Polysaccharide additive for improving weight gain of donkey and feed conversion efficiency and preparation method of polysaccharide additive

Abstract

The invention relates to the technical field of feed additives, in particular to a polysaccharide additive for improving donkey weight gain and feed conversion efficiency and a preparation method thereof.The polysaccharide additive is prepared by mixing one or more of astragalus polysaccharide, ganoderma lucidum polysaccharide and zymosan serving as active ingredients with a carrier, when the feed additive is added into basic ration, the growth performance and the health state of donkeys in the fattening period can be remarkably improved; the additive can significantly improve the final weight and the whole-period average daily gain of the donkey, significantly reduce the feed-to-weight ratio, comprehensively enhance the immune function of the body, effectively improve the apparent digestibility of nutrient substances such as crude fat, acidic and neutral detergent fibers and the like, promote the generation of volatile fatty acids in the intestinal tract and optimize the health of the intestinal tract. The product is natural and safe, and an efficient and reliable alternative scheme is provided for overcoming the defects of a traditional feed additive in the aspects of growth promotion, immune enhancement and digestion and absorption.

Description

Technical Field

[0001] This invention relates to the field of feed additive technology, specifically to a polysaccharide additive for improving donkey weight gain and feed conversion efficiency, and its preparation method. Background Technology

[0002] In donkey farming, feed additives are widely used to improve animal growth performance, enhance immunity, and improve feed utilization efficiency. Traditional feed additives mainly include antibiotics, chemically synthesized substances, minerals, and vitamins. While these additives may provide some growth-promoting effects in the short term, long-term use has many drawbacks. Furthermore, with increasing consumer demands for food safety and animal welfare, and the growing prominence of antibiotic resistance, the development of green, safe, and efficient alternatives has become an urgent need for the industry. Existing feed additives commonly used in the field suffer from the following main drawbacks: 1) Limited Immunomodulatory Effects: While many traditional additives (such as certain antibiotics or chemical growth promoters) can promote weight gain to some extent, their effects on enhancing the animal's immune system are not significant, and may even suppress immune function. For example, long-term use of antibiotics may lead to intestinal flora imbalance, affecting intestinal mucosal immunity and reducing the animal's resistance to disease. In addition, existing additives mostly focus on single nutritional supplementation and lack synergistic enhancement of systemic immune indicators, such as serum immunoglobulin (IgA, IgG, IgM) and complement (C3, C4) levels, which often do not show significant improvement.

[0003] 2) Insufficient improvement in growth performance and feed conversion efficiency: Traditional additives are inconsistent in their effects on increasing daily weight gain and reducing feed conversion ratio, especially in the later stages of fattening, where weight gain often plateaus. Many additives can only stimulate growth in the short term but cannot maintain long-term effects, leading to low overall breeding efficiency. In addition, these additives often neglect their synergistic effect with feed digestibility; animals have low digestibility and absorption rates of crude protein, crude fat, and fiber, resulting in feed waste.

[0004] 3) Low apparent digestibility of nutrients: Existing additives are ineffective in improving the digestibility of key nutrients in feed (such as crude protein, crude fat, acid detergent fiber, and neutral detergent fiber). This is especially true for diets high in crude fiber (such as wheat straw and wheat bran), where animals have limited digestive capacity, resulting in a large amount of nutrients being excreted without being fully utilized. This not only increases farming costs but also exacerbates environmental pollution.

[0005] 4) Insignificant improvement in gut health. Gut health is a key factor affecting animal growth and immunity. Traditional additives have a weak regulatory effect on the gut microbiota and fermentation products, resulting in low concentrations of volatile fatty acids (such as acetic acid and propionic acid) in feces. Volatile fatty acids are an important source of energy for the gut, and low levels indicate inactive gut fermentation activity, which is detrimental to nutrient absorption and metabolic health.

[0006] 5) Safety and residue issues: Chemically synthesized additives and antibiotics may pose risks of drug residues and side effects, such as affecting liver function (manifested as elevated alanine aminotransferase ALT) or kidney function (abnormal creatinine CRE levels). Long-term use poses a threat to animal health and product safety. Summary of the Invention

[0007] In view of the above problems, the present invention provides a polysaccharide additive for improving donkey weight gain and feed conversion efficiency, and feed containing the additive.

