Feedstuff of high abrasion resistance and good stability in water, containing PUFAs

Abstract

According to the invention, it was found that, surprisingly, a feedstuff having a very high abrasion resistance and very high water stability can be obtained when a PUFA-containing biomass having a high sulphate content is used for producing the feedstuff.

Claims

1. A PUFA (polyunsaturated fatty acid)-containing feedstuff, comprising 2 to 22% by weight of dry biomass, wherein: a) said biomass is obtained by the fermentation of Labyrinthulea cells; b) said biomass comprises 25-60 g/kg of sulphate by weight of dry biomass; c) the 25-60 g/kg of sulphate in said dry biomass is from sulphate present during the fermentation of said Labyrinthulea cells; and wherein the PUFA-containing feedstuff is characterized by an abrasion resistance, based on its Pellet Durability Index (PDI), of at least 91% and a water stability of at least 96%.

2. The PUFA-containing feedstuff of claim 1, wherein the Labyrinthulea cells are in the family Thraustochytriaceae.

3. The PUFA-containing feedstuff of claim 2, wherein said feedstuff contains biomass in an amount of 9 to 20% by weight.

4. The PUFA-containing feedstuff of claim 2, wherein the Labyrinthulea cells in the family Thraustochytriaceae are of the species Schizochytrium or Aurantiochytrium.

5. The PUFA-containing feedstuff of claim 1, and wherein said feedstuff is coated with oil in an amount of 3-18% by weight.

6. The PUFA-containing feedstuff of claim 5, wherein said feedstuff is coated with 7-13% by weight of a coating that is a vegetable oil.

7. The PUFA-containing feedstuff of claim 1, wherein the Labyrinthulea biomass is present in an amount of 11-18% by weight.

8. The PUFA-containing feedstuff of claim 1, wherein the Labyrinthulea biomass is present in an amount of 4 to 20% by weight and said feedstuff is coated with oil in an amount of 5-15% by weight.

9. The PUFA-containing feedstuff of claim 1, wherein the abrasion resistance is at least 94%.

10. The PUFA-containing feedstuff of claim 9, wherein the water stability is at least 98%.

11. The PUFA-containing feedstuff of claim 1, wherein the water stability is at least 98%.

12. The PUFA-containing feedstuff of claim 1, further comprising one or more of the following: a) a polyunsaturated fatty acid (PUFA) content of 0.8 to 8% by weight; b) an omega-3 fatty acid content of 0.8 to 8% by weight; and c) a DHA content of 0.1 to 4.0% by weight.

13. The PUFA-containing feedstuff of claim 1, comprising the following properties: a) a total protein content of 33 to 67% by weight; b) a total fat content of 5 to 25% by weight; c) a total starch content of at most 25% by weight; and wherein the PUFA-containing feedstuff of claim 1, further comprises one or more of the following: e) a polyunsaturated fatty acid (PUFA) content of 0.8 to 8% by weight; f) an omega-3 fatty acid content of 0.8 to 8% by weight; and/or g) a DHA content of 0.1 to 4.0% by weight.

14. The PUFA-containing feedstuff of claim 1, wherein said biomass comprises 25-40 g/kg of sulphate by weight of dry biomass.

15. A process for producing the PUFA-containing feedstuff of claim 1, wherein said process comprises extruding a PUFA-containing biomass having a sulphate content of 25 to 60 g per kilogram of biomass together with other feedstuff components.

16. The process of claim 15, wherein the extrudate is dried and then loaded with oil.

17. The process of claim 16, wherein extrusion and drying is followed by coating of the extrudate with oil in an amount of 3 to 17% by weight.

18. The process of claim 15, wherein the extrusion is carried out at an energy input of 12-28 Wh/kg.

19. The process of claim 15, wherein the composition used for extrusion comprises: a) a total protein content of 33 to 67% by weight; b) a total fat content of 5 to 25% by weight; c) a total starch content of at most 25% by weight.

20. The process of claim 19, wherein the composition used for extrusion further comprises one or more of the following: e) a PUFA content of 0.8 to 8% by weight; f) an omega-3 fatty acid content of 0.8 to 8% by weight; g) a DHA content of 0.1 to 4.0% by weight.

