Silkworm selenium-rich egg preparation method

Abstract

The invention discloses a preparation method of silkworm selenium-rich eggs, and belongs to the technical field of functional egg production. The preparation method of the silkworm selenium-rich eggs provided by the invention comprises the four steps of preparation of nano-selenium mulberry leaves, selenium-rich breeding of silkworms, preparation of silkworm selenoprotein and feeding management of laying hens. According to the method disclosed by the invention, the defects of low selenium utilization rate, high cost, serious pollution and the like in the traditional technology are overcome through collaborative optimization of a biological chain, efficient conversion and directional enrichment of selenium resources are realized, the selenium content of the obtained eggs is stabilized at 36.8 + / -1.9 mu g / egg, the proportion of selenomethionine is as high as 87.9%, the nutritional value and safety of the eggs are remarkably improved, and the method is suitable for industrial production. The method is suitable for industrial production.

Description

Technical Field

[0001] The present application belongs to the technical field of functional poultry egg production, and in particular relates to a method for preparing selenium-enriched silkworm eggs. Background Art

[0002] Selenium-enriched eggs contain dozens of times more selenium than regular eggs, including free-range eggs, and are lower in cholesterol. They have been shown to slow aging, boost immunity, prevent and treat angina, myocardial infarction, cerebral thrombosis, and cancer. Selenium's primary role in the body is as an antioxidant, playing a crucial role in an enzyme that eliminates free radicals in the body. A deficiency in selenium can lead to a higher risk of heart disease and cancer.

[0003] Currently, the production of selenium-enriched eggs relies primarily on selenium-fortified feed, but existing technologies present the following key challenges: 1. Limitations of traditional selenium sources: Inorganic selenium addition (e.g., sodium selenite): The absorption rate in laying hens is less than 30%, with most of it excreted in feces, causing environmental pollution and a high risk of toxicity. Long-term ingestion by laying hens can easily lead to selenium accumulation in the liver (>5 mg / kg wet weight). Plant-derived organic selenium (e.g., selenium yeast): Selenomethionine accounts for only 50-60%, with limited bioavailability. Yeast cultivation requires specialized fermentation equipment, resulting in high production costs. 2. Technical bottleneck of unstable selenium forms: Existing processes suffer from the easy oxidation of selenium in feed to ineffective forms (e.g., selenate), with a loss rate exceeding 20% after 30 days of storage. The excessively high proportion of methylselenocysteine in eggs (>15%) reduces their nutritional value. 3. Lack of synergy in the industrial chain: Byproducts of the silkworm industry, such as silkworm pupae and mulberry branches, are not efficiently utilized, and traditional disposal methods, such as landfilling or incineration, result in the loss of selenium resources. Therefore, developing an efficient, safe, and sustainable selenium bioconversion method has become a pressing challenge for those skilled in the art. Summary of the Invention

[0004] In order to overcome the above-mentioned defects in the prior art, the present application provides a method for preparing selenium-enriched silkworm eggs.

[0005] In order to achieve the above-mentioned invention objectives, this application provides the following technical solutions:

[0006] In one aspect, the present application provides a method for preparing silkworm selenium-enriched eggs, comprising the following steps:

[0007] (1) Preparation of nano-selenium mulberry leaves: Spraying nano-selenium solution during the mulberry tree's peak leaf stage to obtain nano-selenium mulberry leaves;

[0008] (2) Selenium-enriched silkworm breeding: using the nano-selenium mulberry leaves to feed 5-year-old silkworms to obtain selenium-enriched silkworm pupae;

[0009] (3) Preparation of silkworm selenoprotein: using a composite enzyme to perform gradient cooling enzymolysis on the selenium-rich silkworm pupae to obtain silkworm selenoprotein;

[0010] (4) Feeding management of laying hens: feed laying hens with basic diet A during the brooding period, feed laying hens with basic diet B during the rearing period, feed laying hens with advanced feed A during the pre-laying period, and feed laying hens with advanced feed B during the laying period, and the silkworm selenium-enriched eggs are obtained during the laying period;

[0011] In step (4), the components of the basic diet A include corn residue, soybean meal, fish meal, rock powder, calcium hydrogen phosphate, special premix for chicks, and vegetable oil;

[0012] The components of the basic diet B include corn residue, soybean meal, bran, stone powder, special premix for growing chickens, and mushroom residue;

[0013] The components of the advanced feed A and the advanced feed B both contain the silkworm selenoprotein.