[0008] The preparation method of the polysaccharide additive is as follows: the polysaccharide and the carrier are crushed separately, the polysaccharide is passed through a 100-mesh sieve and the carrier is passed through a 60-mesh sieve, and the crushed polysaccharide and the carrier are mixed at a mass ratio of 1:3 to obtain the polysaccharide additive.

[0009] Preferably, the polysaccharide is one or more of Astragalus polysaccharide (APS), Ganoderma lucidum polysaccharide (GLP), and yeast polysaccharide (YPS).

[0010] Preferably, the carrier comprises starch and rice husk in a mass ratio of 1:2. Most preferably, the starch is corn starch.

[0011] When using the polysaccharide additive, add 500-1500g of the polysaccharide additive per ton of basal diet.

[0012] Preferably, the basic diet includes wheat straw, wheat bran, corn, wheat bran, soybean meal, concentrate, premix one and premix two, with a mass ratio of 38.5:38.5:5.8:3.0:0.8:10:1.9:1.5.

[0013] Most preferably, the premix one contains ≥45% dry-basis protein + dry-basis fat, ≤35-45% moisture, ≤9% crude ash, and ≤10.5% crude fiber; the premix two includes 250,000-350,000 IU of vitamin A acetate, 30,000-80,000 IU of vitamin D3, 12-25% calcium, ≥2.5% phosphorus, 180-360 mg copper, 1150-3600 mg iron, and 1200-3600 mg zinc. The concentrated supplement includes 60,000-150,000 IU of vitamin A, ≥30 mg vitamin B1, ≥80 mg vitamin B2, ≥2.5% total phosphorus, 5% ≤ sodium chloride ≤12%, 10% ≤ calcium ≤16%, and ≥2.4% lysine.

[0014] The present invention has the following advantages: (1) Comprehensive enhancement of immune function and improved disease resistance: The additive of this invention can significantly increase the levels of immunoglobulins (IgA, IgG, IgM) and complement (C3, C4) in donkey serum. Experimental data show that in the middle and end of the experiment, the groups with added polysaccharides all showed significant improvements in immune indicators at different time points. For example, the Astragalus polysaccharide group significantly increased IgA and IgG levels at multiple time points (p<0.01), and the Ganoderma lucidum polysaccharide and yeast polysaccharide groups also showed similar effects. This comprehensive and sustained immune enhancement helps donkeys resist disease stress and reduce the risk of disease during the fattening period, which is something that traditional additives cannot achieve.

[0015] (2) Significantly improves weight gain rate and feed conversion efficiency. The additive of this invention can significantly increase the final body weight and average daily gain (ADG) of donkeys, while reducing the feed conversion ratio (F / G). Experimental results show that, compared with the control group, the final body weight of the polysaccharide-added group increased by about 8-10%, the average daily gain increased by about 16-22% throughout the experimental period, and the feed conversion ratio decreased by about 15-20%. This effect is particularly prominent in the later stage of the experiment, indicating that the additive has a sustained growth-promoting effect and avoids the problem of the decay of the effect of traditional additives.

[0016] (3) Significantly improves the apparent digestibility of nutrients. The additive of this invention can effectively enhance the digestion and absorption of key nutrients in feed by donkeys. At the end of the experiment, the groups with added polysaccharides showed significantly higher apparent digestibility of crude protein, crude fat, acid detergent fiber, and neutral detergent fiber than the control group. In particular, the digestibility of neutral detergent fiber in the Astragalus polysaccharide group was significantly improved (p<0.01), and the digestibility of crude fat in the yeast polysaccharide group was also significantly improved (p<0.05). This indicates that the additive enhances the intestinal capacity to break down complex nutrients and reduces feed waste.

[0017] (4) Promoting intestinal health and enhancing microbial fermentation: By measuring the volatile fatty acids in feces, the additive of this invention can significantly increase the concentrations of total volatile acids, acetic acid, and isobutyric acid. For example, the concentration of total volatile acids in the Ganoderma lucidum polysaccharide group was significantly higher than that in the control group (p<0.01), and the concentration of isobutyric acid in the Astragalus polysaccharide group was also significantly increased (p<0.01). These volatile fatty acids are products of intestinal microbial fermentation, and their elevated levels indicate an active intestinal flora, which is beneficial to energy metabolism and nutrient absorption, thereby indirectly supporting growth and immunity.

