A black soldier fly rich in carotenoids, its breeding method and application

Abstract

This application relates to the field of poultry feed. More specifically, it relates to a black soldier fly rich in carotenoids, its breeding method and application. A breeding method for a black soldier fly rich in carotenoids, comprising the following steps: Step 1: Prepare the black soldier fly feed: Mix vegetable oil, plant-based raw materials, and compound feed evenly to obtain the black soldier fly feed; the plant-based raw materials are at least one of carrot, tomato powder, and chili meal; the vegetable oil is at least one of soybean oil, sunflower oil, and linseed oil; Step 2: Feed the black soldier fly larvae with the black soldier fly feed and raise them for 8-12 days to obtain a black soldier fly rich in carotenoids. The breeding method of this application extracts natural plant carotenoids with the black soldier fly, effectively alleviating the problems of instability and easy oxidation of carotenoids. Feeding it to poultry as feed can significantly improve the quality of its meat and eggs, and has good economic benefits.

Description

Technical Field

[0001] The present application relates to the field of poultry feed, and more specifically, to a black soldier fly rich in carotenoids and a breeding method and application thereof. Background Art

[0002] Carotenoids are tetraterpenoid pigments widely distributed in photosynthetic bacteria, some archaea and fungi, algae, plants and animals. They first appeared in archaea about 3 billion years ago and are one of the oldest known molecules. As of 2018, about 850 natural carotenoids have been reported, of which about 800 are luteins and about 50 are carotenes. Carotenoids are recognized to have important health-promoting functions, such as provitamin A and antioxidant activity, strengthening the immune system, and reducing the risk of degenerative diseases such as cancer, cardiovascular disease, cataracts and macular degeneration. In addition to their biological properties, carotenoids can also be used in the production of natural colorants, food additives, nutraceuticals, health products, pharmaceuticals, cosmetics and bioengineering products.

[0003] Carotenoids are widely used as feed additives in poultry farming. In addition to being vitamin precursors, these pigments can also be deposited in the skin, beaks and egg yolks of poultry, thereby improving meat and egg quality.

[0004] It is reported that the global market size of synthetic food pigments is estimated to be US$590 million in 2022, while the natural food pigments market has reached US$1.54 billion in 2021 and is expected to grow at a compound annual growth rate of 7.4%. The global carotenoid market is worth approximately US$1.165 billion in 2020 and is expected to reach US$1.206 billion in 2026, with an estimated annual compound growth rate of 0.9% from 2021 to 2026. As the mainstay of carotenoid products, about two-thirds of the β-carotene on the market comes from artificial synthesis, and the supply of natural β-carotene is far from sufficient. Considering the improvement of people's living standards and the concern for nutrition and health, the market demand for natural carotenoids will continue to increase. At present, the main methods for producing carotenoids are natural extraction, chemical synthesis and microbial fermentation.

[0005] Most natural extraction methods use organic solvents to extract carotenoids from plants or algae through various techniques, including Soxhlet extraction, immersion method, microwave-assisted extraction, accelerated solvent extraction, pulsed electric field-assisted extraction, supercritical fluid extraction, and enzyme-assisted extraction. However, the content of carotenoids in plants and algae is limited, and the waste gas, waste liquid, and waste residue generated during the extraction process will cause many problems such as environmental pollution, low extraction efficiency, complex process, and low recovery rate, which ultimately lead to high production costs and the inability to supply natural carotenoids on a large scale at a low price. Therefore, even the continuous development of extraction technology cannot meet the growing demand for natural carotenoids.

[0006] At present, chemical synthesis mainly uses different intermediates to synthesize carotenoids through Witting olefination reaction. This method has low raw material cost, mild reaction conditions, high reaction rate, and easy separation of products, and has been put into production and application. However, double bond stereoselectivity is difficult to control, and there are chemical reagent residues to varying degrees. The quality, safety and scope of use of some types of products are restricted. Carotenoids synthesized by other chemical methods have more or less problems such as impure synthetic products, complex synthesis technology, and lack of natural activity.

