NZ241426A

NZ241426A - Abalone feed composition containing casein and acidity adjusters providing for good extrusion and stability in sea water

Info

Publication number: NZ241426A
Application number: NZ241426A
Authority: NZ
Inventors: Neil William Walker
Original assignee: Kiwi Co Op Dairies Ltd
Priority date: 1992-01-28
Filing date: 1992-01-28
Publication date: 1995-07-26
Also published as: GB9315059D0; AU657190B2; AU3188493A; JPH0638688A; GB2280091A

Description

<div class="application article clearfix" id="description"> New Zealand Paient Spedficaiion for Paient Number £41426 24i< NEW ZEALAND PATENTS ACT, 1953 No.: 241426 Date: 28 January 1992 *M?rx 22 Qri ic£ JAN 1993 •'vJo" COMPLETE SPECIFICATION IMPROVEMENTS IN OR RELATING TO ABALONE FEED We, KIWI CO-OP DAIRIES LIMITED, a New Zealand company, of 23 Regent Street, Hawera, New Zealand, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- - 1 -(followed by page 1A) 1A This invention relates to an artificial feed for abalone (paua). The feed currently used in New Zealand by abalone aquaculturists is largely seaweed. Using seaweed is expensive, as it requires a large amount of labour to harvest and dry, and electricity for storage. It is also not an ideal food source for the abalone, being low in protein content (eg kelp has 5% protein) and high in watci content. An alternative food source which avoids these disadvantages would therefore be desirable. The requirements for an ideal food for abalone are that it be of high nutritional value, tasty, to encourage the abalone to feed, stable in seawater for a long time, and, of course, relatively inexpensive. Some artificial feed products have been developed, for example containing fishmeal or soybean meal. These protein sources are not ideal in quality, and casein has been found to be a much better protein source for abalone. Some experimental casein-containing foods have been developed, but these have used large amounts of sodium alginate as a stabiliser to bind the feed mixture, and would therefore be unacceptably expensive. It is thus an object of the present invention to go some way towards overcoming the disadvantages of the prior art or at least to offer the public a useful choice. Accordingly, in a first aspect the present invention consists in a method of producing a feed composition for abalone, comprising 2 24JU;, preparing a homogeneous mixture comprising: (i) casein in an amount of about 30-50% by weight of the mixture, (ii) a source of insoluble carbohydrate, in an amount of about 15-30% by weight of the mixture, (iii) an insoluble alginate salt, or other source of alginate ions, in an amount of about 0.5-2% by weight of the mixture, (iv) a source of lipid, in an amount of about 0.1-3% by weight of the mixture, (v) lecithin, in an amount of about 0.5-5% by weight of the mixture, (vi) Glucono-delta-lactone, (vii) a base, wherein the base is present in an amount sufficient to adjust the pH of the mixture to about 55-6, or slightly above, being a level at which extrusion is possible, and (viii) water, in an amount of from about 15-30% by weight of the mixture; and extruding the homogeneous mixture into a desired shape, wherein the extrusion temperature and amount of glucono-delta-lactone present are such that the glucono-delta-lactone will decompose whereby after extrusion of the mixture sufficient gluconic acid is produced to decrease the pH of the extruded product to about 4.9 or below. Preferably the casein is lactic casein, present in an amount of about 39-43% by of the mixture. 3 Preferably the source of insoluble carbohydrate is bran, present in an amount of about 19-24% by weight of the mixture. Preferably the insoluble alginate salt is added to the mixture by adding alginate ions in a soluble form and also adding a source of calcium ions to precipitate the alginate ions. Preferably sodium alginate is added, in an amount of about 0.8-1.6% by weight of the mixture, and calcium sulphate, preferably in an amount of about 0.8-1% by weight of the mixture is added to precipitate the alginate ions. Preferably the lipid is protein-bound. Preferably the source of protein-bound lipid is whole milk powder, added in an amount of about 1.5-2.5% by weight of the mixture. Preferably, the lecithin is added in a powdered form, in an amount of about 2-4% by weight of the mixture. Alternatively, the lecithin comprises a formulation comprising about 70% phospholipid and about 30% soybean oil, and is added in an amount of about 2-6% by weight of the mixture. Preferably the glucono-delta-lactone is added in an amount of about 4-7% by weight of the mixture. 