Field of the Invention

The present invention relates to aquaculture in general and more particularly to an aquaculture feed and a method for producing the same.

Background of the Invention

In shrimp farming, adult shrimps are used as broodstock to produce shrimp larvae. These adult shrimps have high nutritional demands, especially for egg production. To meet the nutritional needs, shrimp broodstocks are typically fed with fresh feed ingredients such as, for example, squid, fish, mussels, clams, polychaetes (sandworms) and bloodworms. With the exception of polychaetes, the other fresh feed ingredients may be substituted with dry feed ingredients.

Obtaining a suitable supply of polychaetes for shrimp broodstocks is however fraught with problems. For one, polychaetes also require cultivation and it takes at least six (6) months before the polychaetes are of suitable size for harvesting. Survival rates for polychaetes are also low. Furthermore, processing of polychaetes such as, for example, by heating, freezing, irradiation or freeze-drying, reduces the efficacy of the polychaetes as feed for shrimp broodstocks. Locally cultivated polychaetes are known to carry deadly shrimp diseases. Live specific-pathogen- free (SPF) polychaetes are however expensive and if locally unavailable, must be air-flown from other countries. Importation of live polychaetes is also complicated and may involve quarantining of the polychaetes.

It would therefore be desirable to provide an aquaculture feed that reduces reliance on live polychaetes and a method for producing such an aquaculture feed.

Summary of the Invention Accordingly, in one aspect, the present invention provides an aquaculture feed including a plurality of feed units. Each of the feed units includes a plurality of whole organisms bound together to form an individual feed unit.

In a second aspect, the present invention provides a method for producing an aquaculture feed. The method includes preparing a mixture of feed ingredients, and producing a plurality of feed units from the mixture of feed ingredients, each of the feed units including a plurality of whole organisms bound together to form an individual feed unit.

Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

Brief Description of the Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic flow diagram illustrating a method for producing an aquaculture feed in accordance with an embodiment of the present invention;

FIG. 2 is a photograph of an aquaculture feed in accordance with an embodiment of the present invention;

FIGS. 3A through 3H are a series of photographs illustrating a method for producing an aquaculture feed in accordance with one embodiment of the present invention; and

FIGS. 4A through 4C are a series of photographs illustrating a method for producing an aquaculture feed in accordance with another embodiment of the present invention. Detailed Description of Exemplary Embodiments

The detailed description set forth below is intended as a description of presently preferred embodiments of the invention, and is not intended to represent the only forms in which the present invention may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the scope of the invention.

The term “feed units” as used herein refers to discrete, regularly or irregularly shaped units of feed of suitable size for ingestion by aquatic organisms.

The term “whole” as used herein refers to being in a complete, unbroken or undamaged state.

The term “unprocessed” as used herein refers to not having been subjected to mechanical or chemical operations such as, for example, heating, freezing, irradiation or freeze-drying in order to effect change or preservation.

The term “live” as used herein refers to being alive or not dead.

The term "about" as used herein refers to both numbers in a range of numerals and is also used to indicate that a value includes the standard deviation of error for the device or method being employed to determine the value. The term "about" as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1 % of a stated value or of a stated limit of a range.

The term “casing” as used herein refers a material for enclosing a filling or stuffing in a close-fitting surround. Examples of casings include, but are not limited to, natural casings made from animal intestines or skin and artificial or synthetic casings made of collagen and/or cellulose. The term “collagen” as used herein refers to all forms of collagen, including those that have been processed or otherwise modified.

The term “alginate” as used herein collectively refers to alginic acid, salts and esters thereof. Alginate is naturally occurring as it is made from algae. Alginate solidifies on contact with a calcium source, without the need for heating.

The term “binder” as used herein refers to a substance that helps to hold or bind together one or more substances. Examples of binders include, but are not limited to, alginate, cellulose, gelatin, guar gum, xanthan gum, other natural binders such as, for example, egg white and fish myosin, and combinations thereof.

The term “substantially” as used herein is a term of approximation and means the same as or very close to that which is specified and is intended to indicate something that is largely, but not necessarily wholly, that which is specified. Furthermore, the term "substantially" as used herein includes the qualitative condition of exhibiting total or near-total extent or degree of a characteristic or property of interest. In quantitative terms, the term "substantially" as used herein means much more than a majority, and may be taken to mean 80% or more.

The term “similar” as used herein when referring to properties and characteristics that can be measured and/or quantified, refers to an absence of a detectable and/or a statistically significant difference, having a resemblance in appearance, character or quantity, and is intended to also encompass identical comparisons.