[0007] Microbial fermentation mainly utilizes the biological metabolism of microorganisms such as bacteria, algae and yeast to convert raw materials such as glucose, starch, and soybean cake powder into carotenoids. It has the advantages of being non-toxic and harmless, not affected by factors such as season, region, and climate, and having a short production cycle. In addition, the synthesized carotenoids are consistent with natural carotenoids in terms of configuration and activity. However, there are problems such as low yield and strict culture conditions. At present, it is mostly limited to laboratory research and is not suitable for large-scale industrial production.

[0008] Chemical synthesis usually requires the use of more organic solvents, and the synthesized carotenoids are impure; carotenoids produced by natural extraction and microbial fermentation are easily degraded by light and heat oxidation. The oxidatively degraded carotenoids used in poultry feed cannot improve the meat and egg quality of poultry. Therefore, there is still room for improvement. Summary of the invention

[0009] In order to solve the above problems, the present application provides a black soldier fly rich in carotenoids and a breeding method and application thereof.

[0010] In a first aspect, the present application provides a method for raising black soldier flies rich in carotenoids, which adopts the following technical solution:

[0011] A method for raising black soldier flies rich in carotenoids comprises the following steps:

[0012] Step 1: Prepare black soldier fly feed:

[0013] Mix vegetable oil, plant-based raw materials, and formulated feed evenly to obtain black soldier fly feed;

[0014] The plant-based raw materials are at least one of carrots, tomato powder, and chili meal;

[0015] The vegetable oil is at least one of soybean oil, sunflower oil, and linseed oil;

[0016] Step 2: Feed black soldier fly larvae with the black soldier fly feed and raise them for 8 - 12 days to obtain black soldier flies rich in carotenoids.

[0017] By adopting the above method, a new method for extracting natural plant carotenoids with black soldier flies is created. Compared with the methods of artificial synthesis, extraction with chemical reagents, or microbial fermentation, the production efficiency of carotenoids is greatly improved.

[0018] The feeding method provided by this application uses black soldier flies as a carrier to consume a large amount of black soldier fly feed containing carotenoids, thereby obtaining black soldier flies rich in carotenoids. Compared with the chemical synthesis method, the black soldier flies in this application are organisms and are more environmentally friendly; compared with any synthetic or microbial fermentation methods, since carotenoids are enriched in the bodies of black soldier flies and are isolated from the air, they are not easily oxidized and are well protected. Directly using the specially raised black soldier flies to feed poultry can supplement carotenoids for poultry and play the role of improving the quality of meat and eggs. Black soldier flies are not only rich in biological macromolecules such as proteins and oils, but also the carotenoids contained in them will be deposited in the feathers, beaks, and egg yolks of poultry, thereby improving the quality of poultry and eggs. Compared with artificial pigment additives, they are safer, have better effects, and lower costs.

[0019] Moreover, carotenoids in traditional feed are an unstable organic compound and are affected by factors such as the variety of grains, harvest season, climate, and storage conditions. However, the insect feed of this application is less affected by seasons and climate, has a short cycle, can be produced in large quantities in a short time, and can achieve large-scale production.

[0020] In actual research and development, it is found that if black soldier flies are fed alone with plant-based raw materials containing carotenoids, the bioavailability is relatively low. Therefore, specific vegetable oils are further selected and mixed with plant-based raw materials and formulated feed to prepare black soldier fly feed.

[0021] Black soldier flies are rich in proteins and oils. There is a certain intermolecular force between the protein substances in the bodies of black soldier flies and carotenoids, which can enhance the stability of carotenoids. Carotenoids are fat-soluble functional pigments. When carotenoids (plant-based raw materials) and oils (vegetable oils) are ingested simultaneously, the oils are digested to produce free fatty acids, which form a micellar phase in the small intestine and can enhance the bioavailability of carotenoids.

