did not catch water mould during the ex periment .

EXAMPLE 3

In the experiment, small pieces of pure coniferous resins acid(s) as well as pellets including polyethylene, 30 wt . - % coniferous resins acid(s) and block-polyether-block- polyethylene polymer (Pelestat 230).

Gram-negative Flavobacterium psychrophilum was first al lowed to fill the petri dish in agar solution. Then, the small pieces and the pellets were added to the dish. The dish was kept at a temperature of 15 °C for five days.

Figure 2 shows a cell-culture dish comprising Flavobacte rium and coniferous resins acid(s) after five days of add ing the active agent. The concentration of the active agent in water was about 0,5 ppm. As it can readily be seen, Flavobacterium psychrophilum was effectively inhib ited .

EXAMPLE 4 This test was designed to study rosin' s inhibition on gram-negative Flavobacterium columnaris on petri dish. Test included small pieces of rosin, polyethylene granules that had 30 wt.-% rosin and water contact angle adjustment with Pelestat 230.

Gram-negative Flavobacterium psychrophilum was first al lowed to fill the petri dish in agar solution. Then, the small pieces and the pellets were added to the dish. The dish was kept at a temperature of 20 °C for five days.

Result can be seen in Figure 3. Rosin's solubility to wa ter at this temperature is about 1 ppm. Inhibition zones were 16 mm for rosin modified polyethylene (at three o' clock in Figure 3) and 32 mm for rosin (at 11 o'clock) . Polyethylene granule without rosin did not show any inhi bition at position 6 o'clock. The result indicates clearly that rosin effectively inhibits Flavobacterium columnaris .

EXAMPLE 5

Rainbow trout ( Onchorhynchus mykiss) eggs were treated in hatchery with salt derivative of coniferous rosin. Typi cally, hatchery uses formalin in this treatment in very dilute concentration of about 150 ppm calculated for for maldehyde content in water. Eggs are treated with this so lution every third day for fifteen minutes. This treatment is repeated until hatching. Treatment results double or even triple survival rate of eggs against watermould (Saprolegnia diclina) . Typical statistical survival rate of rainbow trout eggs is from 40 % to 70 % with formalin treatment. Without formalin treatment almost all eggs can be lost.

Formalin treatment was substituted with the treatment based on sodium salt of coniferous rosin as an active chemical. Otherwise the procedure was unchanged. Three different concentrations were tested. The active chemical had concentrations of 150 ppm, 1500 ppm and 5 wt.-%. The highest concentration (5 wt.-%) turned out to be too much and all eggs died in the first treatment. Two other con- centrations were used until the eggs hatched after four weeks. Survival rate with concentration 1500 ppm was 47 %. This is a satisfactory result against statistical result of suspected carcinogenic formaldehyde. Concentration 150 ppm turned out to be less effective, but still resulting survival rate of 27 %.

The invention is not limited solely to the embodiments de scribed above, but instead many variations are possible within the scope of the inventive concept defined by the claims below. Within the scope of the inventive concept the attributes of different embodiments and applications can be used in conjunction with or replace the attributes of another embodiment or application. The description is only intended to illustrate the idea of the invention. The invention may vary in detail within the scope of the inventive idea defined in the following claims .

REFERENCE SYMBOLS

1 filtering element

2 structural element 3-5 water pipe

6 water basin

100 arrangement