[0014] Optionally, in step (1), the formula of the nano-selenium solution is that per 100L of solution, the solution contains: 70-80g of red elemental nano-selenium, 250-350g of lignin glue, 45-55g of gypenosides, 10-20L of sodium citrate buffer, and deionized water to make up to 100L.

[0015] Preferably, in step (1), the formula of the nano-selenium solution is that per 100L of solution, the solution comprises: 75g of red elemental nano-selenium, 300g of lignin glue, 50g of gypenoside, 15L of sodium citrate buffer, and deionized water to make up to 100L.

[0016] In the present application, the lignin glue added to the above-mentioned nano-selenium solution can form a complex with the red elemental nano-selenium, thereby enhancing the mulberry leaves' resistance to rain erosion; the added gypenosin can wrap the red elemental nano-selenium, and the triterpene skeleton of gypenosin can form a "pinning effect" with the nano-selenium, thereby enhancing the adhesion of the nano-selenium on the leaf surface and promoting the penetration of the nano-selenium; the added sodium citrate buffer can stabilize the pH and prevent the stomata of the mulberry leaves from closing due to pH fluctuations.

[0017] Optionally, the red elemental nano-selenium has a particle size of 45 to 55 nm and a purity of ≥99.9%;

[0018] The pH of the sodium citrate buffer is 6.3-6.6.

[0019] Preferably, the particle size of the red elemental nano-selenium is 50 nm and the purity is 99.9%;

[0020] The pH of the sodium citrate buffer is 6.5.

[0021] Optionally, in step (1), the spraying is foliar spraying;

[0022] The spraying time is 7:30-9:30 in the morning;

[0023] The spraying amount of the nano-selenium solution is 8 to 12 L / mu;

[0024] The standard for completion of spraying is that the selenium content of nano-selenium mulberry leaves reaches 14-17 mg / kg.

[0025] Preferably, in step (1), the spraying amount of the nano-selenium solution is 10 L / mu.

[0026] Optionally, in step (2), the temperature of the selenium-enriched silkworm culture is 25-27°C;

[0027] The feeding frequency of the nano-selenium mulberry leaves is 3 to 4 times per day;

[0028] The feeding amount of the nano-selenium mulberry leaves each time is 1 to 1.5 times of the total weight of the silkworms.

[0029] Preferably, in step (2), the temperature of the selenium-enriched silkworm culture is 26°C;

[0030] The feeding frequency of the nano-selenium mulberry leaves is 4 times / d;

[0031] The feeding amount of the nano-selenium mulberry leaves each time is 1.3 times of the total weight of the silkworms.

[0032] Optionally, in step (2), the qualified feeding standard is that the hemolymph selenium concentration of the 5th-instar silkworm reaches 28-32 μg / mL.

[0033] Optionally, in step (3), the complex enzyme includes cellulase and papain;

[0034] The mass ratio of the cellulase to the papain is 1:1-2;

[0035] The cellulase activity is ≥100,000 U / g;

[0036] The enzymatic activity of the papain is ≥200,000 U / g;

[0037] The total added amount of the cellulase and papain is 750-850 U per gram of selenium-enriched silkworm pupae.

[0038] Preferably, in step (3), the mass ratio of the cellulase to the papain is 1:1.5;

[0039] The enzymatic activity of the cellulase is 100,000 U / g;

[0040] The enzymatic activity of the papain is 200,000 U / g;

[0041] The total amount of cellulase and papain added is 815 U per gram of selenium-enriched silkworm pupae.

[0042] Optionally, in step (3), the conditions for the gradient cooling enzymatic hydrolysis are: 50°C, 2h→45°C, 1h→40°C, 0.5h;

[0043] The pH value during the gradient cooling enzymatic hydrolysis process is 5.8-6.2.

[0044] Preferably, in step (3), the pH during the gradient cooling enzymatic hydrolysis process is 6.

[0045] Optionally, in step (4), the basic diet A comprises the following components in parts by weight: 60-63 parts of corn residue, 25-30 parts of soybean meal, 1-5 parts of fish meal, 1-2 parts of rock powder, 1-2 parts of calcium hydrogen phosphate, 3-5 parts of premix for chicks, and 0.1-0.5 parts of vegetable oil;

[0046] The basic diet B comprises the following components in parts by mass: 63-66 parts of corn residue, 18-22 parts of soybean meal, 5-10 parts of bran, 2-3 parts of stone powder, 3-5 parts of premix for growing chickens, and 0.4-0.6 parts of mushroom residue.

