AN AQUACULTURE FEED WITH HIGH WATER AND OIL CONTENT AND A SYSTEM AND METHOD FOR MANUFACTURING SAID AQUACULTURE FEED

Abstract

The present invention relates to a system and a method of manufacturing a feed product for farmed animals in an aquaculture environment, including but not limited to fish, shrimps, and crabs. The method of manufacturing the aquaculture feed comprising the steps of providing and contacting water, a fatty acid component, a protein source, and a feed stabiliser, and a suspension is formed. The feed stabiliser has a setting condition represented by a setting component. The feed stabiliser is contacted with the water at an activation condition, and the concentration of the setting component in the shaped suspension is increased to the setting condition of the feed stabiliser to obtain the aquaculture feed.

Claims

1-24. (canceled)

25. A method of manufacturing an aquaculture feed comprising the steps of: providing water, a fatty acid component, a protein source, and a feed stabiliser having an activation condition and a setting condition represented by a setting component; contacting the feed stabiliser and/or the protein source with the fatty acid component; contacting the feed stabiliser with the water at the activation condition; mixing the feed stabiliser, the fatty acid component, the protein source and the water to provide a suspension; shaping the suspension into a shaped suspension; and increasing the concentration of the setting component in the shaped suspension to the setting condition of the feed stabiliser to obtain the aquaculture feed.

26. The method of manufacturing an aquaculture feed according to claim 25, wherein the suspension is a dough.

27. The method of manufacturing an aquaculture feed according to claim 25, wherein the feed stabiliser is a carbohydrate-based feed stabiliser.

28. The method of manufacturing an aquaculture feed according to claim 27, wherein the feed stabiliser is selected from kappa-carrageenan, iota-carrageenan, alginate, pectin, carboxymethyl cellulose (CMC), ethyl cellulose, gums, agar, and their mixtures.

29. The method of manufacturing an aquaculture feed according to claim 25, wherein the concentration of the setting component is increased to a threshold level of the setting component.

30. The method of manufacturing an aquaculture feed according to claim 25, wherein the setting component is contained in the protein source and/or the fatty acid component.

31. The method of manufacturing an aquaculture feed according to claim 25, wherein the setting component is selected from the list consisting of alkaline metal ions, earth alkaline metal ions, transition metal ions, H.sup.+ and OH.sup.−, or a combination of these.

32. The method of manufacturing an aquaculture feed according to claim 25, wherein the method is performed at ambient temperature.

33. The method of manufacturing an aquaculture feed according to claim 25, wherein at least one heat-labile additive is added to the suspension at or below an intermediate temperature, which intermediate temperature is in the range of 45° C. to 55° C.

34. The method of manufacturing an aquaculture feed according to claim 33, wherein the heat-labile additive is selected from the list consisting of amino acids, enzymes, colourants, flavourings, vitamins, medicine, organic minerals, bacteria, probiotic bacteria, palatants, peptides, antioxidants, steroids or pre-vitamins, and their mixtures.

35. The method of manufacturing an aquaculture feed according to claim 25, wherein the feed stabiliser is dissolved in water at the activation condition prior to mixing the feed stabiliser, the fatty acid component, and the protein source to provide the suspension.

36. The method of manufacturing an aquaculture feed according to claim 25, wherein the shaped suspension is formed into droplets, which droplets are allowed to fall into a liquid at the setting condition.

37. The method of manufacturing an aquaculture feed according to claim 25, wherein no starch is used in the method.

38. The method of manufacturing an aquaculture feed according to claim 26 further comprising the step of adding gas to the dough.

39. The method of manufacturing an aquaculture feed according to claim 38, wherein the gas is selected from the group consisting of nitrogen (N.sub.2), CO.sub.2, O.sub.2 and N.sub.2O, and combinations thereof.

40. The method of manufacturing an aquaculture feed according to claim 26, wherein the step of shaping the dough is performed by passing the dough through a pipe.

41. The method of manufacturing an aquaculture feed according to claim 26 further comprising the step of washing the aquaculture feed to obtain a washed aquaculture feed and a residue portion, said residue portion comprising surface oils and/or loose dough material.

