A rumen-protected melatonin product, its preparation method and application

Abstract

The present invention provides a rumen-protected melatonin product, its preparation method and application, belonging to the technical field of livestock breeding. The rumen-protected melatonin product includes a core material, a first wall material and a second wall material. The core material is sequentially coated with the first wall material and the second wall material; the core material is melatonin, and both the first wall material and the second wall material include stearic acid and hypromellose; the preparation method includes first preparing melatonin fluidized pellets, then coating the first wall material, and then coating the second wall material; the prepared rumen-protected melatonin product is used for feeding dairy cows, so as to reduce the somatic cell count in the milk of dairy cows, increase the milk protein content in the milk of dairy cows, and increase the milk yield of dairy cows. The rumen-protected melatonin product prepared by the present invention has a high rumen passage rate and a high small intestine release rate, and the application effect of melatonin is good.

Description

Technical Field

[0001] The present invention relates to melatonin and its applications, and particularly to a rumen-protected melatonin product and its applications, belonging to the technical field of livestock breeding. Background Art

[0002] With the increasing demand for dairy products, the dairy industry has gradually grown, and there are more and more large-scale dairy farms. However, with the expansion of the scale of dairy farms, problems in dairy cattle breeding have gradually emerged. Among them, the most harmful and difficult to solve is the problem of high somatic cell count in dairy cows. The high or low somatic cell count in dairy cows reflects the health status of the udder and is closely related to milk production. The problem of high somatic cell count in dairy cows causes huge economic losses to dairy cattle breeding enterprises every year. The milk components in China, especially the milk protein content, are significantly lower than those in developed countries. Milk with a high milk protein content has higher nutritional value.

[0003] Melatonin is an amine neuroendocrine hormone secreted by the pineal gland and derived from tryptophan. It is also known as melatonine, melanin inhibiting hormone, pinealotropin, etc. It is an endogenous substance produced by animals, plants, and microorganisms. It is insoluble in water and soluble in organic solvents such as acetone. It can act on multiple organs, tissues, and cells throughout the animal body and has various physiological and pharmacological effects such as regulating biological rhythms, improving sleep, regulating reproductive activities, antioxidation, anti-tumor, and scavenging free radicals in the body.

[0004] The main sources of melatonin are chemical synthesis or natural secretion by the body. However, the amount of melatonin secreted by the body itself is small and can only meet the needs of the animal body itself. Due to the cumbersome synthesis and extraction process of melatonin and the high cost, its application in livestock production is only limited to experimental animals, and there are limitations in the batch production of livestock products. At the same time, most of the existing melatonin used in livestock production is given to animals in the form of injection, which is inconvenient to operate and has a high cost.

[0005] Due to the special digestive system of ruminants, nutrients will be degraded in large quantities in the rumen of ruminants. Therefore, directly adding melatonin to ruminants cannot achieve the desired purpose. To enable melatonin to play its due role and effect in the production practice of ruminants, rumen-protected melatonin needs to be used. The rumen-protection technology is to use physical or chemical methods to protect some nutrients that are easily destroyed by rumen microorganisms so that they are not decomposed by rumen microorganisms, pass through the rumen intact, reach the abomasum and intestine, and then be released to play their role in the small intestine, thereby meeting the body's demand for nutrients.

[0006] Patent CN110447778A - Application of rumen - protected melatonin in improving rumen microbial flora structure of ruminants and enhancing milk quality discloses that rumen - protected melatonin can reduce the somatic cell count in ruminant milk, increase the milk protein content, increase the milk fat rate, and reduce the lactose content, etc. The rumen - protected melatonin consists of two parts, namely a coating and a core. The coating is rumen - protected fat powder, and the active ingredient of the core is melatonin; the core is a granule prepared from the active ingredient melatonin and excipients; the excipients consist of a first excipient and a second excipient. The first excipient is calcium stearate or silica, and the second excipient consists of starch, dextrin, and sodium carboxymethylcellulose. The mass ratio of the core to the coating is 45:55 - 50:50. Through experiments on fistulated cows, the rumen - passing rate of this rumen - protected melatonin is 83% - 85%. The types of excipients in this rumen - protected melatonin product are complex, and the rumen - passing rate is low, resulting in more loss of melatonin, and the release rate in the small intestine is also unknown. Summary of the Invention

[0007] In view of the above - mentioned problems, the present invention provides a rumen - protected melatonin product, its preparation method and application, to improve the rumen - passing rate of rumen - protected melatonin, improve the small intestine release rate of rumen - protected melatonin, and thus improve the application effect of melatonin.

[0008] To achieve the above object, the technical solution of the present invention is: A rumen - protected melatonin product, comprising a core material, a first wall material, and a second wall material. The core material is sequentially coated with the first wall material and the second wall material; the core material is melatonin, and both the first wall material and the second wall material include stearic acid and hypromellose.

[0009] Further, the mass ratio of melatonin, the first wall material, and the second wall material in the rumen - protected melatonin product is 0.9 - 1.1:0.9 - 1.1:0.9 - 1.1.

[0010] Further, the mass ratio of stearic acid to hypromellose in the first wall material is 1:2 - 3, and the mass ratio of stearic acid to hypromellose in the second wall material is 2 - 3:1.