4 ^4142* | 1 ^ v Preferably the base is sodium carbonate, added in an amount of about 1-2% by weight of the mixture. Preferably the water is added in an amount of about 18-22% by weight of the mixture. Preferably vitamins and minerals are also added to the mixture, in a combined amount of about 1-4% by weight of the mixture. Preferably a mould inhibitor and feeding stimulants are also added at step (i). Preferably the mould inhibitor comprises potassium sorbate, present in an amount of about 0.8-1.2% by weight of the mixture. Preferably the mixture is formed by (1) combining all of the components except the glucono-delta-lactone, (2) homogenising the mixture and leaving the mixture to stand for 5-20 hours, and (3) adding the glucono-delta-lactone. Preferably a stabilising salt is also added to the mixture in an amount of about 0.1-1% by weight of the mixture. Preferably the stabilising salt comprises calcium orthophosphate, in an amount of about 03% by weight of the mixture. 5 Preferably a source of highly unsaturated fatty acids, preferably fishmeal in an amount of about 0.5-2% by weight of the mixture (more preferably about 1%) is also added to the mixture. Preferably sodium chloride is also added to the mixture, in an amount of about 0.1 to 1% by weight of the mixture (more preferably about 03%). Preferably the extrusion temperature increases gradually from ambient temperature at the point of entry of the mixture to about 100°C-125°C at the point of exit of the extruded product from the nozzle of extruder. Preferably the extruded product is air-dried. In a further aspect the present invention consists in an abalone feed composition, comprising (i) casein, in an amount of about 40-60% of the dry weight of the composition, (ii) a source of insoluble carbohydrate, in an amount of about 2040% of the dry weight of the composition, (iii) an insoluble alginate salt, or other source of alginate ions, in an amount of about 0.5-3% of the dry weight of the composition, (iv) a source of lipid, in an amount of about 0.1-4% of the dry weight of the composition, (v) lecithin, in an amount of from about 0.5-6% of the diy weight of the composition, and 6 241426 (vi) decomposition products of glucono-delta-lactone, in a sufficient amount to maintain the pH of the composition at about 4.9 or below. Preferably the casein is lactic casein and comprises about 42-53% of the dry weight of the composition. Preferably the source of insoluble carbohydrate is bran, and comprises about 23-32% of the dry weight of the composition. Preferably the insoluble alginate salt comprises calcium alginate and comprises about 1 to 2% of the dry weight of the composition. Preferably the lipid is protein-bound, and comprises whole milk powder, present in an amount of about 2 to 3% of the dry weight of the composition. Preferably the lecithin comprises about 2 to 5% of the dry weight of the composition. Preferably the composition further comprises vitamins and minerals, wherein the vitamins and minerals each comprise about \% of the dry weight of the composition. Preferred forms of the invention will now be described in more detail. The abalone feed of the present invention is an extruded product, comprising casein as the main ingredient and protein source. As noted above, casein is known to be an excellent source of protein for abalone, and is relatively inexpensive. A problem with making an extruded casein product for use as abalone food is that the pH of the mixture to be extruded must be about 5.5-6 or slightly above, in order to prevent the extruded product from breaking up and becoming powdeiy. The difficulty with this requirement, however, is that the extruded product is required to be insoluble in seawater (since the abalone feed will remain underwater for considerable periods of time), and casein forms a colloidal suspension in seawater at a pH of above about 4.9, so the product will show decreased stability in seawater if the pH is greater than about this level. Therefore, it was necessary to determine some means whereby both (a) the casein mixture could be extruded successfully, and (b) the final product would have a