Method for culturing low-cadmium organic-selenium-rich tenebrio molitor by using cadmium-containing feed and application thereof

Abstract

The invention belongs to the technical field of animal breeding and agricultural product deep processing, and particularly relates to a method for culturing low-cadmium organic-selenium-rich tenebrio molitor by using cadmium-containing feed and application of the low-cadmium organic-selenium-rich tenebrio molitor. Specifically, low-concentration selenium is added into a feed containing cadmium bran and rice bran to feed 3-4-year-old tenebrio molitor, and the tenebrio molitor is transferred into a feed only containing selenium in the later period of feeding to discharge cadmium. Therefore, the content of cadmium in tenebrio molitor bodies does not exceed relevant standards, and the purposes of efficiently treating cadmium-containing agricultural wastes and obtaining low-cadmium selenium-rich tenebrio molitor products are achieved. And finally, extracting lipid in the tenebrio molitor powder in one step by adopting low-boiling-point petroleum ether to obtain the low-cadmium organic-selenium-rich tenebrio molitor protein powder. In a word, the method is simple and low in cost, low-cadmium selenium-rich high-quality tenebrio molitor products and tenebrio molitor protein powder can be harvested while cadmium-containing materials are efficiently treated, the yield of tenebrio molitor is not affected, multiple purposes are achieved, and the method has good practical application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of animal breeding and deep processing of agricultural products, and particularly relates to a method for culturing low-cadmium and selenium-rich organic yellow mealworms using cadmium-containing feed and its application. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present invention, and it is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Heavy metal cadmium (Cd) has characteristics such as high toxicity, difficult degradation, wide pollution distribution, and difficult treatment, which seriously affect the stability of the ecosystem, food safety, and the health of animals and humans, and is a major threat to the ecological environment and biological safety. Generally, grains such as rice and wheat harvested in Cd-polluted areas usually contain a certain amount of Cd element, and it accumulates in their epidermis and aleurone layer. Therefore, the Cd content in the edible part of grains can be effectively removed by processing and milling. However, agricultural waste products such as bran or rice bran after dehulling / shelling cannot be effectively utilized due to their high concentration of Cd element, and random disposal is likely to cause adverse effects such as environmental pollution. Therefore, it is necessary to find a suitable and efficient way to treat such heavy metal-containing agricultural waste.

[0004] Yellow mealworms, commonly known as breadworms, mainly feed on organic materials such as bran. The crude protein content in the worm body can reach 40%-60%, and the amino acid types are complete, including 18 essential amino acids required by the human body (the content of essential amino acids accounts for 39.14% of the total amino acids, basically meeting the standard that the essential amino acids of excellent proteins recommended by FAO / WHO should account for 40% of the total amino acids). At the same time, it is rich in nutrients such as crude fat, carbohydrates, vitamins, enzymes, and minerals. Its nutritional value can be comparable to that of livestock such as beef and mutton, and it has important application values in livestock, poultry, and aquatic animals. It can also be used as human food and is one of the currently highly concerned renewable high-protein biological resources.

[0005] The breeding of yellow mealworms has advantages such as high feed conversion rate, low breeding cost, fast reproduction speed, short cycle, small required space, and low greenhouse gas emissions. Yellow mealworms mainly feed on organic materials such as bran and rice bran, and they have certain tolerance and low accumulation characteristics for pollutants such as heavy metals. They can be used to treat waste organic materials such as Cd-polluted bran and rice bran, and at the same time obtain high-protein yellow mealworm products. However, the yellow mealworms obtained in this way contain a certain amount of Cd element, and how to effectively reduce the heavy metal concentration in the worm body is also a problem that needs to be considered.

[0006] Selenium (Se) is an essential trace element for the growth and development of humans and animals. It participates in the composition of many important functional enzymes in the body and plays various important biological functions such as antioxidant, anti-aging, detoxification, cancer prevention and anti-cancer in the body, and plays an extremely important role in maintaining human health and normal physiological metabolism. At present, the cultivation method of selenium-rich yellow mealworms is generally to add a high concentration of inorganic selenium to the feed. However, the long-term action of high-concentration selenium will cause variety degradation and decreased reproduction rate, and can only be cultivated for one or two generations, unable to be continuously cultivated, and cannot meet the long-term cultivation and acquisition of selenium-rich yellow mealworms. Some people also convert inorganic selenium into organic selenium through plants and then feed it to yellow mealworms to cultivate selenium-rich yellow mealworms. This method has cumbersome procedures, high costs, and long cycles, and is not conducive to the efficient feeding and harvesting of selenium-rich yellow mealworms. Summary of the Invention