[0018] (5) Safe and residue-free with low side effects: This invention uses natural polysaccharide components, avoiding the potential risks of chemical additives and antibiotics. Blood biochemical indicators showed that the groups with added polysaccharides did not show abnormal fluctuations in liver function (ALT) and kidney function (CRE), and there were no significant differences between the groups at the end of the experiment, indicating that the additive has no adverse effects on the animal's internal environment and meets the requirements of green farming.

[0019] 6) The polysaccharide feed additive of this invention exhibits excellent effects in immune regulation, growth promotion, digestion improvement and intestinal health through multi-target action, effectively overcoming the defects of existing additives and providing an efficient and safe solution for the healthy breeding of donkeys. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Figure 1 This study investigated the effects of dietary supplementation with Astragalus polysaccharide, Ganoderma lucidum polysaccharide, and yeast polysaccharide on immune indicators in fattening donkey foals. The vertical axis represents the content of five serum immune proteins, and the horizontal axis represents six sampling time points. AE indicates mid-term sampling results; FJ indicates final-term sampling results. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The composition of the feed additives and basal diets in the following examples and comparative studies is as follows: YPS is a pale yellow powder with a purity >50%, purchased from Angel Yeast Co., Ltd. (Hubei, China). Main components and content: Moisture ≤8.0%, mannan oligosaccharides ≥20.0%, 20.0%≤β-glucan≤40.0%.

[0022] APS is a brown powder with a purity of >50%, purchased from Shaanxi Ronglin Biotechnology Co., Ltd. (Xi'an, Shaanxi). Main components and content: polysaccharides >50%.

[0023] GLP is a dark brown powder with a purity of >50%. Its main components are Ganoderma lucidum polysaccharides and Ganoderma lucidum triterpenes. It was purchased from Shaanxi Ronglin Biotechnology Co., Ltd. (Xi'an, Shaanxi).

[0024] Table 1. Composition and Nutritional Components of the Basal Diet

[0025] Note: Guaranteed component values ​​for Premix 1: Dry basis protein + dry basis fat ≥ 45%, moisture ≤ 35-45%, crude ash ≤ 9%, crude fiber ≤ 10.5%. Guaranteed component values ​​for Premix 2: Vitamin A acetate 250,000-350,000 IU, Vitamin D3 30,000-80,000 IU, Calcium 12-25%, Phosphorus ≥ 2.5%, Copper 180-360 mg, Iron 1150-3600 mg, Zinc 1200-3600 mg. Guaranteed component values ​​for Concentrated Supplement: Vitamin A 60,000-150,000 IU, Vitamin B1 ≥ 30 mg, Vitamin B2 ≥ 80 mg, Total Phosphorus ≥ 2.5%, 5% ≤ Sodium Chloride ≤ 12%, 10% ≤ Calcium ≤ 16%, Lysine ≥ 2.4%.

[0026] Example 1 APS and the carrier were pulverized separately. The APS was passed through a 100-mesh sieve, and the carrier was passed through a 60-mesh sieve. The pulverized polysaccharide and the carrier were mixed at a mass ratio of 1:3 to obtain the APS additive. The carrier consisted of corn starch and rice husk in a mass ratio of 1:2.

[0027] Example 2

[0028] The difference from Example 1 is that this example uses YPS.

[0029] Example 3

[0030] The difference from Example 1 is that this example uses GLP.

[0031] Experimental Example 1 Twenty-eight Dezhou donkey foals aged 6 months and with similar weights (94.93±3.02 kg) were selected for the experiment. A randomized block design was used, randomly assigning the foals to four treatment groups: APS, GLP, YPS, and CTR, with seven replicates per group and one foal per pen. The control group (CTR) was fed a basal diet, while the treatment groups (APS, GLP, and YPS) were fed a basal diet supplemented with 5 g / (head·day) of polysaccharide additive. The experiment lasted 90 days, with a 3-day pre-feeding period and an 87-day trial period. The donkey sheds were semi-enclosed, house-style structures with suitable temperature and humidity, good ventilation, and sufficient space. Before the experiment, the sheds and each pen were disinfected to ensure cleanliness. Each pen was equipped with an independent water trough and feed trough. During the pre-feeding period, each donkey was assigned an individual ear tag for accurate data recording. Throughout the feeding period, the foals were fed twice a day, once at 9:00 and once at 17:00. The foals had free access to food, water, and exercise.

