Feed for adult Holotrichia parallela and preparation method thereof

Abstract

The invention provides a holotrichia parallela adult feed and a preparation method thereof. The adult holotrichia parallela feed is prepared from the following raw materials in percentage by mass: 3%-7% of a basic gel premixed component A, 25%-40% of a nutrient medium premixed component B, 1%-1.8% of a micronutrient premixed component C, 0%-0.5% of a cross-linking agent component D and the balance of a solvent component E. A process taking a normal-temperature gelation technology as a core is adopted, a gel agent is firstly and fully hydrated to form a uniform colloid, and then a cross-linking reaction is triggered to form a stable solid gel feed, so that the solid gel feed has the characteristic of no heating, is convenient to store, and is simple in rehydration (or re-gelatinization) operation. The prepared holotrichia parallela adult feed is comprehensive in nutrition, moderate in hardness and not limited by regions and seasons, subculture feeding of holotrichia parallela adults in a laboratory is facilitated, the survival rate of the holotrichia parallela adults can be increased, the spawning period of the holotrichia parallela adults can be prolonged, and the spawning amount and the spawning hatching rate of the holotrichia parallela adults can be increased.

Description

Technical Field

[0001] This invention belongs to the field of insect breeding technology, specifically relating to a feed for adult dark-gill beetles and its preparation method. Background Technology

[0002] The dark-skinned scarab beetle, belonging to the family Scarabaeidae in the order Coleoptera, is mainly distributed in the middle and lower reaches of the Yangtze River and areas north of the Yangtze River, extending to a vast region in southern Heilongjiang Province. It is one of the most damaging underground pests in farmland. The adults are omnivorous, preferring elm leaves but also feeding on the leaves of poplar, locust, mulberry, and pear trees. The larvae can damage various economic crops such as corn, wheat, and peanuts, causing severe losses. It is characterized by its underground, concealed feeding habits, difficulty in investigation, and complex occurrence patterns, making it one of the most difficult-to-control major pests both domestically and internationally.

[0003] To control the damage caused by the dark-browed scarab beetle, researchers have conducted biological experiments using large numbers of insects. Currently, indoor rearing relies mainly on fresh leaves that are difficult to preserve or traditional artificial feed that requires heat treatment, resulting in frequent adult mortality and low, unstable egg production. Therefore, providing a stable feed that is not limited by region or season and can significantly improve adult survival and reproductive performance is a crucial issue that urgently needs to be addressed in dark-browed scarab beetle rearing techniques. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a feed for adult dark-browed scarab beetles and its preparation method. This feed consists of dry powder materials and liquid components, and uses room-temperature gelation technology to form a stable solid gel feed. It is easy to store, and the rehydration (or regelation) operation is simple. It can significantly improve the survival rate of adult dark-browed scarab beetles, prolong the oviposition period, increase the number of eggs laid, and improve the egg hatching rate.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a dark-gill beetle adult feed, which is composed of the following raw materials in mass percentage: basic gel premix component A 3%-7%, nutrient matrix premix component B 25%-40%, micronutrient premix component C 1%-1.8%, crosslinking agent component D 0%-0.5%, and the balance being solvent component E.

[0006] Preferably, the basic gel premix component A includes a gelling agent and sugars. The gelling agent is at least one of sodium alginate, κ-carrageenan, λ-carrageenan, gellan gum, xanthan gum, locust bean gum, and instant gelatin, and is used in an amount of 0.4-4%. The sugars are sucrose, honey, or brown sugar, and are used in an amount of 3%-4%.

[0007] Preferably, the nutrient matrix premix component B comprises 10%-15% cooked corn flour, 8%-10% soybean flour, 0%-5% peanut flour, 6%-8% wheat germ flour, and 5%-8% elm leaf powder. The cooking process reduces the impact of phytic acid and improves digestion and absorption.

[0008] Preferably, the micronutrient premix component C comprises 0.2%-0.3% of complex vitamin B, 0.2%-0.4% of vitamin C, 0.5%-0.8% of lysine, 0.05%-0.1% of choline chloride, 0.05%-0.1% of preservative, and 0-0.1% of citric acid; the preservative is at least one of potassium sorbate and sodium dehydroacetate; the vitamin C is microencapsulated vitamin C or buffered sodium vitamin C salt to enhance stability.