42. The method of manufacturing an aquaculture feed according to claim 41 further comprising the step of separating the aquaculture feed in a first fraction comprising the washed aquaculture feed and a second fraction comprising the residue portion.

43. The method of manufacturing an aquaculture feed according to claim 25, wherein the aquaculture feed is added to a flowing water stream whereby the aquaculture feed is hydraulically transported.

44. The method of manufacturing an aquaculture feed according to claim 26 further comprising the step of drying the dough to a moisture content in the range of 4% w/w to 12% w/w.

45. A feed manufacturing system for producing an aquaculture feed wherein the feed manufacturing system is adapted for being coupled to a recirculation conduit of a recirculating aquaculture system (RAS) and arranged such that the aquaculture feed manufactured in the feed manufacturing system is allowed to enter the recirculation conduit, said feed manufacturing system comprising: a storage tank for storing an aqueous solution of feed stabiliser having an activation condition and a setting condition represented by a setting component, the storage tank being in fluid communication with a mixing chamber; the mixing chamber comprising mixing means, the mixing chamber being provided with at least one inlet allowing entry of powder and liquid raw materials into the mixing chamber, the mixing chamber having an outlet allowing a feed mixture to exit the mixing chamber, a shaping arrangement fluidly connected and located adjacent to the outlet of the mixing chamber, the shaping arrangement comprising a flow channel configured to shape the feed mixture flowing through the flow channel, and the shaping arrangement optionally comprising cooling means for cooling a feed mixture flowing through the flow channel.

46. The feed manufacturing system according to claim 45, which feed manufacturing system does not comprise a heat exchanger.

47. The feed manufacturing system according to claim 45, wherein the feed manufacturing system further comprises a washing arrangement comprising: a washing chamber being configured to allow entry of an aquaculture feed from the shaping arrangement and for containing a washing liquid, a liquid driving force for providing movement of the washing liquid to wash the aquaculture feed, and a transport arrangement configured to remove the aquaculture feed from the washing chamber, draining the washing liquid from the aquaculture feed and delivering the aquaculture feed to the water recirculation conduit.

48. The feed manufacturing system according to claim 45, wherein the feed manufacturing system further comprises a gas adding arrangement, said gas adding arrangement being located adjacent the mixing chamber and the shaping arrangement and comprising: a gas adding chamber having an inlet configured for receiving a feed mixture from the mixing chamber, and an outlet for providing a flow of feed mixture comprising air to the shaping arrangement, and a gas adding means configured for adding gas into the aquaculture feed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0108] FIG. 1 shows the gelling temperature for 1% solutions of kappa carrageenan as a function of added salt type and concentration;

[0109] FIG. 2 shows the gelling temperature for 1% solutions of iota carrageenan as a function of added salt type and concentration.

DETAILED DESCRIPTION

Example 1

[0110] Four experimental types of fish feed, B, D, C, E were manufactured, and a commercially available fish feed for the aquaculture market was acquired from Biomar (OrbitCPK40). Feed type B and D were produced under conditions mimicking known methods for industrial production of salmon feed, i.e. grinding of raw materials, pre-conditioning, hot extrusion, drying, vacuum coating, and cooling, whereas feed type C and E are embodiments of the present disclosure.

[0111] The four experimental types of fish feed were manufactured with the purpose of testing the digestibility of fish feed with different levels of moisture, the B and D feed being dry fish feeds and the C and E feeds being moist fish feeds. Further, the feeds were manufactured to investigate the impact of binder concentration (i.e. carrageenan). A major difference in feed composition is thus the moisture content in B and D versus C and E. As the moisture content is more than seven times higher for C/E compared to B/D, the concentrations of the remaining ingredients are relatively lower. However, the dry matter ratios in C and E are aimed to correspond to B and D, respectively. The main difference in dry matter composition in B/C and D/E is the content of carrageenan. In the dry feeds, starch (in this case originating from the wheat) is required to extrude a stable and strong pellet. However, starch is not required for the moist feed of the type described in the present invention. Conversely, carrageenan is not required to produce the extruded dry pellets but allows shaping of the moist feed. Even though wheat is required in B/D and carrageenan is advantageous in C/E, they are partially included in both types of feed. The reason for doing so is to reduce the potential impact on the microbiota of the fish. However, to take advantage of the reduced starch requirement in the recipe for moist feed, C and E have low wheat inclusions and, consequently, relatively higher dry matter concentrations of protein and fat. The commercial control feed OrbitCPK40 is included as a reference for comparing the digestibility of an industrially optimized feed recipe to embodiments of the present disclosure.