[0011] The preparation method of the above - mentioned rumen - protected melatonin product comprises the following steps:

[0012] S1 Take melatonin, add an appropriate amount of water and mix evenly, make it into strip - shaped granules in a granulator, then transfer it to a shot - blasting machine for rotary fluidized shot - blasting, and then dry to obtain melatonin pellets; transfer the melatonin pellets to a fluidized bed for fluidization treatment to obtain fluidized pellets;

[0013] S2 Take the first wall material, heat it to 120°C and melt it, then cool it to 80 - 100°C, and coat it on the surface of the fluidized pellets to obtain an intermediate of rumen - protected melatonin;

[0014] In step S3, the second wall material is heated to 120 °C for melting and then cooled to 80 - 100 °C, and coated on the surface of the rumen bypass melatonin intermediate to obtain the rumen bypass melatonin product.

[0015] Furthermore, the moisture content of the melatonin pellets after drying in step S1 is ≦ 10 wt%.

[0016] Furthermore, in the fluidization treatment in step S1, the atomization pressure of the fluidized bed is 3.5 kg / cm 2 , the rotation speed is 90 - 95 r / min, the inlet air temperature is 35 - 45 °C, and the outlet air temperature is 25 - 45 °C.

[0017] The above application of the rumen bypass melatonin product is used for feeding dairy cows, thereby reducing the somatic cell count in the milk of dairy cows, increasing the milk protein content in the milk of dairy cows, and increasing the milk yield of dairy cows.

[0018] Furthermore, the breed of the dairy cows is Holstein dairy cows.

[0019] Furthermore, each dairy cow is fed 400 - 450 mg of the rumen bypass melatonin product per day.

[0020] Furthermore, after feeding the dairy cows with the rumen bypass melatonin product, compared with the dairy cows not fed with the rumen bypass melatonin product, the milk protein content in the milk produced is increased by 30 - 40%, the somatic cell count is reduced by 60 - 70%, and the milk yield is increased by 10 - 15%.

[0021] The beneficial effects of a rumen bypass melatonin product, its preparation method and application of the present invention are as follows:

[0022] The rumen bypass melatonin product prepared by the present invention has a high rumen bypass rate and a high small intestine release rate, and the application effect of melatonin is good. The rumen bypass melatonin product prepared by the present invention is used for feeding dairy cows, thereby reducing the somatic cell count in the milk of dairy cows, increasing the milk protein content in the milk of dairy cows, and increasing the milk yield of dairy cows.

[0023] The wall material raw materials used for the rumen bypass melatonin of the present invention are stearic acid and hydroxypropyl methylcellulose. Stearic acid is also called octadecanoic acid, which is produced by hydrolysis of oils and fats. The pure product is a white crystal, insoluble in water and soluble in organic solvents; it belongs to long-chain saturated fatty acids and has stable chemical properties. Hydroxypropyl methylcellulose is prepared by specifically etherifying highly pure cotton cellulose under alkaline conditions. It is a white powder, soluble in water, and has certain film-forming properties and enzyme resistance. When using stearic acid or hydroxypropyl methylcellulose alone as the wall material to coat melatonin, the degradation rate in the rumen is extremely high, and the loss of melatonin is large, which has a great impact on the intestinal absorption of melatonin. The present invention uses stearic acid and hydroxypropyl methylcellulose in combination, interacting with each other, improving the coating effect of melatonin in the bovine rumen, and effectively avoiding the degradation of melatonin in the bovine rumen.

[0024] The rumen-protected melatonin of the present invention is coated with two layers of wall materials, which not only improves the rumen bypass rate of melatonin in the rumen but also increases the release rate in the small intestine. The first wall material is a combination of relatively high content of hypromellose and relatively low content of stearic acid, and the outermost second wall material is a combination of relatively high content of stearic acid and relatively low content of hypromellose. Since there are obvious differences between the rumen and small intestine environments of cattle, with a large difference in pH values (the rumen environment is close to neutral and the small intestine environment is strongly acidic), the outermost second wall material has a high content of stearic acid and stable chemical properties. Combining with hypromellose having a certain coating effect and itself having a certain adhesiveness, the interaction between the two enhances the coating effect of the second wall material and reduces the degradation rate in the rumen of cattle. At the same time, it also compensates for the defect of poor coating effect of stearic acid alone as a wall material; the second wall material of the present invention will be degraded to a certain extent after passing through the rumen of cattle. When melatonin reaches the small intestine of cattle, the change in the environment such as pH requires the wall material to quickly degrade and release the melatonin therein for absorption in the small intestine. The first wall material is located inside the second wall material. The second wall material degrades first, and then the first wall material degrades. The content of hypromellose in the first wall material is relatively high. The high content of hypromellose combined with stearic acid is more likely to degrade in a strongly acidic environment, thus quickly releasing melatonin and playing a role in increasing the release rate of melatonin in the small intestine.

[0025] The two materials used for the wall material of the coated melatonin of the present invention are easily available and low in cost; moreover, the content of melatonin in the rumen-protected melatonin product is high and the content of the wall material is low, reducing the coating cost; in addition, although the content of the coating material of the present invention is low, the coating effect is much better than that of a single coating material.