The term “polychaete” as used herein refers to a sandworm typically from class Polychaeta of phylum Annelida or a bloodworm Glycera (annelid). Examples of polychaetes include, but are not limited to, Perinereis sp., Marphysa sp., Arenicola marina and Nereis virens.

The term "paste" as used herein refers to a smooth or semi-smooth, thick, viscous and flowable material. The term "calcium solution" as used herein refers to a setting bath containing calcium. Examples of calcium solutions include, but are not limited to, calcium chloride solution and calcium lactate solution.

Referring now to FIG. 1 , a method 10 for producing an aquaculture feed in accordance with an embodiment of the present invention is shown.

The method 10 begins at step 12 with preparation of a mixture of feed ingredients.

At step 14, a plurality of feed units or pellets is produced from the mixture of feed ingredients, each of the feed units including a plurality of whole organisms bound together to form an individual feed unit.

By incorporating whole organisms into the feed units, leaching of nutrients from the organisms may be prevented and this helps ensure that the full nutritional load of the organisms is received by aquatic organisms that ingest the feed units.

The whole organisms may be one or more selected from a group consisting of adult Artemia, Artemia nauplii, Artemia cysts, maggots, insects, insect eggs, insect larvae, rotifers, copepods, Daphnia, Tubifex and algae. The Artemia cysts may be decapsulated embryos. Advantageously, in embodiments involving Artemia nauplii, the Artemia nauplii in the feed units were found to have a positive effect on egg production of female shrimp broodstocks. Further advantageously, the Artemia nauplii may be cultivated over a relatively short period of time at locations in close proximity to broodstock farms under well-controlled conditions to avoid viruses or vibrio. Furthermore, by providing the Artemia nauplii as a feed unit, size issues due to the minuteness (approximately 500 microns) of the Artemia nauplii relative to the size of the broodstocks can be resolved.

The whole organisms in the individual feed unit may be unprocessed. Advantageously, this helps ensure that the nutritional value and efficacy of the organisms incorporated into the feed units is preserved. In one or more embodiments, the step 12 of preparing the mixture of feed ingredients may include adding live organisms to the mixture of feed ingredients. Advantageously, this helps ensure that the nutritional value and efficacy of the organisms incorporated into the feed units is preserved.

In one or more embodiments, each of the feed units may include between about 5 percentage by mass (wt%) and about 90 wt% of the whole organisms on wet weight basis, more preferably, between about 40 wt% and about 70 wt% of the whole organisms on wet weight basis.

Apart from the whole organisms, the mixture of feed ingredients may include one or more of fresh ingredients such as, for example, squid, fish and mussels, dry ingredients such as, for example, fish meal, wheat flour, vitamins, minerals and krill meal, and other nutritional supplements such as, for example, fish oils. The step 12 of preparing the mixture of feed ingredients may include blending feed ingredients other than the whole organisms into a paste before adding the whole organisms into the paste to produce the mixture of feed ingredients. The fresh ingredients such as squid and fish may be cut into pieces before blending into paste form.

In one or more embodiments, each of the feed units may further include a binder, the whole organisms in each of the feed units being bound together by the binder to form the individual feed unit. Advantageously, the binder helps to bond the whole organisms together to form the feed units. In such embodiments, each of the feed units may include between about 0.1 wt% and about 30 wt% of the binder, more preferably, between about 0.5 wt% and about 10 wt% of the binder. The binder may be alginate, cellulose, gelatin, guar gum, xanthan gum, a natural binder such as, for example, egg white and fish myosin or combinations thereof.

Advantageously, in embodiments involving alginate as the binder, alginate is naturally occurring, does not require heating and may be used alone without any other binders. In embodiments with alginate as the binder, the step 14 of producing the feed units from the mixture of feed ingredients may include dispensing the mixture of feed ingredients into a calcium solution or calcium rich bath. The calcium solution or calcium rich bath may be calcium chloride solution having a calcium concentration of between about 1 % to about 50 % by mass or calcium lactate solution having a calcium concentration of about 0.5 to about 8 grams per litre (g/l) of water. In such embodiments, the mixture of feed ingredients in paste form mixed with alginate may be introduced directly into the calcium solution or calcium bath in elongated or worm-shaped portions using a nozzle. When the alginate in the dispensed mixture of feed ingredients comes into contact with calcium in the calcium solution, the alginate solidifies, binding the feed ingredients including the whole organisms to produce an elongated or worm-shaped feed. To produce the feed units, the mixture of feed ingredients may be dispensed into the calcium solution or calcium rich bath in individual portions or a lengthy piece of feed may be cut up into individual pieces after solidification of the alginate.

