Folic acid nanoemulsion for increasing spawning rate of protaetia brevitarsis as well as preparation method and application of folic acid nanoemulsion

Abstract

The invention discloses a folic acid nanoemulsion capable of increasing the egg laying rate of protaetia brevitarsis and application of the folic acid nanoemulsion. The folic acid nanoemulsion comprises the following components in percentage by mass: 0.003%-0.005% of folic acid, 0.02%-0.1% of sodium bicarbonate, 3%-4% of ultrapure water, 16%-19% of a surfactant, 6%-9% of a cosurfactant and 67.895%-74.977% of an oil phase. The method has the remarkable effects that the folic acid content ranges from 0.02 mg / kg to 0.05 mg / kg in a feed mixing and administration mode, the single female egg laying rate of the protaetia brevitarsis can be increased by 5.72% to 25.29% when the protaetia brevitarsis is fed to female protaetia brevitarsis, and nutrition preparation support is provided for increasing the egg laying rate in the large-scale breeding process of the protaetia brevitarsis.

Description

Technical Field

[0001] The invention relates to the technical field of insect breeding, and in particular to a folic acid nanoemulsion which can improve the egg-laying rate and hatching rate of white-spotted flower beetles and can quickly expand the breeding scale of white-spotted flower beetles and its application. Background Art

[0002] The white-spotted flower beetle is an important resource insect, and its larvae are also called white grubs. White grubs have a significant effect in transforming livestock and poultry manure, straw, etc. through their stomachs. The larvae produced can be used as feed and medicine, and the insect sand (i.e., insect feces) produced is a good organic fertilizer. Under natural conditions, white-spotted flower beetles have one generation per year, and under artificial breeding conditions, they can have two or three generations. In addition, by artificially adjusting the breeding conditions of white-spotted flower beetles, their single female egg production and hatching rate can be increased. However, the current methods for increasing single female egg production and hatching rate are limited to the adjustment of culture medium type, male-female ratio, feed type, and breeding temperature. There are no reports on the role of folic acid nanoemulsion in increasing the egg production rate and hatching rate of white-spotted flower beetles.

[0003] For example, invention patent 1 "A large-scale breeding method for increasing the egg-laying capacity of adult white-spotted flower beetles" (patent number CN202210202338.1) mainly includes the following steps: (1) setting up a breeding site and a breeding device; (02) preparing an egg-laying matrix; (03) preparing an adult feed; (04) laying eggs and hatching. The method is set up in terms of the breeding box, the material ratio of the egg-laying matrix, the adult feed formula, the thickness of the egg-laying matrix, humidity, and temperature for egg-laying (hatching), thereby increasing the egg-laying capacity and hatching rate. However, this method still has some disadvantages, namely (1) there are many steps involved and they are closely related to each other. If one step cannot be met, the other steps will be affected, hindering the realization of the purpose of the invention. (2) The egg-laying matrix material preparation process involves fermentation time and different material ratios, and the adult feed preparation steps and ingredients involved are many, which increases the difficulty of realizing the invention. Therefore, the method described in the above invention does not fully meet the requirements of simply, efficiently, and economically increasing the egg-laying rate and hatching rate of white-spotted flower beetles.

[0004] Invention Patent 2 "A method for increasing the egg-laying capacity of adult white-spotted flower beetles" (patent number CN202011116189.2, Xinjiang Agricultural University), this invention mainly includes the following steps: (01) adult rearing device; (2) preparation of composite egg-laying matrix and newly hatched larval food; (3) configuration and maintenance of the optimal male-female ratio; (4) adult food; (5) environmental condition control. The rearing device, preparation of egg-laying matrix, preparation of newly hatched larval food, male-female ratio, adult food, egg-laying (hatching) egg-laying matrix thickness, humidity, temperature, and light duration were set to increase the egg-laying capacity and hatching rate. However, these methods still have some disadvantages, namely (1) the steps and elements involved are complicated and closely related to each other. If one step cannot be met, the other steps will be affected, hindering the realization of the purpose of the invention. (2) The egg-laying matrix fermentation process involves fermentation time and different material ratios. There are many steps involved in the adult male-female ratio, mating conditions and daily management, which increases the difficulty of realizing the invention. Therefore, the method described in the above invention does not fully meet the requirements of simply, efficiently and economically improving the egg-laying rate and hatching rate of white-spotted flower beetles.

