Application of 25-hydroxyvitamin D3 in preparation of feed for improving growth performance of broiler chickens

Abstract

The invention provides application of 25-hydroxyvitamin D3 in preparation of feed for improving growth performance of broiler chickens, and belongs to the technical field of animal feed. In the application provided by the invention, the feed for improving the growth performance of the broiler chickens comprises a low-calcium and low-phosphorus feed, and the calcium and phosphorus levels in the low-calcium and low-phosphorus feed are as follows: the mass percent of total calcium is 0.6-1%, and the mass percent of available phosphorus is 0.2-0.45%. According to the invention, 60-65 [mu] g / kg of 25-hydroxyvitamin D3 is added into the broiler feed, especially the 25-hydroxyvitamin D3 is added into the low-calcium and low-phosphorus feed, so that the cost of the feed can be reduced, and the growth performance of broilers can be improved; the bone quality and the pectoral muscle rate of the broiler chicken are improved; absorption of calcium and phosphorus is promoted; the immune function of the broiler chicken is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of animal feed technology, and in particular relates to the application of 25-hydroxyvitamin D3 in the preparation of feed to improve the growth performance of broilers. Background Technology

[0002] Calcium and phosphorus are the main components of bones, primarily increasing bone strength and enhancing bone health. They also participate in various metabolic processes, including regulating nerve and muscle excitation, enzyme activity, energy metabolism, and the formation of cell membrane phospholipids and genetic material. Therefore, adequate calcium and phosphorus levels are crucial for ensuring broiler bone health and growth performance. To meet the calcium and phosphorus requirements of broilers, excessive amounts are often added to their diets. However, feeding chickens with excessive calcium and phosphorus not only increases feeding costs but also results in high levels of calcium and phosphorus in their excrement, polluting soil and groundwater, and negatively impacting crops and the ecological environment. Therefore, to reduce broiler feeding costs and minimize environmental damage, it is essential to address the technical challenge of maintaining or improving broiler growth performance, bone quality, breast muscle mass, and immune function while reducing calcium and phosphorus levels in broiler feed formulations.

[0003] Vitamin D3 plays a crucial role in the absorption and metabolism of calcium and phosphorus. After absorption in the intestines, dietary vitamin D3 is converted into 25-hydroxyvitamin D3 in the liver, and subsequently into 1,25-dihydroxyvitamin D3 in the kidneys. 1,25-dihydroxyvitamin D3 is transported to target organs such as the intestines, bones, muscles, kidneys, and immune system by vitamin D-binding proteins, thereby exerting its corresponding biological functions, such as promoting the absorption and transport of calcium and phosphorus in the intestines, promoting the reabsorption of calcium and phosphorus in the renal tubules, and promoting bone mineralization. However, after reducing the levels of calcium and available phosphorus in the feed formulation to below the recommended addition levels for broilers by the US NRC (1994), how to adjust the broiler feed formulation to maintain or improve the growth performance, bone quality, breast muscle rate, and immune function of broilers remains a pressing technical problem to be solved in this field. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide the application of 25-hydroxyvitamin D3 in the preparation of feed to improve the growth performance of broilers. By adding 25-hydroxyvitamin D3 to broiler feed, especially low-calcium and low-phosphorus broiler feed, it is possible to reduce feed costs while promoting the absorption of calcium and phosphorus, and maintaining or improving the growth performance, bone quality, breast muscle rate, and immune function of broilers.

[0005] This invention provides the application of 25-hydroxyvitamin D3 in the preparation of feed to improve the growth performance of broilers, wherein the amount of 25-hydroxyvitamin D3 added to the feed is 60-65 μg / kg.

[0006] Preferably, the feed comprises a low-calcium, low-phosphorus feed, wherein the calcium and phosphorus levels in the low-calcium, low-phosphorus feed are: 0.6% to 1% by mass of total calcium and 0.2% to 0.45% by mass of available phosphorus.

[0007] Preferably, the 25-hydroxyvitamin D3 can improve the growth performance of broilers.

[0008] Preferably, the 25-hydroxyvitamin D3 can improve the bone quality of broilers.

[0009] Preferably, the bone quality of the broiler chicken includes the ash content, calcium content, phosphorus content, and strength of the tibia.

[0010] Preferably, the 25-hydroxyvitamin D3 can increase pectoral muscle rate.