[0026] The rumen-protected melatonin prepared by the present invention has the wall material selected to maximally protect melatonin from passing through the rumen, with minimal loss of melatonin. It can be quickly and completely released in the intestinal environment of cattle. The two wall materials are completely degraded and melatonin is completely released, enabling the intestine to fully absorb melatonin, thereby improving the milk quality of dairy cows.

[0027] In addition, the preparation method of the present invention is relatively simple, with high production efficiency and suitable for large-scale production. Detailed implementation mode

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar promotions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0029] A rumen-protected melatonin product, comprising a core material, a first wall material and a second wall material, wherein the core material is sequentially coated with the first wall material and the second wall material; the core material is melatonin, and both the first wall material and the second wall material include stearic acid and hypromellose. Preferably, the mass ratio of melatonin, the first wall material and the second wall material in the rumen-protected melatonin product is 0.9-1.1:0.9-1.1:0.9-1.1. Further preferably, the mass ratio of stearic acid to hypromellose in the first wall material is 1:2-3, and the mass ratio of stearic acid to hypromellose in the second wall material is 2-3:1.

[0030] The preparation method of the above-mentioned rumen-protected melatonin product comprises the following steps:

[0031] S1 Take melatonin, add an appropriate amount of water and mix well, make it into strip-shaped granules in a granulator, then transfer it to a shot blasting machine for rotary fluidized bed shot blasting, and then dry to obtain melatonin pellets; transfer the melatonin pellets to a fluidized bed for fluidization treatment to obtain fluidized pellets; preferably, the water content of the dried melatonin pellets is ≦10wt%; when performing fluidization treatment, the atomization pressure of the fluidized bed is 3.5kg / cm 2 , the rotation speed is 90-95r / min, the inlet air temperature is 35-45°C, and the outlet air temperature is 25-45°C;

[0032] S2 Take the first wall material, heat it to 120°C to melt, and then cool it to 80-100°C, and coat it on the surface of the fluidized pellets to obtain a rumen-protected melatonin intermediate;

[0033] S3 Take the second wall material, heat it to 120°C to melt, and then cool it to 80-100°C, and coat it on the surface of the rumen-protected melatonin intermediate to obtain the rumen-protected melatonin product.

[0034] The application of the above-mentioned rumen-protected melatonin product is used for feeding dairy cows, so as to reduce the somatic cell count in the milk of dairy cows, increase the milk protein content in the milk of dairy cows, and increase the milk yield of dairy cows. Preferably, the breed of the dairy cows is Holstein cows; further preferably, each dairy cow is fed 400-450mg of the rumen-protected melatonin product per day; further preferably, after feeding the rumen-protected melatonin product to dairy cows, compared with dairy cows not fed the rumen-protected melatonin product, the milk protein content in the milk produced is increased by 30-40%, the somatic cell count is reduced by 60-70%, and the milk yield is increased by 10-15%.

[0035] Example 1

[0036] Take 35 kg of melatonin and 7 kg of water, mix them evenly, make strip-shaped granules in a granulator, then perform rotary boiling shot peening in a shot peening machine, dry at a temperature of 50 °C for 80 min until the moisture content ≤ 10 wt%, to obtain dried melatonin pellets. Pour the dried melatonin pellets into the storage tank of the fluidized bed, adjust the atomization pressure to 3.5 kg / cm2, the rotation speed to 90 revolutions / min, the inlet air temperature to 35 °C, and the outlet air temperature to 25 °C, to obtain fluidized pellets.

[0037] Take 11 kg of stearic acid and 22 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 80 °C, and coat on the surface of the fluidized pellets to obtain a rumen-protected melatonin intermediate.

[0038] Take 23.3 kg of stearic acid and 11.7 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 80 °C, and coat on the surface of the fluidized pellets to obtain rumen-protected melatonin, and the mass concentration of melatonin is about 30%.

[0039] Example 2

[0040] Take 35 kg of melatonin and 7 kg of water, mix them evenly, make strip-shaped granules in a granulator, then perform rotary boiling shot peening in a shot peening machine, dry at a temperature of 50 °C for 80 min until the moisture content ≤ 10 wt%, to obtain dried melatonin pellets. Pour the dried melatonin pellets into the storage tank of the fluidized bed, adjust the atomization pressure to 3.5 kg / cm2, the rotation speed to 90 revolutions / min, the inlet air temperature to 35 °C, and the outlet air temperature to 25 °C, to obtain fluidized pellets.

[0041] Take 11.7 kg of stearic acid and 23.3 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 100 °C, and coat on the surface of the fluidized pellets to obtain a rumen-protected melatonin intermediate.

[0042] Take 22 kg of stearic acid and 11 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 100 °C, and coat on the surface of the fluidized pellets to obtain rumen-protected melatonin, and the mass concentration of melatonin is about 30%.

[0043] Example 3

[0044] Take 38 kg of melatonin and 8 kg of water, mix them evenly, make strip-shaped granules in a granulator, then perform rotary boiling shot peening in a shot peening machine, dry at a temperature of 50 °C for 80 min until the moisture content ≤ 10 wt%, to obtain dried melatonin pellets. Pour the dried melatonin pellets into the storage tank of the fluidized bed, adjust the atomization pressure to 3.5 kg / cm2, the rotation speed to 90 revolutions / min, the inlet air temperature to 35 °C, and the outlet air temperature to 25 °C, to obtain fluidized pellets.