[0005] Invention patent 3 "A good production technique of protaetia brevitarsisseulensis by continuous rearing" (patent number KR100937154B1, Kyungpook National University Industry-Academic Cooperation Foundation), this invention mainly includes the following steps: (1) construction of adult breeding facilities; (2) adult breeding density and feed formula; (3) increasing the body weight of pupating larvae. The breeding device, adult breeding density control, feed formula and pupating larvae weight are designed respectively to increase the egg laying rate. However, these methods still have some disadvantages, namely (1) the breeding device involves ventilation duct design, adult breeding density adjustment, and temperature control conditions for the body weight of pupating larvae. The steps involved are relatively large and strict, which increases the difficulty of realizing the invention; at the same time, the delay or obstruction of a certain step will affect the realization of this invention purpose. (2) The egg hatching rate is also an important factor affecting the expansion of the white-spotted flower beetle population, but the present invention does not involve the discussion of the role of improving the egg hatching rate. Therefore, the method described in the above invention does not fully meet the requirements of simply, efficiently and economically improving the egg-laying rate and hatching rate of white-spotted flower beetles.

[0006] In addition, in the journal article “Effects of Nutrition and Humidity on the Reproduction of Adult White-spotted Flower Beetles” (Journal of Shandong Agricultural University (Natural Science Edition), 2014, 45(4), 498-501), Yang Cheng et al. increased the egg-laying capacity of adult white-spotted flower beetles by changing the type of feed and / or the humidity of the egg-laying matrix, and found that fruits with high sugar content and 15% humidity of the egg-laying matrix were both beneficial to increasing the egg-laying capacity. However, the sugar content of the fruit described in the result was only a qualitative indicator and could not be quantified; in addition, the result only described the change in egg-laying capacity and lacked a description of the effect on the egg hatching rate. Therefore, it is impossible to meet the requirements of simultaneously increasing the egg-laying capacity and hatching rate of white-spotted flower beetles.

[0007] In summary, the existing methods for improving the egg-laying rate of female white-star flower beetles have the following defects:

[0008] (1) Changes in the egg-laying matrix: The egg-laying rate and hatching rate of female insects can be increased by changing the softness of the egg-laying matrix and the degree of fecal fermentation. However, if the proportion of the matrix components changes, especially if the important nutrients in the matrix are reduced, the egg-laying rate and hatching rate will decrease. In addition, the differences in the matrix components also make the control effect unstable;

[0009] (2) The sugar content in the feed is positively correlated with the egg-laying rate of female insects. The higher the sugar content, the higher the egg-laying rate. However, the composition of the same fruit may vary in different batches, which will affect the repeatability and stability of production;

[0010] (3) Proper adjustment of the male-female ratio can help improve the spawning rate, but the differences between individuals still affect the stability of spawning results;

[0011] (4) Factors such as temperature, humidity, and light cycle can affect the mating and egg-laying rhythms of male and female insects. Optimizing these conditions can help increase the egg-laying rate. However, these external conditions are difficult to control accurately, and different control methods can also lead to differences in the effects, which in turn affects the stability of egg-laying and hatching. Summary of the invention

[0012] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a folic acid nanoemulsion and its application for improving the egg-laying rate of white-spotted flower beetles. Considering the nutrients required by the white-spotted flower beetles themselves, the folic acid nanoemulsion prepared by applying nanotechnology can effectively improve the egg-laying rate and hatching rate of white-spotted flower beetles.

[0013] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0014] In the first aspect, the present invention proposes a folic acid nanoemulsion for improving the egg-laying rate of white-spotted flower beetles, the key of which is that it includes the following components by mass percentage: folic acid 0.003%-0.005%, sodium bicarbonate 0.02%-0.1%, ultrapure water 3%-4%, surfactant 16%-19%, co-surfactant 6%-9%, and oil phase 67.895%-74.977%.