[0112] The composition of each feed is presented in the below Table 1.

TABLE-US-00001 TABLE 1 Feed recipes Dry fish feed Moist fish feed of Commercial control (prior art) the invention (dry fish feed) Ingredient B D C E OrbitCPK40 Fish meal [%] 32.1 31.3 16.0 15.5 — Caseinate [%] 19.7 19.2 9.78 9.55 — Carrageenan [%] 1.84 3.88 0.910 1.83 — Fish oil [%] 21.8 21.3 10.8 10.6 — Wheat [%] 14.7 14.7 1.60 1.60 — Premix [%] 1.84 1.84 0.910 0.910 — Water [%] 8.00 8.00 60.0 60.0 —

[0113] The five feed types B, D, C, E, and OrbitCPK40 were respectively fed to five salmon batches, each batch consisting of 45 salmons (approximate initial unit weight: 40 g), equally distributed in three separate tanks. In total 15 tanks containing 225 salmons. Results from the digestibility study are presented below in Table 2.

TABLE-US-00002 TABLE 2 Digestibility of individual classes of nutrients for test feeds as well as commercial reference Com- mercial Dry fish feed Moist fish feed of the control (dry (prior art) invention fish feed) Code B D C E OrbitCPK40 Pro- tein [%] 93.6 ± 0.36.sup.a 93.9 ± 0.61.sup.a 95.0 ± 0.21.sup.b 95.3 ± 0.32.sup.b 93.0 ± 0.28.sup.a Fat [%] 92.7 ± 0.27.sup.a 92.5 ± 1.7.sup.a   97.3 ± 0.29.sup.c 96.4 ± 0.72.sup.bc 96.2 ± 0.27.sup.b NFE [%] 58.5 ± 2.7.sup.b  60.6 ± 3.4.sup.b   61.1 ± 1.6.sup.b   63.6 ± 4.2.sup.b 47.9 ± 0.77.sup.a Ash [%] 30.8 ± 3.4.sup.a  33.0 ± 8.4.sup.a   55.5 ± 4.5.sup.b   52.2 ± 3.7.sup.b 40.5 ± 1.2.sup.a   DM [%] 82.5 ± 0.64.sup.a 82.3 ± 2.0.sup.a   90.1 ± 0.39.sup.b 89.1 ± 0.81.sup.b 82.6 ± 0.33.sup.a

[0114] The numbers in Table 2 have superscripted letters a, b and/or c. These letters indicate how the numbers are grouped according to statistical significance. Thus, numbers with “a” are not statistically different from each other, numbers with “b” are not statistically different from each other, and numbers with “c” are not statistically different from each other, but numbers with a “b” are statistically significantly different from numbers with an “a” or a “c”, numbers with an “a” are statistically significantly different from numbers with an “b” or a “c”, numbers with a “c” are statistically significantly different from numbers with an “a” or a “b”, and numbers with both a “b” and a “c” are statistically significantly different from numbers with an “a”. The significance is at p<0.05.

CONCLUSION

[0115] The embodiments of the present disclosure, fish feeds C and E, had significantly greater digestibility relative to the commercially available dry fish feed (OrbitCPK40) and the dry fish feeds B and D. Both feeds C and E had approximately 3%-points improved digestibility of protein relative to all other tested feed types. Further, feed type C had 1 to 5%-points improved digestibility of fat relative to the corresponding dry feed types. As such, the present disclosure provides fish feeds with improved digestibility over existing dry fish feeds.