[0045] Take 12 kg of stearic acid and 24 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 110 °C, and coat it on the surface of the fluidized pellets to obtain the rumen-protected melatonin intermediate.

[0046] Take 23.3 kg of stearic acid and 11.7 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 110 °C, and coat it on the surface of the fluidized pellets to obtain rumen-protected melatonin, and the mass concentration of melatonin is about 34%.

[0047] Example 4

[0048] Take 38 kg of melatonin and 8 kg of water, mix evenly, make into strip-shaped granules in a granulator, then perform rotary boiling shot peening in a shot peening machine, dry at a temperature of 50 °C for 80 min until the moisture content ≤ 10 wt% to obtain the dried melatonin pellets. Pour the dried melatonin pellets into the storage tank of the fluidized bed, adjust the atomization pressure to 3.5 kg / cm2, the rotation speed to 90 revolutions / min, the inlet air temperature to 35 °C, and the outlet air temperature to 25 °C to obtain the fluidized pellets.

[0049] Take 13 kg of stearic acid and 26 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 90 °C, and coat it on the surface of the fluidized pellets to obtain the rumen-protected melatonin intermediate.

[0050] Take 26 kg of stearic acid and 13 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 90 °C, and coat it on the surface of the fluidized pellets to obtain rumen-protected melatonin, and the mass concentration of melatonin is about 30%.

[0051] Example 5

[0052] Take 35 kg of melatonin and 7 kg of water, mix evenly, make into strip-shaped granules in a granulator, then perform rotary boiling shot peening in a shot peening machine, dry at a temperature of 50 °C for 80 min until the moisture content ≤ 10 wt% to obtain the dried melatonin pellets. Pour the dried melatonin pellets into the storage tank of the fluidized bed, adjust the atomization pressure to 3.5 kg / cm2, the rotation speed to 90 revolutions / min, the inlet air temperature to 35 °C, and the outlet air temperature to 25 °C to obtain the fluidized pellets.

[0053] Take 8 kg of stearic acid and 24 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 80 °C, and coat it on the surface of the fluidized pellets to obtain the rumen-protected melatonin intermediate.

[0054] Take 24 kg of stearic acid and 8 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 80 °C, and coat it on the surface of the fluidized pellets to obtain rumen-protected melatonin, and the mass concentration of melatonin is about 34%.

[0055] Example 6

[0056] Take 40 kg of melatonin and 8 kg of water. After mixing evenly, make strip-shaped granules in a granulator, and then perform rotary boiling shot peening in a shot peening machine. Dry at a temperature of 50 °C for 80 min until the moisture content ≤ 10 wt%, to obtain dried melatonin pellets. Pour the dried melatonin pellets into the storage tank of the fluidized bed, adjust the atomization pressure to 3.5 kg / cm2, the rotation speed to 90 revolutions / min, the inlet air temperature to 35 °C, and the outlet air temperature to 25 °C to obtain fluidized pellets.

[0057] Take 10 kg of stearic acid and 30 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 110 °C, and coat it on the surface of the fluidized pellets to obtain the rumen-protected melatonin intermediate.

[0058] Take 30 kg of stearic acid and 10 kg of hypromellose, heat to 120 °C and melt and mix evenly, then cool to 110 °C, and coat it on the surface of the fluidized pellets to obtain rumen-protected melatonin, and the mass concentration of melatonin is about 30%.

[0059] Test Example 1 Effect Verification

[0060] In order to verify the product performance of the rumen-protected melatonin prepared by the present invention, an in vitro method (In Vitro) was used to simulate the digestive tract of ruminants for stability inspection and evaluation.

[0061] 1. Materials and Methods

[0062] Buffers with a pH value of 6.6 and a pH value of 2.4 were used to simulate the rumen environment and duodenal environment of ruminants, respectively. The formulations of the buffers with different pH values are shown in Table 1.

[0063] Table 1 Formulations of buffer solutions with different pH values (unit: g)

[0064] Reagent pH value is 6.6 pH value is 2.4 Citric acid 5.7225 19.698 Disodium hydrogen phosphate 52.089 4.4392

[0065] Dissolve the substances with the weights listed in Table 1 in a small amount of distilled water and make up to 1000 ml.

[0066] 2. Test Samples

[0067] Select the rumen-protected melatonin prepared in Examples 1-6, a total of 6 samples. Each sample has 3 production batches, each 400 g, for standby.

[0068] 3. Stability Inspection of Rumen-Protected Melatonin in Different pH Buffers

[0069] Accurately weigh 1.00 g of each of the above 6 samples and place them at the bottom of a 50-ml stoppered test tube. Add 20 ml of buffer solution, tighten the test tube stopper, and digest in a constant temperature water bath shaker at 39 °C for 2, 4, 8, 12, 24, 48, and 72 hours. After taking out, rinse and filter, make the volume of the filtrate constant, and measure the content of melatonin in the filtrate, and then calculate the rumen bypass rate and small intestine release rate of melatonin. Each coated rumen bypass melatonin has three replicates at each time point.

[0070] 4. Detection method of melatonin

[0071] Refer to GB / T5009.170 to determine the content of melatonin. The calculation formula is:

[0072] Rumen bypass rate (W1) of the product = (A1 - A2) / A1 × 100%

[0073] Where: A1 - content of melatonin in the product;

[0074] A2 - content of melatonin in the filtrate of the product in the buffer solution with a pH of 6.6.