[0047] Preferably, in step (4), the basic diet A comprises the following components by mass: 62 parts of corn residue, 28 parts of soybean meal, 3 parts of fish meal, 1.2 parts of rock powder, 1.5 parts of calcium hydrogen phosphate, 4 parts of premix for chicks, and 0.3 parts of vegetable oil;

[0048] The basic diet B contains the following components in parts by mass: 65 parts of corn residue, 20 parts of soybean meal, 8 parts of bran, 2.5 parts of stone powder, 4 parts of premix for growing chickens, and 0.5 parts of mushroom residue.

[0049] Optionally, the particle size of the corn residue is 1.5 to 2.5 mm;

[0050] The particle size of the stone powder is 0.3 to 0.8 mm;

[0051] The selenium content of the special premix for chicks is 0.08-0.12 mg / kg;

[0052] The vegetable oil is soybean oil;

[0053] The selenium content of the special premix for growing chickens is 0.14-0.16 mg / kg;

[0054] The particle size of the mushroom residue is 0.1-0.4 mm.

[0055] Preferably, the particle size of the corn residue is 2 mm;

[0056] The particle size of the stone powder is 0.7 mm;

[0057] The selenium content of the special premix for chicks is 0.1 mg / kg;

[0058] The selenium content of the special premix for growing chickens is 0.15 mg / kg;

[0059] The particle size of the mushroom residue is 0.3 mm.

[0060] Optionally, in step (4), the advanced feed A comprises the following components in parts by mass: 60-63 parts of corn residue, 20-25 parts of soybean meal, 5-7 parts of stone powder, 1.5-2 parts of calcium hydrogen phosphate, 0.2-0.32 parts of silkworm selenoprotein, 1-2 parts of mushroom residue, 0.4-0.6 parts of soybean oil, and 3-5 parts of a premix for growing chickens;

[0061] The advanced feed B contains the following components in parts by mass: 55-60 parts of corn residue, 20-25 parts of soybean meal, 8-10 parts of stone powder, 1-2 parts of calcium hydrogen phosphate, 0.5-0.7 parts of silkworm selenoprotein, 2-2.5 parts of mushroom residue, 1-1.5 parts of brewer's yeast residue, 0.4-0.6 parts of soybean oil, and 3-5 parts of special premix for laying hens.

[0062] Preferably, in step (4), the advanced feed A comprises the following components in parts by mass: 62 parts of corn residue, 22 parts of soybean meal, 6 parts of stone powder, 1.8 parts of calcium hydrogen phosphate, 0.2-0.32 parts of silkworm selenoprotein, 1.5 parts of mushroom residue, 0.5 parts of soybean oil, and 4 parts of a premix for growing chickens;

[0063] The advanced feed B contains the following components in parts by mass: 58 parts of corn residue, 24 parts of soybean meal, 8 parts of stone powder, 1.5 parts of calcium hydrogen phosphate, 0.6 parts of silkworm selenoprotein, 2 parts of mushroom residue, 1.2 parts of brewer's yeast residue, 0.5 parts of soybean oil, and 4 parts of premix for laying hens.

[0064] Optionally, in the advanced feed A, silkworm selenoprotein is added in a gradient of 0.2 parts by mass in the first week and 0.32 parts in the second week.

[0065] Optionally, the particle size of the corn residue is 1.5 to 2.5 mm;

[0066] The particle size of the stone powder is 0.3 to 0.8 mm;

[0067] The particle size of the mushroom residue is 0.1 to 0.4 mm;

[0068] The selenium content of the beer yeast residue is 1.5-2 mg / kg;

[0069] The selenium content of the special premix for growing chickens and the special premix for laying hens are both 0.14-0.16 mg / kg.

[0070] Preferably, the particle size of the corn residue is 2 mm;

[0071] The particle size of the stone powder is 0.7 mm;

[0072] The particle size of the mushroom residue is 0.3 mm;

[0073] The selenium content of the brewer's yeast residue is 1.7 mg / kg;

[0074] The selenium content of the premix specially for growing chickens and the premix specially for laying hens is both 0.15 mg / kg.

[0075] In the present application, the reason why the feed during the brooding and growing periods does not contain silkworm selenoprotein is that during the brooding period, the chicken's digestive system is not fully developed (gizzard pH>4.0), and the ability to decompose selenoprotein is insufficient. Some selenium remains in inorganic form, resulting in increased selenium accumulation in the liver and may also cause inhibition of immune organ development; while the core goal of the growing period is bone development and weight control, and the selenium demand is relatively low, which can be met by the basic daily diet.

