Application of isatis root polysaccharide in improving egg quality or intestinal health of poultry

Abstract

This invention discloses the application of Isatis root polysaccharide in improving egg quality or gut health in poultry, belonging to the field of poultry farming technology. This invention provides the application of Isatis root polysaccharide in improving egg quality or gut health in poultry. Applying Isatis root polysaccharide to poultry farming can effectively improve egg quality and gut health. Furthermore, the preparation process of the Isatis root polysaccharide of this invention is simple, as it can be directly obtained from the pharmaceutical process of Isatis root granules, resulting in low cost. A small amount of the polysaccharide can achieve good results. The Isatis root polysaccharide of this invention can reduce poultry farming costs, alleviate the economic burden on farmers, and is suitable for widespread promotion.

Description

Technical Field

[0001] This invention belongs to the field of poultry farming technology, and in particular relates to the application of Isatis indigotica polysaccharide in improving the quality of poultry egg production or intestinal health. Background Technology

[0002] Poultry refers to birds raised in captivity, primarily for their meat, eggs, and feathers, but also for other purposes. Poultry mainly includes chickens, ducks, geese, and quails. Chickens, as an important type of poultry, are increasingly standardized and branded due to growing emphasis on biosafety, food safety, and environmental protection. Egg quality is receiving increasing attention. Industry standards such as the "National Food Safety Standard for Eggs and Egg Products" (GB2749-2015) use objective indicators such as albumen, yolk, and Haugh units to set entry requirements and quality grades for eggs. Egg quality directly affects the economic benefits of related industries. In laying hen farming, egg quality has always been a headache, especially in the later stages of egg production, when quality declines significantly, manifesting as cracked eggs, soft-shelled eggs, and blood-spotted eggs. Factors affecting egg quality are complex, including genetic, environmental, disease, and nutritional factors. Existing research indicates that adding appropriate amounts of fermented products, trace elements, and traditional Chinese medicine to the diet of laying hens can effectively improve egg quality and the health of the hens. As restrictions on the addition of growth-promoting chemicals and antibiotics to feed continue to increase, the importance of traditional Chinese medicine in poultry and livestock farming is growing.

[0003] Isatis root, the dried root of the cruciferous plant Isatis indigotica, is a classic traditional Chinese medicine used for clearing heat and detoxifying. It can be used for treating febrile diseases, fever and sore throat, febrile rashes, mumps, erysipelas, epidemic parotitis, erysipelas, and carbuncles. Modern research shows that Isatis root contains various compounds such as indole alkaloids, polysaccharides, lignans, and steroids, possessing pharmacological effects including antiviral, anti-inflammatory, and immunomodulatory properties. However, research on the application of Isatis root extracts in poultry farming is limited. Summary of the Invention

[0004] In order to overcome the problems existing in the prior art, one of the objectives of the present invention is to provide the application of Isatis indigotica polysaccharide in improving the quality of poultry egg production or improving intestinal health.

[0005] The second objective of this invention is to provide a product comprising Isatis indigotica polysaccharide.

[0006] The third objective of this invention is to provide a poultry feed.

[0007] The fourth objective of this invention is to provide a method for raising poultry.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] The first aspect of the present invention provides the application of Isatis indigotica polysaccharide in improving the quality of poultry egg production or improving intestinal health.

[0010] Preferably, the polysaccharide is prepared from Isatis indigotica by water extraction and alcohol precipitation.

[0011] Preferably, the Isatis root polysaccharide is prepared by a method comprising the following steps:

[0012] S1. Boil Isatis root in water, filter the decoction, and concentrate the filtrate to obtain a clear extract;

[0013] S2. Ethanol is added to the clear extract for alcohol precipitation. The precipitate is separated, dried, and pulverized to obtain the polysaccharide from Isatis indigotica root.

[0014] Preferably, the mass ratio of Isatis root to water is 1:(5-10).

[0015] Preferably, in step S1, the water is distilled water or deionized water.

[0016] Preferably, in step S1, the decocting temperature is 80–100°C.

[0017] Preferably, in step S1, the decocting is performed 1 to 3 times; more preferably 2 times.

[0018] Preferably, in step S1, the simmering time is 0.5 to 5 hours; more preferably, it is 2 to 4 hours.