[0075] Small intestine release rate (W2) of the product = A3 / A1 × 100%

[0076] Where: A1 - content of melatonin in the product;

[0077] A3 - content of melatonin in the filtrate of the product in the buffer solution with a pH of 2.4.

[0078] Statistical method: Use SPSS19.0 for data analysis.

[0079] 5. Result analysis

[0080] (1) The rumen bypass rates (pH = 6.6) of each product at different time points are shown in Table 2.

[0081] Table 2 Rumen bypass rates (%) of each product at different time points when pH = 6.6

[0082] Time / Sample 2h 4h 8h 12h 24h 48h 72h Example 1 99.88 99.21 97.89 96.78 95.47 93.26 91.57 Example 2 99.92 99.31 98.01 96.89 95.34 93.19 91.73 Example 3 99.34 99.02 97.45 96.23 94.79 93.01 90.98 Example 4 99.36 99.11 97.39 96.43 94.58 93.07 91.06 Example 5 99.67 99.29 97.67 96.35 95.12 93.38 91.27 Example 6 99.33 99.01 97.82 96.44 95.16 93.09 90.11

[0083] By simulating the rumen environment of ruminants with a buffer solution with a pH of 6.6 and culturing each test sample in a constant temperature water bath at 39 °C, the results listed in Table 2 are obtained. It can be seen from Table 2 that the rumen bypass melatonin prepared in the examples of the present invention has a high rumen bypass rate, and the rumen bypass rate after 72 h is still above 90%, and the rumen bypass melatonin of the present invention has stable properties.

[0084] (2) The small intestine release rates (pH = 2.4) of each product at different time points are shown in Table 3.

[0085] Table 3 Small intestine release rate (%) of each product at different time points when the pH value is 2.4

[0086]

[0087]

[0088] By simulating the duodenal environment of ruminants with a buffer solution at pH 2.4, each test sample was cultured in a constant temperature water bath at 39 °C, and the results listed in Table 3 were obtained. It can be seen from Table 3 that the small intestine release rate of the rumen-protected melatonin prepared in the examples of the present invention is high, and each sample is basically completely released at 4 h.

[0089] Methodology verification of Test Example 2

[0090] The following uses the measurement methods of rumen passage rate and small intestine release rate in the effect verification of Test Example 1 for effect verification. Only the rumen passage rate and small intestine release rate at 2 h, 4 h, 8 h and 12 h were detected below.

[0091] 1) Selection of wall material

[0092] Stearic acid is a commonly used wall material in existing rumen-protected coating technologies. It is produced by hydrolysis of oils and fats, insoluble in water, soluble in organic solvents, belongs to long-chain saturated fatty acids, and has stable chemical properties. In the prior art, lysine is coated with stearic acid, and the passing rate is relatively high after culturing in the rumen. In this experiment, stearic acid was selected as the wall material for rumen-protected melatonin.

[0093] The coating of melatonin was carried out by using the commonly used condensation method in the art (i.e., the preparation method of the examples of the present invention). The mass ratio of melatonin to stearic acid was set as 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5. The results of the rumen passage rate showed that (Table 4 below) when the mass ratio of melatonin to stearic acid was from 5:1 to 1:2, the rumen passage rate tended to increase with the increase of the stearic acid ratio. A high wall material content can slow down the exposure of the core material, thereby increasing the rumen passage rate; when the mass ratio of melatonin to stearic acid was 1:3, the rumen passage rate was not much different from that at 1:2. When the ratio reached 1:4 and 1:5, the rumen passage rate no longer increased, indicating that simply increasing the content of the wall material does not necessarily increase the coating effect of the wall material, which is related to the properties of the wall material itself - degradation difficulty / pH sensitivity, etc.; however, when the ratio of melatonin to stearic acid was 1:2 or 1:3 with better rumen passage rate effect, the rumen passage rate was less than 60% at 2 h, and the rumen passage rate dropped below 50% at 8 h, indicating that stearic acid as the wall material has a poor rumen passage rate effect on melatonin, and still needs to be optimized.

[0094] Table 4 Rumen passage rate (%) under different ratios of melatonin to stearic acid

[0095] Ratio 2h 4h 8h 12h 5:1 21.33 16.51 9.73 5.38 4:1 22.46 19.72 15.35 9.47 3:1 25.72 20.31 18.72 15.31 2:1 30.44 25.36 21.33 18.42 1:1 41.79 39.26 32.16 24.78 1:2 57.89 51.35 47.92 43.26 1:3 58.02 51.77 48.56 42.17 1:4 57.99 52.06 48.13 42.69 1:5 58.10 51.33 47.96 42.78

[0096] Existing researchers also encountered the problem of low rumen bypass rate when coating methionine with stearic acid. After adding a certain amount of bentonite, the rumen bypass rate increased significantly. Bentonite is a non-metallic mineral deposit with montmorillonite as the main mineral component and has a certain viscosity. It is believed that the viscosity of bentonite improved the coating effect of stearic acid.