[0007] Aiming at the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to provide a method for cultivating low-cadmium and selenium-rich organic yellow mealworms using cadmium-containing feed and its application. Specifically, the present invention uses a feed containing cadmium bran + rice bran and adds a low concentration of selenium to feed 3-4 instar yellow mealworms, and transfers them to a feed containing only selenium in the later stage of feeding to further "enrich selenium" and "remove cadmium", so as to ensure that the cadmium content in the insect body does not exceed the relevant standards and achieve the purpose of efficiently treating cadmium-containing agricultural waste and obtaining low-cadmium and selenium-rich yellow mealworm products. Finally, low-boiling petroleum ether is used to extract the lipids in the insect powder in one step to obtain high-quality low-cadmium and selenium-rich organic yellow mealworm protein powder. Based on the above research results, the present invention is completed.

[0008] In order to achieve the above technical objectives, the technical solutions provided by the present invention are as follows:

[0009] In the first aspect of the present invention, there is provided a method for cultivating low-cadmium and selenium-rich organic yellow mealworms using cadmium-containing feed, the method comprising: mixing cadmium-containing bran and cadmium-containing rice bran, and adding sodium selenite solution thereto to obtain the first yellow mealworm feed, using the first yellow mealworm feed to feed and cultivate 3-4 instar yellow mealworms (1-1.2 cm in length), and then transferring the yellow mealworms to a second yellow mealworm feed containing only selenium and continuing to feed and cultivate; in the first yellow mealworm feed, the cadmium concentration is 0.5-5 mg / kg; in the first yellow mealworm feed and the second yellow mealworm feed, the selenium concentration is 1-4 mg / kg.

[0010] In the second aspect of the present invention, there is provided the application of the above method in the production of low-cadmium and selenium-rich high-quality yellow mealworm products and yellow mealworm protein powder. The application method comprises drying and dehydrating the obtained yellow mealworms, pulverizing them to obtain insect powder, and extracting with petroleum ether to remove the grease in the insect powder in one step, so as to increase the proportion of selenium, protein and other nutrients in the yellow mealworm protein powder product and their absorption and utilization efficiency in the body, thereby obtaining high-quality low-cadmium and selenium-rich organic yellow mealworm protein powder.

[0011] Beneficial technical effects of one or more of the above technical solutions:

[0012] 1) After selenium supplementation in the diet, the final harvest yield of Tenebrio molitor increased by 5.91% - 17.05% compared with that cultured with feed containing 0.5 - 5 mg / kg cadmium alone, and the mortality rate of Tenebrio molitor in each treatment group did not exceed 2%.

[0013] 2) After the "cadmium excretion" stage, the cadmium concentration in Tenebrio molitor was below 1 mg / kg, not exceeding the standard of ≤2 mg / kg specified in the feed standard, and the cadmium content was reduced by more than 90% compared with Tenebrio molitor cultured with feed containing 0.5 - 5 mg / kg cadmium alone.

[0014] 3) After selenium supplementation in the diet, the selenium content in Tenebrio molitor reached 1.52 - 2.38 mg / kg, meeting the selenium-enriched standard, which was 5 - 8 times higher than that of Tenebrio molitor cultured with feed containing 0.5 - 5 mg / kg cadmium alone.

[0015] 4) After selenium supplementation in the diet, the organic selenium content in Tenebrio molitor reached 1.37 - 2.26 mg / kg, accounting for 90.01% - 95.62%, that is, Tenebrio molitor basically converted all the ingested inorganic selenium into organic selenium, and the conversion rate reached more than 90%.

[0016] 5) After Soxhlet extraction with petroleum ether, the lipid content of high-insect powder decreased significantly, the selenium content increased to 2.17 - 3.42 mg / kg, and the protein content was 68.12% - 74.23%, which was increased by about 25 - 30% compared with that before defatting.

[0017] 6) The selenium in the Tenebrio molitor protein powder obtained after defatting mainly exists in two forms of organic selenium, methylselenocysteine (MeSeCys) and selenomethionine (SeMet).