[0022] Preferably, the compound feed comprises at least one or a mixture of more than one of wheat bran, soybean meal and alfalfa meal.

[0023] By adopting the above technical solution, the compound feed, plant raw materials and vegetable oil are combined together, which can effectively increase the nutrition of the black soldier fly feed and make the black soldier fly larvae grow more rapidly.

[0024] Preferably, the compound feed is wheat bran, soybean meal and alfalfa meal, and the mass ratio of wheat bran, soybean meal and alfalfa meal is (4-6):(2-4):(1-3).

[0025] By adopting the above technical solution, the type and mixing ratio of the compound feed are further defined. After being mixed with plant raw materials and vegetable oil, the black soldier fly larvae can better absorb nutrients and carotenoids, effectively enhancing the content of carotenoids in the black soldier fly.

[0026] Preferably, the weight ratio of the plant raw materials to the compound feed is 1:(0.5-1.5) based on the mass of the plant raw materials.

[0027] Preferably, based on the total weight of the plant raw materials and the compound feed, the addition amount of the vegetable oil is 1-5%.

[0028] Preferably, based on the total weight of the plant raw materials and the compound feed, the addition amount of the vegetable oil is 5%.

[0029] By adopting the above technical solution, the dosage cooperation relationship among the plant raw materials, the compound feed and the vegetable oil is further defined. Under this limitation, the molecular force between the protein substances and the carotenoids in the black soldier fly is stronger, further improving the stability of the carotenoids and the content in the black soldier fly, and enabling the black soldier fly to have a richer nutritional composition as feed.

[0030] Preferably, when preparing the black soldier fly feed, the vegetable oil, plant raw materials, compound feed and water are mixed evenly together, and the water content of the prepared black soldier fly feed is 70-80%.

[0031] Adding water for mixing is to provide a liquid environment for the black soldier fly larvae to feed.

[0032] Preferably, after the black soldier fly eggs are hatched, they are nursed with nursing feed. After growing into larvae at 4-6 days old, the black soldier fly feed is used for feeding.

[0033] Preferably, the hatching conditions of the black soldier fly eggs are 28±2°C, the humidity is 65±5%, and the hatching time is 2-4 days.

[0034] Preferably, after raising black soldier fly larvae for 8 - 12 days, the harvested larvae are cleaned and frozen.

[0035] Preferably, when using black soldier fly feed to feed black soldier fly larvae, if a plastic box is used, when the size of the plastic box is 18cm * 12cm * 7cm, 150 larvae are put into each plastic box.

[0036] Preferably, when using black soldier fly feed to feed black soldier fly larvae, the breeding environmental temperature is 28 ± 2°C, the relative humidity is 65 ± 5%, and they are raised in the dark.

[0037] Preferably, before harvesting black soldier fly larvae raised for 8 - 12 days, they are starved for 24h to empty the intestines.

[0038] Preferably, the ratio of black soldier fly feed (dry feed) to black soldier fly larvae is (0.5 - 1.5) g:1 head, based on the number of black soldier fly larvae.

[0039] By adopting the above technical solutions, the specific conditions for raising black soldier fly larvae are further defined, providing better growth conditions for black soldier fly larvae, which is beneficial to increasing the content of carotenoids in black soldier flies and being better utilized by poultry.

[0040] In the second aspect, the present application provides a kind of black soldier fly rich in carotenoids.

[0041] In the third aspect, the present application provides an application of a kind of black soldier fly rich in carotenoids in poultry feed.

[0042] The present application raises black soldier flies in a special way, so that a large amount of carotenoids are extracted in the black soldier flies, and then this special kind of black soldier fly is fed to poultry for ingestion, effectively supplementing nutrition for poultry. And the carotenoids are extracted in this way, which is natural, pollution - free, the carotenoids are purer, and the performance is more stable, which can further improve the meat quality and egg quality of poultry and has good economic benefits.