[0011] Preferably, the 25-hydroxyvitamin D3 can promote the absorption of calcium and phosphorus.

[0012] Preferably, the 25-hydroxyvitamin D3 can enhance the immune function of broilers.

[0013] The present invention also provides a low-calcium and low-phosphorus feed, characterized in that the amount of 25-hydroxyvitamin D3 added to the feed is 60-65 μg / kg; the calcium and phosphorus levels in the feed are: the mass percentage of total calcium is 0.6%-1%, and the mass percentage of available phosphorus is 0.2%-0.45%.

[0014] Preferably, when the feed is used to feed 1-21 day old broilers, the total calcium content in the feed is 0.7%-1% by mass, and the available phosphorus content is 0.3%-0.45% by mass; when the feed is used to feed 22-42 day old broilers, the total calcium content in the feed is 0.6%-0.9% by mass, and the available phosphorus content is 0.2%-0.35% by mass.

[0015] The beneficial effects of this invention are:

[0016] This invention provides the application of 25-hydroxyvitamin D3 in the preparation of feed to improve the growth performance of broilers. The dosage of 25-hydroxyvitamin D3 in this invention not only promotes bone development and improves the growth performance, breast muscle rate, and immune function of broilers when added to normal feed, but also promotes the absorption and utilization of calcium and phosphorus when added to low-calcium and low-phosphorus feed, maintaining bone development, ensuring the growth performance of broilers, improving breast muscle rate, and enhancing the immune function of broilers. Furthermore, reducing the levels of calcium and phosphorus in the formula also saves on feed costs, which is of great significance for achieving cost reduction and efficiency improvement in broiler farming and reducing environmental pollution. Detailed Implementation

[0017] This invention provides the application of 25-hydroxyvitamin D3 in the preparation of feed to improve the growth performance of broilers. The amount of 25-hydroxyvitamin D3 added to the feed is 60-65 μg / kg (equivalent to 2400 IU / kg-2600 IU / kg), preferably 62-63 μg / kg, and more preferably 62.5 μg / kg.

[0018] Adding 25-hydroxyvitamin D3 to broiler feed can improve the absorption and utilization of calcium and phosphorus, which can not only promote bone development, but also ensure the growth performance of broilers, increase breast muscle rate, and enhance the immune function of broilers.

[0019] The feed preferably includes a low-calcium, low-phosphorus feed. The preferred calcium and phosphorus levels in the low-calcium, low-phosphorus feed are: a total calcium mass percentage of 0.6%–1% and an available phosphorus mass percentage of 0.2%–0.45%. More preferably, when the feed is used to feed 1–21-day-old broilers, the total calcium mass percentage is 0.7%–1% and the available phosphorus mass percentage is 0.3%–0.45%; when the feed is used to feed 22–42-day-old broilers, the total calcium mass percentage is 0.6%–0.9% and the available phosphorus mass percentage is 0.2%–0.35%. Even more preferably, when the feed is used to feed 1–21-day-old broilers, the feed… The total calcium content is greater than or equal to 0.7% and less than 1% by mass. In one embodiment, it can be 0.9%, 0.8%, or 0.7%. The available phosphorus content is greater than or equal to 0.3% and less than 0.45% by mass. In one embodiment, it can be 0.4%, 0.35%, or 0.3%. When the feed is used to feed 22-42 day old broilers, the total calcium content is greater than or equal to 0.6% and less than 0.9% by mass. In one embodiment, it can be 0.8%, 0.7%, or 0.6%. The available phosphorus content is greater than or equal to 0.2% and less than 0.35% by mass. In one embodiment, it can be 0.3%, 0.25%, or 0.2%.

[0020] In this invention, the addition of 25-hydroxyvitamin D3 to broiler feed preferably improves the growth performance of broilers; the preferred growth performance includes daily feed intake (g / d), daily weight gain (g / d), and feed conversion ratio. Preferably, the 25-hydroxyvitamin D3 also improves the bone quality of broilers; the preferred bone quality includes tibia ash content, tibia calcium content, tibia phosphorus content, and tibia strength. Preferably, the 25-hydroxyvitamin D3 also improves pectoral muscle percentage. Preferably, the 25-hydroxyvitamin D3 also promotes calcium and phosphorus absorption, increasing the calcium and phosphorus content in broiler serum. Preferably, the 25-hydroxyvitamin D3 also enhances the immune function of broilers; the enhancement of the immune function preferably includes increasing the levels of IgG and anti-inflammatory factor IL-10 in broiler serum and / or decreasing the level of pro-inflammatory factor IL-1β.