pH such that it would not dissolve or break up in seawater. It was discovered, that by adding glucono-delta-lactone to the mixture before extrusion, these two objects could be achieved. Since glucono-delta-lactone slowly decomposes to form gluconic acid and the rate of decomposition is increased at higher temperatures, the pH of the final product will decrease to about 4.9 or below, more preferably about 45 or below, after extrusion has been completed. In this regard it is desirable that the temperature increase along the extruder be gradual, with a final temperature of preferably about 110-125°C, as the product emerges from the extruder. The pH of the pre-extrusion mixture is adjusted if required, using a base such as sodium carbonate, to about 5.5-6, and the pH will not drop significantly until the extrusion has been completed. An extruded composition has the advantages of being able to be any desired shape, and also good structural stability. The abalone feed of the present invention is formulated to provide all of the nutritional requirements of abalone, as well as being tasty to the abalone, and stable under seawater. A discussion of each component follows: (1) Casein As noted above, casein provides the protein source for the abalone. It is added in an amount of from about 30-50 weight % of the mixture to be extruded, preferably about 39-43%, for example 40.5%. Preferably an acid casein, more preferably lactic casein of a smaller mesh (eg 80 mesh) is used. Rennet casein may also be used, although this is less preferred. (2) Carbohydrate source This provides the carbohydrates required by the abalone for optimum nutrition. Any convenient source of insoluble carbohydrate can be used, in an amount of about 15-30 weight % of the pre-extrusion mixture. Preferably bran is used, in an amount of about 19 to 24 weight %, for example 23 weight %, of the pre-extrusion mixture. (3) Insoluble alginate salt Alginate is a known feeding stimulant for abalone. Also, in the form of an insoluble salt, eg calcium alginate, it acts as a stabiliser or 'glue', helping to bind the mixture together. The primaiy function however of the alginate in the 10 composition is as a feeding stimulant The alginate can conveniently be added in the form of sodium alginate (or another water soluble alginate salt, eg potassium or magnesium) which, since it is soluble in water, can be easily dispersed throughout the mixture. A source of cation which will precipitate the alginate ion is also added to the mixture. Calcium sulphate is the preferred salt. The sodium alginate is added in an amount of about 0.5-2% by weight of the mixture, preferably about 0.8-1.6%, for example 1.4%, and calcium sulphate (or another suitable salt), is also added, at a level of around 0.5-2 weight %t preferably about 0.8-1%, for example 0.9%. Alternatively, kelp is rich in alginic acid and it may be possible to use this, for example air-dried kelp, as the source of alginate. Source of lipid It is known that the growth of abalone is reduced if the diet is excessively low in fat, and so a source of fat is included in the feed mixture. It is difficult, however, to extrude fat-containing materials since fat tends to coagulate and form globules during the extrusion process. It was discovered however during the course of the present invention, that adding fat in a protein-bound form will avoid this problem, since the fat remains bound during the extrusion process, and therefore does not form globules. We have found whole milk powder to be a convenient source of such lipid (eg spray dried whole milk powder), and the whole milk powder is generally added in an amount of from 0.1-3 weight % of the mixture, more preferably 1.6-2%, for example about 1.8%. r. jj 4 11 Lecithin (phosphatidyl choline) Lecithin is an attractant and slight stimulant for abalone, encouraging the animals to start feeding. It is also believed that it may assist in growth of the animals. Lecithin in powder form, such as MC thin P-l manufactured by Lucas-Myers, or Centrolex F6450, food grade fine granules lecithin, oil-free phosphatides may be used. Preferably about 0,5-5% lecithin by weight of the mixture is added, more preferably about 2 to 4%, for example about 1.8% Alternatively, the lecithin may be added to the mixture in a commercially available form, eg standard refined soybean lecithin, such as the product MC