[0076] Optionally, in step (4), the temperature during the feeding and management of laying hens is 18-24° C. and the humidity is 55-65%;

[0077] The lighting conditions during the brooding period are: 23 hours of light and 1 hour of darkness, with a light intensity of 20 to 30 Lux;

[0078] The lighting conditions during the growth period are: 12 hours of light and 12 hours of darkness, with a light intensity of 20-30 Lux;

[0079] The lighting conditions during the expected delivery period are: 14 hours of light and 10 hours of darkness, with a light intensity of 20 to 30 Lux;

[0080] The lighting conditions during the egg-laying period are: 16 hours of light and 8 hours of darkness, with a light intensity of 20 to 30 Lux.

[0081] Preferably, in step (4), the temperature during the feeding and management of laying hens is 21° C. and the humidity is 60%;

[0082] The lighting conditions during the brooding period were: 23 h light, 1 h dark, and a light intensity of 25 Lux;

[0083] The lighting conditions during the incubation period were: 12 h light, 12 h dark, and a light intensity of 25 Lux;

[0084] The lighting conditions during the expected delivery period were: 14 h light, 10 h dark, and a light intensity of 25 Lux;

[0085] The lighting conditions during the egg-laying period are: 16 hours of light, 8 hours of darkness, and a light intensity of 25 Lux.

[0086] Optionally, in step (4), the feeding method during the brooding period is: feeding frequency is 6 to 7 times per day, and the daily feeding amount is 12 to 35 g per bird;

[0087] The feeding method during the rearing period is: feeding frequency is 3 to 4 times per day, and the daily feeding amount is 65 to 80 g per bird;

[0088] The feeding method during the expected period of calving is: feeding frequency is 2 to 3 times per day, and the daily feeding amount is 90 to 105 g per bird;

[0089] The feeding method during the laying period is: feeding frequency is 2 to 3 times per day, and the daily feeding amount is 110 to 125 g per bird.

[0090] Preferably, in step (4), the feeding method during the brooding period is: feeding frequency is 6 times / day, and the daily feeding amount is 30g / bird;

[0091] The feeding method during the rearing period is: feeding frequency is 3 times / day, and the daily feeding amount is 75g / bird;

[0092] The feeding method during the expected period is: feeding frequency is 2 times / day, and the daily feeding amount is 100g / bird;

[0093] The feeding method during the laying period is: feeding frequency is 2 times / day, and the daily feeding amount is 115g / bird.

[0094] Compared with the prior art, this application has the following beneficial effects:

[0095] (1) The method for preparing selenium-enriched eggs from silkworms provided in this application adopts nano-selenium-modified mulberry leaves to feed silkworms, and uses live silkworms as selenium conversion carriers. Through the four-stage biotransformation chain of "nanoselenium mulberry leaves → silkworm enrichment → enzymatic conversion → laying hen feeding", the transformation and targeted enrichment of selenium resources are achieved. The selenium content of the obtained eggs is stabilized at 36.8±1.9μg / piece (the national standard selenium-enriched eggs ≥20μg / piece), and the proportion of selenomethionine is as high as 87.9%, which significantly improves the nutritional value and safety of eggs.

[0096] (2) This application utilizes agricultural by-products such as silkworm pupae and mushroom residues to reduce the cost of selenium additives. At the same time, it constructs a closed-loop system of "mulberry garden → breeding → fertilizer", so that selenium resources can be recycled and the environmental load can be reduced.

[0097] (3) This application develops a gradient cooling enzymatic hydrolysis process and a dynamic gradient selenium supplementation technology, which can retain the activity of selenoproteins and ensure the stability of selenium form. Combined with other feed components, the egg production rate of laying hens is increased to 94.5% and the egg breakage rate is reduced to 1.2%, which is suitable for large-scale industrial production. DETAILED DESCRIPTION

[0098] The present application will be further described below in conjunction with specific embodiments. The following description is merely a few embodiments of the present application and does not limit the present application in any form. Although the present application discloses the preferred embodiments below, it is not intended to limit the present application. Any person skilled in the art who, without departing from the scope of the technical solution of the present application, makes slight changes or modifications using the above disclosed technical content is equivalent to an equivalent implementation case and falls within the scope of the technical solution.

[0099] Unless otherwise specified, the raw materials in the examples of this application were purchased from commercial channels and used directly without any special treatment.

