Animal lick brick and preparation method thereof

Abstract

The invention relates to the technical field of animal nutritional supplements, in particular to a lick brick for animals and a preparation method of the lick brick. According to the lick brick, the structure of the lick brick is kept intact under non-ingestion conditions such as high humidity, rain and the like through a matrix consisting of a plurality of core nutrition microcapsules and an adjustable bonding material which is used for separately bonding at least parts of the core nutrition microcapsules into a whole, and the reduction value of the bonding force of the adjustable bonding material when the adjustable bonding material is licked by animals is greater than that of the adjustable bonding material when the adjustable bonding material encounters water; the microcapsule is triggered to fall off and release nutrition through alpha-amylase in saliva only when animals lick, excellent weather resistance, controllable release performance and good palatability are shown in different livestock species such as pigs and cattle, and the utilization efficiency of the nutrition is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of animal nutritional supplement technology, specifically to the field of licking blocks for animal nutritional supplementation, and more particularly to an animal licking block and its preparation method. Background Technology

[0002] In animal husbandry, licking bricks are a widely used form of nutritional supplement. By allowing animals to freely lick them, they receive a continuous supply of functional components such as trace elements, vitamins, and amino acids. This method enhances the animal's immunity and disease resistance. Furthermore, licking bricks helps maintain healthy and balanced oral activity, preventing dental problems.

[0003] However, existing brick-licking products generally suffer from the following technical defects in actual use:

[0004] On the one hand, to improve the physical strength of licking blocks in humid or rainy environments, inorganic binders with high adhesion and low solubility (such as bentonite and gypsum) or high-melting-point waxy materials are often used. Although such licking blocks have a sturdy structure, their internal nutrients are difficult to release effectively, resulting in insufficient intake by animals and poor nutritional supplementation. Animals have a low willingness to lick them, especially when a dense hardened layer forms on the surface of the licking block, which significantly hinders the dissolution of microcapsules or active ingredients. For example, CN101606641A discloses a special nutritional licking block for fattening lambs of Tan sheep and its preparation method, which includes trace elements, salt, bentonite, and molasses, using bentonite as a binder and salt and molasses as flavoring agents.

[0005] On the other hand, the use of water-soluble binders (such as starch) or low-density compression molding processes to improve nutrient release rates can cause lick bricks to soften, disintegrate, or even completely dissolve rapidly in high-humidity environments or under rainwater erosion, resulting in a significant loss of nutrients. This not only wastes feed resources but may also pollute the rearing environment. For example, CN1305733A discloses a composite livestock lick brick that uses binders such as cellulose, gelatin, or starch paste.

[0006] Furthermore, existing licking bricks typically cannot distinguish between the effects of environmental moisture and animal saliva. Therefore, even when not feeding (such as at night or on rainy days), the licking brick will continue to slowly dissolve and release nutrients, reducing its effective utilization rate. Summary of the Invention

[0007] The purpose of this invention is to provide an animal licking brick and its preparation method, which solves the problems of easy breakage or insufficient nutrient release of existing licking bricks in humid environments. It achieves stability in non-licking environments and releases nutrients on demand triggered by saliva during licking, so that it maintains structural integrity in humid environments and only triggers the effective release of nutrients when the animal actively licks it, thereby taking into account both physical durability and nutrient supplementation efficiency.

[0008] To achieve the above objectives, in a first aspect, the present invention provides an animal licking block comprising a matrix consisting of a plurality of core nutrient microcapsules and an adjustable adhesive that at least partially separates and bonds the plurality of core nutrient microcapsules together, wherein the adhesive strength decreases more when the microcapsules are licked by an animal than when they are wet.

[0009] The core nutrient microcapsule includes a core material and a wall material layer encapsulating the core material, wherein the core material contains functional nutrients and the wall material layer is made of a salivary enzyme-sensitive polymer.