thin AF-1, manufactured by Lucas-Myers which contains about 70% phospholipids and about 30% soybean oil. Glucono-delta-lactone and source of hydroxide ion As discussed above, a pH-adjusting agent such as glucono-delta-lactone is required to decrease the pH of the final extruded product to around pH 4.9 or below, to confer stability in seawater on the product. Sufficient glucono-delta-lactone is added to produce the required pH change. Preferably about 4-7% glucono-delta-lactone by weight of the mixture is added, for example about 5%. A source of hydroxide ions, preferably a weak base such as sodium carbonate, is also added, as required (preferably in an amount of about 1.5-2% by weight of the mixture), to adjust the pH of the mixture to about 5.5 or above (ie to a suitable pH for extrusion). 12 (7) Water Water is added in an amount of about 15-30% by weight of the mixture to be extruded, preferably about 18-22%, for example about 21%. Water is necessary both to combine the mixture and for extrusion thereof. (8) Mould inhibitor A mould inhibitor is preferably added to prevent mould growing on the composition during storage. A suitable mould inhibitor is potassium sorbate, present in an amount of from about 0.5-1.5 weight % of the mixture, for example about 0.9%. (9) Vitamins and minerals It is desirable to include in the composition additional sources of vitamins and minerals, in order to ensure that the abalone will have a complete diet not lacking in any nutrients. A convenient way to add the vitamins and minerals is in the form of pre-mixed powders. Such premixes are described in more detail later in the example below. (10) Additional feeding stimulants Additional feeding stimulants may also be added to the mixture, if desired, preferably in amounts of about 0.5 to 2% by weight of the mixture. Suitable feeding stimulants include digalactosyldiacylglycerols, oleoic acid, trimethylonene, almitic acid and phosphatidylcholines. 13 2414.'«o (11) Stabilising salt It is desirable that a stabilising salt be added to the mixture. Suitable stabilising salts, for example phosphate and citrate salts, will be known to persons skilled in the art, but a particularly suitable stabilising salt is calcium orthophosphate, which is preferably added in an amount of about 0.1-1%, more preferably about 03% by weight of the mixture. Calcium orthophosphate has beneficial effects on the stability of the mixture, for example it improves its heat stability, minimises gelation, alters the buffering capacity and affects the water binding of the protein. (12) Sodium chloride It is also desirable that sodium chloride be added to the mixture for flavour and as a preservative. A suitable amount is from about 0.1-1% by weight of the mixture, preferably about 03%. (13) Highly unsaturated fattv acids It is desirable for optimum nutrition of the abalone to include a source of highly unsaturated fatty acids in the composition. Preferably hoki fishmeal is added in an amount of from 0.5-2%, more preferably 1% by weight of the mixture. Method of preparation The extruded abalone feeds of the present invention may be obtained using the following sequence of steps: (1) All of the ingredients except the glucono-delta-lactone are combined. 14 *4U:„ (2) The mixture is homogenised (for example by sieving) and left for about 5-20 hours, conveniently overnight. (3) Glucono-delta-lactone is added, and the mixture is extruded. If desired, a glucono-delta-lactone addition feed directly into the extruder screw may be provided. (4) The extruded product is air dried. A suitable extruder for extruding the abalone feeds of the present invention is the Miltenz series 1001 food extruder. Other suitable machines will be evident to those skilled in the art In the extrusion process, the pre-extrusion mixture is fed into the extruder through the hopper, and the extruder screws transfer the product down through the barrel(s) of the extruder and out through the nozzle system. Thus, the transportation process has two distinct zones • the feeding zone and the cooking/pressure chamber zone. The screw where the mixture enters the extruder should preferably be cool, to avoid the mixture binding together excessively and thus making it difficult to transport along the barrel(s). In the extrusion process the extruder should apply a steady gradual compression to the mixture as it is transported