Method for promoting growth of hermetia illucens and improving nutritional value of hermetia illucens

Abstract

The invention discloses a method for promoting the growth of hermetia illucens and improving the nutritional value of hermetia illucens, and belongs to the technical field of insect breeding. According to the method, a solution containing Zn < 2 + > is added into feed, the concentration of Zn < 2 + > in the feed is made to be 20-100 mg / kg, hermetia illucens larvae are inoculated into the feed containing Zn < 2 + > for a biotransformation experiment, when 50-60% of the hermetia illucens larvae enter a pre-pupa stage, the experiment is ended, and hermetia illucens and larva sand are separated. By adding low-concentration Zn < 2 + > into the feed, the growth of the hermetia illucens larvae can be promoted, and the nutritional value of the hermetia illucens larvae can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of insect breeding, and particularly relates to a method for promoting the growth of black soldier flies and improving their nutritional value. Background Art

[0002] In modern agriculture and animal husbandry, improving feed conversion rate and enhancing animal growth performance are key goals. In recent years, black soldier flies (Hermetia illucens) have attracted widespread attention due to their high feed conversion rate and potential as a high-protein feed ingredient. The main indicators for evaluating the nutritional value of black soldier flies as feed include protein content, lipid content, essential amino acids, unsaturated fatty acids, and some saturated fatty acids (such as lauric acid). Essential amino acids are the cornerstones of protein synthesis, and adequate intake of essential amino acids can promote the normal growth and development of animals. Certain essential amino acids such as arginine and glutamic acid play an important role in the function of the immune system and can enhance the resistance of animals. A reasonable ratio of essential amino acids can improve feed utilization efficiency and reduce waste. Unsaturated fatty acids are involved in the construction of cell membranes and are essential for cell function and tissue growth. Appropriate intake of unsaturated fatty acids can improve the texture and taste of animal products, improve the nutritional value and market competitiveness of products, and reduce inflammatory responses and improve the health of animals. Lauric acid is a saturated fatty acid commonly found in coconut oil and palm kernel oil. It is a medium-chain fatty acid with unique metabolic properties and physiological activity. Lauric acid has significant antibacterial activity, can inhibit the growth of a variety of pathogenic microorganisms, and help maintain animal health. At the same time, lauric acid can be quickly absorbed and utilized by animals, promoting energy metabolism and fat oxidation, and helping to improve the energy utilization rate of feed.

[0003] At present, black soldier flies are generally raised with traditional feeds, or feed ingredients are optimized and nutrients are added. However, the growth efficiency of the black soldier fly larvae raised is not high, and the nutritional value of the obtained insect biomass is insufficient. Summary of the invention

[0004] [Technical issues]

[0005] The invention aims to solve the problem that the black soldier flies have low growth efficiency and low nutritional value when they are fed with traditional feed, optimized feed ingredients and added nutrients.

[0006] [Technical solution]

[0007] The invention provides a method for adding Zn into feed. 2+ Method for promoting growth and improving nutritional value of black soldier flies, providing Zn for black soldier flies during breeding process 2+The growth of the black soldier fly is promoted, and black soldier fly body biomass with higher protein and lipid content is harvested; meanwhile, the harvested black soldier fly biomass has higher content of essential amino acids and unsaturated fatty acids.

[0008] The first object of the present invention is to provide a method for adding Zn to feed. 2+ Method for promoting the growth of black soldier flies and improving the nutritional value of black soldier flies, containing Zn 2+ The solution was added to the feed, and 6-8-day-old black soldier fly larvae were inoculated into the medium containing Zn 2+ The bioconversion experiment is carried out in the feed, and the black soldier flies and insect sand are separated when 50-60% of the black soldier flies larvae enter the prepupa stage, which mainly includes the following steps:

[0009] (1) placing black soldier fly eggs in a constant temperature and humidity incubator for hatching to obtain black soldier fly larvae;

[0010] (2) incubating the hatched black soldier fly larvae in wheat bran having a moisture content of 50 to 60% for 6 to 8 days, and then separating the black soldier fly larvae from the wheat bran to obtain 6 to 8 day old black soldier fly larvae;

[0011] (3) Containing Zn 2+ Add the solution to the feed and adjust the moisture content of the feed to 70-75%, so that the Zn 2+ Concentration is 20-100 mg / kg;

[0012] (4) Inoculate the 6- to 8-day-old black soldier fly larvae obtained in step (2) into the Zn-containing 2+ Bioconversion experiments were conducted in feeds;

[0013] (5) When 50-60% of the black soldier fly larvae enter the prepupae stage, separate the black soldier flies and the insect sand.