[0015] Furthermore, the surfactant is selected from Span 83, Span 85, Span 60, Span 80 or Span 40.

[0016] Furthermore, the co-surfactant is a short-chain alcohol.

[0017] Furthermore, the oil phase is natural vegetable oil.

[0018] Furthermore, the oil phase is rapeseed oil, olive oil, vitamin E, corn oil or coconut oil.

[0019] Furthermore, the zeta potential of the folic acid nanoemulsion is 10.06-32.79 mv, the polydispersity coefficient is 0.086-0.112, and the particle size distribution range is 30.45-51.74 nm.

[0020] In a second aspect, the present invention further provides a method for preparing a folic acid nanoemulsion for improving the egg-laying rate of white-spotted flower beetles as described in the first aspect, comprising the following steps:

[0021] Weigh the folic acid aqueous solution, surfactant, co-surfactant and oil phase respectively according to the proportion;

[0022] The folic acid aqueous solution, the surfactant and the co-surfactant are mixed to obtain an aqueous phase;

[0023] The oil phase is added and mixed to obtain the folic acid nanoemulsion.

[0024] Furthermore, the zeta potential of the folic acid nanoemulsion is 10.06-32.79 mv, the polydispersity coefficient is 0.086-0.112, and the particle size distribution range is 30.45-51.74 nm.

[0025] In a third aspect, the present invention further proposes an application of the folic acid nanoemulsion as described in the first aspect in improving the egg-laying rate of the white-spotted flower beetle.

[0026] The remarkable effects of the present invention are:

[0027] (1) Improving the bioavailability of folic acid preparations: Preparing folic acid aqueous solution into folic acid nanoemulsion can improve the solubility of poorly soluble drugs and have a sustained-release and controlled-release effect on drugs. Its small particle size can promote drug absorption and improve drug bioavailability, which is beneficial to prolonging the action time of folic acid in the body and greatly promoting the development of ovaries, egg production and hatching rate.

[0028] (2)(2) Improve the egg-laying efficiency of white-star flower beetles: Standardized folic acid nanoemulsion preparation technology is used to ensure the consistency of components and the stability of effects. This allows female insects to maintain high reproductive performance under different breeding conditions, and achieves an increase of 5.72%-25.29% in egg-laying capacity and 5.68%-17.54% in hatching rate under different environmental conditions. It has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a sample diagram of the folic acid nanoemulsion of the present invention;

[0030] Figure 2 This is a graph showing the Zeta potential detection result of the folic acid nanoemulsion of the present invention;

[0031] Figure 3 This is a graph showing the particle size detection results of the folic acid nanoemulsion of the present invention;

[0032] Figure 4 This is a comparison of the ovary size of the white-spotted flower beetle during the peak egg-laying period (fifth week) under different folic acid dosages;

[0033] Figure 5 The egg-laying trend of the white-spotted flower beetle before and after adding folic acid nanoemulsion to different fruit feed matrices;

[0034] Figure 6 This is a comparison chart of the number of eggs produced by the white-spotted flower beetle during the peak period of egg-laying (fifth week) with single female egg-laying in culture medium with different humidity levels and folic acid nanoemulsion added. DETAILED DESCRIPTION

[0035] The specific implementation manner and working principle of the present invention are further described in detail below.

[0036] In the field of insect breeding, especially in the process of expanding the scale of resource insect breeding, the improvement of egg-laying rate and hatching rate is a key link. At present, the egg-laying rate and hatching rate are improved by adjusting the external environment, for example, adjusting the breeding temperature, humidity and the type or texture of the culture soil, ignoring the insects' own needs for nutrients. Therefore, the present invention starts from the nutrients required by the insects themselves, and develops a folic acid nanoemulsion that can improve the egg-laying rate of the white-star flower beetle, which can provide nutritional support for the improvement of the egg-laying rate and hatching rate during the large-scale breeding of the white-star flower beetle.

