Compound feed additive for improving follicular development of replacement gilts and breeding method of replacement gilts

Abstract

The invention discloses a compound feed additive for improving follicular development of replacement gilts and a breeding method of the replacement gilts, and belongs to the field of animal husbandry. The compound feed additive is prepared from betaine hydrochloride, araboxylan, folic acid, dimethyl itaconate and filler; the mass ratio of the compound feed additive in the daily ration of the replacement gilts is 0.9%-1.2%; the multi-channel multi-dimensional synergistic effect of methylation reaction, intestinal tract-reproductive axis signal, cell division and ovarian microenvironment regulation and control is realized by utilizing various components in the compound feed additive, and the follicular quantity and luteal quantity of the replacement gilts can be remarkably increased by adding the compound feed additive into the replacement gilt feed; the feed can be suitable for conventional feed for replacement gilts, is simple to operate and outstanding in effect, and has excellent popularization and application prospects.

Description

Technical Field

[0001] The present invention relates to the field of animal husbandry, and particularly relates to a compound feed additive for improving follicular development of gilts and a feeding method thereof. Background Art

[0002] The reproductive capacity of sows is closely related to the breeding efficiency. Large-scale pig farms use various technical means such as breed improvement, nutrition, and feeding management to improve the reproductive capacity of sows. However, in actual production, due to reproductive disorders such as anestrus, low conception rate, and low litter size, the proportion of sows being culled before the third parity is as high as 35%, and they only provide 25 - 30 weaned piglets throughout their lives. The main reason is that follicular development is blocked. Existing studies have shown that the addition of some functional components has a potential improvement effect on follicular recruitment and maturation. For example, betaine hydrochloride, folic acid, etc. can act as methyl donors and directly participate in fat metabolism, amino acid transfer and regeneration, biosynthesis of purines and pyrimidines, and synthesis of active substances such as creatine, carnitine, and norepinephrine. They play important roles in the nervous system, immune system, urinary system, and cardiovascular system, can effectively reduce the content of homocysteine in the body, relieve oxidative stress, improve body metabolism, and have a potential improvement effect on follicular development. Arabinoxylan, as a prebiotic, can improve the intestinal flora, indirectly affect nutrient absorption and hormone secretion, and can improve follicular development. Dimethyl itaconate, as a cell-permeable itaconate derivative, is prominent in anti-inflammatory and antibacterial aspects, and can reduce Escherichia coli-induced endometritis by increasing the Guanosine-CXCL14 axis. However, current existing technologies mostly rely on single components (such as betaine or folic acid) to regulate follicular development, ignoring the synergistic effects of multiple pathways such as intestinal-reproductive axis signal transduction, cell proliferation and differentiation, and immune regulation during the development of the reproductive system. The association between intestinal flora metabolites (such as short-chain fatty acids) and ovarian function has been confirmed, but existing additives have not systematically integrated prebiotics (such as arabinoxylan) with active ingredients targeting the ovaries (such as folic acid, betaine), resulting in the improvement of intestinal health not being effectively transmitted to follicular development regulation. The compound additive formulations for follicular improvement are mostly simple compoundings of nutritional components, without screening ingredients and optimizing dosages based on the key targets and windows of follicular development.

[0003] Therefore, there is an urgent need for a compound feed additive for improving follicular development of gilts. Summary of the Invention

[0004] The object of the present invention is to overcome the disadvantages of the prior art, and provides a compound feed additive for improving the follicular development of gilts and its feeding method, belonging to the field of animal husbandry. The compound feed additive of the present invention is composed of betaine hydrochloride, arabinoxylan, folic acid, dimethyl itaconate and filler; the mass ratio of the compound feed additive in the diet of gilts is 0.9% - 1.2%; the present invention utilizes various components in the compound feed additive to achieve a multi-path and multi-dimensional synergistic effect of methylation reaction, intestinal-reproductive axis signal, cell division and ovarian microenvironment regulation. Adding this compound feed additive to the feed of gilts can significantly improve the number of follicles and corpus luteum in gilts, and it can be applied to the conventional feed of gilts, with simple operation and outstanding effects, and has excellent prospects for popularization and application.

[0005] To achieve the above technical effects, the following technical solutions are adopted: A compound feed additive for improving the follicular development of gilts, which is composed of betaine hydrochloride, arabinoxylan, folic acid, dimethyl itaconate and filler.