[0100] Unless otherwise specified, the analytical methods in the examples all adopt conventional settings and conventional analytical methods of instruments or equipment.

[0101] Example 1

[0102] 1. Experimental Location and Conditions

[0103] Location: Zongxi Town, Xunyang City, Ankang City, Shaanxi Province

[0104] Climate characteristics: average annual temperature 15.4℃, annual precipitation 755mm, mulberry tree growing period ≥240 days, meeting the needs of multi-batch silkworm breeding.

[0105] Variety selection:

[0106] Mulberry trees: “Shaan Sang 305” (a selenium-tolerant variety, purchased from Shaanxi Hongshengrui Agriculture and Forestry Technology Co., Ltd.) were planted at a spacing of 3 m × 1.5 m.

[0107] Silkworm: “Shaanxi Silkworm No. 3” (5th instar weight ≥ 4.5 g / piece, purchased from the Sericulture and Silk Research Institute of Northwest Agriculture and Forestry University).

[0108] Layers: Hailan brown-shell laying hens (1-day-old chicks, purchased from Ningxia Xiaoming Agriculture and Animal Husbandry Co., Ltd.).

[0109] 2. Specific implementation steps

[0110] 1. Preparation of Nano-Selenium Mulberry Leaves

[0111] (1) Spray solution formula (100 L): red elemental nano-selenium (50 nm, 99.9%, purchased from Xi'an Qiyue Biotechnology Co., Ltd.) 75 g, lignin glue (purchased from Shanghai Sudao Weiye Technology Co., Ltd.) 300 g, gypenoside (purchased from Shaanxi Fuerbang Biotechnology Co., Ltd.) 50 g, 0.1 M sodium citrate buffer (pH 6.5, purchased from Shanghai Shangbao Biotechnology Co., Ltd.) 15 L, and deionized water was added to 100 L.

[0112] Preparation of spray solution: first dry-mix red elemental nano-selenium and gypenosin (1:1), then dissolve in lignin glue, then add sodium citrate buffer and deionized water, mix well to obtain nano-selenium solution.

[0113] (2) Spraying operation:

[0114] Time: May 10, 2023, 07:30-09:30 (Mulberry trees in full bloom)

[0115] Method: Drone spraying (atomized particle size 40 μm, pressure 3 bar)

[0116] Dosage: 10 L / mu. After spraying the nano-selenium solution for 7 days, the selenium content of mulberry leaves reaches 15.7±1.2 mg / kg (drying basis), and nano-selenium mulberry leaves are obtained.

[0117] 2. Selenium-rich silkworm breeding

[0118] (1) Feeding management:

[0119] Temperature: 26±0.5℃ (ground source heat pump control)

[0120] Feeding: Feed nano-selenium mulberry leaves 4 times a day (06:00 / 11:00 / 16:00 / 21:00), the feeding amount each time = total silkworm weight × 1.3, and the total consumption of selenium mulberry leaves during the 5th instar is 38 kg / 10,000 silkworms.

[0121] (2) Quality Control:

[0122] Hemolymph selenium concentration: 29.3±1.2 μg / mL (colloidal gold rapid test strip, purchased from Shaanxi Selenium Valley Biotechnology, product model SX-Se-Rapid).

[0123] Selenium content of qualified silkworm pupae: 62.5±2.1μg / g (detected by atomic fluorescence spectrometry (AFS)).

[0124] 3. Preparation of silkworm selenoprotein

[0125] (1) Enzymatic hydrolysis process:

[0126] Complex enzyme: Cellulase (purchased from Hebei Jiuyu Biotechnology Co., Ltd., enzyme activity is 100,000 U / g): Papain (purchased from Nanning Pangbo Bioengineering Co., Ltd., enzyme activity is 200,000 U / g) = 1:1.5 (mass ratio)

[0127] Total added amount of complex enzyme: 815U / g silkworm pupa

[0128] (2) Enzymatic hydrolysis conditions (gradient cooling enzymatic hydrolysis): 50℃ (2h) → 45℃ (1h) → 40℃ (0.5h), pH 6.

[0129] (3) Product indicators:

[0130] The hydrolysis degree of selenoprotein is 48.7%, and the molecular weight <3000Da accounts for 88.3% (HPLC detection)

[0131] Selenium content: 480±15mg / kg (organic selenium accounts for 88.6%).