[0037] Embodiment 1:

[0038] This embodiment proposes a folic acid nanoemulsion for improving the egg-laying rate of white-spotted flower beetles, which is prepared by mixing the following raw materials: 1 mg of folic acid, 10 mg of sodium bicarbonate, 1 g of ultrapure water, 6.03 g of surfactant, 2.01 g of co-surfactant, and 23.43 g of oil phase, that is, the mass ratio of folic acid is 0.003%, sodium bicarbonate is 0.029%, ultrapure water is 3%, surfactant is 18.02%, co-surfactant is 6.01%, and oil phase is 72.938%.

[0039] The surfactant is Span 80, the co-surfactant is anhydrous ethanol, and the oil phase is rapeseed oil.

[0040] This embodiment also proposes a method for preparing the folic acid nanoemulsion, the specific steps are:

[0041] Step 1, weigh folic acid, ultrapure water, sodium bicarbonate, surfactant, co-surfactant, and oil phase respectively according to proportion;

[0042] Step 2, vortex-mix the ultrapure water, folic acid, sodium bicarbonate, surfactant, and co-surfactant for 30 seconds to prepare an aqueous phase;

[0043] Step 3: adding the oil phase and vortex mixing for 1 minute to prepare the folic acid nanoemulsion.

[0044] Embodiment 2:

[0045] The difference between this embodiment and embodiment 1 is that the folic acid nanoemulsion is prepared by mixing the following raw materials: 10 mg sodium bicarbonate, 1 g ultrapure water, 5.31 g surfactant, 1.77 g cosurfactant, and 22.05 g oil phase, that is, the mass ratio of folic acid is 0.0032%, sodium bicarbonate is 0.032%, ultrapure water is 3.22%, surfactant is 17.26%, cosurfactant is 8.63%, and oil phase is 70.8548%.

[0046] The surfactant is span 60, the co-surfactant is 1,2-propylene glycol, and the oil phase is olive oil.

[0047] In the preparation method, in step 2, folic acid, ultrapure water, sodium bicarbonate, surfactant, and co-surfactant are vortex-mixed for 40 seconds; in step 3, the oil phase is added and vortex-mixed for 50 seconds.

[0048] Embodiment 3:

[0049] The difference between this embodiment and embodiment 1 is that the folic acid nanoemulsion is mixed by the following raw materials: 1.5 mg folic acid, 16 mg sodium bicarbonate, 1.5 g ultrapure water, 5.421 g surfactant, 2.711 g cosurfactant, and 22.36 g oil phase, that is, the mass ratio of folic acid is 0.0047%, sodium bicarbonate is 0.049%, ultrapure water is 4.65%, surfactant is 16.81%, cosurfactant is 8.41%, and oil phase is 70.0763%.

[0050] The surfactant is Span 40, the co-surfactant is polyethylene glycol-200, and the oil phase is corn oil.

[0051] In the preparation method, in step 2, folic acid, ultrapure water, sodium bicarbonate, surfactant, and co-surfactant are vortex-mixed for 50 seconds; in step 3, the oil phase is added and vortex-mixed for 40 seconds.

[0052] Embodiment 4:

[0053] The difference between this embodiment and embodiment 1 is that the folic acid nanoemulsion is mixed by the following raw materials: 1.6 mg folic acid, 16 mg sodium bicarbonate, 1.6 g ultrapure water, 8.63 g surfactant, 4.3 g co-surfactant, and 38.37 g oil phase, that is, the mass ratio of folic acid is 0.003%, sodium bicarbonate is 0.03%, ultrapure water is 3.02%, surfactant is 16.31%, co-surfactant is 8.359%, and oil phase is 72.278%.

[0054] The surfactant is span 83, the co-surfactant is polyethylene glycol-200, and the oil phase is coconut oil.

[0055] In the preparation method, in step 2, folic acid, ultrapure water, sodium bicarbonate, surfactant, and co-surfactant are vortex-mixed for 60 seconds; in step 3, the oil phase is added and vortex-mixed for 45 seconds.