[0021] This invention also provides a low-calcium, low-phosphorus feed, characterized in that the amount of 25-hydroxyvitamin D3 added to the feed is 60-65 μg / kg, preferably 62-63 μg / kg, and more preferably 62.5 μg / kg. The calcium and phosphorus levels in the feed are: total calcium 0.6%-1% by mass, and available phosphorus 0.2%-0.45% by mass. More preferably, when the feed is used to feed 1-21 day old broilers, the total calcium content is 0.7%-1% by mass, and the available phosphorus content is 0.3%-0.45% by mass; when the feed is used to feed 22-42 day old broilers, the total calcium content is 0.6%-0.9% by mass, and the available phosphorus content is 0.2%-0.35% by mass. More preferably, when the feed is used to feed 1-21 day old broilers, the total calcium content in the feed is greater than or equal to 0.7% and less than 0.1% by mass; in one embodiment, 0.9%, 0.8%, or 0.7% can be selected. The available phosphorus content is greater than or equal to 0.3% and less than 0.45% by mass; in one embodiment, 0.4%, 0.35%, or 0.3% can be selected. When the feed is used to feed 22-42 day old broilers, the total calcium content in the feed is greater than or equal to 0.6% and less than 0.9% by mass; in one embodiment, 0.8%, 0.7%, or 0.6% can be selected. The available phosphorus content is greater than or equal to 0.2% and less than 0.35% by mass; in one embodiment, 0.3%, 0.25%, or 0.2% can be selected.

[0022] This invention does not impose any special restrictions on the source of the calcium, available phosphorus, and 25-hydroxyvitamin D3; conventional commercially available products in the art can be used. In one embodiment, 900–1100 U / kg of phytase may also be added to the broiler feed, preferably 1000 U / kg, wherein the phytase activity is 10000 U / g.

[0023] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0024] Unless otherwise specified, the following embodiments are all conventional methods.

[0025] Unless otherwise specified, all materials and reagents used in the following examples are commercially available. The 25-hydroxyvitamin D3 used in the following examples was obtained from Keinger Biotechnology (Yichang) Co., Ltd.

[0026] Example 1

[0027] A feed to improve the growth performance of broilers

[0028] Adding 62.5 μg / kg of 25-hydroxyvitamin D3 to the basic broiler feed yields a feed that improves broiler growth performance.

[0029] The basal broiler feed for the early stage of the experiment (broilers aged 1-21 days) and the later stage of the experiment (broilers aged 22-42 days) consisted of the ingredients listed in Tables 1 and 2:

[0030] Table 1. Basic feed formulation for the early stage of the experiment (broilers 1-21 days old)

[0031]

[0032]

[0033] Table 2. Basic feed formulations for the later stage of the experiment (broilers 22-42 days old).

[0034]

[0035] Note: (1) The premix provides the following per kilogram of basal broiler feed: Vitamin A 12000 IU; Vitamin D3 2760 IU; Vitamin E 30 IU; Vitamin K3 2 mg; Vitamin B1 2.1 mg; Vitamin B2 8 mg; Vitamin B6 4 mg; Vitamin B 12 0.015mg; niacin 40mg; choline chloride 450mg; pantothenic acid 11mg; biotin 0.2mg; folic acid 1mg; manganese 90mg; iron 70mg; zinc 75mg; copper 8mg; iodine 0.8mg; selenium 0.3mg; (2) Nutritional levels are all calculated values.

[0036] Example 2

[0037] A feed to improve the growth performance of broilers

[0038] By adding 60 μg / kg of 25-hydroxyvitamin D3 to the basic broiler feed in Example 1, a feed that improves the growth performance of broilers was obtained.

[0039] Example 3

[0040] A feed to improve the growth performance of broilers

[0041] By adding 65 μg / kg of 25-hydroxyvitamin D3 to the basic broiler feed in Example 1, a feed that improves the growth performance of broilers was obtained.