[0010] As described in the background section, existing licking bricks cannot distinguish between licking and non-licking environments, which is detrimental to the release of their effective components. In the above-described solution of this invention, the licking brick is mainly composed of two parts. Multiple core nutrient microcapsules achieve targeted release through a salivary enzyme-sensitive wall material, being degraded only by enzymes in saliva during animal licking, thus precisely delivering functional nutrients and avoiding premature loss due to environmental factors. A regulating binder binds at least partially of the aforementioned core nutrient microcapsules together to form a licking brick matrix. This matrix maintains structural stability in humid environments, only locally failing under mechanical friction and enzyme / acid stimulation from licking, allowing for controllable detachment of the microcapsules, thus balancing weather resistance and feeding responsiveness. The core nutrient microcapsules and the regulating binder of this invention not only play different functional roles but also have a more targeted release mechanism, jointly achieving precise release of the licking brick's effective components, fundamentally solving the core contradiction of traditional licking bricks where "weather resistance and release are mutually exclusive."

[0011] Preferably, the mass ratio of the core nutrient microcapsules to the regulating binder is (50–70):(30–50). In this scheme, the microcapsules account for 50% or more, ensuring a high concentration of functional nutrients in the licking block and avoiding excessive dilution of the effective ingredients due to excessive binder. This increases the amount of nutrition obtained per unit of licking behavior, enhancing the supplementation effect, given the limited intake by the animal per lick. The regulating binder accounts for no less than 30%, sufficient to form a continuous network structure, giving the licking block sufficient mechanical strength and environmental tolerance (such as rain resistance and deliquescence resistance). Simultaneously, the regulating binder is not excessive (≤50%), avoiding over-encapsulation of microcapsules leading to excessive release resistance or requiring prolonged licking to obtain nutrients, thus affecting palatability and feeding willingness. Moreover, at this ratio, the microcapsules are distributed in a "dense but not compact" manner within the matrix, and the surface microcapsules are easily detached under licking friction and enzymatic action. This achieves synergistic optimization between high nutrient content, structural stability, and controllable release performance.

[0012] Preferably, the salivary enzyme-sensitive polymer comprises 70-80 wt% corn starch and 20-30 wt% maltodextrin, wherein the degree of crosslinking of the corn starch is ≤0.1%, and the DE value of the maltodextrin is 10-15. In this formulation, corn starch serves as the main wall material component, providing film-forming properties and a basic framework; its extremely low degree of crosslinking (≤0.1%) imparts only trace chemical crosslinking between its molecular chains, which slightly enhances moisture resistance without hindering the hydrolysis of glycosidic bonds by α-amylase, ensuring rapid disintegration upon licking. If the crosslinking is too high (e.g., >0.1%), the enzyme has difficulty penetrating or breaking the network, resulting in delayed release; if it is completely uncrosslinked, it is easily softened and lost upon contact with moisture. ≤0.1% is the critical window for balancing storage stability and enzyme response rate. Maltodextrin optimizes solubility, enzymatic hydrolysis rate, and palatability, rapidly wetting in saliva and assisting amylase diffusion.

[0013] Therefore, the wall material composed of the above has sufficient mechanical strength to wrap the core material, while introducing an appropriate amount of hydrophilic maltodextrin to prevent the pure starch film from being too dense and hindering release.

[0014] Preferably, the modulating binder comprises 40-50 wt% hydrophobic skeleton, 30-40 wt% acid-responsive binder, 10-15 wt% tackifier, and 2-5 wt% lubricant, wherein the hydrophobic skeleton has a melting point of 45-60°C. In this design, the hydrophobic skeleton remains solid at room temperature (typically <35°C) and in high humidity environments, effectively blocking moisture penetration and preventing the licking brick from softening and disintegrating under rain or humid conditions; its temperature is close to but slightly higher than that of an animal's oral cavity (approximately 38–40°C), ensuring structural stability when not ingesting food, while locally softening under the combined effects of heat generated by licking friction and saliva wetting, promoting the release of microcapsules. Animal saliva typically has a pH of 6.2–7.4, but in some livestock (such as pigs), the oral cavity may become slightly acidic (pH≈5.5–6.0) due to microbial metabolism or feed composition during feeding. Acid-responsive binders are stable in neutral environments but undergo protonation or bond breakage under slightly acidic conditions, leading to local dissociation of the binding network. By forming a dual enzyme and pH response mechanism with salivary enzyme-sensitive microcapsules, the specificity and reliability of release are improved, avoiding the risk of failure that may arise from relying on a single stimulus. Tackifiers enhance the cohesiveness of the binder and its adhesion to the microcapsules, preventing breakage during transportation or hanging; their content is controlled at 10–15% to avoid excessive adhesion that could make the microcapsules difficult to detach. Lubricants reduce friction during molding, improve demolding and product surface smoothness, adjust the surface hardness and smoothness of the licking block, prevent excessive hardness from damaging the animal's tongue, and improve palatability and licking comfort.