[0043] Preferably, the addition amount of black soldier fly rich in carotenoids in the daily diet is 5 - 15%.

[0044] In summary, the present application has the following beneficial effects:

[0045] 1. The present application has created a new method for extracting natural plant carotenoids from black soldier flies. Compared with the methods of artificial synthesis, extraction with chemical reagents or microbial fermentation, the production efficiency of carotenoids is greatly improved.

[0046] 2. The present application preferably uses a specific vegetable oil, specific plant raw materials and compound feed to prepare black soldier fly feed, feeds black soldier fly larvae, and uses the protein substances in black soldier flies to improve the stability of carotenoids and increase the bio - utilization rate of carotenoids.

[0047] 3. The black soldier flies raised in this application can be used as feed for poultry. The black soldier flies are rich in carotenoids, and the carotenoids have stable properties and are not easily oxidized and degraded by light and heat, and can be utilized by poultry to a greater extent, thereby improving the meat quality and egg quality of poultry and providing nutrients for poultry. Specific Embodiments

[0048] The following further elaborates on this application in conjunction with embodiments.

[0049] The raw materials used in the following examples and comparative examples are all commercially available products.

[0050] A method for raising black soldier flies rich in carotenoids includes the following steps:

[0051] Step 1: Hatching eggs:

[0052] Place the black soldier fly eggs in a constant temperature and humidity incubator at 28 ± 2°C and a relative humidity of 65 ± 5%, and incubate for 2 - 4 days. After hatching, rear them with nursery feed until they grow into larvae at 4 - 6 days old.

[0053] The hatching temperature can be any value among 26°C, 27°C, 28°C, 29°C, 30°C, etc.

[0054] The relative humidity can be any value among 60%, 62%, 65%, 67%, 69%, 70%, 72%, 75%, etc.

[0055] The hatching time can be any value among 2 days, 2.5 days, 3 days, 3.5 days, 4 days, etc.

[0056] The larvae can be any one of larvae at 4 days old, 5 days old, 6 days old, etc.

[0057] The nursery feed includes wheat bran, soybean meal, and alfalfa meal, and the mass ratio of wheat bran, soybean meal, and alfalfa meal is (4 - 6):(2 - 4):(1 - 3). Specifically, the mass ratio of wheat bran, soybean meal, and alfalfa meal can be 4:4:2, can be 6:2:2, can be 5:4:1, can be 4:3:3, etc., any ratio.

[0058] Step 2: Prepare black soldier fly feed:

[0059] Crush the plant-based raw materials, then add compound feed, add vegetable oil and water, and mix until uniform.

[0060] The feed ratio of black soldier fly feed (dry feed) to black soldier fly larvae is (0.5 - 1.5) g:1 larva. Specifically, the feed ratio of black soldier fly feed (dry feed) to black soldier fly larvae can be 0.5 g:1 larva, can be 0.8 g:1 larva, can be 1 g:1 larva, can be 1.2 g:1 larva, can be 1.5 g:1 larva, etc., any of these feed ratios.

[0061] The compound feed includes wheat bran, soybean meal and alfalfa meal, and the mass ratio of wheat bran, soybean meal and alfalfa meal is (4 - 6):(2 - 4):(1 - 3). Specifically, the mass ratio of wheat bran, soybean meal and alfalfa meal can be 4:4:2, can be 6:2:2, can be 5:4:1, can be 5:3:2, can be 4:3:3, etc., any of these ratios.

[0062] The plant-based raw material can be one or a mixture of carrots, tomato powder, and chili meal.

[0063] The weight ratio of the plant-based raw material to the compound feed is 1:(0.5 - 1.5). Specifically, the weight ratio of the plant-based raw material to the compound feed can be 1:0.5, can be 1:0.8, can be 1:1, can be 1:1.2, can be 1:1.5, etc., any of these weight ratios.

[0064] The vegetable oil can be one or a mixture of soybean oil, sunflower oil and linseed oil.