[0042] Example 4

[0043] A feed to improve the growth performance of broilers

[0044] The only difference between the basic broiler feed and Example 1 is that, in the early stage of the experiment (broilers 1-21 days old), the calcium and available phosphorus levels were 0.9% and 0.4%, respectively, and in the later stage of the experiment (broilers 22-42 days old), the calcium and available phosphorus levels were 0.8% and 0.3%, respectively. These calcium and phosphorus levels were adjusted by reducing the levels of limestone powder and dicalcium phosphate in the feed formulation. After reducing the addition of calcium and phosphorus, the addition of corn, soybean meal, soybean oil, and amino acids were slightly adjusted to maintain the original levels of crude protein, metabolizable energy, and amino acids. Everything else was the same as in Example 1.

[0045] Adding 62.5 μg / kg of 25-hydroxyvitamin D3 to the basic broiler feed yields a feed that improves broiler growth performance.

[0046] Example 5

[0047] A feed to improve the growth performance of broilers

[0048] The only difference between the basic broiler feed and Example 1 is that, in the early stage of the experiment (broilers 1-21 days old), the calcium and available phosphorus levels were 0.8% and 0.35%, respectively, and in the later stage of the experiment (broilers 22-42 days old), the calcium and available phosphorus levels were 0.7% and 0.25%, respectively. These calcium and phosphorus levels were adjusted by reducing the levels of limestone powder and dicalcium phosphate in the feed formulation. After reducing the calcium and phosphorus levels, the amounts of corn, soybean meal, soybean oil, and amino acids were slightly adjusted to maintain the original levels of crude protein, metabolizable energy, and amino acids. Everything else was the same as in Example 1.

[0049] Adding 62.5 μg / kg of 25-hydroxyvitamin D3 to the basic broiler feed yields a feed that improves broiler growth performance.

[0050] Example 6

[0051] A feed to improve the growth performance of broilers

[0052] The only difference between the basic broiler feed and Example 1 is that, in the early stage of the experiment (broilers 1-21 days old), the calcium and available phosphorus levels were 0.7% and 0.3%, respectively, and in the later stage of the experiment (broilers 22-42 days old), the calcium and available phosphorus levels were 0.6% and 0.2%, respectively. These calcium and phosphorus levels were adjusted by reducing the levels of limestone powder and dicalcium phosphate in the feed formulation. After reducing the calcium and phosphorus levels, the amounts of corn, soybean meal, soybean oil, and amino acids were slightly adjusted to maintain the original levels of crude protein, metabolizable energy, and amino acids. Everything else was the same as in Example 1.

[0053] Adding 62.5 μg / kg of 25-hydroxyvitamin D3 to the basic broiler feed yields a feed that improves broiler growth performance.

[0054] Example 7

[0055] By adding 60 μg / kg of 25-hydroxyvitamin D3 to the basic broiler feed in Example 6, a feed that improves the growth performance of broilers was obtained.

[0056] Example 8

[0057] By adding 65 μg / kg of 25-hydroxyvitamin D3 to the basic broiler feed in Example 6, a feed that improves the growth performance of broilers was obtained.

[0058] Test Example 1

[0059] 1. Test Plan

[0060] A total of 768 healthy Cobb 500 broilers of similar weight and 1 day old were selected for the experiment and randomly divided into 8 groups using a 4×2 completely randomized design. The grouping details are shown in Table 3. Groups 1-4 were fed a basal broiler feed, which was prepared according to the basal broiler feeds of Examples 1 (Group 1), 4 (Group 2), 5 (Group 3), and 6 (Group 4), respectively. Groups 5-8 were fed a broiler growth performance-enhancing feed, which was prepared according to the broiler growth performance-enhancing feeds of Examples 1 (Group 5), 4 (Group 6), 5 (Group 7), and 6 (Group 8), respectively. There were 8 replicates per group, with 12 chickens per replicate. The experiment lasted for 42 days, divided into two phases based on the age of the broilers: the early phase (days 1-21) and the later phase (days 22-42). During the experiment, the broilers had free access to feed and water and were vaccinated according to the standard immunization schedule.

[0061] Table 3. Grouping and calcium and phosphorus levels in feed.