[0014] In one embodiment of the present invention, in step (1), the environmental conditions for hatching black soldier fly eggs are a temperature of 29-31° C. and a relative humidity of 68-72%.

[0015] In one embodiment of the present invention, in step (3), the feed is wheat bran.

[0016] In one embodiment of the present invention, in step (4), 3 to 4 6-8 day old black soldier fly larvae are inoculated for every 1 to 2 g of dry matter feed, wherein the dry matter feed refers to feed from which water has been removed.

[0017] In one embodiment of the present invention, in step (4), the temperature is controlled at 29-31° C. and the relative humidity is controlled at 68-72% during the bioconversion experiment.

[0018] The present invention also provides black soldier flies obtained by the method described above.

[0019] The present invention also provides the use of the above-mentioned black soldier fly in the field of animal feed production.

[0020] [Beneficial Effects]

[0021] (1) Adding low concentrations of Zn to feed 2+ It promotes the growth of black soldier fly larvae, and the harvested black soldier fly larvae have a higher body weight. The total weight of black soldier flies is 7.04-12.98% higher than that of black soldier flies raised with wheat bran as feed alone.

[0022] (2) Adding low concentrations of Zn to feed 2+ The protein and lipid contents of the black soldier flies are 42.44-43.97% and 26.94-28.36% respectively, which are increased by 1.31-4.97% and 10.67-16.37% compared with the protein and lipid contents of the black soldier flies raised when wheat bran is used as feed alone;

[0023] (3) Adding low concentrations of Zn to feed 2+ The protein and lipid production efficiencies of the black soldier flies are 52.98-62.35% and 33.61-40.21%, which are increased by 6.15-24.92% and 15.66-38.37% compared with the protein and lipid production efficiencies of the black soldier flies raised when wheat bran is used as feed alone.

[0024] (4) Adding low concentrations of Zn to feed 2+ The essential amino acid and total amino acid contents of the black soldier flies are 18.10% and 47.83%, which are increased by 4.93% and 3.02% compared with the essential amino acid and total amino acid contents of the black soldier flies raised when wheat bran is used as feed alone.

[0025] (5) Adding low concentrations of Zn to feed 2+ The unsaturated fatty acid and lauric acid content of the black soldier flies are respectively 30.23-31.89% and 38.23-38.72%, which are respectively increased by 2.47-8.10% and 4.08-5.42% compared with the unsaturated fatty acid and lauric acid content of the black soldier flies raised when wheat bran is used alone as feed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The weight change trends of black soldier fly larvae in different groups of Examples 1 to 3 and Comparative Examples 1 to 3;

[0027] Figure 2 The protein and lipid contents of black soldier fly larvae of different groups in Examples 1 to 3 and Comparative Examples 1 to 3;

[0028] Figure 3The protein and lipid production efficiencies of the black soldier fly larvae of different groups in Examples 1 to 3 and Comparative Examples 1 to 3. DETAILED DESCRIPTION

[0029] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the embodiments are intended to better explain the present invention, but are not limited to the present invention. If no specific conditions are specified in the embodiments, the conditions are carried out according to conventional conditions or manufacturer recommendations. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0030] Method for determination of protein and lipid in black soldier fly:

[0031] Weigh 0.5g of the dried sample and place it in a dry digestion tube. Add 0.2g of copper sulfate, 3g of potassium sulfate and 10mL of concentrated sulfuric acid, and digest it in a digestion furnace. No sample is added to the blank sample. The digestion temperature is set to 120℃, 30min, 240℃, 40min, 320℃, 40min, 380℃, 30min, and then 420℃, 1.5h. Then use a Kjeldahl nitrogen analyzer for distillation; after the sample is distilled, add 2 drops of indicator (2% boric acid: methyl red: bromocresol green = 100: 1 / 6: 5 / 6), titrate the sample with 0.1mol of hydrochloric acid standard solution until it turns red, boil for 2min, cool, and titrate again until it turns red. When the solution color is still red after heating and cooling, the titration endpoint is determined.