[0018] In summary, the above technical solution is simple in method and low in cost. It can efficiently treat cadmium-containing materials while harvesting high-quality Tenebrio molitor products and Tenebrio molitor protein powder with low cadmium and rich in organic selenium, without affecting the yield of Tenebrio molitor, achieving multiple benefits at one stroke. Therefore, it has good practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1This invention relates to the determination of selenium species in defatted Tenebrio molitor after treatment with 1 and 4 mg Se / kg feed by HPLC-ICP-MS; A, five selenium standard sample solutions with a concentration of 20 mg / L each; B, selenium species in defatted Tenebrio molitor after treatment with 4 mg Se / kg feed; C, selenium species in defatted Tenebrio molitor after treatment with 1 mg Se / kg feed; 1, selenocysteine (SeCys2); 2, methylselenocysteine (MeSeCys); 3, sodium selenite (Se(IV)); 4, selenomethionine (SeMet); 5, sodium selenate (Se(VI)). Detailed implementation manners

[0021] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0022] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary implementation manners according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their combinations.

[0023] In a typical specific implementation manner of the present invention, a method for culturing low-cadmium and selenium-rich Tenebrio molitor using cadmium-containing feed is provided. The method includes: mixing cadmium-containing wheat bran and cadmium-containing rice bran, and then adding sodium selenite solution thereto to obtain the first feed for Tenebrio molitor. Using the first feed for Tenebrio molitor to feed and culture 3-4 instar Tenebrio molitor (with a length of 1-1.2 cm), and then transferring the Tenebrio molitor to the second feed for Tenebrio molitor that contains only selenium without cadmium for continuous feeding and culturing; in the first feed for Tenebrio molitor, the cadmium concentration is 0.5-5 mg / kg; in the first feed for Tenebrio molitor and the second feed for Tenebrio molitor, the selenium concentration is 1-4 mg / kg.

[0024] Among them, in the first feed for Tenebrio molitor, the mass ratio of cadmium-containing wheat bran to cadmium-containing rice bran is 4:1-1:1;

[0025] The preparation method of the second feed for Tenebrio molitor is the same as that of the first feed for Tenebrio molitor, except that the wheat bran and rice bran used are clean and pollution-free and do not contain cadmium; specifically, the preparation method of the second feed for Tenebrio molitor is as follows: mixing wheat bran and rice bran according to a mass ratio of 4:1-1:1, and then adding sodium selenite solution thereto.

[0026] In another specific embodiment of the present invention, the water content of the first Tenebrio molitor feed and the second Tenebrio molitor feed is controlled to be 8-15%, which is the optimal moisture content of the Tenebrio molitor food.

[0027] The specific method of feeding and culturing is as follows: the feeding density is 3000-5000 per square meter, fruits and vegetables (such as carrots, pumpkins, etc.) are added every 1-2 days to provide additional nutrition and moisture, the feces are cleaned every 3-4 days and the same feed is added, and it is cultured in a dim environment with a temperature of 25-30°C, a humidity of 50-70%, and a light intensity of 0-300 lx.

[0028] In another specific embodiment of the present invention, the feeding and culturing time using the first Tenebrio molitor feed is controlled to be 15-22 days; the feeding and culturing time using the second Tenebrio molitor feed is controlled to be 7-12 days, and the total culturing time is 22-34 days.

[0029] By adopting the above feeding method, not only the overall yield of Tenebrio molitor and the selenium content in Tenebrio molitor are effectively increased, but also the cadmium content in Tenebrio molitor is effectively reduced.

[0030] In another specific embodiment of the present invention, the method further includes drying and dehydrating the obtained Tenebrio molitor, pulverizing it to obtain insect powder, and extracting with petroleum ether to remove the grease in the insect powder in one step, so as to increase the proportion of selenium, protein and other nutrients in the Tenebrio molitor protein powder product and their absorption and utilization efficiency in the body, thereby obtaining high-quality low-cadmium selenium-rich Tenebrio molitor protein powder.

[0031] Among them, the drying adopts freeze-drying technology; the Soxhlet extraction technology is adopted and low-boiling-point petroleum ether is used as the extraction agent; the extraction time is controlled to be 3-5 hours.