[0032] During the mid-term of the experiment (day 35), blood was collected at six time points over two days (1:00, 5:00, 9:00, 13:00, 17:00, 21:00); during the final stage of the experiment (day 87), blood was collected at six time points over two days (2:00, 6:00, 10:00, 14:00, 18:00, 22:00). At the mid-term (5:00, 13:00) and final stage (6:00, 14:00) time points, an additional 10mL heparin sodium blood collection tube and a 10mL EDTA blood collection tube were drawn for routine blood count and biochemical analysis. At the other time points, two 10mL EDTA blood collection tubes were centrifuged at 3000×g for 10 minutes to separate the plasma, which was then stored at -80℃ for later analysis. The routine blood test included white blood cell count (WBC), lymphocyte count (Lym), monocyte count (Mon), neutrophil count (Gran), red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular hemoglobin (MCH), and platelet count (MPV), all measured using a fully automated hematology analyzer. Biochemical tests included albumin (ALB), total serum protein (TP), globulin (GLO), glucose (GLU), blood urea nitrogen (BUN), cholesterol (CHOL), alanine aminotransferase (ALT), total bilirubin (TBIL), alkaline phosphatase (ALP), creatinine (CRE), and creatine kinase (CK), all measured using a fully automated biochemical analyzer. Immunological markers included immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), complement C3, and complement C4, all measured using a 96T ELISA kit. Results are shown in Table 2 and Appendix. Figure 1 .

[0033] Table 2. Effects of adding polysaccharide additives to feed on blood routine and blood biochemical indicators of Dezhou donkey foals.

[0034] Note: TP, Total Protein; GLU, Glucose; CHOL, Cholesterol; ALT, Alanine Aminotransferase; ALP, Alkaline Phosphatase; CRE, Creatinine; WBC, White Blood Cells; RBC, Red Blood Cells; HGB, Hemoglobin. YPS, Yeast Polysaccharide Group; CTR, Control Group. No letter or the same letter in the same row indicates no significant difference (p>0.05), different lowercase letters indicate significant difference (p<0.05), and different uppercase letters indicate extremely significant difference (p<0.01). The same applies to the following table.

[0035] As shown in Table 2, during the mid-term tests, the serum TP levels in the APS and GLP groups were significantly higher than those in the YPS and CTR groups (p<0.01); the serum ALT levels in the APS group were significantly higher than those in the YPS and CTR groups (p<0.01); the serum ALP levels in the APS, GLP, and YPS groups were significantly higher than those in the CTR group (p<0.01); and the serum CRE levels in the APS group were significantly higher than those in the YPS and CTR groups (p<0.01), while those in the GLP group were significantly higher than those in the YPS and CTR groups (p<0.05). At the end of the experiment, there were no significant differences among the groups (p>0.05).

[0036] Depend on Figure 1 visible, Figure 1 In Group A, the serum IgA and IgG levels of donkey foals in the APS, GLP, and YPS groups were all higher than those in the CTR group. Specifically, the serum IgA level in the APS group was significantly higher than that in the CTR group at 5:00, 13:00, and 17:00 (p<0.05), and extremely significantly higher at 9:00 and 21:00 (p<0.01). The serum IgA level in the GLP group was significantly higher than that in the CTR group at 1:00 (p<0.05), and extremely significantly higher at 13:00 and 21:00 (p<0.01). The serum IgA level in the YPS group was significantly higher than that in the CTR group at 5:00, 9:00, and 17:00 (p<0.05). In the APS group, the serum IgG level of donkey foals was significantly higher than that of the CTR group at 5:00 (p<0.05), and significantly higher at 1:00 and 17:00 (p<0.01); in the YPS group, the levels were significantly higher than those of the CTR group at 1:00, 5:00 and 21:00 (p<0.05). Figure 1 In the C group, the serum IgM levels of donkey foals in the APS and YPS groups were higher than those in the CTR group at all time points. The difference was significant in the APS group at 17:00 (p<0.05), and extremely significant in the YPS group at 1:00 and 5:00 (p<0.01). The difference was extremely significant in the GLP group at 5:00 (p<0.01). Figure 1 In the D-group, the serum complement C3 level of donkey foals showed better performance at four time points: 5:00, 9:00, 13:00, and 17:00. Among them, the YPS group showed significantly higher levels than the CTR group at 9:00 and 17:00 (p<0.05). Figure 1In the GLP group, serum complement C4 levels in donkey foals were significantly higher than those in the CTR group at all time points, with significant differences at 1:00 and 5:00 (p<0.05), and highly significant increases at 9:00, 13:00, 17:00, and 21:00 (p<0.01). In the APS group, serum complement C4 levels were significantly higher than those in the CT group at 1:00 (p<0.05), and highly significant increases at 13:00 and 21:00 (p<0.01). In the YPS group, serum complement C4 levels were significantly higher than those in the CTR group at 1:00, 9:00, and 17:00 (p<0.05), and highly significant increases at 13:00 and 21:00 (p<0.01).