[0056] Embodiment 5:

[0057] The difference between this embodiment and embodiment 1 is that the folic acid nanoemulsion is mixed with the following raw materials: 2 mg folic acid, 20 mg sodium bicarbonate, 2 g ultrapure water, 11.37 g surfactant, 3.79 g cosurfactant, and 44.52 g oil phase, that is, the mass ratio of folic acid is 0.0032%, sodium bicarbonate is 0.0324%, ultrapure water is 3.24%, surfactant is 18.43%, cosurfactant is 6.13%, and oil phase is 72.1644%.

[0058] The surfactant is Span 85, the co-surfactant is 1,2-propylene glycol, and the oil phase is vitamin E.

[0059] In the preparation method, in step 2, folic acid, ultrapure water, sodium bicarbonate, surfactant, and co-surfactant are vortex-mixed for 45 seconds; in step 3, the oil phase is added and vortex-mixed for 45 seconds.

[0060] The folic acid nanoemulsions prepared in Examples 1 to 5 satisfy the following general physicochemical characteristics. Figure 1 The results of potential detection are shown in Figure 2 As shown in ae, the zeta potentials are 10.06±4.74mV, 15.88±5.43mV, 24.49±4.18mV, 28.25±6.27mV, and 32.79±5.89mV, respectively. The results of the particle size distribution and polydispersity index (PDI) tests are shown in Figure 3 As shown in ae, the particle sizes are 30.45±8.78nm, 36.12±4.05nm, 44.32±4.65nm, and 47.46±6.43nm, respectively; the polydispersity coefficients are 0.112, 0.112, 0.105, 0.091, and 0.086, respectively.

[0061] The general conditions for realizing the functions or efficacies of the present invention are as follows: (1) the dosage range of folic acid nanoemulsion mixing feed is 0.02 to 0.05 mg / kg (calculated as folic acid); (2) the sugar content of fruit feed matrix is ​​5%-15%; (3) the culture matrix is ​​dry cow dung and rice straw (1:1, w / w) passed through a 15-mesh sieve, with a humidity of 40%-65% and a thickness of 6 cm; the daylight exposure time is 8h-12h; (4) the characteristics of adult white-spotted flower beetles, female (weight 0.620±0.05g, body length 18.8±0.5mm, body width 10.2±0.5mm), male (weight 0.51±0.05g, body length 19.0±0.5mm, body width 10.0±0.5mm); (5) the male-female ratio is 1:1 and the breeding box is placed in a plastic material breeding box (length 10cm, width 10cm, height 8cm) with a mesh window on the top.

[0062] That is, among the general conditions (1)-(5) for realizing the functions or utilities of the present invention, except for (4) and (5) which are fixed conditions, any change in one or more of the conditions (1)-(3) within the prescribed range can realize the functions of the present invention. For the convenience of description, the functions and utilities of the present invention will be described in the form of specific cases.

[0063] Case 1: Effects of different folic acid dosages:

[0064] The folic acid nanoemulsion described in Example 1 was used, apples were used as the fruit feed matrix, the culture matrix was dry cow dung and rice straw (1:1, w / w) that passed through a 15-mesh sieve, the humidity was 60%, the thickness was 6 cm; the daylight duration was 8 hours. The effects of different doses of folic acid nanoemulsion on the size of the ovaries of the white-star flower beetle during the peak egg-laying period (fifth week) were tested. Specifically, folic acid nanoemulsion group 1 (folic acid dose 0.02 mg / kg) and group 2 (folic acid dose 0.05 mg / kg) were set up, and a blank control group (fed with apples alone) and an auxiliary material control group (except folic acid, the rest of the feeding ingredients were the same as folic acid nanoemulsion group 2) were set up. The statistical results of the average mass of the ovaries of the white-star flower beetle during the peak egg-laying period (fifth week) under different folic acid doses are shown in Table 1, and the comparison of the size of the ovaries of the white-star flower beetle during the peak egg-laying period (fifth week) under different folic acid doses is shown in Table 1. Figure 4 shown.

[0065] Figure 4 The blank control group was fed with apples alone; the supplementary control group (except folic acid, the other ingredients were the same as the 0.05 mg / kg folic acid nanoemulsion group). The effective amount of folic acid in folic acid nanoemulsion group 1 and group 2 was 0.02 mg / kg and 0.05 mg / kg, respectively.