[0019] Preferably, in step S1, the decoction is performed twice, with the first decoction lasting 1.5 to 3 hours and the second decoction lasting 0.5 to 1.5 hours.

[0020] When the decoction is boiled more than once, the decoction needs to be filtered separately, and the filtrates should be combined and then concentrated.

[0021] Preferably, in step S1, the relative density of the ointment at 50°C is 1 to 1.5; more preferably, it is 1.1 to 1.3.

[0022] Preferably, in step S2, ethanol is added until the alcohol content is 40-80 vv%; more preferably 50-70 vv%.

[0023] Preferably, in step S2, the alcohol precipitation time is 8 to 24 hours; more preferably, it is 10 to 15 hours.

[0024] Preferably, in step S2, the water content is dried to less than 20 wt%; more preferably less than 10 wt%.

[0025] Preferably, in step S2, the material is pulverized to a mesh size of 10-30 mesh; more preferably, it is pulverized to a mesh size of 15-25 mesh.

[0026] Preferably, the polysaccharide from Isatis indigotica root includes water-soluble polysaccharides and proteins from Isatis indigotica root; more preferably, the polysaccharide is composed of mannose, glucose, or a combination thereof.

[0027] Preferably, in the application, the poultry includes at least one of chicken, duck, goose or quail; more preferably, at least one of chicken, duck or goose; and even more preferably, chicken.

[0028] Preferably, the chicken includes broiler chickens, laying hens, or a combination thereof; more preferably, it is a laying hen.

[0029] Preferably, the present invention provides the application of Isatis indigotica polysaccharide in the preparation of products that improve the quality of poultry egg production or improve intestinal health.

[0030] A second aspect of the present invention provides a product comprising Isatis indigotica polysaccharide; the product having at least one of the following functions:

[0031] 1) Improve the quality of poultry eggs;

[0032] 2) Improve the gut health of poultry.

[0033] In the product, the isatis root polysaccharide is the isatis root polysaccharide used in the application described in the first aspect of the present invention.

[0034] Preferably, the mass percentage of the Isatis indigotica polysaccharide in the product is 0.01-0.2%; more preferably 0.015-0.18%; and even more preferably 0.018-0.15%.

[0035] Preferably, the product includes food additives, feed, or drugs; more preferably, the product is selected from feed.

[0036] A third aspect of the present invention provides a poultry feed comprising a basal diet and Isatis indigotica polysaccharide.

[0037] In the poultry feed, the isatis root polysaccharide is the isatis root polysaccharide used in the first aspect of this invention.

[0038] Preferably, the mass percentage of the Isatis indigotica polysaccharide in the poultry feed is 0.01-0.2%; more preferably 0.015-0.18%; and even more preferably 0.018-0.15%.

[0039] Preferably, the basal diet of the poultry feed includes corn, soybean meal, soybeans, oil, amino acids, and minerals; more preferably, the basal diet includes corn, extruded soybeans, soybean meal, whey powder, fish meal, soybean oil, lysine, methionine, threonine, dicalcium phosphate, limestone powder, and salt; even more preferably, the basal diet includes the following components in parts by weight: 56-57 parts corn, 7-8 parts extruded soybeans, 21-22 parts soybean meal, 5-6 parts whey powder, 4.5-5.5 parts fish meal, 0.5-1.5 parts soybean oil, 0.2-0.6 parts lysine, 0.1-0.5 parts methionine, 0.1-0.3 parts threonine, 0.3-1 part dicalcium phosphate, 0.1-1 part limestone powder, and 0.1-0.5 parts salt.

[0040] The basic diet should be sufficient to meet the nutritional needs of poultry during egg production. When the poultry is chicken, it is preferred to formulate the diet according to standard NY / T33-2004.

[0041] Preferably, the poultry feed is divided into a low-dose group feed, a medium-dose group feed, and a high-dose group feed; the low-dose group feed includes 0.01-0.03% by weight of Isatis indigotica polysaccharide; the medium-dose group feed includes 0.03-0.07% by weight of Isatis indigotica polysaccharide; and the high-dose group feed includes 0.07-0.2% by weight of Isatis indigotica polysaccharide.