[0032] The collected black soldier fly larvae samples were dried at 105°C to constant weight, 2 g of the dried sample was accurately weighed, wrapped in a filter paper box, and placed in a Soxhlet extractor. The dried sample was extracted with petroleum ether as solvent in a 60°C water bath for 12 h. The flask containing the fat was dried and weighed.

[0033] Protein content calculation method: Protein content = 1.401 × V1 × 0.1 × 6.25 / M

[0034] V1 is the volume of the hydrochloric acid standard solution consumed in the titration, and M is the mass of the dry sample weighed.

[0035] Calculation method of lipid content: lipid content = (M1-M0) / (M2-M0).

[0036] M0 refers to the weight of the filter paper box, M1 refers to the weight of the filter paper box containing the dry sample, and M2 refers to the weight of the filter paper box after lipid extraction.

[0037] Protein output efficiency calculation method: Protein output efficiency = (total dry weight of black soldier fly larvae × protein content) / dry weight of consumed feed

[0038] The lipid production efficiency was calculated as follows: lipid production efficiency = (total dry weight of black soldier fly larvae × lipid content) / dry weight of feed consumed.

[0039] Example 1

[0040] (1) placing 20 g of black soldier fly eggs in a constant temperature and humidity incubator at a temperature of 30° C. and a relative humidity of 70% for incubation;

[0041] (2) incubating the hatched black soldier fly larvae in wheat bran with a moisture content of 60% for 8 days, separating the black soldier fly larvae from the wheat bran, and obtaining 8-day-old black soldier fly larvae;

[0042] (3) 40.53 mg ZnSO4·7H2O was added to distilled water to make the volume 1 L, and the moisture content of wheat bran was adjusted to 70% with the prepared solution as the feed for black soldier flies. 2+ The concentration is 20 mg / kg;

[0043] (4) 300 8-day-old black soldier fly larvae were inoculated into 100 g of dry matter feed, which refers to wheat bran with water removed, and placed in an environment with a temperature of 30° C. and a relative humidity of 70% for a bioconversion experiment;

[0044] (5) When 50% of the black soldier fly larvae entered the prepupal stage, the experiment was terminated and the black soldier flies and insect sand were separated. The experimental group was named Z1.

[0045] Example 2

[0046] (1) placing 20 g of black soldier fly eggs in a constant temperature and humidity incubator at a temperature of 30° C. and a relative humidity of 70% for incubation;

[0047] (2) incubating the hatched black soldier fly larvae in wheat bran with a moisture content of 60% for 8 days, separating the black soldier fly larvae from the wheat bran, and obtaining 8-day-old black soldier fly larvae;

[0048] (3) 101.33 mg ZnSO4·7H2O was added to distilled water to make the volume 1 L, and the moisture content of wheat bran was adjusted to 70% with the prepared solution as the feed for black soldier flies. 2+ The concentration is 50 mg / kg;

[0049] (4) 300 8-day-old black soldier fly larvae were inoculated into 100 g of dry matter feed, which refers to wheat bran with water removed, and placed in an environment with a temperature of 30° C. and a relative humidity of 70% for a bioconversion experiment;

[0050] (5) The experiment was terminated when 50% of the black soldier fly larvae entered the prepupal stage. The black soldier flies and insect sand were separated and the experimental group was named Z2.

[0051] Example 3

[0052] (1) placing 20 g of black soldier fly eggs in a constant temperature and humidity incubator at a temperature of 30° C. and a relative humidity of 70% for incubation;

[0053] (2) incubating the hatched black soldier fly larvae in wheat bran with a moisture content of 60% for 8 days, separating the black soldier fly larvae from the wheat bran, and obtaining 8-day-old black soldier fly larvae;

[0054] (3) Add 202.65 mg ZnSO4·7H2O to distilled water to make the volume 1 L, and use the prepared solution to adjust the moisture content of wheat bran to 70% as the feed for black soldier flies. 2+ The concentration is 100 mg / kg;

[0055] (4) 300 8-day-old black soldier fly larvae were inoculated into 100 g of dry matter feed, which refers to wheat bran with water removed, and placed in an environment with a temperature of 30° C. and a relative humidity of 70% for a bioconversion experiment;

[0056] (5) The experiment was terminated when 50% of the black soldier fly larvae entered the prepupal stage. The black soldier flies and insect sand were separated and the experimental group was named Z3.