[0015] Therefore, the overall formulation of the regulated binder makes the binder dominated by a hydrophobic skeleton, which is highly stable in the non-feeding state, but triggers local failure through multiple stimuli such as heat, acid and mechanical shear during licking.

[0016] Preferably, the hydrophobic framework is hydrogenated vegetable oil.

[0017] Preferably, the acid-responsive binder is a starch-gelatin copolymer, a starch-protein copolymer, etc.

[0018] Preferably, the starch-gelatin copolymer is prepared as follows: corn starch and gelatin are cross-linked by transglutaminase (TG enzyme) under pH 6.0-6.5 and 40-42℃ conditions to form a starch-gelatin copolymer.

[0019] Preferably, the modulating binder also includes a carrier, such as maltodextrin, in the core material.

[0020] Preferably, the conditioning binder also includes a flavoring agent to enhance palatability.

[0021] Preferably, the flavoring agent is a sugar alcohol, such as mannitol or maltitol, added at 0.5–8% of the mass of the binder. Traditional sugars such as sucrose and glucose, while palatable, are highly hygroscopic and soluble, damaging the lick brick structure. In this design, a sugar alcohol is used, added to a molten hydrophobic framework, utilizing its partial solubility to form a sugar-lipid dispersion. After cooling, the sugar crystals are encapsulated by the fat and are only exposed during licking and rubbing.

[0022] A second aspect of the present invention provides a method for preparing the above-mentioned animal licking brick, comprising the following steps:

[0023] S1. Preparation of core nutrient microcapsules

[0024] S11. Core material premix: According to the nutritional requirements of the target animal, the functional nutrients and carrier are mixed under an inert atmosphere;

[0025] S12. Wall material emulsification and embedding: The wall material raw materials are prepared in proportion to form an aqueous emulsion, and the core material is uniformly dispersed in it to form an O / W type emulsion.

[0026] S13. Microcapsule formation: O / W emulsion is formed into microcapsules;

[0027] S2: Synthetic modulating binder with dual-response properties

[0028] S21. Preparation of acid-responsive binder: Corn starch and gelatin were dissolved in a pH 6.0–6.5 buffer system at a mass ratio, and transglutaminase was added at 40–42°C to catalyze the formation of starch-gelatin copolymer;

[0029] S22. Skeleton assembly: After heating and melting the hydrophobic skeleton, starch-aminobutyric acid copolymer, thickener and lubricant are added in sequence to form a homogeneous melt under high shear conditions, which is then cooled and granulated.

[0030] S3: Composite molding of microcapsules and binders

[0031] S31. Mix the core nutrient microcapsules obtained in step S1 with the conditioning binder obtained in step S2 according to the mass ratio;

[0032] S32. Press molding: Control the pressing temperature ≤ the melting point of the hydrophobic skeleton, the pressure 6–12 MPa, and the holding time 10–30 seconds to obtain the lick brick.