[0066] Table 1 Average ovary weight of white-spotted flower beetles fed apples with different folic acid concentrations during the peak egg-laying period

[0067]

[0068] Note: The data in the table are mean ± standard error. Different lowercase letters after the data in the same column indicate significant differences (P<0.05). The blank control group was fed with apples alone; the auxiliary control group (except folic acid, the other ingredients were the same as folic acid nanoemulsion group 2). The effective folic acid content in apples of folic acid nanoemulsion group 1 and group 2 was 0.02mg / kg and 0.05mg / kg, respectively.

[0069] Case 2: Effects of folic acid nanoemulsions fed with different fruit feed matrices:

[0070] The folic acid nanoemulsion prepared by the method described in Example 2 was mixed with feed (the effective amount of folic acid was 0.03 mg / kg); the culture matrix was dry cow dung and rice straw (1:1, w / w) with a humidity of 60% and a thickness of 6 cm; the daylight duration was 8 hours. The effect of folic acid nanoemulsion on the egg-laying tendency of white star flower beetles was tested under the condition of different fruits (apple, watermelon or peach) as feed matrix. Under the condition that apples were used as the feed matrix, a folic acid nanoemulsion test group (Group A1), an apple control group (A2) fed with apples alone, and an auxiliary material control group (except folic acid, the other feeding ingredients were the same as Group A1 and Group A3) were set up; under the condition that watermelon was used as the feed matrix, a watermelon test group (Group B1), a watermelon control group (Group B2) fed with watermelon alone, and an auxiliary material control group (except folic acid, the other feeding ingredients were the same as Group B1 and Group B3) were set up; under the condition that peach was used as the feed matrix, a peach test group (Group C1), a peach control group (Group C2) fed with peaches alone, and an auxiliary material control group (except folic acid, the other feeding ingredients were the same as Group C1 and Group C3) were set up. In case 2, the egg-laying trend chart of white-spotted flower beetles before and after adding folic acid nanoemulsion to different fruit feed matrices can be obtained as follows Figure 5 As shown ( Figure 5 Groups A1-C1 were the apple, watermelon and peach test groups (the effective folic acid content was 0.03 mg / kg); groups A2-C2 were the auxiliary material control groups (except folic acid, the other ingredients were the same as the corresponding A1-C1); groups A3-C3 were the blank control groups, i.e., they were fed apples, watermelons and peaches alone).

[0071] Case 3: Effect of feeding folic acid nanoemulsion under different humidity culture substrates

[0072] The folic acid nanoemulsion prepared by the method described in Example 3 was fed with apple mix (the effective amount of folic acid was 0.04 mg / kg); the culture substrate was dry cow dung and rice straw (1:1, w / w) passed through a 15-mesh sieve, with a thickness of 6 cm and a daylight exposure time of 10 h. The effect of folic acid nanoemulsion on the number of eggs of the white-spotted flower beetle during the peak period of single female egg-laying (fifth week) under culture substrate conditions of different humidity (40%, 50% and 60%) was tested. Specifically, under the condition of a culture substrate with a humidity of 40%, a folic acid nanoemulsion test group (Group A1), a blank control group fed with apples alone (Group A2), and an auxiliary material control group (except folic acid, the other feeding ingredients are the same as Group A1 and Group A3) were set up; under the condition of a culture substrate with a humidity of 50%, a folic acid nanoemulsion test group (Group B1), a blank control group fed with apples alone (Group B2), and an auxiliary material control group (except folic acid, the other feeding ingredients are the same as Group B1 and Group B3) were set up; under the condition of a culture substrate with a humidity of 50%, a folic acid nanoemulsion test group (Group C1), a blank control group fed with apples alone (Group C2), and an auxiliary material control group (except folic acid, the other feeding ingredients are the same as Group C1 and Group C3) were set up. In the fifth week, a comparison chart of the number of eggs produced by the white-spotted flower beetle at the peak period of single female egg-laying (fifth week) with folic acid nanoemulsion added under different humidity culture substrates can be obtained as shown below. Figure 6 As shown ( Figure 6 A1 is the folic acid nanoemulsion group (the effective amount of folic acid is 0.04 mg / kg); A2 is the blank control group (fed with apples alone), and A3 is the auxiliary material control group (except folic acid, the other ingredients are the same as A1). The grouping design of "B1-B3" and "C1-C3" is the same as "A1-A3").