[0057] Comparative Example 1

[0058] (1) placing 20 g of black soldier fly eggs in a constant temperature and humidity incubator at a temperature of 30° C. and a relative humidity of 70% for incubation;

[0059] (2) incubating the hatched black soldier fly larvae in wheat bran with a moisture content of 60% for 8 days, separating the black soldier fly larvae from the wheat bran, and obtaining 8-day-old black soldier fly larvae;

[0060] (3) adjusting the moisture content of wheat bran to 70% with distilled water as feed for black soldier flies;

[0061] (4) Inoculating 8-day-old black soldier fly larvae into feed and placing it in an environment with a temperature of 30°C and a relative humidity of 70% for a bioconversion experiment;

[0062] (5) When 50% of the black soldier fly larvae entered the prepupal stage, the experiment was terminated and the black soldier flies and insect sand were separated. The control group was named CK.

[0063] Comparative Example 2

[0064] (1) placing 20 g of black soldier fly eggs in a constant temperature and humidity incubator at a temperature of 30° C. and a relative humidity of 70% for incubation;

[0065] (2) incubating the hatched black soldier fly larvae in wheat bran with a moisture content of 60% for 8 days, separating the black soldier fly larvae from the wheat bran, and obtaining 8-day-old black soldier fly larvae;

[0066] (3) 405.31 mg ZnSO4·7H2O was added to distilled water to make the volume 1 L, and the moisture content of wheat bran was adjusted to 70% with the prepared solution as the feed for black soldier flies. 2+ The concentration is 200 mg / kg;

[0067] (4) 300 8-day-old black soldier fly larvae were inoculated into 100 g of dry matter feed, which refers to wheat bran with water removed, and placed in an environment with a temperature of 30° C. and a relative humidity of 70% for a bioconversion experiment;

[0068] (5) The experiment was terminated when 50% of the black soldier fly larvae entered the prepupal stage. The black soldier flies and insect sand were separated and the experimental group was named Z4.

[0069] Comparative Example 3

[0070] (1) 20 g of black soldier fly eggs were placed in a constant temperature and humidity incubator at 30° C. and 70% relative humidity for incubation.

[0071] (2) incubating the hatched black soldier fly larvae in wheat bran with a moisture content of 60% for 8 days, separating the black soldier fly larvae from the wheat bran, and obtaining 8-day-old black soldier fly larvae;

[0072] (3) 1013.28 mg ZnSO4·7H2O was added to distilled water to make the volume 1 L, and the moisture content of wheat bran was adjusted to 70% with the prepared solution as the feed for black soldier flies. 2+ The concentration is 500mg / kg;

[0073] (4) 300 8-day-old black soldier fly larvae were inoculated into 100 g of dry matter feed, which refers to wheat bran with water removed, and placed in an environment with a temperature of 30° C. and a relative humidity of 70% for a bioconversion experiment;

[0074] (5) The experiment was terminated when 50% of the black soldier fly larvae entered the prepupal stage. The black soldier flies and insect sand were separated and the experimental group was named Z5.

[0075] The performance test results are as follows:

[0076] By comparing the total weight of black soldier flies harvested from different groups after the biotransformation experiment, the results are as follows Figure 1 The total insect weight of black soldier flies in Example 1 (Z1) and Example 2 (Z2) increased by 12.98% and 7.04% respectively compared with that in Comparative Example 1 (CK), while the total insect weight of black soldier flies in Comparative Example 2 (Z4) and Comparative Example 3 (Z5) decreased compared with that in Comparative Example 1 (CK). This indicates that the addition of low concentration Zn 2+ It is beneficial to the growth of black soldier flies, while high concentrations will inhibit the growth of black soldier flies.

[0077] By measuring the protein and lipid indexes of the dry weight of the black soldier fly prepupae in each group, the changes in the protein and lipid content of the black soldier flies in different groups and the changes in the protein and lipid production efficiency were determined. The results are as follows: Figure 2 and Figure 3 As shown. The protein content in the black soldier flies of Example 1 (Z1) and Example 2 (Z2) was increased by 4.97% and 1.31% compared with that of Comparative Example 1 (CK), and the lipid content in the black soldier flies of Example 1 (Z1) and Example 2 (Z2) was increased by 16.37% and 10.67% compared with that of Comparative Example 1 (CK). This shows that the addition of low concentration Zn 2+ It is beneficial to improve the protein and lipid content of black soldier flies. At the same time, the protein production efficiency of black soldier flies in Example 1 (Z1) and Example 2 (Z2) is increased by 24.92% and 6.15% compared with that in Comparative Example 1 (CK), and the lipid production efficiency of Example 1 (Z1) and Example 2 (Z2) is increased by 38.37% and 15.66% compared with that in Comparative Example 1 (CK), indicating that the addition of low concentration Zn 2+ It can improve the ability of black soldier fly larvae to convert feed into insect body protein and lipid.