[0033] By implementing the above technical solution, the present invention has the following beneficial effects:

[0034] This invention constructs a composite system consisting of salivary enzyme-sensitive core nutrient microcapsules and a multi-responsive regulatory binder. This system enables animal licking bricks to maintain structural stability under high humidity or rain conditions and precisely release nutrients only when the animal licks them. The microcapsule wall material uses an optimized ratio of low-crosslinked corn starch and maltodextrin with a specific DE value to ensure rapid enzymatic hydrolysis and good palatability. The regulatory binder, through the synergistic effect of functional components such as a hydrophobic framework and acid-responsive binders, ensures mechanical strength while achieving controllable failure triggered by licking. The overall technical solution significantly improves nutrient utilization efficiency, environmental adaptability, and animal feeding willingness, effectively solving the core problems of traditional licking bricks such as easy loss, difficult release, and poor palatability. It has outstanding practical value and industrialization prospects. Detailed Implementation

[0035] The present invention will be further described in detail below through specific embodiments.

[0036] It should be noted that the following embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0037] Example 1: Preparation of pig licking bricks

[0038] 1. Core Nutrition Microcapsules

[0039] (1) Core material formulation (by weight percentage)

[0040] Vitamin premix (containing VA 2 million IU / kg, VD3 400,000 IU / kg, VE 5000 mg / kg, VB1 200 mg / kg, VB2 600 mg / kg, VB6 300 mg / kg, VB...) 12 2 mg / kg): 18%;

[0041] Organic acid mixture (citric acid: fumaric acid = 3:1): 12%;

[0042] Prebiotic blend (fructooligosaccharides FOS: mannan oligosaccharides MOS = 2:1): 10%;

[0043] Amino acid (L-lysine:DL-methionine = 4:1): 8%;

[0044] Antioxidant (ethoxyquinoline): 0.3%;

[0045] Carrier (maltodextrin, DE=10): Make up to 100%.

[0046] The above components were mixed in a three-dimensional mixer for 30 minutes to obtain a uniform core material powder.

[0047] (2) Preparation of emulsion for wall material layer

[0048] Weigh 75 kg of phosphate distarch (crosslinking degree 0.08%, food grade) and 25 kg of maltodextrin (DE=12), add deionized water to prepare an emulsion with a solid content of 20%, and stir at 60°C for 30 minutes until completely dispersed.

[0049] (3) Microencapsulation

[0050] Spray drying method: core material powder is dispersed in wall material emulsion at a mass ratio of 1:3, homogenized (10,000 rpm, 5 min), inlet air temperature 180°C, outlet air temperature 85°C, to obtain core nutrient microcapsules.

[0051] 2. Preparation of Modified Binders

[0052] (1) Synthesis of starch-gelatin copolymer

[0053] Dissolve 50 kg of corn starch and 50 kg of edible gelatin in 400 L of pH 6.3 phosphate buffer solution and stir at 40°C;

[0054] Add 0.5 kg of transglutaminase (TG enzyme, activity 100 U / g) and react for 2 h;

[0055] After the reaction is complete, cool to room temperature, add 2 volumes of 95% ethanol to precipitate, filter, wash, and dry under vacuum at 60°C;

[0056] A white powdery copolymer was obtained, which was then partially hydrolyzed by treating it with 0.1 M dilute hydrochloric acid at 40°C for 30 min to adjust its molecular weight distribution so that it retains enough starch segments that can be recognized by α-amylase.

[0057] (2) Mixing of binders

[0058] 45 kg of hydrogenated palm oil (melting point 52°C) was heated to 60°C to melt.

[0059] Add 35 kg of the above copolymer, 12 kg of microcrystalline cellulose (MCC, PH102), and 3 kg of calcium stearate in sequence;

[0060] Shear mixing at 800 rpm for 15 min in a planetary mixer, followed by cooling and crushing into particles with a diameter of 0.5–2 mm, yields an conditioned binder.

[0061] 3. Brick forming

[0062] Mix 60 kg of core nutrient microcapsules with 40 kg of conditioning binder in a V-type mixer for 20 min, transfer to a rotary tablet press, set the pressure to 8 MPa, and press into licking bricks, each weighing about 1000 g.