[0009] Preferably, if the gelling agent is sodium alginate, gellan gum, or κ-carrageenan, the gel system needs to be cross-linked, and the cross-linking agent component D is a calcium-based or potassium-based cross-linking agent. When the gelling agent is sodium alginate or gellan gum, calcium lactate and calcium gluconate are used as calcium-based cross-linking agents at a dosage of 0.3%-0.5%. When the gelling agent is κ-carrageenan, potassium chloride is used as a potassium-based cross-linking agent at a dosage of 0.2%-0.4%. The cross-linking agent component D is prepared into a solution with purified water before use.

[0010] Preferably, the solvent component E is purified water.

[0011] This invention also provides a method for preparing adult feed for the dark-gill beetle, comprising the following steps: S1. Pretreatment: Pass components A, B, and C through a 60-mesh sieve. After mixing the powders in component B, the enzymes in the mixture must be inactivated at 100°C for 30 minutes to complete the maturation process. S2. Preparation of colloidal base liquid: Under stirring, add component A to component E and mix evenly to form a homogeneous colloidal base liquid; S3. Preparation of nutrient suspension: Add component B and component C to the colloidal base liquid obtained in S2, stir evenly to obtain nutrient suspension; S4. Gelation: For a gel system that requires cross-linking, component D is added in a gradient to the nutrient suspension obtained in S3 under stirring to trigger gelation and obtain a mixture. S5. Shaping and Curing: Pour the mixture obtained in S4 into a mold, let it stand to shape and cure.

[0012] Compared with the prior art, the present invention has the following significant technical effects: This invention provides a method for preparing adult feed for the dark-browed scarab beetle. The feed consists of dry powder materials and liquid components. It adopts a process with room temperature gelation technology as the core. The gelling agent is first fully hydrated to form a homogeneous colloid, and then a cross-linking reaction is triggered to form a stable solid gel feed. It is easy to store and the rehydration (or regeling) operation is simple.

[0013] The core of the preparation process of the adult Dark-Gill Beetle feed of the present invention lies in the "heat-free" characteristic, that is, the key gelation and cross-linking process is completed at room temperature, which is different from the traditional hot-melt and condensation gelation process.

[0014] Natural feeds, such as elm and poplar leaves, are seasonally limited and prone to spoilage and rot. However, the adult feed formula for the *Dark-browed Scarab Beetle* of this invention allows for preservation for over 3 months for dry components: component A (sealed below 25°C), component B (vacuum-sealed at 4°C in the dark), and component C (vacuum-sealed at room temperature in the dark). Solution component D is readily prepared and easy to use. This artificial adult feed is nutritionally complete, has a suitable consistency, and is not limited by region or season, making it ideal for the sub-generation of adult *Dark-browed Scarab Beetles* in the laboratory. Experiments have demonstrated that this adult feed can improve the survival rate of adult *Dark-browed Scarab Beetles*, extend their oviposition period, and increase the number of eggs laid and the hatching rate.

[0015] The present invention will be further described in detail below with reference to the embodiments. Detailed Implementation

[0016] Example 1 This embodiment is a diet for adult dark-browed scarab beetles, using a sodium alginate-xanthan gum composite gel system.

[0017] Sodium alginate was chosen as the main gelling agent, which is readily soluble at room temperature and requires no heating. Xanthan gum thickens the mixture, prevents water separation, and improves elasticity. A mixture of 1.2% sodium alginate and 0.15% xanthan gum was used, and calcium lactate and calcium gluconate were selected as the gelling and cross-linking agents to prepare a stable, high-nutrient, room-temperature gel-formulated solid adult insect feed that requires no heating. The specific formula is as follows: Table 1. Feed formula for adult Dark-browed Scarab Beetles The preparation process for adult Dark-browed Scarab Beetle feed involves controlling the ambient temperature at 28±3℃ and the humidity at 55±5%, and the steps are as follows: S1. Pretreatment: Pass components A, B, and C through a 60-mesh sieve. Mix the powders in component B and inactivate the enzymes at 100°C for 30 minutes to complete the maturation process. S2. Preparation of colloidal base liquid: Under stirring conditions of 600 rpm, component A is slowly added to component E, stirred at high speed of 1500 rpm for 15 minutes, and allowed to stand for 30 minutes to hydrate, forming a homogeneous colloidal base liquid. S3. Preparation of nutrient suspension: Under stirring at 600 rpm, add component B and component C to the colloidal base liquid obtained in S2, and stir at 1000 rpm for 10 minutes to obtain the nutrient suspension. S4. Gelation: Under stirring at 300 rpm, component D (dissolved in 50 g of purified water) is slowly added to the nutrient suspension obtained in S3 in three steps (30%, 50%, 20%) to obtain a mixture. S5. Shaping and Curing: Pour the mixture obtained in S4 into a mold, let it stand at room temperature for 90 minutes, and then refrigerate at 4°C for 12 hours.