[0032] In another specific embodiment of the present invention, the application of the above method in the production of low-cadmium selenium-rich high-quality Tenebrio molitor products and Tenebrio molitor protein powder is provided.

[0033] The present invention innovates the selenium-rich Tenebrio molitor feeding method, that is, by culturing Tenebrio molitor with cadmium-polluted feed, the reuse of heavy metal pollutants is achieved to a certain extent and the purpose of obtaining high-quality Tenebrio molitor protein powder is achieved.

[0034] Specifically, the present invention can at least achieve the following technical effects:

[0035] 1) The present invention proposes a biological treatment technology for using Tenebrio molitor to treat agricultural wastes such as cadmium-containing bran and rice bran, which can efficiently promote the recycling of wastes and prevent environmental pollution;

[0036] 2) Using 3-4 instar Tenebrio molitor with certain adversity resistance instead of newly hatched larvae to treat cadmium-containing materials has a high feeding rate, which can enhance the material decomposition efficiency without affecting the normal growth of Tenebrio molitor;

[0037] 3) Directly add an appropriate amount of selenium to the cadmium-containing material to promote the growth and development of Tenebrio molitor, and inhibit the absorption of cadmium by Tenebrio molitor or promote its excretion through antagonism, thereby reducing its net accumulation in the insect body. At the same time, Tenebrio molitor can achieve the purpose of selenium biofortification by ingesting, accumulating and transforming selenium elements, and obtain Tenebrio molitor rich in organic selenium. The method is simple and efficient;

[0038] 4) Transfer it to a feed containing only selenium for "cadmium excretion" feeding in the later stage of feeding, so as to ensure that the cadmium content in the insect body does not exceed the relevant standards;

[0039] 5) Use petroleum ether to remove the grease in Tenebrio molitor powder by a one-step method to increase the proportion of selenium, protein and other nutrients in the insect powder and their absorption and utilization efficiency in the body, and obtain high-quality Tenebrio molitor protein powder with low cadmium and rich in organic selenium.

[0040] The present invention will be further described below in conjunction with embodiments. The present invention will be further illustrated by the following embodiments, but the present invention is not limited to the scope of the described embodiments. Based on the embodiments of the present invention, any changes to the present invention made by those skilled in the art without creative efforts fall within the protection scope of the present invention. At the same time, in the embodiments of the present invention, unless otherwise specified, all preparation raw materials are commercially available products well-known to those skilled in the art.

[0041] Example 1

[0042] A method for culturing Tenebrio molitor with low cadmium and rich in selenium using cadmium-containing feed, comprising:

[0043] 1) Preparation of cadmium-containing wheat bran and rice bran feed: Mix cadmium-containing wheat bran and rice bran in a ratio of 1:1 and fully mix and prepare them with the same ratio of two clean and pollution-free materials, so that the final cadmium concentration of the feed reaches 0.5 mg / kg;

[0044] 2) Preparation of selenium-containing feed: Add a certain amount of sodium selenite solution prepared with deionized water to the above-mentioned cadmium-containing mixed feed to make the selenium content of the feed 2 mg / kg. Place the prepared cadmium-containing and selenium-containing feed in the sun to dry until its water content is about 8%; at the same time, prepare a feed containing only 2 mg / kg selenium concentration with the same clean and pollution-free materials and dry it for later use;

[0045] 3) Use 3-4 instar Tenebrio molitor (1-1.2 cm in length) instead of newly hatched larvae to process the cadmium-containing and selenium-containing material in 2) above. The feeding density is 3000-5000 per square meter. Add carrots, pumpkins and other fruits and vegetables once every 1-2 days to provide additional nutrition and moisture. Clean the insect feces once every 3-4 days and add the same feed. Place it in a dim environment at a temperature of 25 °C, a humidity of 70%, and a light intensity of 100 lx and raise it for 15 days;

[0046] 4) Transfer the Tenebrio molitor in step 3) to the feed containing only 2 mg / kg selenium concentration in step 2) and continue culturing for 7 days to promote further selenium enrichment in the Tenebrio molitor and excrete heavy metal cadmium in the insects, so as to ensure that the cadmium content in the insects does not exceed the relevant standards. The management method and feeding environment are the same as in 3);

[0047] 5) The finally harvested Tenebrio molitor is dehydrated by freeze-drying technology, ground into powder, and then continuously extracted with petroleum ether for 3 hours by Soxhlet extraction technology to remove the oil in the insect powder in one step, so as to increase the proportion of selenium, protein and other nutrients in the insect powder and their absorption and utilization efficiency in the body, and obtain high-quality low-cadmium selenium-rich Tenebrio molitor protein powder 1.