In one or more embodiments, the step 14 of producing the feed units from the mixture of feed ingredients may include filling a plurality of casings with the mixture of feed ingredients, the whole organisms in each of the feed units being bound together by one of the casing to form the individual feed unit. Advantageously, the casings not only help to hold the feed ingredients together, but also help to maintain water quality in broodstock tanks by preventing contamination of water in the broodstock tanks by the feed ingredients, especially fresh ingredients such as squid and fish. Further advantageously, these casings may be used to contain heatsensitive ingredients or ingredients that dissolve easily in water as the casings protect such ingredients from leaching out into the water before being eaten by the broodstocks. The casings may be made of cellulose, animal intestines, animal skin, collagen, alginate or a combination thereof. To fill the casings, the mixture of feed ingredients may be pumped into edible casings using commercially available machines.

In one or more embodiments, the step 14 of producing the feed units from the mixture of feed ingredients may include extruding the mixture of feed ingredients through a nozzle, simultaneously forming a casing of alginate around the mixture of feed ingredients as the mixture of feed ingredients is passed through the nozzle, and then dispensing the encased mixture of feed ingredients into a calcium solution. In such embodiments, a commercially available dual-nozzle machine or a machine with a multi-function nozzle may be used to simultaneously form the casing of alginate around the mixture of feed ingredients as the mixture of feed ingredients is passed through a nozzle. On contact with the calcium source in the calcium solution, the alginate casing solidifies and binds the whole organisms in the mixture of feed ingredients together.

As the broodstocks may not swallow the feed units whole and may instead pierce the casings before consuming the feed, the binder in the mixture, if present, may further advantageously prevent the mixture of feed ingredients from spilling out of the casings and leaching nutrients once the casings are ruptured. Further advantageously, in embodiments with alginate as the binder, the encased mixture of feed ingredients may be introduced directly into broodstock tanks without pretreatment with calcium because the calcium naturally present in seawater is sufficient to seal the paste and prevent leaching of nutrients after the casing is ruptured by the broodstocks.

Referring now to FIG. 2, an aquaculture feed 50 produced in accordance with the method 10 of FIG. 1 is shown. The aquaculture feed 50 includes a plurality of feed units 52. Each of the feed units 52 includes a plurality of whole organisms bound together to form an individual feed unit.

By incorporating whole organisms into the feed units 52, leaching of nutrients from the organisms may be prevented and this helps ensure that the full nutritional load of the organisms is received by aquatic organisms that ingest the feed units 52.

The whole organisms may be one or more selected from a group consisting of adult Artemia, Artemia nauplii, Artemia cysts, maggots, insects, insect eggs, insect larvae, rotifers, copepods, Daphnia, Tubifex and algae. The Artemia cysts may be decapsulated embryos. Advantageously, in embodiments involving Artemia nauplii, the Artemia nauplii in the feed units 52 were found to have a positive effect on egg production of female shrimp broodstocks. Further advantageously, the Artemia nauplii may be cultivated over a relatively short period of time (approximately 24 hours) at locations in close proximity to broodstock farms under well-controlled conditions to avoid viruses or vibrio. Furthermore, by providing the Artemia nauplii in pellet form, size issues due to the minuteness (approximately 500 microns) of the Artemia nauplii relative to the size of the broodstocks can be resolved.

The whole organisms in the individual feed unit 52 may be unprocessed. Advantageously, this helps ensure that the nutritional value and efficacy of the organisms incorporated into the feed units 52 is preserved.

Each of the feed units 52 may include between about 5 percentage by mass (wt%) and about 90 wt% of the whole organisms on wet weight basis, more preferably between about 40 wt% and about 70 wt% of the whole organisms on wet weight basis.

In one or more embodiments, the whole organisms in each of the feed units 52 may be bound together by a casing to form the individual feed unit. The casing may be made of cellulose, animal intestines, animal skin, collagen, alginate or a combination thereof.

Each of the feed units 52 may further include a binder, the whole organisms in each of the feed units 52 being bound together by the binder to form the individual feed unit. Each of the feed units 52 may include between about 0.1 wt% and about 30 wt% of the binder, more preferably, between about 0.5 wt% and about 10 wt% of the binder. The binder may include alginate, cellulose, gelatin, guar gum, xanthan gum, other natural binders such as, for example, egg white and fish myosin, or combinations thereof.

In one or more embodiments, each of the feed units 52 may be of substantially similar dimensions to a polychaete. Advantageously, this makes the aquaculture feed 50 more palatable to the broodstocks as a polychaete replacement. Each of the feed units 52 may have a diameter of between about 1 millimetre (mm) and about 15 mm. In preferred embodiments, the diameter of each of the feed units 52 may be between about 3 mm and about 9 mm. Each of the feed units 52 may have a length of between about 10 mm and about 300 mm. In preferred embodiments, the length of each of the feed units 52 may be between about 50 mm and about 200 mm.