[0073] Case 4: Effects of folic acid nanoemulsion under different light cycles:

[0074] The folic acid nanoemulsion prepared by the method described in Example 4 was mixed with watermelon for feeding (the effective amount of folic acid was 0.05 mg / kg); the culture matrix was dry cow dung and rice straw (1:1, w / w) through a 15-mesh sieve, and the humidity of the egg-laying matrix was adjusted to 60% and the thickness was 6 cm. The effect of the nanoemulsion on the egg-laying quality under different light cycles (6h, 8h and 12h) was tested. Specifically, under a 6h light cycle, a folic acid nanoemulsion test group, a blank control group fed with watermelon alone, and an auxiliary control group (except folic acid, the rest were the same as the folic acid nanoemulsion test group) were set; under an 8h light cycle, a folic acid nanoemulsion test group, a blank control group fed with watermelon alone, and an auxiliary control group (except folic acid, the rest were the same as the folic acid nanoemulsion test group) were set; under a 12h light cycle, a folic acid nanoemulsion test group, a blank control group fed with watermelon alone, and an auxiliary control group (except folic acid, the rest were the same as the folic acid nanoemulsion test group) were set. In the fifth week, 30 eggs were randomly selected from each group, weighed one by one, and the mean and standard deviation of egg weight in each group were calculated, and the biostatistical differences were compared. The results are shown in Table 2.

[0075] Table 2 Effects of folic acid nanoemulsion on the average egg mass of the white-spotted flower beetle during the peak egg-laying period under different photoperiods

[0076]

[0077] Note: The data in the table are mean ± standard error. Different lowercase letters after the data in the same column represent significant differences (P<0.05). The group design of each light cycle (6h, 8h and 12h) is the same: the blank control group is fed with watermelon alone, the auxiliary material control group (except folic acid, the rest of the ingredients are the same as the folic acid nanoemulsion test group), and the folic acid nanoemulsion test group (folic acid effective amount 0.05mg / kg).

[0078] From Table 1, Table 2 and Figure 4-Figure 6 It can be seen that folic acid nanoemulsion can improve the reproductive performance of female white-spotted flower beetles, greatly promote the development of their ovaries, egg production, and egg quality, and has different improvement effects under different environmental conditions.

[0079] Statistics show that the egg-laying rate of female white-spotted flower beetles fed with fruit feed mixed with folic acid nanoemulsion increased by 5.72%-25.29%. Compared with the existing methods for increasing the egg-laying rate of white-spotted flower beetles, the folic acid nanoemulsion used in the present invention can be efficiently absorbed by the body and converted into a coenzyme, participate in the transfer of one-carbon units in the body, and has a positive effect on the biosynthesis of pyrimidine, purine, nucleic acid and protein and the division and growth of cells, promotes gene expression and the ability of cell division and growth, promotes the restart and maturation of oocyte meiosis, is conducive to the maintenance of good oocyte quality, increases the female ovarian index, and finally achieves an increase in the egg-laying rate of female insects.

[0080] In summary, the folic acid nanoemulsion of the present invention adopts an oil-in-water folic acid nanoemulsion, and the folic acid nanoemulsion droplets have good fat solubility and are easier to pass through the cell membrane phospholipid bilayer structure, thereby increasing the bioavailability of folic acid in female insects; the nanoemulsion droplets have good sustained release performance, which is conducive to prolonging the action time of folic acid in the body, greatly promoting the development of the ovaries of the white-star flower beetle, and achieving an increase in egg production; and by clearly defining the dosage of folic acid nanoemulsion fruit dressing to feed the white-star flower beetle, the female insect can maintain a high reproductive performance under different feeding conditions, and the operability is strong. At the same time, the standardized folic acid nanoemulsion preparation technology is adopted to ensure the consistency of the components and the stability of the effect, and reduce the uncertainty caused by different environments or feeding conditions. Through these innovations, the present invention achieves an increase of 5.72%-25.29% in the egg production of female white-star flower beetles under different environmental conditions, and has a wide range of application prospects.