[0048] Example 2

[0049] A method for culturing low-cadmium selenium-rich Tenebrio molitor using cadmium-containing feed, comprising:

[0050] 1) Preparation of cadmium-containing wheat bran and rice bran feed: Mix cadmium-containing wheat bran and rice bran in a ratio of 2:1 and fully mix and blend them with the same ratio of two clean and pollution-free materials, so that the final cadmium concentration of the feed reaches 2 mg / kg;

[0051] 2) Preparation of selenium-containing feed: Add a certain amount of sodium selenite solution prepared with deionized water to the above-mentioned cadmium-containing mixed feed to make the selenium content of the feed 1 mg / kg. Place the prepared selenium-containing cadmium feed in the sun to dry until its water content is 12%; at the same time, prepare a feed containing only 1 mg / kg selenium concentration with the same clean and pollution-free materials and dry it for standby;

[0052] 3) Use 3-4 instar Tenebrio molitor (1-1.2 cm in length) instead of newly hatched larvae to treat the selenium-containing cadmium material in step 2). The feeding density is 3000-5000 per square meter. Add carrots, pumpkins and other fruits and vegetables every 1-2 days to provide additional nutrition and moisture. Clean the insect feces every 3-4 days and add the same feed. Place it in a dim environment with a temperature of 28 °C, a humidity of 60%, and a light intensity of 200 lx and raise it for 18 days;

[0053] 4) Transfer the Tenebrio molitor in step 3) to the feed containing only 1 mg / kg selenium concentration in step 2) and continue culturing for 10 days to promote further selenium enrichment in the Tenebrio molitor and excrete heavy metal cadmium in the insects, so as to ensure that the cadmium content in the insects does not exceed the relevant standards. The management method and feeding environment are the same as in 3);

[0054] 5) The finally harvested Tenebrio molitor is dehydrated by freeze-drying technology, ground into powder, and then continuously extracted with petroleum ether for 4 hours by Soxhlet extraction technology to remove the oil in the insect powder in one step, so as to increase the proportion of selenium, protein and other nutrients in the insect powder and their absorption and utilization efficiency in the body, and obtain high-quality low-cadmium selenium-rich Tenebrio molitor protein powder 2.

[0055] Example 3

[0056] A method for culturing low-cadmium and selenium-rich Tenebrio molitor using cadmium-containing feed, comprising:

[0057] 1) Preparation of cadmium-containing bran and rice bran feed: Mix cadmium-containing bran and rice bran in a ratio of 4:1 and fully mix and blend them with two clean and pollution-free materials in the same ratio to make the final cadmium concentration of the feed reach 5 mg / kg;

[0058] 2) Preparation of selenium-containing feed: Add a certain amount of sodium selenite solution prepared with deionized water to the above-mentioned cadmium-containing mixed feed to make the selenium content of the feed 4 mg / kg. Place the prepared selenium-containing cadmium feed in the sun to dry until its water content is 15%. At the same time, prepare a feed containing only 4 mg / kg selenium concentration using clean and pollution-free materials and dry it for standby;

[0059] 3) Use 3-4 instar Tenebrio molitor (1-1.2 cm in length) instead of newly hatched larvae to process the selenium-containing cadmium material in 2) above. The feeding density is 3000-5000 per square meter. Add carrots, pumpkins and other fruits and vegetables every 1-2 days to provide additional nutrition and moisture. Clean the insect feces every 3-4 days and add the same feed. Raise them in a dim environment at a temperature of 30 °C, a humidity of 50%, and a light intensity of 300 lx for 22 days;

[0060] 4) Transfer the Tenebrio molitor in 3) above to the feed containing only 4 mg / kg selenium concentration in 2) and continue to culture for 12 days to promote the further selenium enrichment of Tenebrio molitor and excrete the heavy metal cadmium in the insect body, so as to ensure that the cadmium content in the insect body does not exceed the relevant standards. The management method and feeding environment are the same as in 3);

[0061] 5) The finally harvested Tenebrio molitor is dehydrated by freeze-drying technology, ground into powder, and continuously extracted with petroleum ether using Soxhlet extraction technology for 5 hours to remove the grease in the insect powder in one step, so as to improve the proportion of selenium, protein and other nutrients in the insect powder and their absorption and utilization efficiency in the body, and obtain high-quality low-cadmium and selenium-rich organic selenium Tenebrio molitor protein powder 3.

