A feed containing astragalus polysaccharide and a preparation method thereof

Abstract

The application discloses a feed containing astragalus polysaccharide and a preparation method thereof, and belongs to the feed field. The application can effectively alleviate the adverse effects of heat stress on female rabbits by adding astragalus polysaccharide in the basic feed, and can improve the conception rate, the number of live kits per litter and the average weight of live kits of the female rabbits, so that the breeding performance is optimized, the growth of kits is promoted, and the economic benefits of breeding are improved. The feed prepared by the application can effectively improve the serum hormone level of animals and reduce the inflammatory factor level, and effectively improve the diversity of intestinal microorganisms of animals under heat stress, so as to provide a scientific basis for precise feeding management of rabbits in summer, and also provide an important reference for the application of astragalus polysaccharide in the field of stress resistance of livestock and poultry.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of feed, and particularly relates to a feed containing astragalus polysaccharide and a preparation method thereof. BACKGROUND

[0002] In a high-temperature and high-humidity environment, when the heat metabolism balance of livestock and poultry is broken, heat stress reaction is easily triggered. Compared with other domestic animals, rabbits are more sensitive to heat stress due to physiological structural characteristics. High-temperature environment not only significantly inhibits the feed intake of rabbits, but also has a significant negative impact on their overall production performance. Heat stress can cause the increase of oxidative stress level and inflammation level, leading to the decrease of estrus rate and fertility rate of does, abnormal placental function and restricted fetal growth and development.

[0003] The improvement of reproductive performance of does is crucial to the rabbit breeding industry, and the heat accumulation of does in a high-temperature environment becomes a key factor limiting their reproductive performance, which poses a significant threat to summer rabbit production. When the environmental temperature exceeds the critical threshold, rabbits will start the heat stress compensation mechanism, causing problems such as reproductive hormone secretion disorder and embryo implantation disorder. Heat stress can cause the decrease of reproductive capacity of does, embryo survival rate and litter size, thereby affecting the lactation performance of does. Studies have shown that high temperature can lead to the increase of ROS content in follicles, causing the apoptosis of granulosa cells (GCs), thereby damaging the structure of oocytes, weakening the quality of oocytes and the in vitro maturation and fertilization capacity. At the same time, the increase of ROS also affects the growth and maturation of oocytes, causes massive apoptosis of ovarian cells, thereby inhibiting follicle development, ultimately affecting the reproductive performance of rabbits, leading to a 30%-50% decrease in fertility rate, a 2-3 decrease in litter size, and a heat stroke mortality rate of more than 15% in extreme cases, which seriously restricts the economic benefits of the industry. At the same time, in a high-temperature environment, the animal body will redistribute blood to enhance heat dissipation, leading to insufficient blood supply to internal organs (such as mammary glands, ovaries and uterus) of pregnant does, and the lack of oxygen causes fetal development to be hindered, leading to an increase in early embryo mortality. In addition, heat stress also reduces mammary blood flow, inhibits mammary gland development, reduces lactation performance, and further affects milk production by reducing dry matter intake and nutrient absorption.

[0004] In intensive breeding in high-temperature seasons, breaking the inhibition of heat stress on the reproductive performance of does has become a key focus of the industry. Traditional cooling management methods have defects such as large equipment investment (the cost of cooling per square meter increases by 40-60 yuan), poor maintenance effect (the temperature in the shed is only reduced by 2-3℃), and are difficult to meet the needs of large-scale production. Therefore, it is of urgent practical significance to seek a new type of low-cost and high-benefit nutritional intervention scheme. SUMMARY

[0005] The technical problem solved by the present application is to provide a feed containing astragalus polysaccharide and a preparation method thereof, so as to solve the technical problem of reduced reproductive capacity of animals in a heat stress state.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is to provide a feed containing astragalus polysaccharide, which is prepared by mixing a basic feed and astragalus polysaccharide at a mass ratio of 1 kg: 200-1000 mg. The basic feed is prepared by using raw materials in a weight ratio of 10-18 parts of corn, 2-6 parts of secondary powder, 6-9 parts of bran, 4-8 parts of sheep grass, 10-20 parts of wine lees, 2-8 parts of peanut shell, 8-12 parts of soybean meal, 0.3-0.7 parts of soybean oil, 2-8 parts of white arborvitae, 7-10 parts of malt root, 2-8 parts of palm cake, 6-9 parts of rice husk, 5-10 parts of peanut stem powder and 4-6 parts of premix.

[0007] On the basis of the above technical scheme, the present application can also be improved as follows:

[0008] Further, the feed is prepared by mixing the basic feed and astragalus polysaccharide at a mass ratio of 1 kg: 400 mg.

[0009] Further, the basic feed is prepared by using raw materials in a weight ratio of 14 parts of corn, 4 parts of secondary powder, 7.6 parts of bran, 6 parts of sheep grass, 15 parts of wine lees, 5 parts of peanut shell, 10 parts of soybean meal, 0.5 parts of soybean oil, 5 parts of white arborvitae, 8.5 parts of malt root, 5 parts of palm cake, 7.3 parts of rice husk, 7 parts of peanut stem powder and 5.1 parts of premix.

[0010] Further, the basic feed is prepared by using raw materials in a weight ratio of 10 parts of corn, 2 parts of secondary powder, 6 parts of bran, 8 parts of sheep grass, 20 parts of wine lees, 8 parts of peanut shell, 8 parts of soybean meal, 0.3 parts of soybean oil, 8 parts of white arborvitae, 10 parts of malt root, 2 parts of palm cake, 6 parts of rice husk, 10 parts of peanut stem powder and 6 parts of premix.

[0011] Further, the basic feed is prepared by using raw materials in a weight ratio of 18 parts of corn, 6 parts of secondary powder, 9 parts of bran, 4 parts of sheep grass, 10 parts of wine lees, 2 parts of peanut shell, 12 parts of soybean meal, 0.7 parts of soybean oil, 2 parts of white arborvitae, 7 parts of malt root, 8 parts of palm cake, 9 parts of rice husk, 5 parts of peanut stem powder and 4 parts of premix.