[0018] Example 2 This embodiment is a feed for adult dark-browed scarab beetles, which uses a κ-carrageenan-locust bean gum composite gel system.

[0019] κ-carrageenan was selected as the main gelling agent due to its high gel strength and good transparency. A mixture of 0.8% κ-carrageenan and 0.2% locust bean gum was used, with potassium chloride solution selected as the gelation and cross-linking agent to prepare a highly nutritious and stable gel-based solid adult insect feed. The specific formula is as follows: Table 2. Feed formula for adult Dark-browed Scarab Beetles The preparation process for adult Dark-browed Scarab Beetle feed involves controlling the ambient temperature at 28±3℃ and the humidity at 55±5%, and the steps are as follows: S1. Pretreatment: Pass components A, B, and C through a 60-mesh sieve. Mix the powders in component B and inactivate the enzymes at 100°C for 30 minutes to complete the maturation process. S2, Preparation of colloidal base solution: Heat component E (pure water) to above 80°C. While stirring at 600 rpm, slowly add component A to component E and maintain the temperature while stirring for 20 minutes to ensure that the colloid is completely dissolved, thus obtaining a colloidal base liquid. S3. Preparation of nutrient suspension: Stop heating and wait for the temperature to drop below 60℃. Add component B and component C to the colloidal base liquid obtained in S2 and stir evenly to obtain the nutrient suspension. S4. Gelation: When the temperature drops to about 45℃, add component D (dissolved in 15g of pure water) to the nutrient suspension obtained in S3 and stir quickly and evenly to obtain a mixture. S5. Shaping and Curing: Pour the mixture obtained in S4 into a mold and let it stand at room temperature for 1 hour to form a solid gel. Then store it at 4°C. This system does not require long curing time.

[0020] Example 3 This embodiment is a feed for adult dark-browed scarab beetles, using a fast-dissolving gelatin system.

[0021] Instant gelatin was chosen as the main gelling agent, which dissolves at room temperature, resulting in good taste, simple processing, and easy feed digestibility. The amount of instant gelatin used was 4%, and no gelling cross-linking agents were used to prepare a high-nutrition, stable gel-based solid adult insect feed. The specific formula is as follows: Table 3. Feed formula for adult Dark-browed Scarab Beetles The preparation process of adult Dark-browed Scarab Beetle feed involves controlling the ambient temperature at 25±3℃ and the humidity at 55±5%, and the steps are as follows: Preparation steps: S1. Pretreatment: Pass components A, B, and C through a 60-mesh sieve. Mix the powders in component B and inactivate the enzymes at 100°C for 30 minutes to complete the maturation process. S2. Preparation of colloidal base solution: Under stirring at 600 rpm, slowly add component A to component E, stir for 5 minutes, let stand for 30 minutes to allow the gelatin particles to fully absorb water and swell, slowly heat the system to 55°C, and stir at this temperature for about 10 minutes until the gelatin is completely dissolved and the solution is clear to obtain the colloidal base solution. S3. Preparation of nutrient suspension: Stop heating and wait for the temperature to drop below 40℃. Add component B and component C to the colloidal base liquid obtained in S2 and stir evenly to obtain the nutrient suspension. S4. Shaping: Immediately pour the nutrient suspension obtained in S3 into a mold and place it in a 4°C refrigerator to cool for at least 4 hours to form a gel.

[0022] Example 4 This embodiment is a diet for adult Dark-browed Scarab Beetles, using a gellan gel system.

