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 and preparing feed as well as 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 includes the steps of providing water, a fatty acid component, a protein source, and a feed stabiliser. The feed stabiliser is contacted with the fatty acid component. The feed stabiliser is contacted with the water. The feed stabiliser and water is heated. The feed stabiliser, the fatty acid component, the protein source, and the water is mixed and shaped into a dough. The dough is cooled to obtain the aquaculture feed.

Claims

1-34. (canceled)

35. 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 temperature and a setting temperature; contacting the feed stabiliser and/or the protein source with the fatty acid component; contacting the feed stabiliser with the water; heating the feed stabiliser and the water to the activation temperature; 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 cooling the suspension to a temperature below the setting temperature of the feed stabiliser to obtain the aquaculture feed.

36. The method of manufacturing an aquaculture feed according to claim 35, wherein the suspension is a dough.

37. The method of manufacturing an aquaculture feed according to claim 35, wherein the feed stabiliser is a carbohydrate-based feed stabiliser.

38. The method of manufacturing an aquaculture feed according to claim 37, wherein the feed stabiliser is selected from kappa-carrageenan, iota-carrageenan, alginate, pectin, carboxymethyl cellulose (CMC), ethyl cellulose, gums, and their mixtures.

39. The method of manufacturing an aquaculture feed according to claim 37, wherein the activation temperature is in the range of 80° C. to 100° C.

40. The method of manufacturing an aquaculture feed according to claim 37, wherein the setting temperature is in the range of 40° C. to 70° C.

41. The method of manufacturing an aquaculture feed according to claim 35, wherein the method further comprises an intermediate cooling step of cooling the dough from the activation temperature to an intermediate temperature above the setting temperature of the feed stabiliser and wherein the dough is shaped at the intermediate temperature.

42. The method of manufacturing an aquaculture feed according to claim 41, wherein the intermediate temperature is in the range of 45° C. to 55° C.

43. The method of manufacturing an aquaculture feed according to claim 41, wherein at least one heat-labile additive is added to the dough at the intermediate temperature.

44. The method of manufacturing an aquaculture feed according to claim 43, 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, and their mixtures.

45. 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; contacting the feed stabiliser and/or the protein source with the fatty acid component; contacting the feed stabiliser with the water; activating the feed stabiliser by exposing the feed stabiliser to the activation condition; mixing the feed stabiliser, the fatty acid component, the protein source and the water to provide a dough; shaping the dough into a shaped dough; and changing the conditions of the dough to the setting condition of the feed stabiliser to obtain the aquaculture feed.

46. The method of manufacturing an aquaculture feed according to claim 35, wherein no starch is used in the method.

47. The method of manufacturing an aquaculture feed according to claim 35, wherein the feed stabiliser is contacted with the fatty acid component to provide a fatty acid component slurry, and contacting said fatty acid component slurry with water.

48. The method of manufacturing an aquaculture feed according to claim 36 further comprising the step of adding gas to the dough.

49. The method of manufacturing an aquaculture feed according to claim 48, wherein the gas is nitrogen (N.sub.2).

50. The method of manufacturing an aquaculture feed according to claim 36, wherein the steps of shaping and cooling the dough are performed by passing the dough through a cooled pipe.

51. The method of manufacturing an aquaculture feed according to claim 36 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.

52. The method of manufacturing an aquaculture feed according to claim 51 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.

53. The method of manufacturing an aquaculture feed according to claim 35, wherein the aquaculture feed is added to a flowing water stream whereby the aquaculture feed is hydraulically transported.

54. The method of manufacturing an aquaculture feed according to claim 35 further comprising the step of drying the dough to a moisture content in the range of 4% w/w to 12% w/w.

55. An aquaculture feed comprising a protein, a feed stabiliser, water and a fatty acid component with the fatty acid and the water being comprised in the same phase, wherein the feed on a dry matter basis comprises 25% w/w or more of the fatty acid component, and wherein the content of water is at least 30% w/w of the aquaculture feed.

56. The aquaculture feed according to claim 55, wherein the aquaculture feed on a dry matter basis comprises 45% w/w to 70% w/w of the fatty acid component.

57. The aquaculture feed according to claim 55, wherein the feed stabiliser is selected from the list consisting of kappa-carrageenan, alginate, iota-carrageenan, CMC, pectin, gums, gelatine, oleogels, caseinates, ethyl cellulose, lecithin, and/or glycerol, and their mixtures and wherein content of the feed stabiliser is at least 2% w/w of the dry weight of the aquaculture feed.

58. The aquaculture feed according to claim 55, wherein the aquaculture feed on a dry matter basis comprises less than 15% w/w of starch.

59. The aquaculture feed according to claim 55, wherein the aquaculture feed on a dry matter basis comprises less than 1% w/w of starch.

60. The aquaculture feed according to claim 55, wherein the aquaculture feed on a dry matter basis comprises 20% w/w to 70% w/w of a protein source.

61. The aquaculture feed according to claim 55, wherein the density of the aquaculture feed is in the range of 800 kg/m.sup.3 to 1200 kg/m.sup.3.

62. The aquaculture feed according to claim 55, wherein the aquaculture feed has a total porosity in the range of 1% to 50%, and wherein the effective porosity of the feed is in the range 0% to 5% independently of the total porosity.

63. The aquaculture feed according to claim 62, wherein the aquaculture feed has a total porosity in the range of 20% to 30%.