along the screw(s). The temperatures along the barrels are not too critical but there should be gradual increase in temperature and the temperature at the final point along the barrels of the extruder before the mixture enters the nozzle system should be from about 90°C to 100°C. The temperature as the product exits from the nozzle system should be about 100-125°C. If the temperature is too low, the mixture will not gel, whereas if it is too high, it will "rough 15 2414^ up". Choke plates are used to create an interruption to the even flow of material down the barrel of the extruder, causing pressure and temperature to increase. Water jackets around the extruder act as a cooling system, controlling the gradual heat generation as the mixture is transported along the screws to the point where the product is extruded from the machine. External port holes near the inlet mixing zone may be used to add small amounts of water to ensure the material keeps moving away from the inlet feed zone, and also to help control the final moisture content of the extruded product. The elevated temperature accelerates the decomposition of glucono-delta-lactone to gluconic acid. As noted previously, the mixture needs to be extruded at a pH of from about 5.5 to about 6, or it will not bind together. It is believed that, following extrusion, the pH of the mixture drops quite rapidly, within a few hours, to around 4.9, although the time course of the pH change has not yet been monitored accurately. Certainly, after a period of about 6 hours after extrusion, the mixture has been observed to be insoluble and stable in seawater, and the pH further decreases to about 4.4. The purpose of air-drying the composition after extrusion is to prevent calcium salts migrating to the surface of the extruded material and forming a thin film, which would detract from the appearance of the finished product. This step allows the moisture to drop to an acceptable level ensuring good microbiological stability. 16 The extruded composition can be of any desired shape, eg tubular, or in the form of a flat sheet, or in strips of varying length, width and thickness. Persons skilled in the art will appreciate that the nozzle system selected will determine the shape and size of the product. The pH of the extruded product may be measured by grinding it and pressing it against a pH probe. Example 1 The following materials were mixed together: 2200g lactic casein (moisture content 190g), 1250g bran (moisture content 13g), 75g sodium alginate (moisture content 2g), lOOg anhydrous sodium carbonate, SOg anhydrous potassium sorbate, SOg anhydrous calcium sulphate, 40g of a vitamin pre-mix (see Table I), 40g of a mineral pre-mix (see Table I) and 1150g water. The mineral premix included 1% by weight of a Trace Element Mixture, for which the formulation is also given in Table 1. lOOg lecithin (insignificant moisture) and lOOg spray wholemilk powder (moisture content 3g) were added to the casein/bran mixture. The mixture was sieved and left overnight at room temperature. 275g anhydrous glucono-delta-lactone was added and the mixture was then extruded using the method described above. The product was air dried. 17 Z4U;«i> Table 1 Mineral Premix Weight % 1.00% 15.00% 25.00% 32.00% 20.00% 2.50% 3.50% Component NaC! MgS047H20 NaH2P042H20 kh2po4 Ca(H2P04)2H20 Fe-Citrate Ca-Lactate 1.00% 3530% 16.20% 3.10% 0.10% 030% 45.00% Trace Element Mixture ZnS047H20 MnS044H20 CuS045H20 Coaz6H20 KI03 CaS04 Vitamin Premix 6mg 5mg 2mg Thiamine HCl Riboflavin Pyridoxine HQ 18 S414J. 40mg Niacin lOmg Ca pantothenate 200mg Inositol 0.6mg Biotin 1.5mg Folic Acid 20mg PABA 4mg Menadione 0.009mg Vitamin B12 200mg Ascorbic Acid 5000IU Vitamin A 100IU Vitamin D to lg CaSO« 5% Palmitic Acid The extruded product contained about 2% fat, 43% protein, and 20-22% moisture. The ingredients used in the composition of the Example and the moisture content of these ingredients are also shown in Table II below. TABLE II 'Ingredient Quantity Added (g) Dry Mass (g) Moisture Content (g) % of Total Composition (pre-extrusion) % of Dry Mass of Total Composition Lactic casein 2200 2010 190 40.5 49.4 Bran 1250 1237 13 23.0 30.4 Sodium alginate 75 73 2 1.4 1.8 Spray wholemilk powder 100 97 3 1.8 2.4 Calcium sulphate (anhydrous) 50 50 0 0.9 1.2 Lecithin 100 100 0 1.8 2.5 Potassium sorbate 50 50 0 0.9 1.2 Glucono-delta-lactone 