[0012] Further, the premix includes Fe 50-100 mg, Cu 10-30 mg, Zn 50-100 mg, Mn 5-15 mg, Co 0.1-0.2 mg, I 0.1-0.3 mg, Se 0.2-0.3 mg, VA 9000-11000 IU, VD 800-1000 IU, VE 30-70 mg, VK 1-3 mg, VB1 1-3 mg, VB2 4-8 mg, VB5 30-70 mg, VB6 1-3 mg, VB12 0.1-0.3 mg, and the like.12 0.01-0.03mg, VB3 30-70mg, VB9 30-60mg, VB4 900-1100mg and VB7 0.1-0.3mg.

[0013] Further, per kg of premix includes: Fe 70mg, Cu 20mg, Zn 70mg, Mn 10mg, Co 0.15mg, I 0.2mg, Se 0.25mg, VA 10000IU, VD 900IU, VE 50mg, VK 2mg, VB1 2mg, VB2 6mg, VB5 50mg, VB6 2mg, VB9 4 4mg, VB4 1000mg and VB7 0.2mg. 12 0.02mg, VB3 50mg, VB9 44mg, VB4 1000mg and VB7 0.2mg.

[0014] The application further discloses a preparation method of the feed containing the astragalus polysaccharide, and the method comprises the following steps: crushing the dandelion, white aspen and rice husk, and then uniformly mixing the crushed dandelion, white aspen and rice husk with the remaining raw materials to obtain the feed containing the astragalus polysaccharide.

[0015] The application has the following beneficial effects:

[0016] 1. By adding the astragalus polysaccharide (APS) in the basic feed, the adverse effects of heat stress on the does can be effectively alleviated, the conception rate, the number of live kits per litter and the average weight of live kits of the does can be improved, the breeding performance is optimized, the growth of kits is promoted, the economic benefits of breeding are improved, and an effective nutritional regulation strategy for meat rabbit breeding in summer is provided.

[0017] 2. By adding the astragalus polysaccharide (APS) in the basic feed, the levels of progesterone (P), estradiol (E2) and IL-10 in the serum of the breeding does can be significantly improved, and the level of IL-6 can be significantly reduced, so that the inflammatory reaction caused by heat stress is effectively alleviated, and the adverse effects of heat stress on the does are reduced.

[0018] 3. By adding the astragalus polysaccharide (APS) in the basic feed, the intestinal microbial diversity of the does under heat stress can be effectively improved, the intestinal microbial community and SCFAs can be well regulated, the abundance of beneficial bacteria (such as the Firmicutes, Bacteroides and Akkermansia) can be increased, and the intestinal microecological balance can be optimized. By promoting the synthesis of SCFAs (especially acetic acid, propionic acid and butyric acid), the APS enhances the intestinal mucosal barrier function, exhibits anti-inflammatory activity, relieves the imbalance of intestinal flora, barrier damage and metabolic disorder induced by heat stress, and reduces the health risk, thereby providing a theoretical basis for the application of the APS in the animal husbandry to improve the intestinal health of animals and improve the production performance. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1For rabbit house temperature and humidity index data;

[0020] Figure 2 For heat stress state statistics chart;

[0021] Figure 3 For the concentration of progesterone (P) in the serum of pregnant rabbits on the 15th day of pregnancy under heat stress;

[0022] Figure 4 For the concentration of estradiol (E2) in the serum of pregnant rabbits on the 15th day of pregnancy under heat stress

[0023] Figure 5 For the concentration of IL-10 in the serum of pregnant rabbits on the 15th day of pregnancy under heat stress;

[0024] Figure 6 For the concentration of IL-6 in the serum of pregnant rabbits on the 15th day of pregnancy under heat stress;

[0025] Figure 7 For intestinal flora Venn diagram;

[0026] Figure 8 For intestinal sample PCoA cluster analysis;

[0027] Figure 9 For the effect of different doses of APS on the relative abundance of rabbit intestinal flora at the door level;

[0028] Figure 10 For the effect of heat stress and astragalus polysaccharide on the relative abundance of Bacteroides at the genus level Bacteroides ;

[0029] Figure 11 For the effect of heat stress and astragalus polysaccharide on the relative abundance of Streptococcus at the genus level Ruminococcus ;

[0030] Figure 12 For the effect of heat stress and astragalus polysaccharide on the relative abundance of Anaeroplasma at the genus level Alistipes ;

[0031] Figure 13 For the effect of heat stress and astragalus polysaccharide on the relative abundance of V9D2013 flora at the genus level V9D2013_group ;

[0032] Figure 14 For the effect of heat stress and astragalus polysaccharide on the relative abundance of Saccharomonospora at the genus level Candidatus_Saccharimonas ;

[0033] Figure 15 For the effect of heat stress and astragalus polysaccharide on the relative abundance of Akkermansia at the genus level Akkermansia ;

[0034] Figure 16 For heat stress and the effect of Astragalus polysaccharide on the NK4A136 group of Trichophyton spp. ( Lachnospiraceae_NK4A136_group Figure 17 The influence of relative abundance values;

[0035] Rikenellaceae_RC9_gut_group For heat stress and the effect of Astragalus polysaccharide on the intestinal flora of the RC9 family at the genus level ( Figure 18 Figure 19 The influence of relative abundance values;

[0036] Figure 20 LEfEse analysis chart;

[0037] Figure 21 A clade diagram of species evolution;

[0038] Figure 1 The Spearman correlation coefficient;

[0039] Figure 2 The results show the association between gut microbiota and short-chain fatty acids. Detailed Implementation

[0040] The specific embodiments of the present invention are described below to facilitate understanding of the invention by those skilled in the art. Unless otherwise specified, specific conditions are applied according to conventional conditions or the manufacturer's recommendations. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various modifications are obvious as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims. All inventions utilizing the concept of this invention are protected.

[0041] Example 1

[0042] A feed containing astragalus polysaccharide is prepared by mixing the basal diet and astragalus polysaccharide at a mass ratio of 1 kg: 400 mg. The raw materials used in the basal diet include, by weight, 12 parts corn, 5 parts wheat middlings, 5 parts corn husks, 8.5 parts wheat bran, 1.5 parts soybean oil, 14 parts soybean meal, 6 parts rapeseed meal, 9 parts dark brewer's grains, 6.5 parts corn germ meal, 1.5 parts artemisia annua powder, 6 parts rice husk powder, 5 parts peanut shell powder, 7 parts white yam powder, 8 parts alkali grass, and 5 parts premix.