64. The aquaculture feed according to claim 55, wherein the surface of the aquaculture feed is non-porous.

65. The aquaculture feed according to claim 55, wherein the aquaculture feed is homogeneous.

66. A feed manufacturing system for producing an aquaculture feed comprising a protein, a feed stabiliser, water and a fatty acid component with the fatty acid and the water being comprised in the same phase, wherein the feed on a dry matter basis comprises 25% w/w or more of the fatty acid component, and wherein the content of water is at least 30% w/w of the 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 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 inlet and/or the mixing chamber comprising heating means for heating the individual and/or mixed raw materials, and 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 comprising cooling means for cooling a feed mixture flowing through the flow channel.

67. The feed manufacturing system according to claim 66, 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.

68. The feed manufacturing system according to claim 66, 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

[0081] FIG. 1 shows the gelling temperature for 1% solutions of kappa carrageenan as a function of added salt type and concentration.

[0082] 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

[0083] A powder mixture of 4.8 kg/h of casein, 4.8 kg/h of fish meal and 0.4 kg/h of kappa-carrageenan was added to the inlet (zone 1) of a Bühler model BTSK-30/28D extruder having 7 zones and provided with a 15 kW motor. 12.5 kg/h of water was added to the powder mixture after the inlet and was mixed in zone 2 to zone 4 during heating to 85° C. 8.75 kg rapeseed oil was added to the mixture in zone 5 under vigorous stirring. The mixture was then cooled to 45° C. in zone 6 and zone 7. After zone 7, the cooled aquaculture feed left the extruder as a long sausage, which easily could be cut into pellets of desired length. Even though the mixture was solidified, the texture was soft and could be deformed or shaped like hand-warm marzipan. After further cooling, the pellet hardened further.

Example 2

[0084] An aquaculture feed was manufactured according to example 1. After the feed was cut into pellets, the pellet was dried with ambient air below 40° C. for 12 hours. Very little odour formed by drying the feed at ambient temperature. After drying the pellet at ambient temperature, the water content had reduced to 20% w/w without any decrease in oil content. The pellets with reduced moist was suitable as feed for e.g. shrimps.

Example 3

[0085] A powder mixture of 4.8 kg/h of casein, 4.8 kg/h of soy protein and 0.4 kg/h of kappa-carrageenan was added to the inlet (zone 1) of a Bühler model BTSK-30/28D together with 6.75 kg/h of rapeseed oil and 2 kg/h of fish oil. The powder mixture was dispersed in the fatty acid component under vigorous stirring in zone 1 to zone 4 of the extruder during heating to 85° C.

[0086] 12.5 kg/h of water was added to the mixture in zone 5 during stirring. The mixture was then cooled to 45° C. in zone 6 and zone 7.

[0087] After zone 7, the cooled aquaculture feed left the extruder as a long sausage, which easily could be cut into pellets of desired length. Even though the mixture was solidified, the texture was soft and could be deformed or shaped like hand-warm marzipan. This pellet showed improved texture compared to the pellet from example 1.

Example 4

[0088] 4 kg/h of rapeseed oil is mixed with 0.4 kg/h of carrageenan in a DynaShear® continuous high-shear mixer while being heated to 85° C. to evenly distribute the carrageenan in the fatty acid component. 12.5 kg/h of water having a temperature of 85° C. is added to the mixture together with the remaining 4.75 kg/h of oil, and mixed under high-shear to form an emulsion.

[0089] 9.6 kg/h of soy protein (SPC) and fish meal is added and kneaded to form a homogenous mass while being cooled from around 85° C. to 50° C.

[0090] The homogenous mass is then forced through a 2 meters long cooling nozzle arrangement having a round internal cross-sectional shape. When the homogenous mass passes through the cooling nozzle arrangement, it is compressed into its final shape and cooled to 40° C. which, in this case, is below the gelling temperature of the carrageenan, whereby the final shape is maintained. At the end of the cooling nozzle, a rotating knife cuts the homogenous mass in the aquaculture feed with a length of 2 cm.

Example 5

[0091] 4 kg/h of rapeseed oil is mixed with 0.4 kg/h of carrageenan in a DynaShear® continuous high-shear mixer while being heated to 85° C. to evenly distribute the carrageenan in the fatty acid component. 12.5 kg/h of water having a temperature of 85° C. is added to the mixture together with the remaining 4.75 kg/h of oil, and mixed under high-shear to form an emulsion.

[0092] 9.6 kg/h of soy protein (SPC) and fish meal is added and kneaded to form a homogenous mass while being cooled from around 85° C. to 50° C.

[0093] The homogenous mass is added to an ejector piper, which injects atmospheric air into the homogenous mass at an overpressure to form air bubbles inside the homogenous mass. The homogenous mass is then further kneaded to distribute the air bubbles and form a low density homogenous mass.

[0094] The low density homogenous mass is then forced through a 2 meter long cooling nozzle arrangement having a round internal cross-sectional shape. When the low density homogenous mass passes through the cooling nozzle arrangement, it is compressed into its final shape and cooled to 40° C. which, in this case, is below the gelling temperature of the carrageenan whereby the final shape is maintained. At the end of the cooling nozzle, a rotating knife cuts the low density homogenous mass in the aquaculture feed with a length of 2 cm and the cut aquaculture feed drops into a water bath and floats at the water surface of the water bath, whereby oils and feed residues located on the surface of the aquaculture feed is removed.

[0095] A conveyer band with rubber vanes located in the water bath conveys the washed aquaculture feed up from the water bath and into a flowing water stream providing water to a fish holding unit. Thereby the washed aquaculture feed is hydraulically transported to the fish holding unit.

Example 6

[0096] 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.

[0097] 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.

[0098] 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 Commercial control (prior art) of 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 —

[0099] 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 Dry fish feed Moist fish feed Commercial control (prior art) of the invention (dry fish feed) Code B D C E OrbitCPK40 Protein [%] 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

[0100] 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

[0101] 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.