[0062]

[0063] During the experiment, the feed intake of broilers was recorded daily, and at 42 days of age, the broilers were weighed after fasting to calculate the average daily feed intake (g / d), average daily weight gain (g / d), and feed conversion ratio (FCR, average daily feed intake / average daily weight gain). After 42 days of the experiment, two broilers of similar weight who had fasted for 12 hours were selected from each replicate, weighed, and slaughtered. Tibial bones were collected to determine the tibia ash content, calcium and phosphorus content, and tibia strength. Blood was collected to separate serum, and the serum levels of 25-hydroxyvitamin D3, calcium, and phosphorus, as well as the concentrations of serum IgG, inflammatory factors IL-10, and IL-1β, were measured.

[0064] 2. Test Results

[0065] 2.1 Broiler growth performance

[0066] The growth performance results of broilers in each experimental group are shown in Table 4. Compared with group 1, appropriately reducing the levels of calcium and available phosphorus (groups 2 and 3) did not affect the growth performance of broilers. However, further reducing the levels of calcium and available phosphorus (group 4) not only reduced the weight gain of broilers but also increased the feed conversion ratio, thus affecting the growth performance of broilers. Although adding 25-hydroxyvitamin D3 to diets with different levels of calcium and available phosphorus could improve the growth performance of broilers (groups 5-8), the effect of adding 25-hydroxyvitamin D3 to reduce the feed conversion ratio was most significant when the calcium and available phosphorus levels in the diet were 0.7% and 0.3% in the early stage (1-21 days old) and 0.6% and 0.2% in the later stage (22-42 days old) (group 8). This also achieved similar weight gain and feed conversion ratio as the calcium and available phosphorus levels in the broiler diet recommended by NRC (1994) (group 1). The study indicates that when the calcium and available phosphorus levels in the diet of broilers in the early stage (1-21 days old) are 0.7% and 0.3% respectively, and the calcium and available phosphorus levels in the diet in the later stage (22-42 days old) are 0.6% and 0.2% respectively, the growth performance of broilers will be reduced. However, the addition of 25-hydroxyvitamin D3 will not affect the growth performance of broilers.

[0067] Table 4 Results of Broiler Growth Performance Testing

[0068]

[0069] 2.2 Broiler bone quality

[0070] The results of broiler bone quality in each experimental group are shown in Table 5. Lowering the calcium and available phosphorus levels in the broiler diet affected bone quality. Adding 25-hydroxyvitamin D3 to diets with different calcium and available phosphorus levels improved tibia ash content, calcium content, phosphorus content, and strength. Furthermore, compared to the NRC (1994) recommended calcium and available phosphorus levels for broiler diets (Group 1), adding 25-hydroxyvitamin D3 did not affect bone health in broilers when the calcium and available phosphorus levels in the early stage (1-21 days old) diet were 0.7% and 0.3%, respectively, and in the later stage (22-42 days old) diet were 0.6% and 0.2%, respectively (Group 8).

[0071] Table 5 Results of broiler bone quality testing

[0072] detection indicators Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 Ash content (%) 47.2 46.8 46.2 45.7 49.1 48.2 47.1 46.9 Calcium content (%) 15.8 15.6 15.1 14.7 16.2 16 15.7 15.4 Phosphorus content (%) 8.34 8.23 7.94 7.75 8.72 8.58 8.42 8.31 Bone strength (N) 385 374 362 349 401 392 386 381

[0073] 2.3 Broiler Breast Muscle Ratio

[0074] The results of broiler breast muscle rate in each experimental group are shown in Table 6. Lowering the calcium and available phosphorus levels in the broiler diet had no significant effect on breast muscle rate, but adding 25-hydroxyvitamin D3 to diets with different calcium and available phosphorus levels all increased breast muscle rate. Furthermore, compared to the calcium and available phosphorus levels recommended by the NRC (1994) for broiler diets (Group 1), adding 25-hydroxyvitamin D3 did not affect breast muscle rate in broiler diets with calcium and available phosphorus levels of 0.7% and 0.3% in the early stage (1-21 days old) and 0.6% and 0.2% in the later stage (22-42 days old), respectively (Group 8).