275 275 0 5.1 6.8 Sodium carbonate 100 100 0 1.8 2.5 Water 1150 0 1150 21.2 0.0 Vitamin premix (see Table 1) 40 40 0 0.7 1.0 Mineral premix (see Table 1) 40 40 0 0.7 1.0 <D i C. 20 Example 2 The ingredients shown in Table III, in the proportions shown, were mixed together, with the exception of the glucono-delta-lactone. The mixture was homogenised and left overnight at room temperature. The glucono-delta-lactone was added and the mixture extruded using the method previously described. The produce was air dried. The percentage of the dry mass of the composition of each component are shown in Table M. TABLE III I Ingredient % (w/w) of Total Composition (pre-extrusion) Moisture Content (% moisture of total composition) % of Dry Mass of Total Composition Acid Casein 41.56 3.36 51.5 Spray Whole Milk Powder 1.93 0.06 2.5 Sodium Alginate SP40 0.97 0.01 13 Oat Bran 2.89 2.87 23.8 CaS042.H20 0.97 0 13 Lecithin (100%) 2.89 0 3.9 Hoki Fishmeal 0.97 0.10 1.2 Potassium sorbate 0.97 0 13 Glucono-delta-lactone 6.04 0 8.1 Na,CO, (anhydrous) 1.21 0 1.6 NaCl 0.29 0 0.4 Vitamin/mineral premix 1.94 0 2.6 Calcium orthophosphate 0.29 0 0.4 Water 19.48 19.48 0 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 241426 It is believed that an extruded casein feed according to the present invention will supply all the nutrients abalone need for optimum growth, as well as being a tasty food which the animals will feed on. The feed compositions have been found to be stable in seawater for several days or more. 1 his invention has been desuibcd in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications apparent to those skilled in the art can be effected within the scope of the invention. It is believed that an abalone feed in accordance with the present invention will find widespread acceptance, in giving those in the industry a more affordable, readily available and effective source of feed. 23 24 1 426 WHAT WE claim IS: 

1. A method of producing a feed composition for abalone, comprising: (a) preparing a homogeneous mixture comprising: (i) casein in an amount of substantially 30-50% by weight of the mixture, (ii) a source of insoluble carbohydrate, in an amount of substantially 15-30% by weight of the mixture, (iii) an insoluble alginate salt, or other source of alginate ions, in an amount of substantially 0.5-2% by weight of the mixture, (iv) a source of lipid, in an amount of substantially 0.1-3% by weight of the mixture, (v) lecithin, in an amount of from substantially 0.5 to 5% by weight of the mixture, (vi) glucono-delta-lactone, (vii) a base, wherein the base is present in an amount sufficient to adjust the pH of the mixture to substantially 5.5-6, or slightly above, being a level at which extrusion is possible, and (viii) water, in an amount of substantially 15-30% by weight of the mixture; and (b) extruding the homogeneous mixture into a desired shape, wherein the extrusion temperature and amount of glucono-delta-lactone present are ^ © F f f ^ such that the glucono-delta-lactone will decompose whereby af$at2xtrusion(v\ *\;241426;of the mixture sufficient gluconic acid is produced to decrease the pH of the extruded product to substantially 4.9 or below.;
2. A method us claimed in claim 1 wherein the casein is lactic casein and is present in an amount of substantially 39-43% by weight of the mixture.;
3. A method as claimed in claim 1 or 2 wherein the source of insoluble carbohydrate comprises bran, and is present in an amount of substantially 19-24% by weight of the mixture.;
4. A method as claimed in claim 3 wherein the alginate ions are added as sodium alginate, in an amount of substantially 0.8-1.6% by weight of the mixture, and calcium sulphate, in an amount of substantially 0.8-1% by weight of the mixture is added to precipitate the alginate ions.;
5. A method as claimed in any one of claims 1 to 4, wherein the lipid is protein-bound lipid.;
6. A method as claimed in any one of claims 1 to 5 wherein the source of lipid is whole milk powder, and is added in an amount of substantially 13-25% by weight of the mixture.;
7. A method as claimed in any one of claims 1 to 6 wherein the lecithin is added in a powdered form, in an amount of from substantially 2-4%;mixture.;25;?4142*
8. A method as claimed in any one of claims 1 to 7 wherein the glucono-delta-lactone is added in an amount of substantially 4-7% by weight of the mixture.