[0042] Preferably, the low-dose feed contains 0.012–0.028% by weight of Isatis indigotica polysaccharide; more preferably 0.015–0.025%; and even more preferably 0.018–0.022%.

[0043] Preferably, the medium-dose feed contains 0.035-0.065% by weight of Isatis indigotica polysaccharide; more preferably 0.04-0.06%; and even more preferably 0.045-0.055%.

[0044] Preferably, the high-dose feed contains 0.075–0.18% by weight of Isatis indigotica polysaccharide; more preferably 0.08–0.15%; and even more preferably 0.09–0.12%.

[0045] In some specific embodiments of the present invention, the feed is used to improve the egg quality of poultry.

[0046] Furthermore, the egg quality includes at least one of egg weight, egg shape index, eggshell strength, yolk color, Haugh unit, albumen height, yolk index, yolk ratio, eggshell thickness, or yolk antioxidant capacity; even further, the egg quality includes at least one of egg shape index, yolk color, Haugh unit, albumen height, eggshell thickness, or yolk antioxidant capacity.

[0047] Preferably, when the egg quality is selected from the egg shape index, the feed is selected from the low-dose group feed, the medium-dose group feed, or the high-dose group feed; more preferably from the low-dose group feed or the medium-dose group feed; and even more preferably from the medium-dose group feed.

[0048] Preferably, when the egg quality is selected from yolk color, the feed is selected from low-dose group feed or high-dose group feed; more preferably from low-dose group feed.

[0049] Preferably, when the egg quality is selected from Haugh units, the feed is selected from the low-dose group feed or the medium-dose group feed; more preferably from the low-dose group feed.

[0050] Preferably, when the egg quality is selected from high albumen count, the feed is selected from low-dose group feed, medium-dose group feed or high-dose group feed; further preferably from low-dose group feed or medium-dose group feed; even more preferably from low-dose group feed.

[0051] Preferably, when the egg quality is selected from eggshell thickness, the feed is selected from the medium-dose group feed.

[0052] Preferably, when the egg quality is selected from the yolk's antioxidant capacity, the feed is selected from the low-dose group feed.

[0053] In some other embodiments of the invention, the feed is used to improve the gut health of poultry.

[0054] Furthermore, the gut health status includes at least one of the following: gut tissue morphology, cecal gene expression level, or connexin expression level.

[0055] Furthermore, the intestinal tissue morphology includes at least one of the following: duodenal villus height, duodenal crypt depth, duodenal villus height / crypt depth, jejunal villus height, jejunal crypt depth, jejunal villus height / crypt depth, ileal villus height, ileal crypt depth, or ileal villus height / crypt depth.

[0056] Among them, when the villus height is high, the crypt depth is low, or the ratio of villus height to crypt depth is large, the intestinal tissue morphology is in a better state.

[0057] Furthermore, the cecal genes include inflammatory factors, antioxidant genes, or combinations thereof.

[0058] Furthermore, the inflammatory factors include pro-inflammatory cytokines, anti-inflammatory cytokines, or combinations thereof.

[0059] Among them, when the expression levels of pro-inflammatory cytokines are low, the expression levels of anti-inflammatory cytokines are high, or the expression levels of antioxidant genes are high, the intestinal tissue morphology is in a better state.

[0060] Furthermore, the pro-inflammatory cytokines include at least one of IL-1β, IL-6, TNF-α, NF-κB, or COX2.

[0061] Furthermore, the anti-inflammatory cytokines include IL-4, IL-10, or a combination thereof.

[0062] Furthermore, the antioxidant gene includes at least one of Nrf2, HO-1, Keap1, or NQO1;

[0063] Furthermore, the connecting protein includes at least one of ZO-1, occludin, or claudin-1.

[0064] When the expression level of connexin is high, the intestinal tissue morphology is in a better state.

[0065] Preferably, when the intestinal health status is selected from the duodenal villus height, duodenal crypt depth, or duodenal villus height / crypt depth in the intestinal tissue morphology, the feed is selected from the low-dose group feed.

[0066] Preferably, when the intestinal health status is selected from the jejunal villus height in the intestinal tissue morphology, the feed is selected from the high-dose group feed.

[0067] Preferably, when the intestinal health status is selected from the jejunal crypt depth or jejunal villus height / crypt depth in the intestinal tissue morphology, the feed is selected from the low-dose group feed or the high-dose group feed.