21. A method for farming animals comprising feeding said animals the PUFA-containing feedstuff of claim 1.

Description

WORKING EXAMPLES

Example 1: Producing Biomass by Fermentation of Aurantiochytrium limacinum SR21 in a Medium Having a High Sulphate Content and Subsequent Drying of the Biomass

(1) The cells were cultured for about 75 h in a feed process using a steel fermenter having a fermenter volume of 2 litres with a total starting mass of 712 g and an attained total final mass of 1.3-1.5 kg. During the process, a glucose solution (570 g/kg glucose) was metered in (fed-batch process).

(2) The composition of the starting medium was as follows:

(3) Medium 1: 20 g/kg glucose; 4 g/kg yeast extract; 16 g/kg sodium sulphate; 2 g/kg ammonium sulphate; 2.46 g/kg magnesium sulphate (heptahydrate); 0.45 g/kg potassium chloride; 4.5 g/kg potassium dihydrogen phosphate; 0.1 g/kg thiamine (HCl); 5 g/kg trace element solution.

(4) The composition of the trace element solution was as follows: 35 g/kg hydrochloric acid (37%); 1.86 g/kg manganese chloride (tetrahydrate); 1.82 g/kg zinc sulphate (heptahydrate); 0.818 g/kg sodium EDTA; 0.29 g/kg boric acid; 0.24 g/kg sodium molybdate (dihydrate); 4.58 g/kg calcium chloride (dihydrate); 17.33 g/kg iron sulphate (heptahydrate); 0.15 g/kg copper chloride (dihydrate).

(5) Culturing was carried out under the following conditions: Culture temperature 28° C.; aeration rate 0.5 vvm, stirrer speed 600-1950 rpm, control of pH in the growth phase at 4.5 using ammonia water (25% v/v). Fermentation was carried out up to a biomass density of 116 g/l.

(6) After the culturing process, the fermentation broths were heated to 60° C. for 20 minutes in order to prevent further cellular activity.

(7) This was followed by a two-stage drying of the biomass: Firstly, the fermentation broth was concentrated by evaporation to a dry mass of about 20% by weight. This was followed by spray drying of the concentrated fermentation broth using a Production Minor™ spray dryer (GEA NIRO) at a drying air inlet temperature of 340° C. By means of spray drying, a powder having a dry mass of more than 95% by weight was thus obtained.

(8) The sulphate content of the biomass obtained was determined by determining the sulphur content of the biomass in accordance with DIN ISO 11885. To this end, an aliquot of the biomass was firstly disrupted under pressure at 240° C. with nitric acid and hydrogen peroxide. The sulphur content ascertained was 11 g/kg of biomass, corresponding to a sulphate content of 33 g/kg of biomass.

Example 2: Producing the Feedstuff by Extrusion

(9) The feedstuff mixtures shown in Table 1 were produced. Besides the biomass to be used according to the invention as per Example 1, two further commercially available Labyrinthulea biomasses and also fish oil as a currently still customary source of omega-3 fatty acids were tested for comparison.

(10) The feedstuff mixtures were each produced by mixing of the components—with the exception of the oils—using a double-helix mixer (model 500L, TGC Extrusion, France). The mixtures thus obtained were then comminuted to particle sizes below 250 μm using a hammer mill (model SH1, Hosokawa-Alpine, Germany).

(11) TABLE-US-00001 TABLE 1 Feedstuff compositions used in the extrusion process (data in % by weight) Ingredient M1 M2 M3 M4 Fish meal 10.00 10.00 10.00 10.00 Soya protein concentrate 23.10 23.20 23.10 20.27 Pea protein concentrate 15.00 15.00 15.00 15.00 Wheat gluten 9.90 9.90 9.90 9.90 Wheat meal 18.12 10.82 10.55 16.46 Fish oil 10.00 — — — Biomass from Example 1 — 16.00 — — Commercially available biomass 1 — — 16.74 — Commercially available biomass 2 — — — 13.52 Rape oil 10.00 11.00 11.00 11.00 Vitamin/mineral premix 1.00 1.00 1.00 1.00 DCP 2.00 2.00 2.00 2.00 Yttrium oxide 0.03 0.03 0.03 0.03 DL-Methionine 0.35 0.36 0.33 0.33 Aquavi Lys 0.17 0.35 0.08 0.19 TrypAmino 0.09 0.09 0.08 0.09 L-Histidine 0.24 0.25 0.19 0.21

(12) For the extrusion process, use was made in each case of 140 kg per feedstuff. The extrusion process was carried out using a twin-screw extruder (CLEXTRAL BC45) having a screw diameter of 55.5 mm and a maximum flow rate of 90-100 kg/h. Pellets of 4.0 mm in size (diameter and length) were extruded. To this end, the extruder was equipped with a high-speed cutter in order to convert the product to the intended pellet size.