[0081] The present invention has the following advantages: the prepared folic acid nanoemulsion can effectively increase the number of eggs laid by female insects, and can meet the needs of improving the egg-laying rate under different environmental conditions, and has a wide range of adaptability; in addition, it also exhibits the advantages of few influencing factors, simple operation, environmental friendliness, and low difficulty in implementation.

[0082] It should be noted that the surfactants and co-surfactants of each embodiment of the present invention can use other types of surfactants with HLB values ​​ranging from 3 to 8 or oil-water two-phase surfactants, which can be optimized according to the experimental results of emulsion stability and adult absorption effect; at the same time, in the preparation process of nanoemulsion folic acid nanoemulsion, not only can different types of short-chain alcohols (1,2-propylene glycol, polyethylene glycol 200) be selected as co-surfactants to enhance emulsification stability; different oil sources can also be selected according to actual needs, and other natural plant oils can be used as substitutes, thereby showing different emulsification stabilities under different preparation conditions. Finally, each embodiment of the present invention only uses the self-emulsification method to prepare folic acid nanoemulsions, but in actual operation, high-pressure homogenization, microfluidization, ultrasonic emulsification and other methods can also be used to prepare folic acid nanoemulsions.

[0083] The technical solution provided by the present invention is described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A folic acid nanoemulsion for improving the egg-laying rate of white-spotted flower beetles, characterized in that: The invention comprises the following components in percentage by mass: 0.003%-0.005% of folic acid, 0.02%-0.1% of sodium bicarbonate, 3%-4% of ultrapure water, 16%-19% of surfactant, 6%-9% of auxiliary surfactant and 67.895%-74.977% of oil phase.

2. The folic acid nanoemulsion for improving the egg-laying rate of the white-spotted flower beetle according to claim 1, characterized in that: The surfactant is selected from Span 83, Span 85, Span 60, Span 80 or Span 40.

3. The folic acid nanoemulsion for improving the egg-laying rate of the white-spotted flower beetle according to claim 1, characterized in that: The co-surfactant is a short-chain alcohol.

4. The folic acid nanoemulsion for improving the egg-laying rate of the white-spotted flower beetle according to claim 1, characterized in that: The oil phase adopts natural vegetable oil.

5. The folic acid nanoemulsion for improving the egg-laying rate of the white-spotted flower beetle according to claim 1, characterized in that: The oil phase is rapeseed oil, olive oil, vitamin E, corn oil or coconut oil.

6. The folic acid nanoemulsion for improving the egg-laying rate of the white-spotted flower beetle according to claim 1, characterized in that: The zeta potential of the folic acid nanoemulsion is 10.06-32.79 mv, the polydispersity coefficient is 0.086-0.112, and the particle size distribution range is 30.45-51.74 nm.

7. A method for preparing a folic acid nanoemulsion for improving the egg-laying rate of a white-spotted flower beetle according to any one of claims 1 to 6, characterized in that: The steps include: Weigh the folic acid aqueous solution, surfactant, co-surfactant and oil phase respectively according to the proportion; The folic acid aqueous solution, the surfactant and the co-surfactant are mixed to obtain an aqueous phase; The oil phase is added and mixed to obtain the folic acid nanoemulsion.

8. The method for preparing the folic acid nanoemulsion for improving the egg-laying rate of the white-spotted flower beetle according to claim 7, characterized in that: The zeta potential of the folic acid nanoemulsion is 10.06-32.79 mv, the polydispersity coefficient is 0.086-0.112, and the particle size distribution range is 30.45-51.74 nm.

9. Use of the folic acid nanoemulsion according to any one of claims 1 to 6 in improving the egg-laying rate of the white-spotted flower beetle.

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