[0097] 2) Screening of adhesives

[0098] Based on the above test results, three substances with certain adhesiveness, namely bentonite, starch, and hydroxypropyl methylcellulose, were selected and added to the wall material respectively to screen for a better adhesive. On the basis of the mass ratio of melatonin to stearic acid being 1:2, a certain amount of the above three adhesives was added, and a screening test was carried out according to the mass ratio of melatonin:stearic acid:adhesive being 1:2:(0.5 or 1 or 1.5). The test results (Table 5 below) showed that the rumen bypass rate increased to a certain extent after adding bentonite and starch, but the increase amplitude was not large, and melatonin degradation was still serious; while after adding hydroxypropyl methylcellulose, the rumen bypass rate increased significantly. The rumen bypass rate first increased and then decreased with the increase of the addition amount of hydroxypropyl methylcellulose. When the mass ratio of melatonin:stearic acid:hydroxypropyl methylcellulose was 1:2:1, the rumen bypass rate was relatively the highest, and still had a relatively high rumen bypass rate after 12 h, indicating that the properties of the wall material were relatively stable; in addition, under the above optimal ratio conditions, the proportion of the wall material was relatively high, which might also be a reason for the relatively long stable time of the properties, suggesting that the content of the wall material could be further reduced and the content of melatonin could be increased; hydroxypropyl methylcellulose can dissolve in water, has a wide stable pH value range (relatively stable when the pH value is 4 - 10), and has a certain adhesiveness. It is speculated that its adhesiveness cooperates with stearic acid to improve the rumen bypass rate of stearic acid as the wall material, and its own pH value stability further improves the rumen bypass rate. Therefore, stearic acid and hydroxypropyl methylcellulose were selected to be used as the wall material in combination.

[0099] Table 5 Rumen bypass rate (%) under different types and dosages of adhesives added

[0100]

[0101] Among them, the ratio in the column of addition amount is melatonin:stearic acid:adhesive.

[0102] 3) Screening of the addition amount of the wall material

[0103] The wall material was prepared according to the mass ratio of stearic acid to hypromellose of 2:1. The mass ratios of melatonin to the wall material were set as 1:0.5, 1:1, 1:1.5, 1:2, and 1:3. The rumen-protected melatonin was prepared according to the method of the example, and its rumen-protection rate was verified. The results are shown in Table 6 below. The results show that when the mass ratio of melatonin to the wall material reaches 1:1 - 1:1.5, it has a relatively high rumen-protection rate. When the content of the wall material increases further, the increase in the rumen-protection rate is not obvious, which is consistent with the conclusion in part 1) when stearic acid is used alone as the wall material (the content of the wall material will affect the rumen-protection rate, but it will not increase continuously with the increase in content).

[0104] Table 6 Rumen-protection rate (%) under different addition amounts of the wall material

[0105] Dosage 2h 4h 8h 12h 1:0.5 95.47 94.36 92.73 90.76 1:1 99.13 98.74 97.03 96.47 1:1.5 99.09 98.96 96.93 96.01 1:2 99.23 98.77 97.62 96.41 1:3 99.22 98.65 97.66 96.03

[0106] 4) Verification of the small intestine release rate

[0107] In addition to having a relatively high rumen-protection rate, the rumen-protected melatonin with good effects should also have a relatively high small intestine release rate, so as to play the role of both protecting melatonin from being degraded in the rumen and promoting its timely absorption in the small intestine.

[0108] The rumen-protected melatonin samples with a melatonin to wall material mass ratio of 1:1 and 1:1.5 and a stearic acid to hypromellose mass ratio of 2:1 selected in 3) were tested for their small intestine release rate. The results (Table 7 below) showed that although the rumen passage rate of the above samples was high, the release rate in the small intestine was low. Considering the different sensitivities of different wall materials to pH values, the small intestine release rates at different ratios of stearic acid to hypromellose in part 2) were further verified, that is, the ratios of stearic acid to hypromellose were 2:0.5, 2:1, and 2:1.5, and the small intestine release rates of rumen-protected melatonin prepared according to the melatonin to wall material ratios of 1:1 and 1:1.5. The results (Table 8 below) showed that under the condition of the same stearic acid and hypromellose ratio, the small intestine release rate did not change significantly with the increase of the wall material content. Under the condition of the same melatonin and wall material ratio, the small intestine release rate changed significantly with the change of the ratio of stearic acid to hypromellose in the wall material. Specifically, with the increase of the dosage of hypromellose, the small intestine release rate showed an obvious increasing trend, indicating an obvious positive correlation between the content of hypromellose and the small intestine release rate. To further verify the relationship between the content of hypromellose and the small intestine release rate, the ratios of stearic acid to hypromellose were 1:2, 1:2.5, 1:3, 1:3.5, and 1:4, and the melatonin to wall material mass ratio was 1:1 for effect verification. The results (Table 9 below) showed that with the increase of the content of hypromellose, the small intestine release rate increased significantly. When the mass ratio of stearic acid to hypromellose in the wall material was 1:2 - 1:3, the small intestine release rate basically reached complete release at 2 h, and the effect improvement was no longer obvious when the content of hypromellose was further increased; combining the above test processes, it can be seen that when the stearic acid content is higher than that of hypromellose, the rumen passage rate of rumen-protected melatonin is high, but the small intestine release rate is low; when the stearic acid content is lower than that of hypromellose, the rumen passage rate of rumen-protected melatonin is low, but the small intestine release rate is high. Since there are obvious differences between the rumen environment and the small intestine environment of ruminants, and the pH values are very different, rumen-protected melatonin is eaten by ruminants and first passes through the rumen and then reaches the small intestine, suggesting that rumen-protected melatonin can be designed with a wall material with a high rumen passage rate on the outer layer and a wall material with a high small intestine release rate on the inner layer during production. The two wall materials cooperate to protect melatonin, enabling it to pass through the rumen well and be effectively released for absorption by the animal intestine.