[0037] Figure 1 In the F group, the serum IgA level of donkey foals in the APS group was significantly higher than that in the CTR group at 2:00 and 6:00 (p<0.01); the level in the GLP group was significantly higher than that in the CTR group at 2:00 and 10:00 (p<0.05), and the difference was extremely significant at 6:00 (p<0.01); the level in the YPS group was significantly higher than that in the CTR group at 2:00 and 6:00 (p<0.05). Figure 1 In the GLP group, the serum IgG level of donkey foals was significantly higher than that in the CTR group, and the differences were extremely significant at the other five time points except 6:00 (p<0.01); in the GLP group, the serum IgG level of donkey foals was significantly higher than that in the CTR group, and the differences were significant at 6:00 and 14:00 (p<0.05), and extremely significant at 2:00 and 18:00 (p<0.01); in the YPS group, the serum IgG level of donkey foals was significantly higher than that in the CTR group, and the differences were significant at 18:00 and 22:00 (p<0.05), and extremely significant at 10:00 and 14:00 (p<0.01). Figure 1 In H, the serum IgM levels of donkey foals in the APS, GLP, and YPS groups were all higher than those in the CTR group. Except for the APS group at 18:00, all other treatment groups showed significant (p<0.05) or highly significant (p<0.01) differences compared to the control group at all time points. Figure 1 In the APS group, serum complement C3 levels were significantly higher than those in the CTR group at 6:00 and 10:00 (p<0.01); in the GLP group, the levels were significantly higher than those in the CTR group at 6:00 (p<0.05) and significantly higher at 10:00 (p<0.01); and in the YPS group, the levels were significantly higher than those in the CTR group at both 6:00 and 10:00 (p<0.01). Figure 1 In the study, the serum complement C4 levels in the three treatment groups of donkey foals showed a significant increase compared to the control group at 6:00. The APS and GLP groups showed extremely significant differences compared to the CTR group (p<0.01), while the YPS group showed a significant difference compared to the CTR group (p<0.05).

[0038] Test Example 2 On the morning before feeding on the 1st day (initial weight), 35th day (mid-term weight), and 87th day (final weight) of the formal trial period, all experimental foals were weighed and the data were recorded, and the average daily gain (ADG) of the foals was calculated. In addition, taking the pen as the unit, dietary feed samples and dietary leftovers were collected continuously for 3 days within each week of the feeding trial, and the dry matter intake (DMI) of the foals was recorded every day. The calculation methods of average daily gain, dry matter intake, and feed-to-gain ratio are as follows, and the results are shown in Table 3: ADG = (final weight - initial weight) / number of trial days; DMI = (fed diet × its DM content) - (remaining diet × its DM content); Feed-to-gain ratio (F / G) = dry matter intake / average daily gain.

[0039] Table 3 Effects of Feed Additives on the Growth Performance of Fattening Foals

[0040] Note: ADG1 is the average daily gain from the start of the trial to the mid-term of the trial; ADG2 is the average daily gain from the mid-term of the trial to the end of the trial; ADG is the average daily gain for the entire trial period.