[0006] Further, in the compound feed additive, the mass ratio of betaine hydrochloride, arabinoxylan, folic acid, dimethyl itaconate and filler is 800 - 1000:800 - 1000:4 - 6:1:195; the filler is talcum powder.

[0007] Further, the weight ratio of the compound feed additive in the diet feed of gilts is 0.9% - 1.2%; the diet feed of gilts includes feed for 28 - 70 days old after weaning; feed for 70 - 110 days old; feed for 110 - 150 days old; feed from 150 days old to the breeding period.

[0008] Further, the weight percentage content of the feed formula for 28 - 70 days old after weaning is: corn 59.8%, soybean meal 18.0%, fish meal 3.0%, extruded soybean 5.0%, whey powder 8%, sucrose 2%, soybean oil 1%, calcium carbonate 0.5%, calcium hydrogen phosphate 1.0%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

[0009] Further, the weight percentage content of the feed formula for 70 - 110 days old is: corn 67.9%, soybean meal 25.2%, soybean oil 2.50%, lysine 0.36%, methionine 0.11%, threonine 0.12%, tryptophan 0.01%, calcium carbonate 0.9%, calcium hydrogen phosphate 1.2%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

[0010] Further, the weight percentage content of the feed formula for 110 - 150 - day - old pigs is as follows: corn 71.50%, soybean meal 22.60%, soybean oil 2.10%, lysine 0.31%, methionine 0.06%, threonine 0.05%, tryptophan 0.01%, calcium carbonate 0.89%, calcium hydrogen phosphate 0.78%, salt 0.30%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

[0011] Further, the weight percentage content of the feed for 150 - day - old pigs to breeding period is as follows: corn 63.6%, soybean meal 22.0%, fish meal 2.0%, soybean oil 3.0%, wheat bran 5.4%, calcium carbonate 0.9%, calcium hydrogen phosphate 1.40%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

[0012] Further, each 4.75 g of the trace element premix contains 150 mg of iron, 20 mg of copper, 150 mg of zinc, 30 mg of manganese, 0.3 mg of selenium, 0.3 mg of iodine and the remaining filler talcum powder; each 0.25 g of the vitamin premix contains 16000 IU of vitamin A, 4000 IU of vitamin D3, 80 IU of vitamin E, 2 mg of vitamin K, 0.8 mg of vitamin B1, 6.4 mg of vitamin B2, 2.4 mg of vitamin B6, 0.015 mg of vitamin B12, 14 mg of niacin, 10 mg of pantothenic acid, 1.3 mg of folic acid and the remaining filler talcum powder.

[0013] Further, the feeding method of the compound feed additive is as follows: Thoroughly disinfect the pig house and clean the feeding trough. The pig house adopts natural ventilation assisted by mechanical ventilation; select healthy 28 - day - old weaned gilts with similar body weights. From 28 - day - old weaning to 150 - day - old, freely feed the daily ration containing the compound feed additive; from 150 - day - old to breeding period, limit the feeding amount of the daily ration with the compound feed additive to 2.5 kg / d; from 28 - day - old weaning to 70 - day - old: feed 4 times a day; from 70 - day - old to breeding period: feed 2 times a day, and drink water freely during this period; after 150 - day - old, check the estrus of the replacement gilts twice a day with a boar; check the estrus status of the replacement gilts through vulva observation and back - pressure reaction and record it; other feeding management and pig herd immunization procedures are carried out according to the conventional feeding management procedures of large - scale pig farms.

[0014] Further, the application of the compound feed additive in improving the homocysteine levels in the plasma and follicular fluid of replacement gilts, as well as the number of follicles and corpora lutea.

[0015] The beneficial effects of the present invention are as follows: 1. In terms of action mechanism and principle, by adding a follicle-improving compound feed additive to the diet of replacement gilts, based on the key targets and window periods of follicle development, the proportions of various components are optimized, and various components in the compound feed additive are used to achieve a multi-path and multi-dimensional synergistic effect of methylation reaction, intestinal-reproductive axis signal, cell division, and ovarian microenvironment regulation, breaking through the technical bottleneck of existing simple compounding; adding this compound feed additive to the feed of replacement gilts can significantly increase the number of follicles and corpora lutea, and it can be applied to the conventional feed of replacement gilts; 2. In terms of application mechanism, the strong antioxidant and moisturizing properties of betaine hydrochloride are used to protect folic acid and dimethyl itaconate from thermal processing degradation, and the action time of active ingredients is prolonged through the slow-release effect of arabinoxylan; 3. This follicle-improving compound feed additive is green, safe, and easy to use, and large-scale industrial production can be achieved without complex equipment, with broad application prospects. Specific embodiments