[0109] Table 7 Small intestine release rate (%) under different wall material addition amounts

[0110]

[0111]

[0112] Table 8 Small intestine release rate (%) under different wall material addition amounts

[0113]

[0114] Table 9 Small intestine release rate (%) under different addition amounts of hypromellose

[0115]

[0116] 5) Screening of the dosages of two wall materials

[0117] The above tests indicated that when the mass ratio of stearic acid to hypromellose was 2:1 - 3:1, the rumen bypass rate was high and it was used as the outer wall material; when the mass ratio of stearic acid to hypromellose was 1:2 - 1:3, the small intestine release rate was high and it was used as the inner wall material; when the mass ratio of melatonin to the wall material was 1:1, both the rumen bypass rate and the small intestine release rate of the wall material were relatively high. The following designed tests were used to screen the appropriate ratio of the two-layer wall material. The mass ratios of melatonin to the inner wall material and the outer wall material were designed as 1:0.5:0.5, 1:1:1, 1:0.5:1, and 1:1:0.5. The mass ratio of stearic acid to hypromellose in the inner wall material was selected as 1:2, and the mass ratio of stearic acid to hypromellose in the outer wall material was selected as 2:1. The results (Table 10 and Table 11 below) showed that when the mass ratio of melatonin to the inner wall material and the outer wall material was 1:1:1 or 1:0.5:1, the rumen bypass rate was the highest and the properties were the most stable. The mass ratio of the outer wall material to melatonin was the same under the above two ratios; when the mass ratio of melatonin to the inner wall material and the outer wall material was 1:1:0.5, the small intestine release rate was the highest, followed by 1:0.5:0.5. The mass ratio of melatonin to the outer wall material was the same under the above two ratios. Since the small intestine release rate verification test directly placed the rumen bypass melatonin in the small intestine simulation environment without passing through the rumen environment treatment, the outer wall material had a greater impact on the release rate. It could also be seen from Table 11 that when the content of the outer wall material was low, the small intestine release rate increased with the decrease of the outer wall material content at 2 h. Under the condition of the same wall material ratio, when the content of the outer wall material was low, the small intestine release rate showed a rapid growth trend with the increase of time. Considering the results of Table 10 and Table 11 comprehensively, finally, the mass ratio of melatonin, the inner wall material, and the outer wall material was selected as about 1:1:1 as the best ratio. The inner wall material was preferably stearic acid:hypromellose of 1:2 - 1:3, and the outer wall material was preferably stearic acid:hypromellose of 2:1 - 3:1.

[0118] Table 10 Rumen bypass rate (%) under different ratios of the two-layer wall material

[0119]

[0120]

[0121] Table 11 Small intestine release rate (%) under different ratios of the two-layer wall material

[0122] Ratio 2h 4h 8h 12h 1:0.5:0.5 88.35 90.38 99.93 100.00 1:1:1 87.38 89.13 97.38 100.00 1:0.5:1 87.42 90.03 98.05 100.00 1:1:0.5 91.45 94.83 100.00 100.00

[0123] Test Example 3 Practical Application Test

[0124] To verify the product performance of the rumen-protected melatonin prepared by the present invention, the rumen-protected melatonin prepared in Example 1, Example 3 and Example 5 was fed to dairy cows. Specifically:

[0125] 1. Forty Holstein cows with similar average parity, lactation days and relatively high somatic cell counts (somatic cells at 400,000 - 500,000 / ml) were selected. Using a single-factor experimental design, they were randomly divided into 5 groups by the randomized block method, including 2 control groups and 3 experimental groups, with 8 cows in each group. Among them, the first group was only fed the basal diet, as Control Group 1; the second group was added with 18 mg of uncoated melatonin (per cow per day) to the basal diet, as Control Group 2; the third to fifth groups were respectively added with 400 mg of rumen-protected melatonin prepared in Example 1, Example 2, and Example 3 per cow, namely Experimental Group 1, Experimental Group 2, and Experimental Group 3, and were orally administered once at 14:00 every day for a feeding period of 28 days.

[0126] Table 4 Average Lactation Days of Test Cows

[0127] Group Control Group 1 Control Group 2 Experimental Group 1 Experimental Group 2 Experimental Group 3 Average lactation days 171.48 172.31 172.33 171.76 173.41

[0128] 2. Experimental Design

[0129] After grouping as above, one group was randomly selected from the above groups as Control Group 1, one group was randomly selected to feed uncoated melatonin, and three groups were randomly selected to orally administer the rumen-protected melatonin prepared by the present invention.

[0130] Diet and Nutritional Management

[0131] During the test period, the test cows and normal lactating cows were housed in the same pen, milked 3 times a day, allowed free access to food and water, moved freely in the pen, and the manure was cleared regularly every day to keep the pen clean. Fed 3 times a day, and the feeding times were 7:00, 14:00, and 19:00 respectively. The experimental animals had free access to food and water. During the test period, the diet composition of the test cows and the composition of feed raw materials are shown in Table 5 and Table 6 below.