[0062] Comparative Example 1

[0063] A method for culturing Tenebrio molitor using cadmium-containing feed, comprising:

[0064] 1) Preparation of cadmium-containing bran and rice bran feed: Mix cadmium-containing bran and rice bran in a ratio of 1:1 and fully mix and blend them with two clean and pollution-free materials in the same ratio to make the final cadmium concentration of the feed reach 0.5 mg / kg. Place the prepared cadmium-containing feed in the sun to dry until its water content is about 8%, and set aside;

[0065] 2) Use 3-4 instar Tenebrio molitor larvae (1-1.2 cm in length) instead of newly hatched larvae to process the above-mentioned cadmium-containing material in 2). The feeding density is 3000-5000 larvae per square meter. Add fruits and vegetables such as carrots and pumpkins every 1-2 days to provide additional nutrition and moisture. Clean the feces every 3-4 days and add the same feed. Raise them in a dim environment at a temperature of 25°C, a humidity of 70%, and a light intensity of 100 lx for 22 days (corresponding to the total culture time in Example 1);

[0066] 3) The finally harvested Tenebrio molitor larvae are dehydrated by freeze-drying technology, ground into powder, and then continuously extracted with petroleum ether using Soxhlet extraction technology for 3 hours to remove the oil in the insect powder in one step, obtaining Tenebrio molitor protein powder 1.

[0067] Comparative Example 2

[0068] A method for culturing Tenebrio molitor using cadmium-containing feed, comprising:

[0069] 1) Preparation of cadmium-containing wheat bran and rice bran feed: Mix cadmium-containing wheat bran and rice bran in a ratio of 2:1 and fully mix and blend them with the same ratio of two clean and pollution-free materials to make the final cadmium concentration of the feed reach 2 mg / kg. Place this prepared cadmium-containing feed in the sun to dry until its water content is about 12%, and set aside;

[0070] 2) Use 3-4 instar Tenebrio molitor larvae (1-1.2 cm in length) instead of newly hatched larvae to process the above-mentioned cadmium-containing material in 2). The feeding density is 3000-5000 larvae per square meter. Add fruits and vegetables such as carrots and pumpkins every 1-2 days to provide additional nutrition and moisture. Clean the feces every 3-4 days and add the same feed. Raise them in a dim environment at a temperature of 28°C, a humidity of 60%, and a light intensity of 200 lx for 28 days (corresponding to the total culture time in Example 2);

[0071] 3) The finally harvested Tenebrio molitor larvae are dehydrated by freeze-drying technology, ground into powder, and then continuously extracted with petroleum ether using Soxhlet extraction technology for 4 hours to remove the oil in the insect powder in one step, obtaining Tenebrio molitor protein powder 2.

[0072] Comparative Example 3

[0073] A method for culturing Tenebrio molitor using cadmium-containing feed, comprising:

[0074] 1) Preparation of cadmium-containing wheat bran and rice bran feed: Mix cadmium-containing wheat bran and rice bran in a ratio of 4:1 and fully mix and blend them with the same ratio of two clean and pollution-free materials to make the final cadmium concentration of the feed reach 5 mg / kg. Place this prepared cadmium-containing feed in the sun to dry until its water content is about 15%, and set aside;

[0075] 2) Use 3-4 instar Tenebrio molitor larvae (1-1.2 cm in length) instead of newly hatched larvae to process the above-mentioned cadmium-containing materials in 2). The feeding density is 3000-5000 larvae per square meter. Add fruits and vegetables such as carrots and pumpkins every 1-2 days to provide them with additional nutrition and moisture. Clean the feces every 3-4 days and add the same feed. Raise them in a dim environment at a temperature of 30 °C, a humidity of 50%, and a light intensity of 300 lx for 34 days (corresponding to the total culture time in Example 3);

[0076] 3) The finally harvested Tenebrio molitor larvae are dehydrated by freeze-drying technology, ground into powder, and then continuously extracted with petroleum ether using Soxhlet extraction technology for 5 hours to remove the grease in the insect powder in one step, obtaining Tenebrio molitor protein powder 3.