[0016] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0018] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0019] Example 1: 1. Experimental design In this study, a single-factor experimental design was adopted. In the blank control group, 9 g / kg of filler talcum powder was added to the basal diet. In the experimental group, 9 g / kg of follicle-improving compound feed additive was added to the basal diet (each 9 g of follicle-improving compound feed additive contained: 4 g of betaine hydrochloride; 4 g of arabinoxylan; 20 mg of folic acid; 5 mg of dimethyl itaconate, and the rest was 975 mg of filler talcum powder). Among them, betaine hydrochloride (>98%), arabinoxylan (>95%), folic acid (>98%), and dimethyl itaconate (>95%) were used to study the effect of adding follicle-improving compound feed additive to the diet of replacement gilts on follicle development. A total of 320 healthy LY gilts with similar body weights (7.29±0.36 kg) at 28 days of age after weaning were selected and randomly assigned to 1 experimental group, 14 control groups, and 1 blank control group, with 10 replicates in each group and 2 pigs in each replicate. They were fed until slaughter on the 19th day of the third estrus period.

[0020] 2. Feeding and management Before the experiment, the pig house was thoroughly disinfected and the feeding troughs were cleaned. The pig house used natural ventilation assisted by mechanical ventilation. From 28 days to 150 days of age after weaning, the pigs were fed ad libitum with the diet containing follicle-improving compound feed additive; from 150 days of age to the breeding period, the diet containing follicle-improving compound feed additive was restricted (2.5 kg / d); from 28 days to 70 days of age after weaning: fed 4 times a day (8:00, 12:00, 16:00, 20:00), from 70 days of age to the breeding period: fed 2 times a day (8:00 and 16:00), and free drinking water was provided at each stage. After 150 days of age, the replacement gilts were checked for estrus twice a day (9:00 and 16:00) (observing the vulva and the back pressure response) and recorded. Other feeding management and pig herd immunization procedures were carried out according to the conventional feeding management procedures of large-scale pig farms.

[0021] The diet formula for replacement gilts at each stage in experimental group 1 was as follows: The compound feed additive contained 4 g of betaine hydrochloride; 4 g of arabinoxylan; 20 mg of folic acid; 5 mg of dimethyl itaconate per 9 g, and the rest was 975 mg of filler talcum powder; The weight percentage of the feed formula from 28 days to 70 days of age after weaning was: corn 59.8%, soybean meal 18.0%, fish meal 3.0%, extruded soybean 5.0%, whey powder 8%, sucrose 2%, soybean oil 1%, calcium carbonate 0.5%, calcium hydrogen phosphate 1.0%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

[0022] The weight percentages of the feed formula for 70-day-old to 110-day-old are as follows: corn 67.9%, soybean meal 25.2%, soybean oil 2.50%, lysine (98%) 0.36%, methionine (98%) 0.11%, threonine (98%) 0.12%, tryptophan (98%) 0.01%, calcium carbonate 0.9%, calcium hydrogen phosphate 1.2%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

[0023] The weight percentages of the feed formula for 110-day-old to 150-day-old are as follows: corn 71.50%, soybean meal 22.60%, soybean oil 2.10%, lysine (98%) 0.31%, methionine (98%) 0.06%, threonine (98%) 0.05%, tryptophan (98%) 0.01%, calcium carbonate 0.89%, calcium hydrogen phosphate 0.78%, salt 0.30%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

[0024] The weight percentages of the feed from 150-day-old to the breeding period are as follows: corn 63.6%, soybean meal 22.0%, fish meal 2.0%, soybean oil 3.0%, wheat bran 5.4%, calcium carbonate 0.9%, calcium hydrogen phosphate 1.40%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

[0025] Each 4.75 g of the trace element premix contains 150 mg of iron, 20 mg of copper, 150 mg of zinc, 30 mg of manganese, 0.3 mg of selenium, 0.3 mg of iodine, and the remaining filler talc powder; Each 0.25 g of the vitamin premix contains 16000 IU of vitamin A, 4000 IU of vitamin D3, 80 IU of vitamin E, 2 mg of vitamin K, 0.8 mg of vitamin B1, 6.4 mg of vitamin B2, 2.4 mg of vitamin B6, 0.015 mg of vitamin B12, 14 mg of niacin, 10 mg of pantothenic acid, 1.3 mg of folic acid, and the remaining filler talc powder.