[0068] Preferably, when the intestinal health status is selected from the expression level of the cecal gene, the feed is selected from the low-dose group feed.

[0069] More preferably, when the intestinal health status is selected from the expression levels of pro-inflammatory cytokines IL-6, NF-κB, or COX2 in the cecal gene, the feed is selected from the low-dose group feed.

[0070] Preferably, when the gut health status is selected from the expression level of the connexin, the feed is selected from the low-dose group feed.

[0071] More preferably, when the gut health status is selected from the expression level of the conjugate protein occludin, the feed is selected from the low-dose group feed.

[0072] A fourth aspect of the present invention provides a method for raising poultry, wherein poultry are fed using the feed described in the third aspect of the present invention.

[0073] Preferably, in the feeding method, the feed amount per poultry is 100-130g; more preferably 105-125g; and even more preferably 110-120g.

[0074] The beneficial effects of this invention are:

[0075] This invention provides the application of Isatis root polysaccharide in improving egg quality or gut health in poultry. The Isatis root polysaccharide of this invention mainly contains polysaccharides composed of monosaccharides such as mannose and glucose, as well as protein components, and possesses rich pharmacological activities: 1) Antiviral activity: Isatis root polysaccharide has antiviral effects against various influenza virus subtypes (H1N1 and H5N1, etc.), chicken infectious bronchitis virus, porcine pseudorabies virus (PRV), ovine infectious pustular virus (ORFV), porcine reproductive and respiratory syndrome virus (PPRSV), etc. 1) Certain inhibitory effects; 2) Immunomodulatory effects: In a cyclophosphamide-induced immunosuppression model in chicks, Isatis root polysaccharide promotes lymphocyte proliferation, increases the IgA ratio, and increases antibody levels, thereby enhancing immunity; Isatis root can also be used as an adjuvant for some vaccines, increasing vaccine antibody titers and improving immunization efficacy; 3) Anti-inflammatory effects: Isatis root polysaccharide can inhibit the levels of pro-inflammatory factors caused by influenza virus infection, thus inhibiting lung inflammation; with the standardization of antibiotic use, Isatis root polysaccharide can be studied as a substitute for anti-inflammatory drugs. This invention applies Isatis root polysaccharide to poultry farming, showing significant effects in improving egg quality and gut health.

[0076] Specifically, compared with the prior art, the present invention has the following advantages:

[0077] 1. Compared to existing reports using single-herb Chinese medicines (gardenia, licorice, etc.), compound Chinese medicines (honeysuckle and scutellaria extracts, yang-boosting formulas, etc.), chemical monomers (rutin, vitamin D3, etc.), and fermentation products (yeast liquid, etc.) to improve egg quality in laying hens, the Isatis root polysaccharide of this invention is simpler to prepare and obtain, has a lower price, and achieves good results with a smaller addition amount. This reduces poultry farming costs and alleviates the economic burden on farmers, making it suitable for widespread promotion. The preparation process of the Isatis root polysaccharide of this invention is simple, and it can be directly obtained from the pharmaceutical process of Isatis root granules. The addition amount in the basal diet can be as low as 100g / t (equivalent to 0.01wt%), resulting in lower costs.

[0078] 2. By adjusting the content of Isatis indigotica polysaccharides in feed, different egg quality parameters such as egg weight, egg shape index, eggshell strength, yolk color, Haugh unit, albumen height, yolk index, yolk ratio, eggshell thickness, and yolk antioxidant capacity can be adjusted to obtain high-quality eggs. Different Isatis indigotica polysaccharide contents in the feed have different effects on different egg quality parameters. The content of Isatis indigotica polysaccharides can be adjusted according to actual needs to obtain corresponding feeds for different egg quality parameters, thereby achieving different high egg production qualities. The Isatis indigotica polysaccharides of this invention can significantly improve egg shape index, yolk color, Haugh unit, eggshell thickness, and yolk antioxidant capacity.