[0041] As can be seen from Table 3, compared with the control group (CTR), adding APS, GLP, and YPS to the diet increased the weight of the experimental foals in the mid-term of the fattening period, but the difference was not significant (p > 0.05); the final weights of the APS group, GLP group, and YPS group were significantly higher than those of the CTR group (p < 0.05), but there was no significant difference among the APS group, GLP group, and YPS group (p > 0.05). Correspondingly, the average daily gain (ADG2) of the foals in the APS group, GLP group, and YPS group from the mid-term of the trial to the end of the trial was significantly higher than that of the CTR group (p < 0.05); the average daily gain (ADG) of the foals in the APS group and GLP group for the entire trial period was significantly higher than that of the CTR group (p < 0.05); the average daily gain (ADG) of the YPS group for the entire trial period increased compared with the CTR group, and there was a significant trend (0.05 < p < 0.1). The average daily gain (ADG1) of the APS group, GLP group, and YPS group from the start of the trial to the mid-term of the trial was greater than that of the CTR group, but the difference was not significant (p > 0.05). In addition, compared with the control group, the feed-to-gain ratio of the foals in the APS group, GLP group, and YPS group was significantly reduced (p < 0.05).

[0042] Test Example 3 Dietary mixture samples were collected using the quartering method, dried at 65℃ for 24 hours to prepare air-dried samples, and stored in sealed bags for the determination of nutrient content in the feed. Before the end of the experiment, 500g of feces samples were collected from each female donkey and foal, prepared as air-dried samples, and stored in sealed bags for the determination of moisture (H2O), ash (Ash), acid-insoluble ash (AIA), crude protein (CP), crude fat (CF), acid detergent fiber (ADF), neutral detergent fiber (NDF), calcium (Ca), and phosphorus (P) content.

[0043] The H2O content of feed samples and fecal samples was determined according to GB / T 6435-2014, the ASH content according to GB / T 23742-2009, the CP content according to GB / T 6432-2018 using a semi-automatic Kjeldahl nitrogen analyzer (K9840), the CF content according to GB / T 6433-2006, the ADF and NDF contents according to NY / T 1459-2007 and GB / T 20806-2006 respectively using a fully automatic crude fiber analyzer (ANKOM-A20001), and the P and Ca contents according to GB / T 6437-2018 and GB / T 6436-2018 respectively. The results are shown in Table 4.

[0044] The apparent digestibility of each nutrient in the diet was calculated using the acid-insoluble ash method (endogenous indicator method). The formula is as follows: Apparent digestibility of a nutrient (%) = (a / cb / d) / (a / c) × 100. Where: a is the content of the nutrient in the diet (%); b is the content of the nutrient in the feces (%); c is the content of the indicator in the diet (%); d is the content of the indicator in the feces (%).

[0045] Table 4. Effects of feed additives on the apparent digestibility of nutrients in fattening donkey foals.

[0046] Note: The data for CTR, APS, GLP, and YPS in the table are percentages.

[0047] As can be seen from Table 4, in the middle stage of the experiment, the apparent digestibility of CP, EE, ADF, and NDF in foal donkeys in the APS group, GLP group, and YPS group increased compared with the CTR group. Among them, there was a significant trend in the apparent digestibility of ADF in the APS group compared with the CTR group (0.05 < p < 0.1). At the end of the experiment, the apparent digestibility of CP, EE, ADF, and NDF in foal donkeys in the APS group, GLP group, and YPS group increased compared with the CTR group. Among them, the apparent digestibility of EE in the YPS group increased and was significantly different from the other three groups (p < 0.05); the apparent digestibility of ADF in the APS group increased and was extremely significantly different from the other three groups (p < 0.01); the apparent digestibility of NDF in the APS group increased and was extremely significantly different from the CTR group (p < 0.01), and increased and was significantly different from the YPS group (p < 0.05).

[0048] Experimental Example 4 Weigh 0.3 g of fecal samples with a balance and place them in a 2 mL centrifuge tube. Add 1 mL of ultrapure water, shake well, centrifuge at 12000 rpm for 10 min, aspirate 500 μL of the supernatant and add 100 μL of 25% (w / v) crotonic acid metaphosphate solution, incubate at -20 °C overnight and then centrifuge at 12000 rpm for 10 min. Aspirate the supernatant and filter it with a 0.22 μm filter membrane before measurement. Use the Beijing East Analytical GC-4000A gas chromatograph to measure the volatile fatty acids (VFA) in feces, and the results are shown in Table 5.

[0049] Table 5 Effects of feed additives on fecal VFA in fattening foal donkeys.