[0026] The feed formula for the replacement gilts at each stage in the comparison group 1 is the same as that in the experimental group 1. The only difference is that: betaine hydrochloride is removed from the compound feed additive, and the weight of betaine hydrochloride is distributed to arabinoxylan; folic acid; dimethyl itaconate according to the original ratio of arabinoxylan; folic acid; dimethyl itaconate, ensuring that the total weight of arabinoxylan, folic acid, and dimethyl itaconate in every 9 g of the compound feed additive is 8.025 g.

[0027] The formula of the diets for replacement gilts in each stage of Group 2 was the same as that of Group 1 in Experiment 1. The only difference was that arabinoxylan was removed from the compound feed additive, and the weight of arabinoxylan was distributed to betaine hydrochloride, folic acid, and dimethyl itaconate according to the original ratio, ensuring that the total weight of betaine hydrochloride, folic acid, and dimethyl itaconate in every 9 g of the compound feed additive was 8.025 g.

[0028] The formula of the diets for replacement gilts in each stage of Group 3 was the same as that of Group 1 in Experiment 1. The only difference was that folic acid was removed from the compound feed additive, and the weight of folic acid was distributed to betaine hydrochloride, arabinoxylan, and dimethyl itaconate according to the original ratio, ensuring that the total weight of betaine hydrochloride, arabinoxylan, and dimethyl itaconate in every 9 g of the compound feed additive was 8.025 g.

[0029] The formula of the diets for replacement gilts in each stage of Group 4 was the same as that of Group 1 in Experiment 1. The only difference was that dimethyl itaconate was removed from the compound feed additive, and the weight of dimethyl itaconate was distributed to betaine hydrochloride, arabinoxylan, and folic acid according to the original ratio, ensuring that the total weight of betaine hydrochloride, arabinoxylan, and folic acid in every 9 g of the compound feed additive was 8.025 g.

[0030] The formula of the diets for replacement gilts in each stage of Group 5 was the same as that of Group 1 in Experiment 1. The only difference was that betaine hydrochloride and arabinoxylan were removed from the compound feed additive, and the weight of betaine hydrochloride and arabinoxylan was distributed to folic acid and dimethyl itaconate according to the original ratio, ensuring that the total weight of folic acid and dimethyl itaconate in every 9 g of the compound feed additive was 8.025 g.

[0031] The formula of the diets for replacement gilts in each stage of Group 6 was the same as that of Group 1 in Experiment 1. The only difference was that betaine hydrochloride and folic acid were removed from the compound feed additive, and the weight of betaine hydrochloride and folic acid was distributed to arabinoxylan and dimethyl itaconate according to the original ratio, ensuring that the total weight of arabinoxylan and dimethyl itaconate in every 9 g of the compound feed additive was 8.025 g.

[0032] The formula of the diets for replacement gilts in each stage of Group 7 was the same as that of Group 1 in Experiment 1. The only difference was that betaine hydrochloride and dimethyl itaconate were removed from the compound feed additive, and the weight of betaine hydrochloride and dimethyl itaconate was distributed to arabinoxylan and folic acid according to the original ratio, ensuring that the total weight of arabinoxylan and folic acid in every 9 g of the compound feed additive was 8.025 g.

[0033] The formula of the diet for replacement gilts in each stage of the comparison group 8 is the same as that of the experimental group 1. The only difference is that: arabinoxylan and dimethyl itaconate are removed from the compound feed additive; the weights of arabinoxylan and dimethyl itaconate are distributed to betaine hydrochloride and folic acid according to the original ratio, ensuring that the total weight of betaine hydrochloride and folic acid in every 9 g of the compound feed additive is 8.025 g.

[0034] The formula of the diet for replacement gilts in each stage of the comparison group 9 is the same as that of the experimental group 1. The only difference is that: folic acid and dimethyl itaconate are removed from the compound feed additive; the weights of folic acid and dimethyl itaconate are distributed to betaine hydrochloride and arabinoxylan according to the original ratio, ensuring that the total weight of betaine hydrochloride and arabinoxylan in every 9 g of the compound feed additive is 8.025 g.