[0063] Example 2: Preparation of cattle licking bricks

[0064] 1. Core Nutrition Microcapsules

[0065] (1) Core material formulation (by weight percentage)

[0066] Vitamin premix (VA, VD3, VE, niacin, biotin): 15%;

[0067] Buffer salt combination (sodium bicarbonate: magnesium oxide = 2:1): 20%;

[0068] Mineral premix (containing organic chelates of cobalt, selenium, zinc, and copper): 12%;

[0069] Prebiotic (yeast cell wall extract, containing ≥20% MOS): 10%;

[0070] Rumen-protected amino acids (rumen-protected lysine, methionine): 8%;

[0071] Antioxidant (TBHQ): 0.2%;

[0072] Carrier (maltodextrin): Make up to 100%.

[0073] The mixing process is the same as in Example 1.

[0074] (2) Wall material: 75% phosphate distarch, 25% maltodextrin, but the microcapsule particle size is controlled at 250–300 μm to adapt to the rough licking characteristics of the bovine tongue and delay rumen degradation.

[0075] 2. Adjustment of Regulating Binder

[0076] Hydrogenated vegetable oil: 48% (selected from high-melting-point hydrogenated rapeseed oil, melting point 55°C, to improve outdoor heat resistance);

[0077] Starch-gelatin copolymer: 32% (extending TG enzyme crosslinking time to 3 h to enhance network strength);

[0078] Microcrystalline cellulose: 13%;

[0079] Calcium stearate: 7%;

[0080] The mixing and granulation processes are the same as in Example 1.

[0081] 3. Brick forming

[0082] The microcapsules and binder are mixed in a 55:45 ratio and pressed into lick bricks using a hydraulic molding machine (pressure 12 MPa), with a single brick weighing approximately 1000g.

[0083] Comparative Example 1 (licking brick prepared in Example 1 of CN101606641A)

[0084] A: Mix 0.10 kg of ferrous sulfate, 0.10 kg of zinc sulfate, 0.07 kg of copper sulfate, 0.12 kg of manganese sulfate, 0.01 kg of sodium selenite, 0.05 kg of potassium iodide, 0.01 kg of cobalt chloride, 0.05 kg of magnesium oxide, 2 kg of chromium nicotinate, 30 kg of sodium sulfate, 50 kg of dicalcium phosphate, and 225.69 kg of puffed corn kernel powder until homogeneous.

[0085] B: Add 300 kg of salt and 300 kg of bentonite to the mixture obtained in process A and stir well;

[0086] C: Take 60 kg of molasses and heat it at 80℃, stirring until it becomes syrup;

[0087] D: Mix the products obtained in processes B and C, stir evenly, and press them into licking bricks in a 1kg batch.

[0088] Comparative Example 2

[0089] Preparation of pig lick bricks

[0090] 1. Core material formulation (by weight percentage)

[0091] Vitamin premix (containing VA 2 million IU / kg, VD3 400,000 IU / kg, VE 5000 mg / kg, VB1 200 mg / kg, VB2 600 mg / kg, VB6 300 mg / kg, VB...) 12 2 mg / kg): 18%;

[0092] Organic acid mixture (citric acid: fumaric acid = 3:1): 12%;

[0093] Prebiotic blend (fructooligosaccharides FOS: mannan oligosaccharides MOS = 2:1): 10%;

[0094] Amino acid (L-lysine:DL-methionine = 4:1): 8%;

[0095] Antioxidant (ethoxyquinoline): 0.3%;

[0096] Carrier (maltodextrin, DE=10): Make up to 100%.

[0097] The above components were mixed in a three-dimensional mixer for 30 minutes to obtain a uniform core material powder.

[0098] 2. Modified binder

[0099] (1) Synthesis of starch-gelatin copolymer

[0100] Dissolve 50 kg of corn starch and 50 kg of edible gelatin in 400 L of pH 6.3 phosphate buffer solution and stir at 40°C;

[0101] Add 0.5 kg of transglutaminase (TG enzyme, activity 100 U / g) and react for 2 h;

[0102] After the reaction is complete, cool to room temperature, add 2 volumes of 95% ethanol to precipitate, filter, wash, and dry under vacuum at 60°C;

[0103] A white powdery copolymer was obtained, which was then partially hydrolyzed by treating it with 0.1 M dilute hydrochloric acid at 40°C for 30 min to adjust its molecular weight distribution so that it retains enough starch segments that can be recognized by α-amylase.