(13) Various extrusion parameters were then tested in order to find out under what extrusion conditions it is possible to obtain an optimal oil load capacity of the extrudate obtained. In this connection, it became apparent that, surprisingly, an optimal oil load capacity can be achieved with a very low energy input. In this connection, the energy input was distinctly lower than when using fish oil. Furthermore, the optimal energy input in the case of a Thraustochytrium biomass to be preferably used according to the invention was again distinctly lower than in the case of commercially available Thraustochytrium biomasses. The results are shown in Table 2.

(14) TABLE-US-00002 TABLE 2 Energy inputs relating to producing pellets having the desired oil load capacity Barrel Barrel 1 2 Feeder Rotational Amount Temp Temp rate speed of water Current SME Diet (° C.) (° C.) (kg/h) (rpm) (0-10) (A) (Wh/kg) M1 31 116-118 112 215 9 11 34.6 M2 32  98-104 141 253 5 7 20.6 M3 32  97-102 136 255 5 8 24.6 M4 31  99-107 133 253 5 8 24.9

(15) In this connection, the variable “SME” is the specific mechanical energy. This is calculated as follows:

(16) $SME\left(Wh/\mathrm{kg}\right)=\frac{U\times I\times \cos \Phi \frac{\mathrm{Test}\mathrm{SS}}{\mathrm{Max}\mathrm{SS}}}{\mathrm{Qs}}$

(17) where

(18) U: operating voltage of the motor (here 460 V)

(19) I: current of the motor (A)

(20) cos ϕ: theoretical performance of the extruder motor (here 0.95)

(21) Test SS: test speed (rpm) of the rotating screws

(22) Max SS: maximum speed (267 rpm) of the rotating screws

(23) Q.sub.S: inlet flow rate of the mash (kg/h)

(24) After extrusion, the extrudate was dried in a vibrating fluidized bed dryer (model DR100, TGC Extrusion, France).

(25) This was followed, after the extrudate had cooled down, by oil coating by means of vacuum coating (vacuum coater PG-10VCLAB, Dinnisen, the Netherlands).

Example 3: Ascertaining Abrasion Resistance and Water Stability

(26) Abrasion resistance was ascertained as follows: Before being loaded with oil, the dried extrusion product was exposed to a mechanical load using the Holmen pellet tester (Borregaard Lignotech, Hull, UK). Before carrying out the test, the samples were screened in order to remove any adherent fine particles. The processed samples (100 g) were subsequently introduced into the pellet tester using a 2.5 mm filter screen. The pellets were subsequently conveyed through a pipe having right-angled pipe bends at high air velocity for 30 seconds. Subsequently, abrasion was determined by weighing. Abrasion resistance was specified as PDI (Pellet Durability Index), defined as the amount in percent of sample remaining in the filter screen. The test was carried out with three samples and then the mean was determined.

(27) Water stability was carried out using the oil-loaded samples. The method was essentially carried out as described by Baeverfjord et al. (2006; Aquaculture 261, 1335-1345), with slight modifications. 10 g samples were introduced into metallic infusion baskets having a mesh size of 0.3 mm. The infusion baskets were subsequently introduced into a plastic trough containing water, and so the samples were completely covered with water. The trough was subsequently exposed for 30 minutes to a shake-agitation of 30 shake units per minute. Thereafter, the samples were carefully dried with blotting paper and then weighed before and after they had been subjected to oven drying at a temperature of 105° C. for 24 hours. Water stability was calculated as the difference in the dry weight of the sample before and after the incubation in water and specified in percent of the dry weight of the sample used before the incubation with water.

(28) The results are shown in Table 3.

(29) TABLE-US-00003 Sample M1 M2 M3 M4 Abrasion 90.0 93.3 88.3 85.2 resistance [%] Water stability [%] 95.7 98.5 93.8 90.2

(30) It can be seen that a feedstuff according to the invention has a distinctly higher abrasion resistance and water stability than feedstuffs which contain a commercially available Labyrinthulea biomass or fish oil as a source of omega-3 fatty acids.