[0065] Based on the total weight of the plant-based raw material and the compound feed, the addition amount of the vegetable oil is 1 - 5%. Specifically, the addition amount of the vegetable oil can be any value among 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, etc.

[0066] The addition amount of water is not strictly limited. Based on the total mass of the black soldier fly feed, the water content is 70 - 80%. That is, the water content can be any value among 70%, 72%, 75%, 78%, 80%, etc.

[0067] There is no strict limit on pulverization. Pulverization is to prepare it into a suitable specification for black soldier fly larvae to eat.

[0068] Step 3: Put the black soldier fly larvae obtained in Step 1 into the black soldier fly feed in Step 2, place them in a culture container, and collect the larvae after breeding for 8 - 12 days.

[0069] The breeding environmental temperature is 28 ± 2 °C, the relative humidity is 65 ± 5%, and it is raised in the dark.

[0070] The breeding environmental temperature can be any value among 26 °C, 27 °C, 28 °C, 29 °C, 30 °C, etc.

[0071] The relative humidity can be any value among 60%, 62%, 65%, 67%, 69%, 70%, 72%, 75%, etc.

[0072] There is no strict limitation on the culture container. Preferably, the size of the culture container is 18 cm * 12 cm * 7 cm, and 150 larvae are put in.

[0073] The breeding days can be any duration among 8 days, 9 days, 10 days, 11 days, 12 days, etc.

[0074] Step 4: When harvesting the larvae in Step 3, make the larvae fast for 24 h and empty their intestines. Then wash the harvested larvae clean and freeze them.

[0075] The larvae are made to fast to remove the residual feed in the insect digestive tract.

[0076] Freezing the larvae is to more conveniently control the insect body and is also more convenient for later ingestion by poultry.

[0077] Examples

[0078] Example 1-1

[0079] A method for raising black soldier fly rich in carotenoids, comprising the following steps:

[0080] Step 1: Hatching eggs:

[0081] Place the black soldier fly eggs in a constant temperature and humidity incubator at 28 °C and a relative humidity of 65% and incubate for 3 days. After hatching, rear them with a nursing feed until they grow into 6-day-old larvae.

[0082] The nursing feed is wheat bran, soybean meal and alfalfa meal, and their mass ratio is 5:3:2.

[0083] Step 2: Preparing the black soldier fly feed:

[0084] Crush the plant raw materials, then add the compound feed, add vegetable oil and water and mix evenly. The feed-to-insect ratio of the black soldier fly feed (dry feed) to the black soldier fly larvae is 1 g:1 head.

[0085] The plant raw material is carrot, the vegetable oil is soybean oil, and the compound feed is wheat bran:soybean meal:alfalfa meal, and their mass ratio is 5:3:2.

[0086] The weight ratio of the plant raw material to the compound feed is 1:1.

[0087] Based on the total weight of the plant raw material and the compound feed, the addition amount of the vegetable oil is 1%.

[0088] The water content of the black soldier fly feed is 75%.

[0089] Step 3: Put the black soldier fly larvae obtained in Step 1 into the black soldier fly feed in Step 2, place them in a culture container, and harvest the larvae after 10 days of cultivation. In this embodiment, the black soldier fly feed is fed in one batch, and no additional feed is required during the feeding process.

[0090] The environmental temperature for cultivation is 28 °C, the relative humidity is 65%, and the cultivation is carried out in the dark.

[0091] The culture container is a disposable plastic box. The size of the disposable plastic box is 18 cm * 12 cm * 7 cm, and 150 larvae are put in.

[0092] Step 4: Separate the insect bodies from the feed with a sieve, rinse the obtained larvae with clean water, perform starvation treatment for 24 h to remove the residual feed in the digestive tract of the larvae, and obtain fasting black soldier flies. Separate impurities such as molt and feces in the black soldier flies with a sieve, rinse them with clean water, and suck off the residual moisture on the surface to obtain black soldier flies rich in carotenoids.