[0104] (2) Mixing of binders

[0105] 45 kg of hydrogenated palm oil (melting point 52°C) was heated to 60°C to melt.

[0106] Add 35 kg of the above copolymer, 12 kg of microcrystalline cellulose (MCC, PH102), and 3 kg of calcium stearate in sequence;

[0107] Shear mixing at 800 rpm for 15 min in a planetary mixer, followed by cooling and crushing into particles with a diameter of 0.5–2 mm, yields an conditioned binder.

[0108] 3. Brick forming

[0109] Mix 60 kg of core material powder and 40 kg of conditioning binder in a V-type mixer for 20 min, transfer to a rotary press, set the pressure to 8 MPa, and press into licking bricks, each weighing about 1000 g in cylindrical shape.

[0110] Comparative Example 3

[0111] Preparation of pig lick bricks

[0112] 1. Core Nutrition Microcapsules

[0113] (1) Core material formulation (by weight percentage)

[0114] Vitamin premix (containing VA 2 million IU / kg, VD3 400,000 IU / kg, VE 5000 mg / kg, VB1 200 mg / kg, VB2 600 mg / kg, VB6 300 mg / kg, VB...) 12 2 mg / kg): 18%;

[0115] Organic acid mixture (citric acid: fumaric acid = 3:1): 12%;

[0116] Prebiotic blend (fructooligosaccharides FOS: mannan oligosaccharides MOS = 2:1): 10%;

[0117] Amino acid (L-lysine:DL-methionine = 4:1): 8%;

[0118] Antioxidant (ethoxyquinoline): 0.3%;

[0119] Carrier (maltodextrin, DE=10): Make up to 100%.

[0120] The above components were mixed in a three-dimensional mixer for 30 minutes to obtain a uniform core material powder.

[0121] (2) Preparation of wall material emulsion

[0122] Weigh 75 kg of phosphate distarch (crosslinking degree 0.08%, food grade) and 25 kg of maltodextrin (DE=12), add deionized water to prepare an emulsion with a solid content of 20%, and stir at 60°C for 30 minutes until completely dispersed.

[0123] (3) Microencapsulation

[0124] Spray drying method: core material powder is dispersed in wall material emulsion at a mass ratio of 1:3, homogenized (10,000 rpm, 5 min), inlet air temperature 180°C, outlet air temperature 85°C, to obtain core nutrient microcapsules.

[0125] 2. Licking brick forming

[0126] Mix 60 kg of core nutrient microcapsules with 40 kg of starch paste in a V-type mixer for 20 min, then transfer to a rotary tablet press, set the pressure to 8 MPa, and press into licking bricks, each weighing approximately 1000 g in cylindrical shape.

[0127] Performance testing

[0128] The following performance tests were performed on the licking bricks obtained in each embodiment and comparative example.

[0129] 1. Environmental stability: Place the bricks in a constant humidity chamber at 30℃ and 90% relative humidity for 14 days, calculate the change in the brick mass, and observe the structural condition.

[0130] 2. Saliva responsiveness: Simulated pig saliva (α-amylase 50 U / mL, pH 6.8) was dropped onto the surface and used in conjunction with a tongue friction simulation device (load 5 N, rotation speed 60 rpm) to record the time of initial shedding and the shedding rate at 10 min.

[0131] 3. Outdoor exposure test: Placed in a summer pasture (average daily temperature 35℃, RH 85%, occasional rainfall) for 30 consecutive days, and the integrity of the brick lick structure was statistically analyzed.

[0132] 4. Animal palatability:

[0133] Thirty healthy weaned piglets were selected and randomly divided into three groups (n=10). Each group was provided with a licking block (Example 1, Comparative Example 1, and Comparative Example 3) and allowed free licking. The piglets were observed for seven consecutive days. A high-definition infrared camera system (24-hour recording) was used to record the licking behavior of each pig daily, and the average value was taken as the final data.