[0079] 3. By adjusting the content of Isatis indigotica polysaccharide in feed, the intestinal health of poultry can be improved. Specifically, it can improve intestinal tissue morphology, cecal gene expression levels, or connexin expression levels. The Isatis indigotica polysaccharide of this invention can improve intestinal tissue morphology and significantly increase villus height; it can affect the expression of cecal-related genes, significantly reduce the expression levels of inflammatory factors IL-6, NF-κB, and COX2, and significantly increase the expression level of the intestinal barrier protein occludin. Attached Figure Description

[0080] Figure 1 The effect of Isatis indigotica polysaccharide on the antioxidant capacity of egg yolk.

[0081] Figure 2 The effect of Isatis indigotica polysaccharide on the height of intestinal villi in laying hens.

[0082] Figure 3 The effect of Isatis indigotica polysaccharide on the morphology of intestinal tissue in laying hens.

[0083] Figure 4 To investigate the effect of Isatis indigotica polysaccharide on the expression of the IL-6 gene in the cecum of laying hens.

[0084] Figure 5 To investigate the effect of Isatis indigotica polysaccharide on the expression of the NF-κB gene in the cecum of laying hens.

[0085] Figure 6 The effect of Isatis indigotica polysaccharide on the expression of the COX2 gene in the cecum of laying hens.

[0086] Figure 7 The effect of Isatis indigotica polysaccharide on the expression of occludin, a connexin in laying hens.

[0087] Figure 8 The effect of Isatis indigotica polysaccharide on the expression of ZO-1 connexin in laying hens.

[0088] Figure 9 The effect of Isatis indigotica polysaccharide on the expression of the IL-1β gene in the cecum of laying hens.

[0089] Figure 10 Effect of Isatis indigotica polysaccharide on the expression of TNF-α gene in the cecum of laying hens

[0090] Figure 11 Effect of Isatis indigotica polysaccharide on the expression of IL-4 gene in the cecum of laying hens

[0091] Among them, A1 is the blank control group, B1 is the low-dose group, B2 is the medium-dose group, and B3 is the high-dose group Specific implementation mode

[0092] The content of the present invention will be further described in detail through specific embodiments below. It should also be understood that the following embodiments are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the principles described in the present invention all fall within the protection scope of the present invention. The specific process parameters and the like in the following examples are also only an example within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description in this article, rather than being limited to the specific data in the examples below. The raw materials, reagents or devices used in the following examples and comparative examples can be obtained from conventional commercial channels or can be obtained by known existing methods without special instructions

[0093] Figures 1-2 、 Figures 4-11 In this article, "ns" means p>0.05, that is, the difference is not significant; "*" means 0.01<p<0.05, that is, the difference is significant; "**" means 0.001<p<0.01, that is, the difference is relatively significant; "***" means p<0.001, that is, the difference is extremely significant

[0094] Example 1

[0095] Preparation of Isatis indigotica polysaccharide

[0096] The Isatis indigotica polysaccharide sample was obtained and provided by Guangzhou Baiyunshan Hutchison Whampoa Chinese Medicine Co., Ltd. during the actual production process of Isatis indigotica granule. The specific preparation process includes: taking 1120 kg of Isatis indigotica, decocting twice with water. The first time is for 2 hours with 8 times the amount of water added, and the second time is for 1 hour with 6 times the amount of water added. The decocting temperature is 80-100 °C. The decocted liquid is filtered, and the filtrates are combined and concentrated to a clear paste with a relative density of about 1.20 (50 °C). Ethanol is added to make the alcohol content reach 60 vv%. It is left standing for 12 hours to precipitate, and the precipitate is filtered. The supernatant is used to prepare Isatis indigotica granule. The precipitate is dried until the water content is lower than 10 wt%, pulverized, and sieved through a 20-mesh sieve to obtain the Isatis indigotica polysaccharide, which can be added to the basal diet for feeding laying hens

[0097] Example 2

[0098] Beneficial functions of Isatis indigotica polysaccharide in feeding

[0099] (I) Laboratory animals and experimental design

[0100] Sixty-fourty 55-week-old Jingfen laying hens with similar egg production rates and health conditions were selected for the experiment. A single-factor completely randomized design was used, dividing the hens into a blank control group, a low-dose group, a medium-dose group, and a high-dose group. The blank control group was fed a basal diet, while the low, medium, and high-dose groups received an additional 200 g / t, 500 g / t, and 1000 g / t of Isatis indigotica polysaccharide, respectively, on top of their basal diet dry matter. All hens had free access to feed and water during the experiment, and were fed twice daily, morning and evening. The experiment lasted 63 days, and egg production rate, egg weight, and feed intake were recorded throughout the period.