[0043] Fe 70mg, Cu 20mg, Zn 70mg, Mn 10mg, Co 0.15mg, I 0.2mg, Se 0.25mg, VA 10000IU, VD 900IU, VE 50mg, VK 2mg, VB1 12mg, VB2 6mg, VB5 50mg, VB6 2mg, VB3 50mg, VB9 44mg, VB4 1000mg and VB7 0.2mg. 12 0.02mg, VB3 50mg, VB9 44mg, VB4 1000mg and VB7 0.2mg.

[0044] Example 2

[0045] A feed containing Astragalus polysaccharide, the feed being a basic feed and Astragalus polysaccharide mixed in a mass ratio of 1 kg: 200mg, the raw materials used in the basic feed including, by weight: corn 10 parts, secondary powder 3 parts, corn husk 3 parts, wheat bran 5 parts, soybean oil 0.5 parts, soybean meal 20 parts, rapeseed meal 9 parts, black beer lees 12 parts, corn germ meal 8 parts, artemisia vulgaris powder 2.5 parts, rice hull powder 3 parts, peanut shell powder 3 parts, white armand pine powder 10 parts, alkali grass 10 parts and premix 7 parts.

[0046] Fe 50mg, Cu 10mg, Zn 50mg, Mn 15mg, Co 0.2mg, I 0.3mg, Se 0.3mg, VA 9000IU, VD 800IU, VE 70mg, VK 1mg, VB1 11mg, VB2 4mg, VB5 30mg, VB6 3mg, VB3 70mg, VB9 60mg, VB4 1100mg and VB7 0.3mg. 12 0.03mg, VB3 70mg, VB9 60mg, VB4 1100mg and VB7 0.3mg.

[0047] Example 3

[0048] A feed containing Astragalus polysaccharide, the feed being a basic feed and Astragalus polysaccharide mixed in a mass ratio of 1 kg: 1000mg, the raw materials used in the basic feed including, by weight: corn 15 parts, secondary powder 7 parts, corn husk 7 parts, wheat bran 10 parts, soybean oil 2.5 parts, soybean meal 10 parts, rapeseed meal 3 parts, black beer lees 6 parts, corn germ meal 5 parts, artemisia vulgaris powder 0.5 parts, rice hull powder 9 parts, peanut shell powder 7 parts, white armand pine powder 5 parts, alkali grass 5 parts and premix 3 parts.

[0049] Fe 100mg, Cu 30mg, Zn 100mg, Mn 5mg, Co 0.1mg, I 0.1mg, Se 0.2mg, VA 11000IU, VD 1000IU, VE 30mg, VK 3mg, VB1 3mg, VB2 8mg, VB5 70mg, VB6 1mg, VB3 70mg, VB9 60mg, VB4 1100mg and VB7 0.3mg.12 0.01 mg, VB3 30 mg, VB9 30 mg, VB4 900 mg and VB7 0.1 mg.

[0050] Comparative Example

[0051] The difference between this comparative example and Example 1 is that Astragalus polysaccharide (APS) is omitted, and the remaining components are the same as in Example 1, to prepare a basic feed ration.

[0052] Experimental Example 1

[0053] 460 body weight, similar to the number of times of pregnancy of Ila rabbit as the test object, and randomly divided into 5 groups (each group contains 92), respectively:

[0054] (1) Control group (CON group): feeding the basic feed prepared in the comparative example;

[0055] (2) APS200 group: feeding the basic feed prepared in the comparative example + 200 mg / kg APS;

[0056] (3) APS400 group: feeding the basic feed prepared in the comparative example + 400 mg / kg APS;

[0057] (4) APS800 group: feeding the basic feed prepared in the comparative example + 800 mg / kg APS;

[0058] (5) APS1000 group: feeding the basic feed prepared in the comparative example + 1000 mg / kg APS.

[0059] From the day when the rabbit house was increased in light (i.e. 6 days before mating), the calculation was started, at which time the corresponding feed was fed to the rabbits in each test group, and lasted until the 35th day after the rabbit gave birth, with a total period of 71 days. The nutritional level of the basic feed used is shown in Table 1.

[0060] Table 1 Nutritional level of basic feed for does (dry basis)

[0061]

[0062] This test uses a 42-day breeding mode, i.e. the does are mated 12 days after giving birth. On the day of mating, artificial insemination technology is used to mate the does; 15 days after mating, the pregnancy status of the does is confirmed by touch examination, and the conception rate is calculated; when the does enter the delivery stage, multiple indexes including reproductive performance are recorded in detail, and the growth performance indexes of the offspring rabbits are subsequently calculated.

[0063] 1. Evaluation of heat stress state

[0064] (1) Determination of temperature and humidity index

[0065] A temperature and humidity recorder was placed inside the rabbit hutch to automatically collect temperature and humidity data. Data was recorded every 30 minutes from the day of mating until the does gave birth. Temperature and humidity values ​​at 14:00, 16:00, and 18:00 daily were selected. The Temperature and Humidity Index (THI) was calculated based on the dry-bulb temperature and relative humidity values ​​using the following formula:

[0066] THI=db-[(0.31-0.31RH)(db-14.4)];

[0067] Where THI is the temperature and humidity index (%), db is the dry-bulb temperature (°C), and RH is the relative humidity (%).

[0068] (2) Test results

[0069] Temperature and humidity index (THI) data as follows Figure 3 As shown. The heat stress threshold (THI) for rabbits is 27.8. Based on the THI assessment value, the degree of heat stress faced by rabbits is divided into the following categories:

[0070] When THI < 27.8, the rabbit was not under heat stress.

[0071] When 27.8 ≤ THI < 28.9, it indicates that the rabbit is in a state of mild heat stress.

[0072] When 28.9 ≤ THI < 30.0, the rabbit is in a state of moderate heat stress;

[0073] When THI ≥ 30.0, the rabbit is in a state of severe heat stress.

[0074] If the test environment is deemed to meet the test conditions for heat stress, then the test environment is considered to be in a state of heat stress if the test conditions are met for more than 50% of the time during the entire test period.