[0132] 4. Feeding management of laying hens

[0133] (1) Brooding period (1-42 days):

[0134] Feed formula (by mass): 62 parts of corn residue (particle size 2 mm, purchased from Wenshang County Zhongcheng Grain Industry Co., Ltd.), 28 parts of soybean meal (purchased from Shandong Xinlongkai Chemical Co., Ltd.), 3 parts of fish meal (purchased from Tianjin Haiwei International Trade Co., Ltd.), 1.2 parts of stone powder (particle size 0.7 mm, purchased from Shijiazhuang Weijia Mineral Products Co., Ltd.), 1.5 parts of calcium hydrogen phosphate (purchased from Shaanxi Yuanyou Biotechnology Co., Ltd.), 4 parts of premix for chicks (selenium content is 0.1 mg / kg, purchased from Anhui Yiyuan Agriculture and Animal Husbandry Technology Co., Ltd.), and 0.3 parts of soybean oil (purchased from Jinan Longze Chemical Co., Ltd.).

[0135] Mixing process: First put corn residue, soybean meal, fish meal and calcium hydrogen phosphate into the mixer, dry mix for 3 minutes, then add special premix for chicks, stone powder and soybean oil and mix for 15 minutes.

[0136] Feeding method: Feeding frequency is 6 times / day (06:00 / 8:30 / 11:00 / 13:30 / 16:00 / 18:30), daily feeding amount is 30g / bird, and drinking water is free during this period.

[0137] Light control: 23h light, 1h dark, LED fill light (intensity: 25Lux, spectrum: 4000K cold white light).

[0138] (2) Growing period (43-105 days):

[0139] Feed formula (by mass): 65 parts of corn residue, 20 parts of soybean meal, 8 parts of bran (wheat bran, purchased from Shandong Huachen Biotechnology Co., Ltd.), 2.5 parts of stone powder, 4 parts of premix for growing chickens (selenium content is 0.15 mg / kg, purchased from Anhui Yiyuan Agriculture and Animal Husbandry Technology Co., Ltd.), and 0.5 parts of mushroom residue (Flammulina velutipes residue, particle size 0.3 mm, purchased from Dezhou Fubang Agricultural Development Co., Ltd.).

[0140] Mixing process: first put corn residue, soybean meal and bran into the mixer and dry mix for 3 minutes, then add special premix for growing chickens, stone powder and mushroom residue and mix for 15 minutes.

[0141] Feeding method: Feeding frequency is 3 times / day (06:30 / 12:00 / 18:00), daily feeding amount is 75g / bird, and drinking water is free during this period.

[0142] Light control: 12h light, 12h dark, LED fill light (intensity 25Lux, spectrum: 4000K cold white light).

[0143] (3) Expected date of birth (106-120 days of age)

[0144] Feed formula (by mass): 62 parts of corn residue, 22 parts of soybean meal, 6 parts of stone powder, 1.8 parts of calcium hydrogen phosphate, silkworm selenoprotein added in a gradient of 0.2 parts in the first week and 0.32 parts in the second week, 1.5 parts of mushroom residue, 0.5 parts of soybean oil, and 4 parts of premix for growing chickens.

[0145] Mixing process: First premix silkworm selenoprotein with mushroom residue for 3 minutes, then add corn residue, soybean meal, and calcium hydrogen phosphate, dry mix for 3 minutes, and finally add special premix for growing chickens, stone powder, and soybean oil and mix for 10 minutes.

[0146] Feeding method: Feeding frequency is 2 times / day (7:00 / 15:00), daily feeding amount is 100g / bird, and drinking water is free during this period.

[0147] Light control: 14h light, 10h dark, LED fill light (intensity 25Lux, spectrum: 4000K cold white light).

[0148] (4) Egg-laying period (121 days old - elimination)

[0149] Feed formula (by mass): 58 parts of corn residue, 24 parts of soybean meal, 8 parts of stone powder, 1.5 parts of calcium hydrogen phosphate, 0.6 parts of silkworm selenoprotein, 2 parts of mushroom residue, 1.2 parts of brewer's yeast residue (selenium content is 1.7 mg / kg, purchased from China Resources Snow Beer Xi'an Branch), 0.5 parts of soybean oil, and 4 parts of premix for laying hens (selenium content is 0.15 mg / kg, purchased from Anhui Yiyuan Agriculture and Animal Husbandry Technology Co., Ltd.).

[0150] Mixing process: First premix silkworm selenoprotein with mushroom residue and brewer yeast residue for 3 minutes, then add corn residue, soybean meal and calcium hydrogen phosphate, dry mix for 3 minutes, and finally add special premix for laying hens, stone powder and soybean oil and mix for 10 minutes.