[0023] Gellan gum, a novel and highly efficient gelling agent with high gel strength, was selected as the gelling agent at a dosage of 0.4%. Calcium lactate and calcium gluconate were used as gelation and cross-linking promoters to prepare a high-nutrient, stable gel-based solid adult insect feed. The specific formula is as follows: Table 4. Feed formula for adult Dark-browed Scarab Beetles The preparation process of adult Dark-browed Scarab Beetle feed involves controlling the ambient temperature at 26±3℃ and the humidity at 55±5%, and the steps are as follows: S1. Pretreatment: Pass components A, B, and C through a 60-mesh sieve. Mix the powders in component B and inactivate the enzymes at 100°C for 30 minutes to complete the maturation process. S2. Preparation of colloidal base liquid: Heat component E to above 85°C, add component A under high-speed stirring at 1500 rpm, and continue stirring for 15 minutes to completely dissolve it to obtain colloidal base liquid; S3. Preparation of nutrient suspension: Cool to below 60℃, add component B and component C to the colloidal base liquid obtained in S2, stir evenly to obtain nutrient suspension; S4. Gelation: When the temperature drops to about 45℃, under low-speed stirring at 200rpm, component D (dissolved in 30g of pure water) is slowly added to the nutrient suspension obtained in S3 in three steps (30%, 50%, 20%) to obtain a mixture. S5. Shaping and Curing: The mixture obtained in S4 is poured into a mold, where it can form a solid gel in a short time at room temperature, and then stored at 4°C.

[0024] Example 5 This embodiment is a feed for adult dark-browed scarab beetles, which adopts an optimized system of sodium alginate-xanthan gum composite gel-composite plant protein source.

[0025] In nutrient matrix premix component B, peanut flour is added as a protein source to increase the diversity and substitutability of protein sources, reduce dependence on single soybean flour, and honey is introduced to replace sucrose as a natural palatability enhancer. The specific formula is as follows: Table 5. Feed formula for adult Dark-gilled Scarab Beetles The preparation method for adult Dark-browed Scarab Beetle feed includes the following steps: S1. Pretreatment: Pass components A, B, and C through a 60-mesh sieve. Mix the powders in component B and inactivate the enzymes at 100°C for 30 minutes to complete the maturation process. S2. Preparation of colloidal base liquid: Under stirring conditions of 600 rpm, component A is slowly added to component E, and the mixture is stirred at high speed of 1500 rpm for 15 minutes. After standing for 30 minutes, the mixture is hydrated to obtain the colloidal base liquid. S3. Preparation of nutrient suspension: Under stirring at 600 rpm, add component B and component C to the colloidal base liquid obtained in S2, and stir at 1000 rpm for 10 minutes to obtain the nutrient suspension. S4. Gelation: Under low-speed stirring at 250 rpm, component D (dissolved in 50 g of purified water) is slowly added to the nutrient suspension obtained in S3 in three steps (30%, 50%, 20%) to obtain a mixture. S5. Shaping and Curing: Pour the mixture obtained in S4 into a mold, let it stand at room temperature for 90 minutes, and then refrigerate at 4°C for 12 hours.

[0026] Test method: Adult Dark-browed Scarab Beetles in their early molting stage, captured in Cangzhou in mid-June, were placed in insect rearing boxes (length:width:height 34.5cm:27cm:12cm). Garden soil and fermented straw, used as the habitat substrate, were thoroughly mixed at a volume ratio of 5:1 and added to half the volume of the rearing box. The substrate moisture content was adjusted to 18±1%. Each rearing box contained 300 insects, with a female-to-male ratio of 2:1. The rearing boxes were fed with the adult feed prepared in Examples 1-5 of this invention, elm leaves, Canadian poplar leaves, pear leaves, and golden privet leaves, respectively. A blank control group of unfed adult Dark-browed Scarab Beetles was used. Fresh food was provided every other day, with each treatment repeated three times. The rearing boxes were placed in a culture room at 26±1℃ and a relative humidity of 70±5%. The substrate humidity in the rearing boxes was maintained throughout the experiment.

[0027] Record the number of dead insects before oviposition daily and calculate the survival rate; record the number of days of oviposition and the number of eggs laid, and calculate the number of eggs laid by a single female; after the eggs appear in the substrate, pick them out in time for centralized incubation, take 30 plump dark-browed scarab beetle eggs, record the number of hatched eggs, calculate the hatching rate, and repeat each treatment 3 times.

[0028] The effects of different diets on the survival rate, oviposition, and hatching rate of adult dark-breasted scarab beetles are shown in Table 6.