[0075] Depend on Figure 4 It can be seen that during the entire experiment, the female rabbits were in a state of mild heat stress for 3.33% of the time, in a state of moderate heat stress for 26.67% of the time, and in a state of severe heat stress for 50% of the time. This indicates that the female rabbits experienced different degrees of heat stress for as much as 80% of the time, far exceeding 50%. Therefore, it can be clearly determined that the conditions of this experiment met the criteria for heat stress, laying the foundation for subsequent research on the effects of heat stress on female rabbits.

[0076] 2. Effects of Astragalus Polysaccharide on the Reproductive Performance of Female Rabbits

[0077] (1) Determination of reproductive performance of female rabbits

[0078] The estrus of the female rabbits was induced by light on the first day of the pre-feeding period. After the female rabbits showed estrus, the mating was performed by artificial insemination on the first day of the test period, and the number of female rabbits participating in mating was recorded. On the 15th day after mating, the pregnancy of the female rabbits was determined by palpation, and the pregnancy rate of each group was recorded. After the female rabbits finished giving birth, the number of litters and the number of live litters were recorded, as well as the total weight of the litters and the total weight of the live litters, and the number of dead fetuses, and other reproductive performance indicators. Among them, the pregnancy rate refers to the proportion of female rabbits that actually successfully conceived after mating, and the farrowing rate is the proportion of female rabbits that actually gave birth after pregnancy, and the specific calculation formula is as follows:

[0079] A= (a / m) x 100%;

[0080] B= (b / m) x 100%;

[0081] Among them, A is the pregnancy rate, %; a is the number of pregnant female rabbits, only; m is the number of mating female rabbits, only; B is the farrowing rate, %; b is the number of female rabbits that gave birth, only.

[0082] (2) Test results

[0083] The data of the reproductive performance of the female rabbits is shown in Table 2.

[0084] Table 2 Effect of adding Astragalus polysaccharides during the whole pregnancy period on the reproductive performance of female rabbits under heat stress

[0085]

[0086] Note: Different lowercase letters after the values in the same row in the table indicate significant differences, P <0.05; control group (basal diet), APS200 group (basal diet + 200 mg / kg APS), APS400 group (basal diet + 400 mg / kg APS), APS800 group (basal diet + 800 mg / kg APS), APS1000 group (basal diet + 1000 mg / kg APS).

[0087] From the data in Table 2, compared with the control group, the pregnancy rate of the female rabbits fed with 200, 400, 800 and 1000 mg / kg APS in the feed was significantly increased by P <0.05) 15.53%, 16.03%, 13.97% and 20.91%. In addition, the farrowing rate of the APS400 and APS800 groups was significantly improved P <0.05), increased by 21.64% and 18.59% respectively, while the other groups had no significant difference with the control group. The number of litters in each test group was significantly higher than that in the control group P<0.05), increased by 0.31, 0.85, 0.62 and 0.42, respectively; the number of live births also increased, by 0.33, 0.83, 0.63 and 0.40, respectively; the number of dead births in each group showed no significant difference. At the same time, the total litter weight and live litter weight of all test groups were significantly improved compared with the control group P <0.05). In the APS400 and APS800 groups, the average weight of the first live birth was significantly improved P <0.05).

[0088] Since the number of live births and the average weight of live births are important indicators of the production efficiency of a rabbit farm, from the above results, it can be seen that the addition of 400 mg / kg APS to the feed can significantly improve the reproductive performance indicators of the mother rabbit under heat stress conditions P <0.05), indicating that 400 mg / kg is the optimal amount for relieving heat stress.

[0089] 3. Effect of Astragalus polysaccharides on the growth of baby rabbits

[0090] (1) Determination of baby rabbit growth performance

[0091] Baby rabbits were evenly distributed to each nest after birth. Hair growth began at 5 days after birth; the eyes of baby rabbits opened at 12 days; and weaning occurred at 35 days. The number of nestlings and the total weight of nestlings at 7 days, 14 days, 21 days and 35 days were recorded, and the average weight was calculated accordingly.

[0092] (2) Test results

[0093] The data of baby rabbit growth performance are shown in Table 3.

[0094] Table 3 Effect of Astragalus polysaccharides added throughout pregnancy on the growth of baby rabbits under heat stress

[0095]

[0096] Note: Different lowercase letters after the values in the same row in the table indicate significant differences, P <0.05.

[0097] As can be seen from Table 3, at 7 days of age, the number of nests and the weight of baby rabbits in each test group were significantly improved compared with the control group P <0.05), the average weight of baby rabbits in the APS400 and APS800 groups was also significantly increased P< 0.05). At 14 days, the weight of baby rabbits in the four test groups and the average weight were significantly improved compared with the control group P <0.05). By 21 days, the weight of baby rabbits in each test group was significantly increased P<0.05), and the average weight of the kits in the APS400, APS800 and APS1000 groups was also significantly improved P < 0.05). Until the weaning day at 35 days, the litter weight and average weight of the kits in each test group were significantly improved compared with the control group P <0.05, indicating that APS at a dose of 400 mg / kg significantly promoted the growth of kits under heat stress.

[0098] From the first day of pregnancy to the weaning period of the kits, the addition of APS significantly improved the growth performance of the kits, especially at 7s, 14d, 21d and 35d, the litter weight and average weight of the kits in the APS400 group were significantly improved. In addition, the feed intake of the does in the 400 and 800 mg / kg APS groups during the early and middle stages of pregnancy and the lactation period was significantly improved compared with the control group and other test groups. Combined with the reproductive performance and growth data of the kits, the 400 mg / kg APS group showed the best performance. Therefore, the addition of 400 mg / kg APS in the diet can significantly improve the reproductive performance and growth performance of the offspring.

[0099] 4. Effect of Astragalus polysaccharides on the feed intake of does

[0100] (1) Record of the feed intake of does

[0101] The feed intake of does was recorded in stages during the early pregnancy (from the 0th day to the 10th day of pregnancy), the middle pregnancy (from the 11th day to the 20th day of pregnancy), the late pregnancy (from the 21st day to the 30th day of pregnancy) and the lactation period. The daily feed intake was the sum of the weight of the test feed fed in the afternoon and the weight of the feed supplemented the next morning.

[0102] (2) Test results

[0103] The data of the feed intake of does is shown in Table 4.