[0093] Example 1-2

[0094] A method for raising black soldier flies rich in carotenoids, which is different from Example 1-1 in that the addition amount of vegetable oil is 2%.

[0095] Example 1-3

[0096] A method for raising black soldier flies rich in carotenoids, which is different from Example 1-1 in that the addition amount of vegetable oil is 5%.

[0097] Example 2-1

[0098] A method for raising black soldier flies rich in carotenoids, which is different from Example 1-1 in that the plant-based raw material is tomato powder and the vegetable oil is sunflower oil.

[0099] Example 2-2

[0100] A method for raising black soldier flies rich in carotenoids, which is different from Example 2-1 in that the addition amount of vegetable oil is 2%.

[0101] Example 2-3

[0102] A method for raising black soldier flies rich in carotenoids, which is different from Example 2-1 in that the addition amount of vegetable oil is 5%.

[0103] Example 3-1

[0104] A method for raising black soldier flies rich in carotenoids, which is different from Example 1-1 in that the plant-based raw material is pepper meal and the vegetable oil is linseed oil.

[0105] Example 3-2

[0106] A method for culturing black soldier fly rich in carotenoids, which is different from Example 3-1 in that the addition amount of vegetable oil is 2%.

[0107] Example 3-3

[0108] A method for culturing black soldier fly rich in carotenoids, which is different from Example 3-1 in that the addition amount of vegetable oil is 5%.

[0109] Control group

[0110] Control group 1

[0111] A method for culturing black soldier fly rich in carotenoids, which is different from Example 1-1 in that no vegetable oil is added.

[0112] Control group 2

[0113] A method for culturing black soldier fly rich in carotenoids, which is different from Example 2-1 in that no vegetable oil is added.

[0114] Control group 3

[0115] A method for culturing black soldier fly rich in carotenoids, which is different from Example 3-1 in that no vegetable oil is added.

[0116] Application example

[0117] Application of black soldier fly rich in carotenoids in poultry feed.

[0118] Specifically, the black soldier fly cultured by the examples is used to feed poultry. The black soldier fly can be directly fed to poultry or can be fed in mixture with the daily ration.

[0119] The addition amount of black soldier fly in the daily ration is not strictly limited, but preferably 5-15%; the addition amount of black soldier fly in the daily ration can be any value among 5%, 8%, 10%, 12%, 15%, etc.

[0120] Application example 1

[0121] Application of black soldier fly rich in carotenoids in poultry feed.

[0122] The black soldier fly of Example 1-1 is used to feed Hy-Line Gray laying hens, and the addition amount of black soldier fly in the daily ration is 10%.

[0123] Performance detection test

[0124] 1. Determination of carotenoid content in black soldier fly:

[0125] Determination of carotenoid content in black soldier fly larvae: 0.5 g of finely ground sample to be tested was extracted with 10 mL of anhydrous ethanol / acetone / n-hexane extractant (1:1:2, v / v / v; containing 0.1% BHT, w / v). After vortexing for 60 s, it was placed in a refrigerator (4 °C) for 18 h.

[0126] The centrifuge tube was taken out of the refrigerator, and then the centrifuge tube containing the sample was vortexed on an oscillator for 60 s, and then sonicated in an ultrasonic bath for 10 min (room temperature, power 40 W), and then centrifuged at 8000 r / min for 10 min.

[0127] The supernatant was transferred to a 250 mL round-bottom flask, and the precipitate was re-extracted with 10 mL of extractant.

[0128] The two supernatants were combined and evaporated to dryness under vacuum at 40 °C. It was fully dissolved with extractant and made up to 10 mL. A part of the solution was taken to measure the absorbance at 450 nm with an ultraviolet-visible spectrophotometer and recorded in Table 1.

[0129] The samples to be tested were black soldier flies obtained from the examples and comparative examples.