[0077] Comparative Example 4

[0078] A method for culturing Tenebrio molitor using ordinary feed, including:

[0079] 1) Preparation of bran and rice bran feed: Mix bran and rice bran in a ratio of 4:1 and fully mix and blend them with two clean and pollution-free materials in the same ratio. Place the prepared feed in the sun to dry until its water content is about 15%, and set aside;

[0080] 2) Use 3-4 instar Tenebrio molitor larvae (1-1.2 cm in length) instead of newly hatched larvae to process the above-mentioned materials in 2). The feeding density is 3000-5000 larvae per square meter. Add fruits and vegetables such as carrots and pumpkins every 1-2 days to provide them with additional nutrition and moisture. Clean the feces every 3-4 days and add the same feed. Raise them in a dim environment at a temperature of 30 °C, a humidity of 50%, and a light intensity of 300 lx for 34 days (corresponding to the total culture time in Example 3);

[0081] 3) The finally harvested Tenebrio molitor larvae are dehydrated by freeze-drying technology, ground into powder, and then continuously extracted with petroleum ether using Soxhlet extraction technology for 4 hours to remove the grease in the insect powder in one step, obtaining Tenebrio molitor protein powder 4.

[0082] Effect verification

[0083] Table 1

[0084]

[0085] As shown in Table 1, the Tenebrio molitor obtained by the cultivation method of the present invention has a low mortality rate and a high yield. At the same time, the selenium concentration in the insect powder is high, while the cadmium content is significantly reduced. At the same time, the lipid content of the insect powder is reduced, while the protein content is significantly increased, having good application value.

[0086] It should be noted that the above examples are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the given examples, those of ordinary skill in the art can modify or equivalently replace the technical solution of the present invention as needed, without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for culturing low-cadmium and selenium-rich organic yellow mealworms using cadmium-containing feed, characterized in that, The method includes: mixing cadmium-containing bran and cadmium-containing rice bran, and adding sodium selenite solution thereto to obtain the first feed for Tenebrio molitor, feeding and culturing 3-4 instar Tenebrio molitor with the first feed for Tenebrio molitor, and then transferring the Tenebrio molitor to the second feed for Tenebrio molitor containing only selenium without cadmium for continuous feeding and culturing; in the first feed for Tenebrio molitor, the cadmium concentration is 0.5-5 mg / kg; in the first feed for Tenebrio molitor and the second feed for Tenebrio molitor, the selenium concentration is 1-4 mg / kg.

2. The method according to claim 1, wherein In the first feed for Tenebrio molitor, the mass ratio of cadmium-containing bran to cadmium-containing rice bran is 4:1-1:

1.

3. The method according to claim 1, wherein For the second feed for Tenebrio molitor, its preparation method is as follows: mixing clean and pollution-free bran and rice bran in a mass ratio of 4:1-1:1, and adding sodium selenite solution thereto.

4. The method according to claim 1, wherein The water content of the first feed for Tenebrio molitor and the second feed for Tenebrio molitor is controlled to be 8-15%.

5. The method according to claim 1, wherein The specific method of the feeding and culturing is: the breeding density is 3000-5000 per square meter, fruits and vegetables are added once every 1-2 days, the feces are cleaned once every 3-4 days and the same feed is added, and it is bred in a dim environment with a temperature of 25-30 °C, a humidity of 50-70%, and a light intensity of 0-300 lx.

6. The method according to claim 1, wherein The time for feeding and culturing with the first feed for Tenebrio molitor is controlled to be 15-22 days; the time for feeding and culturing with the second feed for Tenebrio molitor is controlled to be 7-12 days.

7. The method according to claim 1, characterized in that, The method further includes drying and dehydrating the obtained Tenebrio molitor, pulverizing it to obtain worm powder, and extracting it with petroleum ether.

8. The method according to claim 7, wherein The drying uses freeze-drying technology.

9. The method according to claim 7, characterized in that, The extraction with petroleum ether is Soxhlet extraction; the extraction time is controlled to be 3-5 hours.

10. Application of the method according to any one of claims 1-9 in the production of low-cadmium and selenium-rich high-quality Tenebrio molitor products and Tenebrio molitor protein powder.

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