[0075] Table 6. Breast muscle percentage in broiler chickens

[0076] detection indicators Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 Pectoral muscle percentage (%) 25.8 26.2 25.9 25.6 26.5 27.1 26.9 26.7

[0077] 2.4 Broiler serum 25-hydroxyvitamin D3 and calcium-phosphorus content

[0078] The results of serum 25-hydroxyvitamin D3 and calcium and phosphorus levels in broilers in each experimental group are shown in Table 7. Lowering the calcium and available phosphorus levels in the broiler diet affected serum 25-hydroxyvitamin D3, as well as the levels of calcium and phosphorus. However, adding 25-hydroxyvitamin D3 to diets with different levels of calcium and available phosphorus increased serum 25-hydroxyvitamin D3, as well as the levels of calcium and phosphorus. Furthermore, compared to the NRC (1994) recommended calcium and available phosphorus levels for broilers (Group 1), when the calcium and available phosphorus levels in the early stage (1-21 days old) diet were 0.7% and 0.3%, respectively, and the calcium and available phosphorus levels in the later stage (22-42 days old) diet were 0.6% and 0.2%, respectively, adding 25-hydroxyvitamin D3 did not affect serum 25-hydroxyvitamin D3, calcium, and phosphorus levels (Group 8).

[0079] Table 7. Serum 25-hydroxyvitamin D3 and calcium and phosphorus content in broilers

[0080]

[0081]

[0082] 2.5 Broiler serum immune indicators

[0083] The results of serum immune indicators in broilers from each experimental group are shown in Table 8. Lowering dietary calcium and available phosphorus levels had no significant effect on serum IgG, IL-10, and IL-1β levels. However, adding 25-hydroxyvitamin D3 to diets with different calcium and available phosphorus levels increased serum IgG and the anti-inflammatory factor IL-10, while decreasing the pro-inflammatory factor IL-1β. Furthermore, compared to the NRC (1994) recommended dietary calcium and available phosphorus levels for broilers (Group 1), when the calcium and available phosphorus levels in the early stage (1-21 days old) diet were 0.7% and 0.3%, respectively, and in the later stage (22-42 days old) diet were 0.6% and 0.2%, respectively, adding 25-hydroxyvitamin D3 did not affect the levels of IgG and inflammatory factors (Group 8). This indicates that 25-hydroxyvitamin D3 helps reduce the inflammatory response in broilers and improve their immune function.

[0084] Table 8. Serum Immune Indicators of Broilers

[0085] detection indicators Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 IgG (μg / mL) 1.72 1.78 1.64 1.69 2.05 2.07 1.98 2.03 IL-10 (pg / mL) 15.8 16.2 15.4 15.7 19.6 20.5 19.8 20.3 IL-1β (pg / mL) 24.8 24.5 25.7 25.3 21.5 21.8 22.2 21.1

[0086] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

The application of 1,25-hydroxyvitamin D3 in the preparation of feed to improve the growth performance of broilers, characterized in that, The amount of 25-hydroxyvitamin D3 added to the feed is 60-65 μg / kg.

2. The application according to claim 1, characterized in that, The feed includes a low-calcium, low-phosphorus feed, wherein the calcium and phosphorus levels in the low-calcium, low-phosphorus feed are: 0.6% to 1% by mass of total calcium and 0.2% to 0.45% by mass of available phosphorus.

3. The application according to claim 1 or 2, characterized in that, The 25-hydroxyvitamin D3 can improve the growth performance of broilers.

4. The application according to claim 1 or 2, characterized in that, The 25-hydroxyvitamin D3 can improve bone quality in broilers.

5. The application according to claim 4, characterized in that, The bone quality of the broiler chickens includes the ash content, calcium content, phosphorus content, and strength of the tibia.

6. The application according to claim 1 or 2, characterized in that, The 25-hydroxyvitamin D3 can increase pectoral muscle mass.

7. The application according to claim 1 or 2, characterized in that, The 25-hydroxyvitamin D3 can promote the absorption of calcium and phosphorus.

8. The application according to claim 1 or 2, characterized in that, The 25-hydroxyvitamin D3 can enhance the immune function of broilers.

9. A low-calcium, low-phosphorus feed, characterized in that, The feed contains 60-65 μg / kg of 25-hydroxyvitamin D3; the calcium and phosphorus levels in the feed are: 0.6%-1% of total calcium and 0.2%-0.45% of available phosphorus.

10. The application according to any one of claims 1 to 8 or the feed according to claim 9, characterized in that, When the feed is used to feed broilers aged 1 to 21 days, the total calcium content in the feed is 0.7% to 1% by mass, and the available phosphorus content is 0.3% to 0.45% by mass. When the feed is used to feed broilers aged 22 to 42 days, the total calcium content in the feed is 0.6% to 0.9% by mass, and the available phosphorus content is 0.2% to 0.35% by mass.

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