[0078] The amino acids and fatty acids of the black soldier flies in each group were measured to determine the nutritional value of the black soldier flies in different groups, and the results are shown in Tables 1 and 2. The total amino acid content and essential amino acid content of the black soldier flies in Example 1 (Z1) were increased by 4.93% and 3.02% compared with those in Comparative Example 1 (CK). The unsaturated fatty acid content of the black soldier flies in Example 1 (Z1) and Example 2 (Z2) was increased by 8.10% and 2.47% respectively compared with that in Comparative Example 1 (CK). The lauric acid content of the black soldier flies in Example 1 (Z1) and Example 2 (Z2) was increased by 5.42% and 4.08% respectively compared with that in Comparative Example 1 (CK).

[0079] In summary, the weight and nutritional components of black soldier flies were measured and analyzed respectively, and it was found that low concentration (20-50 mg / kg) of Zn 2+ Promote the growth of black soldier flies and improve the nutritional value of black soldier flies.

[0080] Table 1 Amino acid composition of black soldier fly larvae in different groups of Examples 1-2 and Comparative Example 1

[0081]

[0082]

[0083] Table 2 Fatty acid composition of black soldier fly larvae in different groups of Examples 1-2 and Comparative Example 1

[0084]

[0085]

[0086] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for promoting the growth of black soldier flies and improving the nutritional value, characterized in that: Containing Zn 2+ The solution was added to the feed, and 6-8-day-old black soldier fly larvae were inoculated into the medium containing Zn 2+ A bioconversion experiment was carried out in the feed, and the black soldier flies and insect sand were separated when 50-60% of the black soldier fly larvae entered the prepupae stage.

2. A method for promoting the growth of black soldier flies and improving the nutritional value according to claim 1, characterized in that: Zn in feed 2+ The concentration is 20-100 mg / kg.

3. A method for promoting the growth of black soldier flies and improving the nutritional value according to claim 1, characterized in that: The feed is wheat bran.

4. A method for promoting the growth of black soldier flies and improving the nutritional value according to claim 1, characterized in that: The specific method includes the following steps: (1) placing black soldier fly eggs in a constant temperature and humidity incubator for hatching to obtain black soldier fly larvae; (2) incubating the hatched black soldier fly larvae in wheat bran having a moisture content of 50 to 60% for 6 to 8 days, and then separating the black soldier fly larvae from the wheat bran to obtain 6 to 8 day old black soldier fly larvae; (3) Containing Zn 2+ Add the solution to the feed and adjust the moisture content of the feed to 70-75%, so that the Zn 2+ Concentration is 20-100 mg / kg; (4) inoculating the 6- to 8-day-old black soldier fly larvae obtained in step (2) into the Zn-containing 2+ Bioconversion experiments were conducted in feeds; (5) When 50-60% of the black soldier fly larvae enter the prepupae stage, separate the black soldier flies and the insect sand.

5. A method for promoting the growth of black soldier flies and improving the nutritional value according to claim 4, characterized in that: In step (1), the temperature for hatching black soldier fly eggs is 29-31° C. and the relative humidity is 68-72%.

6. A method for promoting the growth of black soldier flies and improving the nutritional value according to claim 4, characterized in that: In step (4), 3 to 4 6-8 day old black soldier fly larvae are inoculated for every 1 to 2 g of dry matter feed, wherein the dry matter feed refers to feed from which water has been removed.

7. A method for promoting the growth of black soldier flies and improving the nutritional value according to claim 4, characterized in that: In step (4), the temperature during the bioconversion experiment is 29-31°C.

8. A method for promoting the growth of black soldier flies and improving the nutritional value according to claim 4, characterized in that: In step (4), the relative humidity during the bioconversion experiment is 68-72%.

9. The black soldier fly obtained by the method according to any one of claims 1 to 8.

10. Use of the black soldier fly according to claim 9 in the field of animal feed production.

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