[0130] Table 1 Total carotenoid content dry weight

[0131]

[0132]

[0133] According to the comparison of the detection data of Example 1 and Comparative Example 1 in Table 1, the carotenoid contents of the black soldier flies in Example 1-1, Example 1-2, and Example 1-3 were increased by 1.40%, 7.15%, and 45.39% respectively compared with that of Comparative Example 1. It shows that the combination of vegetable oil and plant-based raw materials can indeed improve the stability of carotenoids in black soldier flies. And when the addition amount of soybean oil is 5%, there is a more significant improvement effect.

[0134] According to the comparison of the detection data of Example 2 and Comparative Example 2 in Table 1, the carotenoid contents of the black soldier flies in Example 2-1, Example 2-2, and Example 2-3 were increased by 5.39%, 15.78%, and 21.15% respectively compared with that of Comparative Example 2. The addition of sunflower oil can effectively increase the content of carotenoids in black soldier flies, and when the addition amount of sunflower oil is 2 - 5%, the improvement range is more stable.

[0135] According to the comparison of the detection data of Example 3 and Comparative Example 3 in Table 1, the carotenoid contents of Hermetia illucens in Example 3-1, Example 3-2, and Example 3-3 were increased by 8.44%, 14.10%, and 35.96% respectively compared with those in Comparative Example 3. The addition amount of linseed oil from 1% to 5% can have a relatively significant effect on the improvement of carotenoids. At the same time, compared with the improvement ranges of Examples 1 and 2, the combined effect of linseed oil and chili meal is relatively stable and the improvement range is obvious.

[0136] 2. Influence of Hermetia illucens as feed on poultry

[0137] 180 healthy Hy-Line Gray laying hens at the peak laying period with similar body weights were randomly divided into 3 treatments, with 4 replicates in each treatment and 15 hens in each replicate group. The pre-feeding period was 7 days and the main feeding period was 28 days. Feed was regularly supplied every day, and each hen was fed 115 g of feed per day.

[0138] Group A was the normal group, fed with a normal diet; Group B was the common Hermetia illucens larvae group, with 10% common Hermetia illucens larvae added to the diet; Group C was the carotenoid-rich Hermetia illucens larvae group, with 10% of the carotenoid-rich Hermetia illucens larvae obtained by feeding in Example 1-3 (the addition amount of vegetable oil was 5%) added to the diet.

[0139] In this detection, the normal diet used in Group A included 30% soybean meal, 1.5% soybean oil, 8% stone powder, 1% nucleic acid peptide, and premix, with rice supplemented to 100% of the remainder.

[0140] Among them, the premix provided for each kilogram of normal diet: 2400 mg of copper, 2000 mg of iron, 3400 mg of zinc, 3200 mg of manganese, 35 mg of iodine, 8 mg of selenium, 300 KIU of vitamin A acetate, vitamin D 3 100 KIU, 440 mg of vitamin E, vitamin K 3 40 mg, vitamin B 1 60 mg, vitamin B 2 200 mg, vitamin B 6 120 mg, vitamin B 12 0.6 mg, 4 mg of biotin, 880 mg of nicotinamide, 320 mg of D-pantothenic acid, 24 mg of folic acid, 8000 mg of choline chloride, 1200 mg of phytase, 45 g of methionine, 40 g of total phosphorus, 60 g of sodium chloride.

[0141] The cultivation method of the common Hermetia illucens larvae in Group B was as follows:

[0142] Step 1: Hatching eggs:

[0143] Place the black soldier fly eggs in an incubator with a constant temperature of 28°C and a relative humidity of 65% for 3 days of incubation. After incubation, rear them with the nursery feed until they grow into 6-day-old larvae.

[0144] The nursery feed is wheat bran, soybean meal, and alfalfa meal, and their mass ratio is 5:3:2.

[0145] Step 2: Prepare the black soldier fly feed:

[0146] Mix wheat bran:soybean meal:alfalfa meal evenly at a mass ratio of 5:3:2, and then add water and mix. The water content of the obtained black soldier fly feed is 75%.