[0132] Table 5 Composition of Lactating Cow Diet (Air-dry Basis) and Nutritional Level (DM Basis)

[0133]

[0134]

[0135] Note: In Table 5

[0136] 1) The main component of Megalac is calcium salt of rumen-protected fatty acid.

[0137] 2) Each kilogram of premix includes: 426.633g stone powder, 225g baking soda, 25g table salt, 25g rumen-free fat, 8.75g methionine, 7.5g selenium-rich, 3.313g manganese, 2.75g copper, 97.481g calcium, 1.75g ​​cobalt, 8.188g zinc, 87.5g magnesium, 1.406g biotin, 0.275g VA, 0.11g VD3, and 3.094g VE.

[0138] 3) Nutritional levels are measured values. The levels of nutrients such as dry matter, crude protein, crude fat and crude fiber are determined in accordance with international methods.

[0139] Table 6 Nutritional composition and content of feed raw materials (DM basis)

[0140]

[0141]

[0142] 2. Statistical analysis and test results

[0143] Statistical method: SPSS19.0 was used for data analysis.

[0144] Table 7 Average number of milk cells in the test cows (10,000 / ml)

[0145] Control Group 1 Control Group 2 Experimental Group 1 Experimental Group 2 Experimental Group 3 Fed for 7 days 41.31 40.43 25.76 24.92 23.58 Fed for 14 days 42.53 41.35 19.38 19.67 18.93 Fed for 21 days 41.92 41.78 16.63 17.14 15.78 Fed for 28 days 41.66 41.13 17.19 17.47 15.44

[0146] Table 8 Average value of milk protein content of test cows (%)

[0147] Control Group 1 Control Group 2 Experimental Group 1 Experimental Group 2 Experimental Group 3 Fed for 7 days 3.10 3.14 4.12 4.09 4.18 Fed for 14 days 3.14 3.26 4.33 4.23 4.26 Fed for 21 days 3.09 3.32 4.41 4.39 4.35 Fed for 28 days 3.04 3.38 4.16 4.40 4.37

[0148] Table 9 Average daily milk production of experimental cows (kg)

[0149] Control Group 1 Control Group 2 Experimental Group 1 Experimental Group 2 Experimental Group 3 Fed for 7 days 18.71 18.82 21.36 22.19 21.79 Fed for 14 days 18.63 18.79 21.79 22.32 22.31 Fed for 21 days 18.36 19.12 22.32 22.41 22.18 Fed for 28 days 17.43 19.09 22.27 22.33 22.72

[0150] From the above, it can be seen that feeding the rumen bypass melatonin of the present invention can effectively improve the quality of cow milk, increase the milk protein content, reduce the number of somatic cells, and increase the daily milk production of cow milk.

[0151] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A rumen bypass melatonin product, characterized in that: It includes a core material, a first wall material and a second wall material, wherein the core material is coated with the first wall material and the second wall material in sequence; the core material is melatonin, and the first wall material and the second wall material both include stearic acid and hydroxypropyl methylcellulose; The mass ratio of melatonin, the first wall material, and the second wall material in the rumen-passing melatonin product is 0.9-1.1:0.9-1.1:0.9-1.1; The mass ratio of stearic acid to hydroxypropyl methylcellulose in the first wall material is 1:2-3, and the mass ratio of stearic acid to hydroxypropyl methylcellulose in the second wall material is 2-3:

1.

2. The method for preparing the rumen bypass melatonin product according to claim 1, characterized in that: The steps include: S1: taking melatonin, adding an appropriate amount of water and mixing, making strip-shaped particles in a granulator, transferring the particles to a shot blasting machine for rotary boiling and shot blasting, and then drying to obtain melatonin micro-pellets; transferring the melatonin micro-pellets to a fluidized bed for fluidization treatment to obtain fluidized micro-pellets; S2 takes the first wall material and heats it to 120°C to melt it, then cools it to 80-100°C, and coats it on the surface of the fluidized pellets to obtain the rumen-permeable melatonin intermediate; S3: heat the second wall material to 120° C. to melt it, and then cool it to 80-100° C. to coat the surface of the rumen bypass melatonin intermediate, thereby obtaining a rumen bypass melatonin product.

3. The method for preparing the rumen bypass melatonin product according to claim 2, characterized in that: The moisture content of the melatonin pellets after drying in step S1 is ≤10wt%.

4. The method for preparing the rumen bypass melatonin product according to claim 2, characterized in that: The atomization pressure of the fluidized bed during fluidization treatment in step S1 is 3.5 kg / cm 2 , the speed is 90-95r / min, the inlet air temperature is 35-45℃, and the outlet air temperature is 25-45℃.

5. The use of the rumen bypass melatonin product according to claims 1-4, characterized in that: It is used to feed dairy cows, thereby reducing the number of somatic cells in the cow's milk, increasing the protein content in the cow's milk, and increasing the cow's milk production.

6. The use according to claim 5, characterized in that: The breed of the dairy cow is Holstein cow.

7. The use according to claim 5, characterized in that: Each cow is fed 400-450 mg of rumen bypass melatonin product daily.

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