[0035] The formula of the diet for replacement gilts in each stage of the comparison group 10 is the same as that of the experimental group 1. The only difference is that: arabinoxylan and folic acid are removed from the compound feed additive; the weights of arabinoxylan and folic acid are distributed to betaine hydrochloride and dimethyl itaconate according to the original ratio, ensuring that the total weight of betaine hydrochloride and dimethyl itaconate in every 9 g of the compound feed additive is 8.025 g.

[0036] The formula of the diet for replacement gilts in each stage of the comparison group 11 is the same as that of the experimental group 1. The only difference is that: betaine hydrochloride, arabinoxylan and folic acid are removed from the compound feed additive, and only dimethyl itaconate is retained; the total weight of dimethyl itaconate in every 9 g of the compound feed additive is 8.025 g.

[0037] The formula of the diet for replacement gilts in each stage of the comparison group 12 is the same as that of the experimental group 1. The only difference is that: betaine hydrochloride, arabinoxylan and dimethyl itaconate are removed from the compound feed additive, and only folic acid is retained; the total weight of folic acid in every 9 g of the compound feed additive is 8.025 g.

[0038] The formula of the diet for replacement gilts in each stage of the comparison group 13 is the same as that of the experimental group 1. The only difference is that: betaine hydrochloride, folic acid and dimethyl itaconate are removed from the compound feed additive, and only arabinoxylan is retained; the total weight of arabinoxylan in every 9 g of the compound feed additive is 8.025 g.

[0039] The formula of the diet for replacement gilts in each stage of the comparison group 14 is the same as that of the experimental group 1. The only difference is that: arabinoxylan, folic acid and dimethyl itaconate are removed from the compound feed additive, and only betaine hydrochloride is retained; the total weight of betaine hydrochloride in every 9 g of the compound feed additive is 8.025 g.

[0040] The formula of the diet for the replacement gilts at each stage in the blank control group was the same as that in experimental group 1. The only difference was that: in the blank control group, 9 g / kg of filler talcum powder was added to the basal diet to replace the compound feed additive in experimental group 1.

[0041] 3. Data statistics All data statistical analyses were completed using ANOVA in SPSS software (Version 20.0; IBM Corp., Armonk, NY, US). One-way analysis of variance was used, and multiple comparisons were performed using the Duncan method. The results were expressed as mean ± standard deviation, and P < 0.05 indicated a significant difference. Table 1 shows the results of the numbers of large, medium, and small follicles and corpora lutea in the sows in the experimental group, the comparison group, and the blank control group.

[0042] Table 1 Results of the numbers of large, medium, and small follicles and corpora lutea in the sows in each group Note: The data were expressed as mean ± standard deviation. Values with different letters in the same column indicated a significant difference (P < 0.05). As can be seen from Table 1, adding the compound feed additive to the diet of replacement gilts significantly increased the numbers of large and medium follicles and corpora lutea, indicating that adding the compound feed additive improved the follicular development of replacement gilts. The formula lacking one or more components of the present invention, at the same dosage, had much worse follicular development in replacement gilts than the compound feed additive of the present invention, indicating that each component in the compound feed additive of the present invention was indispensable. Through the multi-path and multi-dimensional synergistic effect of methylation reaction, intestinal-reproductive axis signal, cell division, and ovarian microenvironment regulation among the components, adding this compound feed additive to the feed of replacement gilts could greatly increase the numbers of follicles and corpora lutea in replacement gilts.

[0043] In summary, the present invention discloses a compound feed additive for improving the follicular development of replacement gilts and its feeding method, belonging to the field of animal husbandry. The compound feed additive of the present invention is composed of betaine hydrochloride, arabinoxylan, folic acid, dimethyl itaconate, and filler; the mass ratio of the compound feed additive in the diet of replacement gilts is 0.9% - 1.2%; the present invention utilizes various components in the compound feed additive to achieve the multi-path and multi-dimensional synergistic effect of methylation reaction, intestinal-reproductive axis signal, cell division, and ovarian microenvironment regulation. Adding this compound feed additive to the feed of replacement gilts can significantly increase the numbers of follicles and corpora lutea, and it can be applied to the conventional feed of replacement gilts. It has simple operation and outstanding effects, and has excellent prospects for popularization and application.

[0044] At this point, those skilled in the art will recognize that although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the disclosed content of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A compound feed additive for improving the follicular development of replacement gilts, characterized in that The compound feed additive is composed of betaine hydrochloride, arabinoxylan, folic acid, dimethyl itaconate and a filler.