[0104] Table 4 Effect of the addition of Astragalus polysaccharides on the feed intake of does under heat stress

[0105]

[0106] Note: Different lowercase letters after the same row values in the table indicate significant differences, P <0.05.

[0107] As can be seen from Table 4, after the addition of Astragalus polysaccharides, the feed intake of does during the early and middle stages of pregnancy and the average daily feed intake during the pregnancy period were significantly improved P< 0.05); during the late pregnancy, the feed intake of the APS400 and APS800 groups was significantly increased P<0.05); During lactation, the feed intake of the APS400, APS800, and APS1000 groups was significantly higher than that of the control group ( P< (0.05). The experimental results show that APS has a significant promoting effect on improving feed intake in female rabbits.

[0108] Experiment Example 2

[0109] At 8:00 AM on the 15th day of gestation in female rabbits, ear vein blood was collected from 6 female rabbits randomly selected from each group. The serum was then collected by centrifugation at 2500 rpm for 10 minutes and used to detect P, E2, IL-6 and IL-10 levels.

[0110] The manufacturers of the reagents used in the testing are shown in Table 5.

[0111] Table 5. Information on reagent manufacturers

[0112]

[0113] 1. Effects of APS on serum sex hormones in female rabbits on day 15 of pregnancy

[0114] During pregnancy, the levels of steroid hormones typically rise gradually to ensure a successful pregnancy and the coordination of various physiological functions. P plays a crucial role in pregnancy, while E2 plays a key role in triggering labor. Figure 5 It was found that, in the serum of female rabbits on day 15 of heat-stressed pregnancy, compared with the control group, the addition of 400 mg / kg and 800 mg / kg doses of APS to the diet significantly increased the concentration of progesterone (P). P <0.05); such as Figure 6 As shown, the estradiol (E2) concentration in the 200 mg / kg APS group was significantly higher than that in the control group. P <0.05). The above results indicate that a dose of 400 mg / kg of APS has a significant effect on increasing the levels of progesterone and estradiol in the serum of mid-pregnancy rabbits, suggesting that APS can effectively regulate the reproductive endocrine system of rabbits under heat stress.

[0115] 2. Effects of APS on serum inflammatory markers in heat-stressed rabbits on day 15 of pregnancy

[0116] like Figure 7 and Figure 8 As shown, compared with the control group, the serum IL-10 levels in the experimental groups of rabbits were significantly increased ( P <0.05%. Meanwhile, serum IL-6 concentrations were significantly decreased in both the APS400 and APS800 groups ( P<0.05). In summary, the addition of 400 mg / kg dose of APS has a positive effect on effectively reducing the inflammatory response of does, and APS effectively alleviates the inflammatory response caused by heat stress by reducing IL-6 levels and increasing IL-10 content.

[0117] In summary, under the condition of heat stress, 400 mg / kg of astragalus polysaccharide can significantly improve the reproductive capacity of does, promote the growth and development of kits, and effectively reduce the adverse effects of heat stress on does.

[0118] Experimental Example 3

[0119] To explore the effect of astragalus polysaccharide on intestinal microorganisms and volatile fatty acids of does under heat stress, 460 Ilar does with similar body weight and parity were randomly divided into five groups, namely the control CON group (basal diet), the APS200 group (basal diet supplemented with 200 mg / kg APS), the APS400 group (basal diet supplemented with 400 mg / kg APS), the APS800 group (basal diet supplemented with 800 mg / kg APS), and the APS1000 group (basal diet supplemented with 1000 mg / kg APS). The effect of astragalus polysaccharide on intestinal microbial community of does under heat stress was studied from multiple aspects such as OTU number, diversity index, and flora composition.

[0120] Figure 9 The intestinal flora Venn diagram was analyzed by analyzing the fecal samples, and a total of 26,712 operational taxonomic units (OTUs) were identified, including 2,836 OTUs in the CON group, 3,034 OTUs in the APS200 group, 3,850 OTUs in the APS400 group, 3,408 OTUs in the APS800 group, and 3,501 OTUs in the APS1000 group. There were 844 OTUs in common among the five groups, accounting for 18.86% of the total OTU number. In terms of the total number of OTUs, the order was APS400 group > APS1000 group > APS800 group > APS200 group > CON group. The results showed that compared with the CON group, the types of intestinal microorganisms in each test group increased, thereby improving the diversity level of microbial flora.

[0121] 2. Alpha diversity analysis

[0122] The Chao1 index is a key indicator for measuring bacterial abundance; a higher Chao1 value indicates increased bacterial abundance. The Simpson and Shannon indices, on the other hand, represent bacterial diversity. The Simpson index reflects diversity by showing the proportion of dominant species and the balance of species distribution; a higher Simpson value indicates decreased diversity. Conversely, the Shannon index is directly proportional to bacterial diversity; a higher value indicates greater diversity.

[0123] Table 6 shows the effects of APS on the α-diversity of gut microbiota in heat-stressed rabbits. As can be seen from Table 6, compared with the CON group, the Chao1 and Shannon indices of the APS400, APS800, and APS1000 groups showed an increasing trend, while the Simpson index of the APS200 group was slightly higher than that of the CON group. The Simpson indices of the other experimental groups showed a decreasing trend compared to the control group. This indicates that APS may, to some extent, help improve the diversity and richness of the gut microbiota.

[0124] Table 6 Alpha Diversity Index

[0125]

[0126] 3. Beta diversity analysis

[0127] Beta diversity analysis aims to assess the differences in gut microbiota structure among different samples or groups. By using the weighted Unifrac method, the distance between microbiota in each group can be quantitatively compared, thereby revealing the similarity and differences in the composition of microbiota in each group. The increase in the discrete distance between groups is positively correlated with the increase in inter-group differences, that is, the more closely the sample points are clustered, the smaller the differences between groups.

[0128] like Figure 10 As shown, in the principal coordinate analysis (PCoA) results for intestinal samples, the first principal component (PCoA1) contributed 12.1% to the differentiation of rumen microbiota, while the second principal component (PCoA2) contributed 7.1%. PCoA analysis revealed a certain degree of dispersion in the sample distribution between the heat stress group and the control group, reflecting significant differences in the microbial community structure among individuals within the group. Simultaneously, fecal samples from the CON group, APS200, APS400, and APS800 groups also exhibited obvious dispersion characteristics, indicating that different doses of APS had different effects on the rabbit intestinal microbial community structure.