[0101] (II) Feeding Management and Indicator Measurement

[0102] 1. Laying hen diet and management

[0103] According to the Chinese "Chicken Feeding Standard (NY / T33-2004)," a diet formula was developed to meet the nutritional needs of laying hens during their peak laying period. The ingredients and nutrient composition of the diet are shown in Table 1. The health status of the laying hens was recorded throughout the period (laying rate, rate of deformed eggs, average egg weight, average daily feed intake, feed conversion ratio, and mortality rate). Laying rate = Total eggs laid / Total number of hens in the coop × 100%; Deformed egg rate = Total number of deformed eggs / Total number of eggs laid × 100%; Average egg weight = Total weight of eggs laid / Total number of eggs laid; Daily feed intake = Feed consumption / (Number of days × Number of hens in the coop); Feed conversion ratio = Total feed consumption / Total weight of eggs laid.

[0104] Table 1. Composition of dietary ingredients and nutrients (dry matter basis, wt%)

[0105]

[0106]

[0107] 2. Effects of Isatis root polysaccharides on egg quality

[0108] Egg samples were collected one day before the end of the experiment, and eight eggs were randomly selected from each group for egg quality testing.

[0109] (1) Egg weight: Measured using an Egg Analyzer, accurate to 0.01g.

[0110] (2) Egg shape index: The transverse and longitudinal diameters of each egg are measured using an electronic digital vernier caliper, and then calculated. Formula: Egg shape index = transverse diameter / longitudinal diameter × 100%.

[0111] (3) Eggshell strength: Place the whole egg on an eggshell strength tester for testing.

[0112] (4) Egg yolk color: Crack the egg and place it in an Egg Analyzer for testing.

[0113] (5) Haugh units and albumen height: The eggs were broken and placed in an Egg Analyzer for testing.

[0114] (6) Eggshell thickness: The eggshell thickness of the sharp end, blunt end and middle part of the egg is measured using an eggshell thickness gauge, and the average value is taken as the eggshell thickness.

[0115] (7) Yolk Index: Two egg yolks were selected repeatedly each time, and the height and diameter of the yolks were measured using an electronic digital vernier caliper. Formula: Yolk Index = Yolk Height / Yolk Diameter.

[0116] (8) Yolk-to-Yolk Ratio: Remove the albumen and chalazae from the surface of the yolk, weigh and record the yolk weight on an analytical balance, and compare it with the total egg weight. Formula: Yolk-to-Yolk Ratio = Yolk Weight / Total Egg Weight

[0117] 3. Effects of Isatis indigotica polysaccharides on the antioxidant indices of egg yolks

[0118] One day before the end of the experiment, eight eggs were randomly selected from each group, and the yolks were separated from the albumen and stored at -30℃. The malondialdehyde (MDA) content and total antioxidant capacity (T-AOC) level in the egg yolks were determined according to the kit instructions using relevant kits from Beijing Box Biotechnology Co., Ltd.

[0119] 4. Effects of Isatis root polysaccharides on the morphology of laying hen intestinal tissue

[0120] After preparing paraffin sections from 4 wt% paraformaldehyde-fixed hen intestinal samples, the samples were observed under an optical microscope. Image analysis software was used to measure the villus height and crypt depth of the duodenum, jejunum, and ileum, and the intestinal ratio was calculated, i.e., intestinal ratio = villus height / crypt depth (V / C).

[0121] 5. Effects of Isatis root polysaccharides on the expression of gut-related genes in laying hens

[0122] Using qPCR, the expression levels of relevant genes in the cecum of the blank group and the low, medium and high dose groups were detected: inflammatory factors, including pro-inflammatory cytokines IL-1β, IL-6, TNF-α, NF-κB, COX2 and anti-inflammatory cytokines IL-4, IL-10; antioxidant genes Nrf2, HO-1, Keap1, NQO1; and connexins ZO-1, occludin (intestinal barrier protein), and claudin-1.