[0151] Feeding method: Feeding frequency is 2 times / day (7:00 / 15:00), daily feeding amount is 115g / bird, and drinking water is free during this period.

[0152] Light control: 16h light, 8h dark, LED fill light (intensity: 25Lux, spectrum: 4000K cold white light).

[0153] (5) Other parameter control: temperature 21°C, humidity 60% (atomization humidification in winter), ammonia concentration <10ppm.

[0154] Comparative Example 1

[0155] The only difference from Example 1 is that the nano-selenium solution was not sprayed on the mulberry leaves.

[0156] Comparative Example 2

[0157] The only difference from Example 1 is that the addition of silkworm selenoprotein to the feed is omitted during the pre-laying period and egg-laying period of the laying hens.

[0158] Experimental Example 1

[0159] The laying hens were fed with the methods of Example 1, Comparative Example 1 and Comparative Example 2, and the eggs they laid were tested. The results are shown in Table 1.

[0160] Table 1 Egg index test results

[0161]

[0162] As shown in Table 1, compared with the comparative example, the eggs obtained in Example 1 of the present application have a higher selenium content and better nutrition, meeting the selenium-enriched egg standard of ≥20 μg / piece, and a high proportion of selenomethionine, indicating that the selenium in the eggs of the present application is mainly present in an organic form, is safe, and is more easily absorbed and utilized by the human body. In addition, the feeding scheme of the present application can effectively reduce the egg breakage rate, increase the egg production rate and average egg weight, and achieve higher egg quality.

[0163] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing silkworm selenium-enriched eggs, characterized in that: The steps include: (1) Preparation of nano-selenium mulberry leaves: Spraying nano-selenium solution during the mulberry tree's peak leaf stage to obtain nano-selenium mulberry leaves; (2) Selenium-enriched silkworm breeding: using the nano-selenium mulberry leaves to feed 5-year-old silkworms to obtain selenium-enriched silkworm pupae; (3) Preparation of silkworm selenoprotein: using a composite enzyme to perform gradient cooling enzymolysis on the selenium-rich silkworm pupae to obtain silkworm selenoprotein; (4) Feeding management of laying hens: feed laying hens with basic diet A during the brooding period, feed laying hens with basic diet B during the rearing period, feed laying hens with advanced feed A during the pre-laying period, and feed laying hens with advanced feed B during the laying period, and the silkworm selenium-enriched eggs are obtained during the laying period; In step (4), the components of the basic diet A include corn residue, soybean meal, fish meal, rock powder, calcium hydrogen phosphate, special premix for chicks, and vegetable oil; The components of the basic diet B include corn residue, soybean meal, bran, stone powder, special premix for growing chickens, and mushroom residue; The components of the advanced feed A and the advanced feed B both contain the silkworm selenoprotein.

2. The method for preparing silkworm selenium-enriched eggs according to claim 1, wherein: In step (1), the formula of the nano-selenium solution is as follows: per 100L of solution, the solution comprises: 70-80g of red elemental nano-selenium, 250-350g of lignin glue, 45-55g of gypenosides, 10-20L of sodium citrate buffer, and deionized water to make up to 100L; Preferably, the particle size of the red elemental nano-selenium is 45 to 55 nm, and the purity is ≥99.9%; The pH of the sodium citrate buffer is 6.3-6.

6.

3. The method for preparing silkworm selenium-enriched eggs according to claim 1, wherein: In step (1), the spraying is foliar spraying; The spraying time is 7:30-9:30 in the morning; The spraying amount of the nano-selenium solution is 8 to 12 L / mu; The standard for completion of spraying is that the selenium content of nano-selenium mulberry leaves reaches 14-17 mg / kg.

4. The method for preparing silkworm selenium-enriched eggs according to claim 1, wherein: In step (2), the temperature of the selenium-enriched silkworm culture is 25-27°C; The feeding frequency of the nano-selenium mulberry leaves is 3 to 4 times per day; The feeding amount of the nano-selenium mulberry leaves each time is 1 to 1.5 times of the total weight of the silkworms.

5. The method for preparing silkworm selenium-enriched eggs according to claim 1, wherein: In step (2), the qualified feeding standard is that the hemolymph selenium concentration of the 5th-instar silkworm reaches 28-32 μg / mL.