[0129] 4. Effects of Astragalus polysaccharides on the phylum-level composition of rabbit intestinal flora

[0130] In the intestinal microecosystem, Firmicutes and Bacteroidetes, as the main core flora, play a crucial role in the regulation of host energy balance, nutrient absorption, and intestinal physiological function. Firmicutes has a rich cluster of genes related to sugar metabolism, which can efficiently convert dietary energy and promote fat accumulation. Bacteroidetes, on the other hand, produces SCFAs by degrading cellulose and oligosaccharides, which not only enhances intestinal peristalsis but also strengthens the intestinal epithelial barrier and enhances mucosal immune response.

[0131] The composition and relative abundance of intestinal bacteria at the phylum level were analyzed in depth, and the results are shown in Table 7 and Bacteroides As can be seen, a total of 20 bacterial phyla were detected in the rabbit intestine, and these phyla were distributed in the five groups. According to the abundance from high to low, the main phyla were in turn: Firmicutes, Bacteroidota, Cyanobacteria, Patescibacteria, Proteobacteria, Verrucomicrobiota, Desulfobacterota, Campilobacterota, Fibrobacterota, Actinobacteriota, and Euryarchaeota, etc. At the phylum level, the top six species in the total abundance of each group remained consistent, with Firmicutes and Bacteroidetes occupying a central position. In the CON group, the proportion of Firmicutes and Bacteroidetes was 61.61% and 29.84%, respectively; in the APS200 group, it was 52.00% and 36.86%; in the APS400 group, it was 52.98% and 31.21%; in the APS800 group, it was 54.16% and 30.57%; and in the APS1000 group, it was 53.35% and 26.66%. According to the data analysis results in Table 7, compared with the control group, the abundance of Firmicutes in each test group was significantly increased ( P <0.05). In Bacteroidetes, the abundance of the APS200 group was significantly higher than that of the control group ( P <0.05), and the other test groups showed a decreasing trend. For Cyanobacteria, the abundance of the APS800 and 1000 groups was significantly higher than that of the control group ( P <0.05), and the rest of the test groups showed an increasing trend. The abundance of Patescibacteria increased in each test group compared to the control group. The abundance of Proteobacteria in the APS400 group was significantly higher than that of the control group ( P<0.05), the abundance of Verrucous microbes increased in the APS200 and APS1000 groups, but decreased in the APS800 group. The abundance of Verrucous microbes increased in the APS200, APS400 and APS800 groups compared to the control group.

[0132] Table 7. Effects of different doses of APS on the relative abundance of rabbit gut microbiota at the phylum level.

[0133]

[0134] 5. Effects of Astragalus polysaccharides on the genus-level composition of rabbit intestinal flora

[0135] The composition and relative abundance of gut bacteria at the genus level were analyzed, and the results are shown in Table 8 and... Ruminococcus As shown. The gut microbiota was classified to the genus level, identifying a total of 308 genera. Among them, 13 genera had a relative proportion exceeding 1% of the total sequence count, specifically: *Bacteroides* (…). Alistipes ), Rumenococcus ( V9D2013_group ), genus *Alternaria* ( Candidatus_Saccharimonas ), V9D2013 bacterial group ( Akkermansia ), spp. of glycomonas ( Lachnospiraceae_NK4A136_group ), Akkermania ( Rikenellaceae_RC9_gut_group ), NK4A136 group of Trichophyceae ( Monoglobus ), Riken Bacteria Family RC9 Intestinal Microbiota ( Phascolarctobacterium ), genus Monococcus ( UCG-005 ), Koala spp. Colidextribacter ), UCG-005 bacterial group ( Figure 10 - Figure 17 ) and C. spp. Figure 10 - Figure 17 ).

[0136] BacteroidesThe study revealed significant differences in gut microbiota between the control group and the experimental group supplemented with Astragalus polysaccharide. The nine most abundant dominant bacterial genera and their percentages in each group were: Bacteroides (22.94%), Ruminococcus (28.57%), Alternaria (8.03%), V9D2013 (7.70%), Saccharomyces (3.21%), Akkermansia (1.92%), Trichophyton (NK4A136) (2.67%), and Riken Bacteria (RC9) (6.92%). In the APS200 group, the percentages were as follows: Bacteroides (44.78%), Ruminococcus (15.30%), Alternaria (8.21%), V9D2013 (4.36%), Saccharomyces (4.28%), Akkermansia (2.99%), Trichophyton (NK4A136) (2.87%), and Riken Bacteria (RC9) (0.25%). In the APS400 group, the percentages were as follows: Bacteroides (20.46%), Ruminococcus (17.42%), Alternaria (10.74%), V9D2013 (4.89%), Saccharomyces (6.42%), Akkermansia (2.19%), Trichophyton (NK4A136) (1.57%), and Riken Bacteria (RC9) (1.49%). The percentages of Bacteroides (21.67%), Ruminococcus (26.50%), Alternaria (7.98%), V9D2013 (7.70%), Saccharomyces (7.00%), Akkermansia (4.26%), Trichophyton (NK4A136) (3.16%), and Riken (RC9) intestinal flora (0.57%) were as follows in the APS800 group. The proportions of Bacteroides (18.93%), Ruminococcus (25.25%), Alternaria (11.27%), V9D2013 (8.43%), Saccharomyces (9.40%), Akkermansia (2.13%), Trichophyton (NK4A136) (1.83%), and Riken Bacteria (RC9) (0.10%) intestinal flora in the APS1000 group were as follows:

[0137] like Ruminococcus As shown, compared to the control group APS200 group Alistipes Significant increase ( P <0.05), other experimental groups showed a decreasing trend. In the APS200 group... V9D2013_group The relative abundance decreased significantly ( P <0.05), while other experimental groups also showed a certain decreasing trend. Each experimental group Candidatus_Saccharimonas Both show an upward trend. In the APS800 and APS1000 groups... Akkermansia The content showed an upward trend. In the experimental group...Lachnospiraceae_NK4A136_group and Rikenellaceae_RC9_gut_group The abundance of both Figure 18 had a decreasing trend. The abundance of Figure 19 in the experimental groups were significantly decreased (P < 0.05). P <0.05).