[0123] (III) Results and Discussion

[0124] 1. Effects of Isatis root polysaccharides on laying hen production performance

[0125] The experimental results are shown in Table 2. The results show that compared with the blank control group, the feed conversion ratio of the low-dose group and the high-dose group was significantly improved, but the difference was not significant (p>0.05). This indicates that the addition of water-soluble polysaccharides from Isatis indigotica at the experimental dose has an improving trend on the laying hen production performance and has no negative impact.

[0126] Table 2. Effects of Isatis indigotica polysaccharide on laying hen production performance.

[0127]

[0128] Note: ① Data are from the Animal Nutrition Genomics and Germplasm Innovation Research Center of Hunan Agricultural University; ② Different lowercase letters in the superscript of peer data indicate significant differences (p<0.05), otherwise they indicate no significant differences; ③ SEM represents the standard error of the mean between groups.

[0129] 3. Effects of Isatis indigotica polysaccharides on egg quality

[0130] Eggs weigh 50-65g, are oval-shaped, and have an egg shape index of 0.72-0.76. Egg shape does not affect edibility but does influence breeding value, hatchability, and breakage rate. Eggshell thickness is positively correlated with shell strength; a good eggshell thickness is generally around 0.33-0.35mm. Eggshell thickness below 0.25mm results in approximately 85% broken eggs. Haugh units are an indicator of egg freshness and protein quality; a higher Haugh unit indicates a fresher egg. Fresh eggs have a Haugh unit of 75-85. The yolk-to-female ratio reflects the proportion of yolk in the whole egg; a higher value indicates better quality. Grade 1 eggs have a yolk-to-female ratio ≥0.40, Grade 2 eggs ≥0.36, and Grade 3 eggs ≤0.35.

[0131] The experimental results are shown in Table 3. The results indicate that compared to the blank control group, the egg shape index was significantly increased in the low, medium, and high dose groups (p<0.05); the yolk color was significantly increased in the low and high dose groups (p<0.05); the Haugh unit was significantly increased in the low and medium dose groups (p<0.05); the albumen height was significantly increased in the low, medium, and high dose groups (p<0.05); and the eggshell thickness was significantly increased in the medium dose group (p<0.05). These results suggest that adding a certain dose of Isatis indigotica water-soluble polysaccharide to the feed can significantly improve egg quality, thereby improving the economic benefits of laying hen farming.

[0132] Table 3. Effects of Isatis indigotica polysaccharide on egg quality in laying hens

[0133]

[0134] Note: ① Data are from the Animal Nutrition Genomics and Germplasm Innovation Research Center of Hunan Agricultural University; ② Different lowercase letters in the superscript of peer data indicate significant differences (p<0.05), otherwise they indicate no significant differences; ③ SEM represents the standard error of the mean between groups.

[0135] 4. Effects of Isatis indigotica polysaccharides on the antioxidant capacity of egg yolks

[0136] The results of the effect of Isatis root polysaccharide on the antioxidant capacity of egg yolks in laying hens are as follows: Figure 1 As shown in the figure, compared with the blank control group (A1), the low-dose group (B1) significantly improved the total antioxidant capacity (T-AOC) of egg yolk (p<0.05), indicating that the addition of Isatis indigotica polysaccharide has the effect of improving the nutritional value and freshness of eggs.

[0137] 5. Effects of Isatis indigotica polysaccharide on the morphology of laying hen intestinal tissue

[0138] The effects of Isatis root polysaccharide on the morphology of laying hen intestinal tissue are as follows: Figure 2 , 3 As shown, compared with the blank control group (A1), the low-dose group (B1) showed increased duodenal villus height, significantly decreased crypt depth, and increased intestinal-to-intestinal ratio, but the differences were not significant (p>0.05); the high-dose group (B3) showed significantly increased jejunal villus height, with a significant difference (p<0.05); the low- and medium-dose groups (B1 and B2) showed decreased jejunal crypt depth and increased jejunal-to-intestinal ratio, but the differences were not significant (p>0.05). Villus height and intestinal-to-intestinal ratio (V / C) are generally considered to be positively correlated with intestinal integrity. The higher the villus height and intestinal-to-intestinal ratio (V / C), the stronger the animal's nutrient absorption and utilization capacity, the healthier the intestine, and the better the growth. Therefore, histomorphological analysis indicates that Isatis indigotica polysaccharide can improve intestinal integrity and intestinal health in laying hens.