6. The method for preparing silkworm selenium-enriched eggs according to claim 1, characterized in that: In step (3), the complex enzyme includes cellulase and papain; The mass ratio of the cellulase to the papain is 1:1-2; The cellulase activity is ≥100,000 U / g; The enzymatic activity of the papain is ≥200,000 U / g; The total added amount of the cellulase and papain is 750-850 U per gram of selenium-enriched silkworm pupae.

7. The method for preparing silkworm selenium-enriched eggs according to claim 1, wherein: In step (3), the conditions for the gradient cooling enzymatic hydrolysis are: 50°C, 2h→45°C, 1h→40°C, 0.5h; The pH value during the gradient cooling enzymatic hydrolysis process is 5.8-6.

2.

8. The method for preparing silkworm selenium-enriched eggs according to claim 1, wherein: In step (4), the basic diet A comprises the following components by weight: 60-63 parts of corn residue, 25-30 parts of soybean meal, 1-5 parts of fish meal, 1-2 parts of rock powder, 1-2 parts of calcium hydrogen phosphate, 3-5 parts of premix for chicks, and 0.1-0.5 parts of vegetable oil; The basic diet B comprises the following components by weight: 63-66 parts of corn residue, 18-22 parts of soybean meal, 5-10 parts of bran, 2-3 parts of stone powder, 3-5 parts of premix for growing chickens, and 0.4-0.6 parts of mushroom residue; Preferably, the particle size of the corn residue is 1.5 to 2.5 mm; The particle size of the stone powder is 0.3 to 0.8 mm; The selenium content of the special premix for chicks is 0.08-0.12 mg / kg; The vegetable oil is soybean oil; The selenium content of the special premix for growing chickens is 0.14-0.16 mg / kg; The particle size of the mushroom residue is 0.1-0.4 mm.

9. The method for preparing silkworm selenium-enriched eggs according to claim 1, characterized in that: In step (4), the advanced feed A comprises the following components by weight: 60-63 parts of corn residue, 20-25 parts of soybean meal, 5-7 parts of stone powder, 1.5-2 parts of calcium hydrogen phosphate, 0.2-0.32 parts of silkworm selenoprotein, 1-2 parts of mushroom residue, 0.4-0.6 parts of soybean oil, and 3-5 parts of a premix for growing chickens; The advanced feed B comprises the following components in parts by weight: 55-60 parts of corn residue, 20-25 parts of soybean meal, 8-10 parts of stone powder, 1-2 parts of calcium hydrogen phosphate, 0.5-0.7 parts of silkworm selenoprotein, 2-2.5 parts of mushroom residue, 1-1.5 parts of brewer's yeast residue, 0.4-0.6 parts of soybean oil, and 3-5 parts of premix for laying hens; Preferably, in the advanced feed A, silkworm selenoprotein is added in a gradient of 0.2 parts by mass in the first week and 0.32 parts in the second week; Preferably, the particle size of the corn residue is 1.5 to 2.5 mm; The particle size of the stone powder is 0.3 to 0.8 mm; The particle size of the mushroom residue is 0.1 to 0.4 mm; The selenium content of the beer yeast residue is 1.5-2 mg / kg; The selenium content of the special premix for growing chickens and the special premix for laying hens are both 0.14-0.16 mg / kg.

10. The method for preparing silkworm selenium-enriched eggs according to claim 1, characterized in that: In step (4), the temperature during the feeding and management of the laying hens is 18-24° C. and the humidity is 55-65%; The lighting conditions during the brooding period are: 23 hours of light and 1 hour of darkness, with a light intensity of 20-30 Lux; The lighting conditions during the growth period are: 12 hours of light and 12 hours of darkness, with a light intensity of 20-30 Lux; The lighting conditions during the expected delivery period are: 14 hours of light and 10 hours of darkness, with a light intensity of 20 to 30 Lux; The lighting conditions during the egg-laying period are: 16 hours of light and 8 hours of darkness, with a light intensity of 20 to 30 Lux; Preferably, in step (4), the feeding method during the brooding period is: feeding frequency is 6 to 7 times per day, and the daily feeding amount is 12 to 35 g per bird; The feeding method during the rearing period is: feeding frequency is 3 to 4 times per day, and the daily feeding amount is 65 to 80 g per bird; The feeding method during the expected period of calving is: feeding frequency is 2 to 3 times per day, and the daily feeding amount is 90 to 105 g per bird; The feeding method during the laying period is: feeding frequency is 2 to 3 times per day, and the daily feeding amount is 110 to 125 g per bird.

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