[0138] Table 8. The effect of APS at different doses on the relative abundance of intestinal flora at genus level in rabbits

[0139]

[0140] The distribution of dominant flora from phylum to genus in each group is shown in Table 8 and Table 9. In the CON group, the dominant flora included Bacteroidetes-Bacteroidia-Bacteroidales-Hisemllales (Bacteroides sp.) (0.23%), Bacteroidetes-Bacteroidia-Bacteroidales-Hisemllales-Odoribacter (Odoribacter sp.) (0.22%) and Firmicutes-unclassified class-DTU014 order (0.21%). p_Bacteroidota.c_Bacteroidia.o_ Bacteroidales.f_Marinifilaceae In the APS200 group, the dominant flora included Bacteroidetes-Bacteroidia-Bacteroidales-RC9 gut group-unclassified RC9 gut species (0.23%), Firmicutes-Clostridia-Oscillospirales-UCG_011 family (0.22%) and Bacteroidetes-Bacteroidia-Bacteroidales-Bacteroidaceae (0.21%). p_Bacteroidota.c_Bacteroidia.o_Bacteroidales.f_Marinifilaceae.g_ Odoribacter In the APS400 group, the dominant flora included Cyanobacteria-Haemotofluium-Bacillales-unclassified Gastranaerobiaceae (0.23%), Firmicutes-Clostridia-Lachnospirales-Lachnospiraceae-Acetobacterium-Firmicutes (0.22%) and Firmicutes-Clostridia-Peptococcals- Anaerofustis- Eubacterium-unclassified Eubacterium sp. (0.21%). p_Firmicutes.c_Incertae_Sedis.o_ DTU014 In the APS800 group, the dominant flora included Bacteroidetes-Bacteroidia-Bacteroidales-RC9 gut group- Alistipes-Obesumbacterium sp. (0.23%), Proterobacteria-unclassified class-unclassified order-unclassified family (0.22%) and Bacteroidetes-Bacteroidia-Bacteroidales-Bacteroidaceae (0.21%). p_Bacteroidota.c_Bacteroidia.o_Bacteroidales.f_ Rikenellaceae.g_Rikenellaceae_RC9_gut_group.s_unclassified_g_Rikenellaceae_ RC9_gut_group p_Firmicutes.c_ Clostridia.o_Oscillospirales.f_UCG_0 p_Bacteroidota.c_Bacteroidia.o_Bacteroidales.f_Bacteroidaceae ​ ​ p_ Cyanobacteria.c_Vampirivibrionia.o_Gastranaerophilales.f_unclassified_o_ Gastranaerophilales p_ Firmicutes.c_Clostridia.o_Lachnospirales.f_Lachnospiraceae.g_ Acetitomaculum.s_Firmicutes_bacterium_CAG_194_44_15 p_Firmicutes.c_Clostridia.o_ Peptostreptococcales_Tissierellales.f_Anaerovoracaceae.g__Eubacterium__ nodatum_group.s_unclassified_g__Eubacterium__nodatum_group p_ Bacteroidota.c_Bacteroidia.o_Bacteroidales.f_Rikenellaceae.g_Alistipes.s_ Alistipes_obesi p_Proteobacteria.c_ unclassified_p_Proteobacteria.o_unclassified_p_Proteobacteria.f_unclassified_ p_Proteobacteria ​​​​​​​​​) and Bacteroidetes-Bacteroidia-Bacteroidales-Bacteroidaceae-Bacteroides p_ Bacteroidota.c_Bacteroidia.o_Bacteroidales.f_Bacteroidaceae.g_Bacteroides ). In the APS1000 group, the dominant flora included Firmicutes-Negativicutes- aminoacidicoccus-Aminoacidicoccaceae-unclassified aminoacidicoccus p_Firmicutes.c_Negativicutes.o_Acidaminococcales.f_ Acidaminococcaceae.g_unclassified_f_Acidaminococcaceae ), Cyanobacteria p_ Cyanobacteria ) and Bacteroidetes-Bacteroidia-unclassified Bacteroidales p_Bacteroidota.c_ Bacteroidia.o_unclassified_c_Bacteroidia ).

[0141] The above results show that APS has a positive impact on intestinal health by regulating the structure of intestinal flora, especially increasing the abundance of beneficial bacteria and promoting the production of SCFAs. These findings provide important experimental evidence for a deeper understanding of the regulatory role of APS on intestinal microecology.

[0142] 6. Effect of Astragalus polysaccharides on volatile fatty acids in rabbits

[0143] Short-chain fatty acids (SCFAs) are small-molecule organic carboxylic acids containing 1 to 6 carbon atoms, mainly converted in the intestine by anaerobic fermentation of resistant starch, inulin, cellulose, and pectin. SCFAs are classified as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, and caproic acid according to the number of carbon atoms. Acetic acid, propionic acid, and butyric acid are the main forms of SCFAs, while the concentrations of formic acid, valeric acid, and caproic acid are at a lower level.

[0144] Table 9 Effect of Astragalus polysaccharides on volatile fatty acids in the intestines of female rabbits

[0145]

[0146] As shown in Table 9, compared with the control group, the contents of acetic acid, butyric acid, caproic acid, propionic acid, and valeric acid in the APS200 group showed an increasing trend; the content of caproic acid in the APS400 group showed an increasing trend; the contents of heptanoic acid, decanoic acid, and octanoic acid in the APS800 group significantly increased ( P <0.05). The contents of caproic acid, decanoic acid, heptanoic acid, and octanoic acid in the APS1000 group showed an increasing trend.