9. A method as claimed in any one of claims 1 to 8 wherein the base is sodium carbonate, added in an amount of substantially 1-2% by weight of the mixture.
10. A method as claimed in any one of claims 1 to 9 wherein the water is added in an amount of substantially 18-22% by weight of the mixture.
11. A method as claimed in any one of claims 1 to 10 wherein vitamins and minerals are also added to the mixture, in a combined amount of substantially 1-4% by weight of the mixture.
12. A method as claimed in any one of claims 1 to 11 wherein the mixture further comprises calcium orthophosphate in an amount of substantially 0.1-1% by weight of the mixture.
13. A method as claimed in any one of claims 1 to 12 wherein the mixture further comprises sodium chloride, in an amount of substantially 0.1-1% by weight of the mixture.
14. A method as claimed in any one of claims 1 to 13, wherein the mixture further comprises fishmeal in an amount of substantially 0.5 to 2% by mixture. V. 241426
15. A method as claimed in any one of claims 1 to 14 wherein the mixture is prepared by (1) combining all of the components except glucono-delta-lactone, (2) homogenising the mixture and leaving the mixture to stand for substantially 5 to 20 hours, and (3) adding the glucono-delta-lactone.
16. An abalone feed composition produced by a method as claimed iu any one of claims 1 to 15.
17. An extruded abalone feed composition comprising: (i) casein, in an amount of substantially 40 to 60% of the dry weight of the composition, (ii) a source of insoluble carbohydrate, in an amount of substantially 20 to 40% of the dry weight of the composition, (iii) an insoluble alginate salt, or other source of alginate ions, in an amount of substantially 0.5-3% of the dry weight of the composition, (iv) a source of lipid, in an amount of substantially 0.1 to 4% of the dry weight of the composition, (v) lecithin, in an amount of substantially 0.5 to 6% of the dry weight of the composition, and (vi) decomposition products of glucono-delta-lactone, present in a sufficient amount to maintain the pH of the composition at substantially 4.9 or below. 241426
IS. A composition as claimed in claim 17 wherein the casein is lactic casein and comprises substantially 42-53% of the dry weight of the composition.
19. A composition as claimed in claim 17 or 18, wherein the source of insoluble carbohydrates is bran, and comprises substantially 23-32% of the dry weight of the composition.
20. A composition as claimed in any one of claims 17 to 19 wherein the insoluble alginate salt comprises calcium alginate and comprises substantially 1-2% of the dry weight of the composition.
21. A composition as claimed in any one of claims 17 to 20 wherein the lipid comprises whole milk powder, present in an amount of substantially 2 to 3% of the dry weight of the composition.
22. A composition as claimed in any one of claims 17 to 21 wherein the lecithin comprises substantially 2 to 5% of the dry weight of the composition.
23. A composition as claimed in any one of claims 17-23 further comprising vitamins and minerals, wherein the vitamins comprise about 1% of the dry weight of the composition and the minerals comprise about 1% of the dry weight of the composition.
24. A composition as claimed in any one of claims 17 to 22 produced by a method as claimed in any one of claims 1 to 15. 241426
25. A method of producing a feed composition for abalone substantially as herein described with reference to Examples 1 and 2.
26. An abalone feed composition substantially as herein described with reference to Examples 1 and 2. DATED THIS DAY OF /i(- ^ i A. J. PARK & SON PSC. j; MUb^'TS POR THE APPLICANTS </div>