Examples

Example 1

To prepare 1 kilogram (kg) of aquaculture feed, 5 litres (I) of 5% calcium lactase was prepared by mixing calcium lactate with potable, distilled or drinking water in a ratio of 1 litre (I) of water to 50 grams (g) of calcium lactate and leaving the calcium lactase solution for a while until the calcium lactase solution is clear.

7.5 g of sodium alginate solution was poured into 192.5 g of distilled water and mixed with a slow stirring machine for about 30 minutes (mins). The sodium alginate solution was then set aside for about 1 hour (h) for bubbles to disappear before use.

About 30 g of a liquid enrichment product in the form of an emulsion of high docosahexaenoic acid (DMA) and eicosapentaenoic acid (EPA) marine oils was then mixed into the sodium alginate solution as shown in FIG. 3A and slowly mixed until homogeneous as shown in FIG. 3B.

90 g of Artemia nauplii (Instartl ) was blended before being added to the mixture shown in FIG. 3B and mixing slowly until the mixture is homogeneous. Advantageously, blending shreds the Artemia nauplii and this increases the palatability of the aquaculture feed.

The mixture of feed ingredients was then prepared by pouring the sodium alginate and liquid enrichment product mixture into a mixture of 480 g of Artemia nauplii (Instartl ) and 200 g of decapsulated artemia cysts (M-bryo) as shown in FIG. 3C and mixing until homogeneous as shown in FIG. 3D. Advantageously, this prevents damage to the Artemia nauplii.

The mixture of feed ingredients in paste form was then put into a bottle with 5 mm diameter openings and squeezed into a calcium bath to produce a plurality of feed units as shown in FIG. 3E. When injected directly into the calcium bath, the worm-like mixture solidifies in the calcium bath to form the feed units.

The feed units were allowed to soak for 1 hour (h) as shown in FIG. 3F before removal from the calcium bath and washing with fresh water. The feed units were then soaked in a disinfectant bath for 1 h as shown in FIG. 3G.

The feed units were harvested by filtration. The resulting feed units are shown in FIG. 3H. Advantageously, the Artemia nauplii in the feed units stay intact and do not leach out when being consumed by shrimp broodstocks.

Example 2

To prepare 1 kilogram (kg) of aquaculture feed, 5 litres (I) of 5% calcium lactase was prepared by mixing calcium lactate with potable, distilled or drinking water in a ratio of 1 litre (I) of water to 50 grams (g) of calcium lactate and leaving the calcium lactase solution for a while until the calcium lactase solution is clear.

7.5 g of sodium alginate solution was poured into 242.5 g of fresh whole egg and mixed with a slow stirring machine for about 30 minutes (mins). The sodium alginate solution was then set aside for about 1 hour (h) for bubbles to disappear before use.

About 30 g of a liquid enrichment product was then mixed into the sodium alginate solution and slowly mixed until homogeneous.

The mixture of feed ingredients was then prepared by pouring the sodium alginate and liquid enrichment product mixture into a mixture of 504.1 g of Artemia nauplii (Instartl ) and 215.9 g of decapsulated artemia cysts (M-bryo) and mixing until homogeneous.

The mixture of feed ingredients in paste form was then transferred into a machine that fills a casing with the mixture of feed ingredients as shown in FIG. 4A. The encased mixture of feed ingredients extruded from the machine is then cut up into feed units as shown in FIG. 4B before being discharged into the calcium bath as shown in FIG. 4C.

As is evident from the foregoing discussion, the present invention provides an aquaculture feed that reduces reliance on live polychaetes and a method for producing such an aquaculture feed. The aquaculture feed of the present invention may be a wet aquaculture feed of fresh ingredients mixed together with dry ingredients and bound in a matrix of any shape and size. By overcoming the challenges of using Artemia nauplii as a polychaete replacement, the present invention advantageously provides a nutritionally balanced aquaculture feed that can even be offered fresh to aquaculture farms. Furthermore, by encasing the one or more feed ingredients and the Artemia nauplii in an edible casing, the aquaculture feed of the present invention also solves the issue of feed ingredients and nutrients leaching into aquaculture tanks, losing nutrients and contaminating water in the aquaculture tanks.

While preferred embodiments of the invention have been described, it will be clear that the invention is not limited to the described embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without departing from the scope of the invention as described in the claims.

Further, unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising" and the like are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".