[0147] APS200 treatment group showed an increase in SCFAs such as acetic acid, butyric acid, and propionic acid, indicating that APS promotes energy supply for intestinal epithelial cells, enhances intestinal barrier, effectively resists pathogenic bacteria, and inhibits inflammation. In the APS800 and APS1000 high concentration treatment groups, medium and long chain fatty acids such as hexanoic acid, decanoic acid, and heptanoic acid increased significantly, which can supply energy for intestinal epithelial cells and help to enhance intestinal barrier, thereby improving intestinal health. The increase of decanoic acid and heptanoic acid may also inhibit the growth of pathogenic bacteria and maintain the balance of intestinal flora. The increase of medium and long chain fatty acids is also related to the optimization of energy metabolism and the reduction of the risk of metabolic diseases. Isobutyric acid and isovaleric acid showed an upward trend in the APS200 and APS1000 treatment groups, which may reflect the enhanced protein metabolism activity of intestinal flora, helping to improve energy metabolism status, regulate the immune system, reduce intestinal inflammation, and improve inflammatory bowel disease (IBD). The increase of octanoic acid in the APS800 and APS1000 treatment groups is due to the change of metabolic pathways of intestinal flora caused by high-dose APS, leading to the accumulation of octanoic acid precursors or the enhanced activity of bacteria. The increase of octanoic acid may enhance the antibacterial effect and provide energy, further improving intestinal health and host metabolism. The increase of valeric acid in the APS200 and APS800 groups has a positive impact on intestinal health.

[0148] 7. Correlation analysis of rabbit intestinal microorganisms and short-chain fatty acids

[0149] From Figure 20 and Figure 21 we can see that UCG 005 , Oscillibacter , V9D2013_group , Colidextribacter , Monoglobus is significantly positively correlated with SCFAs, among which UCG-005 is significantly positively correlated with isovaleric acid and octanoic acid content ( P <0.05), Oscillibacter is significantly positively correlated with acetic acid and hexanoic acid ( P <0.05), V9D2013_group is significantly positively correlated with butyric acid and isobutyric acid ( P <0.05), and P is significantly positively correlated with propionic acid, valeric acid, and isovaleric acid ( P <0.01). Colidextribacter is significantly positively correlated with a variety of SCFAs, including acetic acid, valeric acid, isovaleric acid, and hexanoic acid ( P <0.05), as well as butyric acid and propionic acid ( P <0.01); Monoglobus is extremely significantly positively correlated with acetic acid, butyric acid, and propionic acid content ( P <0.01).

[0150] In summary, APS has a good regulatory effect on intestinal microbial community and SCFAs under heat stress, which can increase the abundance of beneficial bacteria (such as Firmicutes, Bacteroides, Akkermansia) and optimize the balance of intestinal microecology. By promoting the synthesis of SCFAs (especially acetic acid, propionic acid, and butyric acid), APS enhances the intestinal mucosal barrier function, exhibits anti-inflammatory activity, relieves heat stress-induced dysbiosis, barrier damage, and metabolic disorders, and reduces health risks. Therefore, APS has important application potential in improving animal intestinal health and improving production performance as a natural prebiotic.

Claims

1. The application of Astragalus polysaccharide in the preparation of feed to improve the reproductive performance of female rabbits under heat stress, characterized in that, The feed is a mixture of basal feed and astragalus polysaccharide at a mass ratio of 1 kg: 200-1000 mg. The raw materials used in the basal feed include, by weight: 10-15 parts corn, 3-7 parts wheat middlings, 3-7 parts corn husks, 5-10 parts wheat bran, 0.5-2.5 parts soybean oil, 10-20 parts soybean meal, 3-9 parts rapeseed meal, 6-12 parts distillers' grains, 5-8 parts corn germ meal, 0.5-2.5 parts artemisia annua powder, 3-9 parts rice husk powder, 3-7 parts peanut shell powder, 5-10 parts white clover powder, 5-10 parts alkali grass, and 3-7 parts premix. Each kilogram of premix contains: Fe 50-100mg, Cu 10-30mg, Zn 50-100mg, Mn 5-15mg, Co 0.1-0.2mg, I 0.1-0.3mg, Se 0.2-0.3mg, VA 9000-11000IU, VD 800-1000IU, VE 30-70mg, VK 1-3mg, VB1 1-3mg, VB2 4-8mg, VB5 30-70mg, VB6 1-3mg, VB... 12 0.01-0.03mg, VB3 30-70mg, VB9 30-60mg, VB4 900-1100mg and VB7 0.1-0.3mg.

2. The application according to claim 1, characterized in that, The feed is a mixture of basic ration and astragalus polysaccharide at a mass ratio of 1 kg: 400 mg.

3. The application according to claim 1, characterized in that, The raw materials used in the basic feed diet, by weight, include: 12 parts corn, 5 parts wheat middlings, 5 parts corn husks, 8.5 parts wheat bran, 1.5 parts soybean oil, 14 parts soybean meal, 6 parts rapeseed meal, 9 parts distillers' grains, 6.5 parts corn germ meal, 1.5 parts artemisia annua powder, 6 parts rice husk powder, 5 parts peanut shell powder, 7 parts white clover powder, 8 parts alkali grass, and 5 parts premix.

4. The application according to claim 1, characterized in that, The raw materials used in the basic feed diet, by weight, include: 10 parts corn, 3 parts wheat middlings, 3 parts corn husks, 5 parts wheat bran, 0.5 parts soybean oil, 20 parts soybean meal, 9 parts rapeseed meal, 12 parts distillers' grains, 8 parts corn germ meal, 2.5 parts artemisia annua powder, 3 parts rice husk powder, 3 parts peanut shell powder, 10 parts white clover powder, 10 parts alkali grass, and 7 parts premix.

5. The application according to claim 1, characterized in that, The raw materials used in the basic feed diet, by weight, include: 15 parts corn, 7 parts wheat middlings, 7 parts corn husks, 10 parts wheat bran, 2.5 parts soybean oil, 10 parts soybean meal, 3 parts rapeseed meal, 6 parts distillers' grains, 5 parts corn germ meal, 0.5 parts artemisia annua powder, 9 parts rice husk powder, 7 parts peanut shell powder, 5 parts white clover powder, 5 parts alkali grass, and 3 parts premix.

6. The application according to claim 1, characterized in that, Each kilogram of premix contains: Fe 70mg, Cu 20mg, Zn 70mg, Mn 10mg, Co 0.15mg, I 0.2mg, Se 0.25mg, VA 10000IU, VD 900IU, VE 50mg, VK 2mg, VB1 2mg, VB2 6mg, VB5 50mg, VB6 2mg, VB 12 0.02mg, VB3 50mg, VB9 44mg, VB4 1000mg and VB7 0.2mg.

7. The application according to claim 1, characterized in that, The method for preparing the feed includes the following steps: mixing the raw materials evenly in a certain proportion to obtain a feed containing astragalus polysaccharide.

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