2. A compound feed additive for improving follicular development of gilts, as described in claim 1, wherein, In the compound feed additive, the mass ratio of betaine hydrochloride, arabinoxylan, folic acid, dimethyl itaconate and the filler is 800 - 1000:800 - 1000:4 - 6:1:195; the filler is talcum powder.

3. A compound feed additive for improving the follicular development of gilts as described in claim 1, characterized in that, The weight proportion of the compound feed additive in the diet of gilts is 0.9% - 1.2%; the diet of gilts includes feed for 28 - 70 days old after weaning; feed for 70 - 110 days old; feed for 110 - 150 days old; feed for 150 days old to breeding period.

4. A compound feed additive for improving the follicular development of gilts as described in claim 3, characterized in that The weight percentage of the feed formula for 28 - 70 days old after weaning is: corn 59.8%, soybean meal 18.0%, fish meal 3.0%, extruded soybean 5.0%, whey powder 8%, sucrose 2%, soybean oil 1%, calcium carbonate 0.5%, calcium hydrogen phosphate 1.0%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

5. A compound feed additive for improving follicular development of replacement gilts as described in claim 3, characterized in that, The weight percentage of the feed formula for 70 - 110 days old is: corn 67.9%, soybean meal 25.2%, soybean oil 2.50%, lysine 0.36%, methionine 0.11%, threonine 0.12%, tryptophan 0.01%, calcium carbonate 0.9%, calcium hydrogen phosphate 1.2%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

6. A compound feed additive for improving the follicular development of gilts as described in claim 3, characterized in that, The weight percentage of the feed formula for 110 - 150 days old is: corn 71.50%, soybean meal 22.60%, soybean oil 2.10%, lysine 0.31%, methionine 0.06%, threonine 0.05%, tryptophan 0.01%, calcium carbonate 0.89%, calcium hydrogen phosphate 0.78%, salt 0.30%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

7. A compound feed additive for improving follicular development of gilts as described in claim 3, characterized in that, The weight percentage of the feed for 150 days old to breeding period is: corn 63.6%, soybean meal 22.0%, fish meal 2.0%, soybean oil 3.0%, wheat bran 5.4%, calcium carbonate 0.9%, calcium hydrogen phosphate 1.40%, salt 0.3%, trace element premix 0.475%, vitamin premix 0.025%, compound feed additive 0.9%.

8. A compound feed additive for improving the follicular development of replacement gilts according to any one of claims 4-7, characterized in that Each 4.75 g of the trace element premix contains 150 mg of iron, 20 mg of copper, 150 mg of zinc, 30 mg of manganese, 0.3 mg of selenium, 0.3 mg of iodine, and the remaining filler talcum powder; each 0.25 g of the trace element premix contains 16,000 IU of vitamin A, 4,000 IU of vitamin D3, 80 IU of vitamin E, 2 mg of vitamin K, 0.8 mg of vitamin B1, 6.4 mg of vitamin B2, 2.4 mg of vitamin B6, 0.015 mg of vitamin B12, 14 mg of niacin, 10 mg of pantothenic acid, 1.3 mg of folic acid, and the remaining filler talcum powder.

9. A compound feed additive for improving the follicular development of gilts, as described in claim 1, wherein The feeding method of the compound feed additive is as follows: Thoroughly disinfect the pigsty and clean the feed trough. The pigsty uses natural ventilation assisted by mechanical ventilation; select healthy weaned gilts at 28 days of age with similar body weights. From 28 days to 150 days of age after weaning, freely feed the daily ration containing the compound feed additive; from 150 days of age to the breeding period, limit the feeding of the daily ration of the compound feed additive to 2.5 kg / d; from 28 days to 70 days of age after weaning: feed 4 times a day; from 70 days of age to the breeding period: feed 2 times a day, and drink water freely during this period; after 150 days of age, check the estrus of the replacement gilts twice a day with a boar; check the estrus status of the replacement gilts through vulva observation and back pressure reaction and record; other feeding management and herd immunization procedures are carried out according to the conventional feeding management procedures of large-scale pig farms.

10. A compound feed additive for improving the follicular development of gilts, as described in any one of claims 1 - 3, characterized in that, The application of the compound feed additive in improving the number of follicles and corpora lutea in replacement gilts.

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