[0050]

[0051] As can be seen from Table 5, the rectal acetic acid concentrations in foal donkeys in the APS group, GLP group, and YPS group increased by 48.85% (p > 0.05), 110.83% (p < 0.01), and 65.19% (p > 0.05) respectively compared with the CTR group. The rectal isobutyric acid concentration in foal donkeys in the APS group was significantly higher than that in the GLP group, YPS group, and CTR group (p < 0.01). The rectal isovaleric acid concentration in foal donkeys in the YPS group was significantly higher than that in the CTR group (p < 0.05). The rectal acetic acid / propionic acid in foal donkeys in the APS group, GLP group, and YPS group was lower than that in the CTR group, but the difference was not significant (p > 0.05). The total volatile acids in the rectum of foal donkeys in the APS group, GLP group, and YPS group were higher than those in the CTR group, and the GLP group was significantly higher than the CTR group (p < 0.05).

[0052] This invention investigated the effects of dietary supplementation with APS, GLP, and YPS on the growth performance of donkey foals during the fattening period. The results showed that, with minimal difference in initial weight between the three treatment groups and the control group, the addition of APS, GLP, and YPS all increased the final weight of the foals. Correspondingly, the average daily weight gain (ADG1, ADG2) of the three treatment groups was higher than that of the control group at both time points and throughout the entire experimental period. Furthermore, the dry matter intake of foals in the APS group was significantly lower than that in the GLP, YPS, and CTR groups. There was no significant difference among the GLP, YPS, and CTR groups, while the feed conversion ratio (FCR) of the APS, GLP, and YPS groups was significantly lower than that of the control group.

[0053] Serum TP levels generally reflect the strength of protein synthesis and metabolism in the body. Increased serum TP levels are beneficial for improving metabolic levels and immunity, promoting healthy growth in animals. Results showed that adding 5g / (head·day) of APS or GLP increased serum TP levels in fattening foals, indicating that adding APS or GLP improved the foals' resistance and promoted healthy growth. ALP is a lysosomal enzyme within the phagocytic cells of foals, playing a crucial role in the phagocytic and bactericidal abilities of these cells. Furthermore, bone is the most common extrahepatic ALP source, and new bone growth is associated with elevated ALP levels, explaining why foals have higher ALP levels than adult donkeys. ALP activity reflects the growth rate and performance of foals. Results showed that ALP levels in the three treatment groups were significantly higher than in the control group, indicating that adding APS, GLP, and YPS to the diet can improve the growth performance of foals. Notably, the blood indicators of each foal were within the healthy range for equines, ensuring the health of each donkey.

[0054] Apparent digestibility of nutrients is an important indicator for evaluating animal feeding performance and diet quality. Currently, reports on the effects of Astragalus polysaccharides and yeast polysaccharides on the apparent digestibility of animal nutrients are relatively common, while reports on Ganoderma lucidum polysaccharides are less frequent. Results showed that the effect of APS on the apparent digestibility of nutrients in Texas donkey foals was mainly reflected in the digestibility of ADF and NDF, while YPS was mainly reflected in the digestibility of EE and NDF, while GLP had no significant effect on the apparent digestibility of nutrients in foals. Dietary supplementation with APS and YPS may improve the growth performance of foals by enhancing their digestion and absorption of nutrients.

[0055] This invention also investigated the effects of adding APS, GLP, and YPS on immune indicators of fattening donkey foals, including IgA, IgG, IgM, C3, and C4. IgA accounts for 10-20% of serum immunoglobulin content. Newborn serum lacks IgA antibodies, and most acquire secretory IgA from breast milk. IgG is the most abundant antibody component in human serum, playing a crucial role in natural passive immunity. IgM is the body's vanguard against infection, a basic antibody secreted by B cells. Complement C3 and C4 are important members of the complement system, playing a key role in immune activation. The experiment measured the levels of the five immune markers in Texas donkey foals at 12 time points. The results showed that the addition of APS, GLP, and YPS increased the levels of the five immune markers in foal serum to varying degrees at each time point, significantly improving the immune function of the foals.