[0029] Table 6. Effects of different diets on the survival rate, oviposition, and hatching rate of adult *Cyprinus pachycarpa*. Note: Different lowercase letters after the data in the same column indicate significant differences between treatments according to Duncan's new multiple range test (p < 0.05).

[0030] In the blank control treatment, all adult *Pterocarya stenoptera* died within 5 days. The results indicate that the adult feeds described in Examples 1-5 of this application are significantly superior to natural tree leaf feeds such as *Populus tomentosa*, pear, and *Ligustrum lucidum* in terms of adult survival rate, oviposition period, number of eggs laid per female, and egg hatching rate (p < 0.05). Notably, despite the use of different gel systems and nutrient sources, there were no significant differences in the aforementioned core performance indicators among the feeds of each example (p > 0.05), demonstrating the universality and stability of the technical solution of this invention. Furthermore, all feeds of the examples significantly outperformed the elm leaves, which *Pterocarya stenoptera* prefer, in terms of egg production and egg hatching rate (p < 0.05), exhibiting excellent rearing effects.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A feed for adult Melolontha melolontha, characterized in that, The base gel premix component A is composed of the following raw materials in percentage by mass: 3%-7% of a gelling agent, 25%-40% of a nutrient matrix premix component B, 1%-1.8% of a micronutrient premix component C, 0%-0.5% of a crosslinking agent component D, and the balance of a solvent component E.

2. The feed for adult Melolontha melolontha according to claim 1, characterized in that, The base gel premix component A includes a gelling agent and a sugar, the gelling agent being at least one of sodium alginate, kappa-carrageenan, lambda-carrageenan, gellan gum, xanthan gum, locust bean gum, and instant gelatin, and the amount of the gelling agent being 0.4-4%; the sugar being sucrose, honey, or brown sugar, and the amount of the sugar being 3%-4%.

3. The feed for adult Melolontha melolontha according to claim 2, characterized in that, The nutrient matrix premix component B includes 10%-15% of corn flour that has been subjected to a curing process, 8%-10% of soybean flour, 0%-5% of peanut flour, 6%-8% of wheat germ flour, and 5%-8% of elm leaf powder.

4. The feed for adult Melolontha melolontha according to claim 3, characterized in that, The micronutrient premix component C includes 0.2%-0.3% of a complex vitamin B, 0.2%-0.4% of vitamin C, 0.5%-0.8% of lysine, 0.05%-0.1% of choline chloride, 0.05%-0.1% of a preservative, and 0-0.1% of citric acid; the preservative being at least one of potassium sorbate and sodium dehydroacetate; and the vitamin C being microencapsulated vitamin C or buffer-type vitamin C sodium salt.

5. The feed for adult Melolontha melolontha according to claim 4, characterized in that, If the gelling agent is sodium alginate, gellan gum, or kappa-carrageenan, the gel system needs to be crosslinked, and the crosslinking agent component D is a calcium source crosslinking agent or a potassium source crosslinking agent; when the gelling agent is sodium alginate or gellan gum, calcium lactate and calcium gluconate are used as the calcium source crosslinking agent, and the amount of the calcium source crosslinking agent is 0.3%-0.5%; when the gelling agent is kappa-carrageenan, potassium chloride is used as the potassium source crosslinking agent, and the amount of the potassium source crosslinking agent is 0.2%-0.4%.

6. The feed for adult Melolontha hippocastani according to claim 5, characterized in that, The solvent component E is pure water.

7. A method for preparing a feed for adult Melolontha melolontha comprising, The method includes the following steps: S1, pretreatment: passing components A, B, and C through a 60-mesh sieve, respectively; mixing the powders in component B and then subjecting the powders to enzyme inactivation at 100°C for 30 minutes to complete the curing process; S2, preparation of a colloidal base liquid: adding component A to component E under stirring, and mixing uniformly to form a uniform colloidal base liquid; S3, preparation of a nutrient suspension liquid: adding components B and C to the colloidal base liquid obtained in S2, and stirring uniformly to obtain a nutrient suspension liquid; S4, gelation: for a gel system that needs to be crosslinked, adding component D to the nutrient suspension liquid obtained in S3 under stirring, triggering gelation, and obtaining a mixture; S5, shaping and curing: pouring the mixture obtained in S4 into a mold, standing to shape, and curing.

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