[0147] The feed-to-insect ratio of the black soldier fly feed (dry feed) to the black soldier fly larvae is 1 g:1 head.

[0148] Step 3: Put the black soldier fly larvae obtained in Step 1 into the black soldier fly feed in Step 2, place them in a culture container, and harvest the larvae after 10 days of cultivation. In this test, the black soldier fly feed is fed in one batch, and no feed needs to be supplemented during the feeding process.

[0149] The cultivation environmental temperature is 28°C, the relative humidity is 65%, and it is cultivated in the dark.

[0150] The culture container is a disposable plastic box. The size of the disposable plastic box is 18 cm * 12 cm * 7 cm, and 150 larvae are put in.

[0151] Step 4: Separate the insect bodies from the feed with a sieve, rinse the obtained larvae with clean water, perform starvation treatment for 24 h to remove the residual feed in the larvae's digestive tract, and obtain fasting black soldier flies. Separate impurities such as molt and feces in the black soldier flies with a sieve, rinse them with clean water, and suck off the residual water on the surface to obtain ordinary black soldier fly larvae.

[0152] Table 2 Egg production rates of different groups

[0153]

[0154]

[0155] Table 3 Average egg weights of different groups

[0156]

[0157] Table 4 Carotenoid contents of egg yolks in different groups

[0158] Egg yolk carotenoid content (μg / g) A B C 7d 11.51±0.04 8.35±0.23 10.13±0.11 14d 16.97±0.39 15.53±0.17 21.58±0.08 21d 16.74±0.20 16.08±0.14 22.63±0.04 28d 13.87±0.32 14.64±0.05 22.39±0.20

[0159] According to the detection data in Tables 2 - 4, when the black soldier fly obtained by the feeding method provided in this application is used as feed for laying hens (poultry), the egg production rate can reach the same level as that of the ordinary diet, and there is a relatively obvious improvement in egg weight, especially a more significant increase in the carotenoid content of the egg yolk. Moreover, in terms of the increase in the carotenoid content of the egg yolk, even if the feeding time is short, a large gap can be opened with the ordinary diet and feed, showing good economic benefits.

[0160] In summary, using the black soldier fly obtained by the feeding method provided in this application as feed for poultry can improve the production performance and egg quality of poultry.

[0161] This specific embodiment is only an explanation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A method for raising black soldier flies rich in carotenoids, characterized in that: The following steps are involved: Step 1: Prepare black soldier fly feed: Evenly mixing vegetable oil, plant raw materials and compound feed to obtain black soldier fly feed; The plant raw material is at least one of carrot, tomato powder and chili meal; The vegetable oil is at least one of soybean oil and sunflower oil; Step 2: Feeding black soldier fly larvae with black soldier fly feed for 8-12 days to obtain black soldier flies rich in carotenoids; The compound feed comprises wheat bran, soybean meal and alfalfa powder, and the mass ratio of wheat bran, soybean meal and alfalfa powder is (4-6): (2-4): (1-3); The weight ratio of the plant raw material to the compound feed is 1:(0.5-1.5), based on the mass of the plant raw material; Based on the total weight of the plant raw materials and the compound feed, the amount of vegetable oil added is 1-5%; When preparing the black soldier fly feed, the vegetable oil, the plant raw material, the compound feed and water are uniformly mixed together, and the water content of the prepared black soldier fly feed is 70-80%.

2. The method for raising black soldier flies rich in carotenoids according to claim 1, characterized in that: After the black soldier fly eggs are hatched, they are nursed with nursery feed, and after they grow into 4-6 day old larvae, they are fed with the black soldier fly feed.

3. The method for raising black soldier flies rich in carotenoids according to claim 1, characterized in that: The black soldier fly egg hatching conditions are 28±2° C., humidity 65±5%, and the hatching time is 2-4 days.

4. An application of the carotenoid-rich black soldier fly according to claim 1 in poultry feed.

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