[0134] Twenty-four mid-lactation Holstein cows were randomly divided into three groups (n=8), and provided with licking blocks according to Example 2, Comparative Example 1, and Comparative Example 3, respectively. They were allowed free access to these blocks and observed for 14 consecutive days. The average number of licks per day was recorded using a high-definition infrared camera system (24-hour recording), and the average value was taken as the final data (times / cow / day).

[0135] The results are shown in Table 1.

[0136] Table 1. Performance test results of the brick licking method obtained from different embodiments and comparative examples.

[0137]

[0138] The results shown in Table 1 above indicate that:

[0139] Examples 1-2: 1.6% ~ 2.1%, indicating only trace amounts of moisture absorption or surface hydration in a humid environment, overall stability, and good structural state. In terms of salivary responsiveness, it achieved a highly efficient response of "starting within 5 minutes and releasing over 60% within 10 minutes." Furthermore, the licking brick also exhibited excellent palatability and weather resistance in animals. Comparative Example 1, a conventional licking brick, did not utilize the core nutrient microcapsules and multi-responsive modulating binder specific to this invention. Its mass change rate of 0.8% seemed low, but its surface was too hardened, resulting in excessively long detachment time in the salivary responsiveness experiment, hindering effective release of nutrients through licking. Its palatability in animals was also unsatisfactory. Comparative Example 2, while comparable to the examples in environmental stability, did not encapsulate its nutrients, leading to excessively rapid release. The quality of the licking bricks in Comparative Example 3 was extremely unstable, and they fell off very quickly. This was clearly due to the strong water absorption and loose structure of the binder or wall material, which caused severe swelling or disintegration. Almost all of them fell off within 10 minutes, and the release was out of control. This easily caused nutrient loss and structural damage. In terms of palatability, the initial stimulation was strong (due to rapid release), but the animals refused to eat them later due to structural disintegration, poor taste, or nutritional imbalance. This did not meet the requirements for long-term feeding.

Claims

1. A licking block for animals, characterized in that, The matrix comprises multiple core nutrient microcapsules and an adjustable binder that binds at least partially separated core nutrient microcapsules together, and whose adhesive strength decreases more when exposed to animal licking than when exposed to water. The core nutrient microcapsule includes a core material and a wall material layer encapsulating the core material, wherein the core material contains functional nutrients and the wall material layer is made of a salivary enzyme-sensitive polymer.

2. The animal licking block according to claim 1, characterized in that, The mass ratio of the core nutrient microcapsule to the regulating binder is (50–70):(30–50).

3. The animal licking block according to claim 1, characterized in that, The salivase-sensitive polymer comprises 70-80 wt% corn starch and 20-30 wt% maltodextrin, wherein the degree of crosslinking of the corn starch is ≤0.1% and the DE value of the maltodextrin is 10-15.

4. The animal licking block according to claim 1, characterized in that, The modulating binder comprises 40-50 wt% hydrophobic skeleton, 30-40 wt% acid-responsive binder, 10-15 wt% tackifier and reinforcing agent, and 2-5 wt% lubricant, wherein the hydrophobic skeleton has a melting point of 45-60°C.

5. The animal licking block according to claim 1, characterized in that, The hydrophobic framework is hydrogenated vegetable oil.

6. The animal licking block according to claim 1, characterized in that, The acid-responsive binder is a starch-gelatin copolymer.

7. The animal licking block according to claim 1, characterized in that, The starch-gelatin copolymer is prepared as follows: corn starch and gelatin are cross-linked under pH 6.0-6.5 and 40-42℃ conditions to form a starch-gelatin copolymer.

8. The animal licking block according to claim 1, characterized in that, The core material also includes a carrier.

9. The animal licking block according to claim 1, characterized in that, The conditioning binder also includes flavoring agents.

10. The animal licking block according to claim 9, characterized in that, The flavoring agent is a sugar alcohol.

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