[0139] 6. Effects of Isatis indigotica polysaccharide on the expression of cecal-related genes in laying hens

[0140] like Figures 4 to 11As shown, compared with the blank control group, the low-dose group significantly reduced the expression levels of pro-inflammatory cytokines IL-6, NF-κB, and COX2 (p<0.05); it also reduced the expression levels of IL-1β and TNF-α, but the differences were not significant (p>0.05); it increased the expression levels of anti-inflammatory cytokines IL-4 and IL-10, but the differences were not significant (p>0.05); it increased the expression levels of antioxidant genes keap1 and NQO1, but the differences were not significant (p>0.05); it increased the expression level of occludin intestinal barrier protein, with a highly significant difference (p<0.001); and it increased the expression level of ZQ-1, with a significant difference (p<0.05). These results further confirm that the addition of Isatis indigotica polysaccharide can reduce intestinal inflammation in chickens, improve the intestinal barrier, and has a function of improving and maintaining the health of chicken intestinal condition.

[0141] The Isatis root polysaccharide of this invention can effectively improve the egg quality of poultry, especially laying hens, and improve their intestinal health. The preparation process of the Isatis root polysaccharide of this invention is simple, and it can be obtained directly from the pharmaceutical process of Isatis root granules. It has low cost, and good results can be achieved with a small amount added; the addition amount in the basal diet can be as low as 100g / t (equivalent to 0.01wt%). The Isatis root polysaccharide of this invention can reduce poultry farming costs, reduce the economic burden on farmers, and is suitable for widespread promotion.

Claims

1. Application of radix isatidis polysaccharide as the only active ingredient in the preparation of a product for improving egg quality or intestinal health of poultry; The product is selected from poultry feed; the poultry is selected from chicken; the poultry feed is selected from chicken feed; the feed is divided into a low-dose group, a medium-dose group and a high-dose group; the low-dose group feed comprises 0.012-0.028% radix isatidis polysaccharide by mass percentage; the medium-dose group feed comprises 0.035-0.065% radix isatidis polysaccharide by mass percentage; and the high-dose group feed comprises 0.075-0.18% radix isatidis polysaccharide; The egg quality comprises at least one of egg shape index, yolk color, Haugh unit, albumen height, shell thickness or yolk antioxidant capacity; When the egg quality is selected from egg shape index, the feed is selected from a low-dose group, a medium-dose group or a high-dose group; when the egg quality is selected from yolk color, the feed is selected from a low-dose group or a high-dose group; when the egg quality is selected from Haugh unit, the feed is selected from a low-dose group or a medium-dose group; when the egg quality is selected from albumen height, the feed is selected from a low-dose group, a medium-dose group or a high-dose group; when the egg quality is selected from shell thickness, the feed is selected from a medium-dose group; and when the egg quality is selected from yolk antioxidant capacity, the feed is selected from a low-dose group. The intestinal health status comprises at least one of expression level of caecal gene or expression level of junction protein; the caecal gene is selected from inflammatory factor; the inflammatory factor is selected from proinflammatory cytokine; the proinflammatory cytokine comprises at least one of IL-6, NF-κB or COX2; and the junction protein comprises at least one of ZO-1 or occludin; When the intestinal health status is selected from expression level of caecal gene, the feed is selected from a low-dose group; and when the intestinal health status is selected from expression level of junction protein, the feed is selected from a low-dose group.

2. Use according to claim 1, characterized in that, The radix isatidis polysaccharide is prepared from radix isatidis by a water extraction and alcohol precipitation process.

3. Use according to claim 2, characterized in that, The radix isatidis polysaccharide is prepared by a preparation method comprising the following steps: S1. Radix isatidis is decocted in water, the decoction is filtered, and the filtrate is concentrated to obtain a clear paste; S2. Ethanol is added to the clear paste for precipitation, the precipitate is separated, dried and pulverized to obtain the radix isatidis polysaccharide.

4. Use according to claim 1, characterized in that, The poultry feed comprises a basic daily ration and radix isatidis polysaccharide.

5. Use according to claim 4, characterized in that, The basic daily ration comprises corn, soybean meal, soybean, oil, amino acid and mineral substance.

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