[0056] The most basic function of volatile fatty acids (VFAs) in monogastric animals is to provide energy. In the hindgut of donkeys, various nutrients undergo fermentation, among which carbohydrate fermentation produces VFAs. VFAs promote intestinal development, with acetic acid, propionic acid, and butyric acid being the main components. The composition of the feed ingested by the animal affects the total amount of fermentation, and the proportion of carbohydrates from different sources in the feed affects the fermentation rate. Acetic acid is mainly used to synthesize fats, while propionic acid is primarily used to synthesize glucose. Sufficient propionic acid production can meet the animal's glucose requirements. In the experiment, the concentrations of acetic acid and propionic acid in the rectum of donkey foals in the APS, GLP, and YPS groups were all higher than those in the CTR group to varying degrees, which has a certain promoting effect on the growth of donkey foals. On the other hand, the acetic acid / propionic acid ratio can reflect energy utilization efficiency to some extent. A lower acetic acid / propionic acid ratio can reduce the loss of feed energy. In this experiment, the acetic acid / propionic acid ratio tended to be consistent, and the difference was not statistically significant, indicating that dietary supplementation with APS, GLP, and YPS had no significant effect on energy utilization. The level of TVFA directly reflects the amount of energy supplied. The results of this experiment show that the TVFA level in the rectum of donkeys in the APS group, GLP group, and YPS group was significantly higher than that in the CTR group. This indicates that the addition of APS, GLP, and YPS to the diet increases the energy metabolism in donkeys, which is beneficial to the growth and development of donkeys and achieves the fattening effect.

[0057] This invention demonstrates that dietary supplementation with APS, GLP, and YPS can increase the average daily weight gain of fattening donkey foals and significantly reduce the feed conversion ratio, thereby improving foal growth performance. Furthermore, the addition of Astragalus polysaccharides, Ganoderma lucidum polysaccharides, and yeast polysaccharides can enhance the apparent digestibility of EE, ADF, and NDF in fattening Dezhou donkey foals. In addition, the polysaccharides increased the levels of TP (total protein) related to metabolism and immunity, and ALP (alcoholic acid) related to animal growth. Monitoring of foal immune function over 24 hours revealed that APS, GLP, and YPS significantly promoted foal immune function. Regarding the VFA (vitamin Acid) content in foal feces, all three polysaccharides increased the concentrations of acetic acid, propionic acid, and total volatile fatty acids, and decreased the acetic acid-to-propionic acid ratio. This indicates that all three polysaccharides can promote the production of VFA in the donkey's gastrointestinal tract, increasing the body's energy supply and thus promoting foal growth.

[0058] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a polysaccharide additive to improve weight gain and feed conversion efficiency in donkeys, characterized in that, The polysaccharide and carrier are crushed separately and then mixed in a mass ratio of 1:3 to obtain the polysaccharide additive.

2. The method for preparing the polysaccharide additive according to claim 1, characterized in that, The polysaccharide is one or more of Astragalus polysaccharide, Ganoderma lucidum polysaccharide and yeast polysaccharide.

3. The method for preparing the polysaccharide additive according to claim 1, characterized in that, The carrier comprises starch and rice husks in a mass ratio of 1:

2.

4. The method for preparing the polysaccharide additive according to claim 3, characterized in that, The starch is corn starch.

5. The polysaccharide additive prepared by the method according to any one of claims 1-4.

6. A feed containing the polysaccharide additive according to any one of claims 1-5, characterized in that, It includes a basal diet and polysaccharide additives, with a mass ratio of 1000:(0.5-1.5).

7. The feed according to claim 6, characterized in that, The basal diet includes wheat straw, wheat bran, corn, wheat bran, soybean meal, concentrate supplement, premix one and premix two, with a mass ratio of 38.5:38.5:5.8:3.1:0.8:10:1.9:1.

5.

8. The feed according to claim 7, characterized in that, The first premix contains ≥45% dry-basis protein + dry-basis fat, ≤35-45% moisture, ≤9% crude ash, and ≤10.5% crude fiber. The second premix contains 250,000-350,000 IU of vitamin A acetate, 30,000-80,000 IU of vitamin D3, 12-25% calcium, ≥2.5% phosphorus, 180-360 mg copper, 1150-3600 mg iron, and 1200-3600 mg zinc. The concentrated supplement contains 60,000-150,000 IU of vitamin A, ≥30 mg vitamin B1, ≥80 mg vitamin B2, ≥2.5% total phosphorus, 5% ≤ sodium chloride ≤12%, 10% ≤ calcium ≤16%, and ≥2.4% lysine.

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