Use of lanosterol substances in the preparation of a feed additive for crustaceans and feed

Abstract

This invention provides the application of lanosterols in the preparation of crustacean feed additives and related feeds, including lanosterols or their feed-acceptable esters, in the preparation of crustacean feed additives to improve the growth performance and maintain the physiological health of crustaceans, including regulating lipid metabolism, enhancing antioxidant capacity, and / or improving digestive enzyme activity. This invention provides a novel, efficient, and cost-optimized functional additive for crustacean feed, offering an effective cholesterol alternative or supplement to reduce feed costs; and significantly improving the growth performance of crustaceans under low-fishmeal feed conditions while systematically regulating and maintaining their physiological health.

Description

Technical Field

[0001] This invention relates to the technical field of feed additives, specifically to the application of lanosterols in the preparation of crustacean feed additives and the feed itself. Background Technology

[0002] In recent years, to control the production cost of aquatic feed, the industry has widely adopted plant protein sources with low cholesterol content to replace traditional animal protein sources rich in cholesterol, such as fishmeal. Low-fishmeal feed has become a trend in the industry. However, this has led to the problem of cholesterol deficiency in crustaceans. Cholesterol is a recognized essential nutrient for crustaceans, directly affecting their growth, molting, and physiological health. Cholesterol deficiency usually leads to decreased growth performance and impaired physiological health in crustaceans, seriously affecting aquaculture efficiency.

[0003] To address the aforementioned cholesterol deficiency issue, directly adding cholesterol would significantly reduce the cost advantage of low-fishmeal feed due to its high price, thus limiting its large-scale application. Furthermore, relying heavily on cholesterol as a single feed additive makes the feed susceptible to market supply fluctuations, making it difficult to guarantee a stable supply and use of feed additives.

[0004] Currently, the industry lacks novel feed additives that meet functional requirements, have stable sources, and are more cost-effective. Furthermore, there is an urgent need for a feed additive that can simultaneously provide antioxidant benefits, regulate digestive enzymes, and improve lipid metabolism, effectively compensating for the comprehensive deficiencies of low-fishmeal feeds and addressing growth and physiological health issues in crustaceans caused by cholesterol deficiency. Therefore, developing new, low-cost, and more stable alternatives and multifunctional feed additives has become a key technological challenge that the aquaculture feed industry urgently needs to overcome.

[0005] Lanosterols are a class of tetracyclic triterpenoids, appearing as white, odorless powders. They can be obtained through natural extraction or biochemical synthesis, serving as important steroidal intermediates and functional active substances. In the pharmaceutical field, lanosterols can be used in the synthesis of drug intermediates, the prevention and treatment of ophthalmic diseases such as cataracts, and immunomodulation. In the cosmetics field, lanosterols, due to their excellent permeability, water absorption, and lubricating properties, can be used as functional additives in the preparation of various high-end cosmetics, especially suitable for skincare and makeup products with moisturizing, repairing, and soothing effects. In the chemical industry, lanosterols, as typical representatives of tetracyclic triterpenoids, can be used as raw materials for chemical synthesis, in the preparation of various terpene derivatives, surfactants, lubricants, and other chemical products.

[0006] Currently, there are no publicly available reports on the use of lanosterols in feed additives, especially in crustacean feed additives. Summary of the Invention

[0007] This invention aims to overcome the shortcomings of existing technologies and provide a novel, efficient, and cost-optimized sterol functional additive—lanosterol—for application in crustacean feed. On one hand, it provides an effective cholesterol alternative or supplement to reduce feed costs; on the other hand, it significantly improves the growth performance of crustaceans under low-fishmeal feed conditions and systematically regulates their lipid metabolism, digestive function, and antioxidant capacity, maintaining their physiological health.

[0008] The first aspect of the invention is to provide the use of lanosterols or their feed-acceptable esters in the preparation of crustacean feed additives to improve the growth performance of crustaceans.

[0009] According to a preferred embodiment of the present invention, the growth performance of crustaceans is improved, specifically by increasing the final average weight, weight gain rate, specific growth rate, and / or reducing the feed conversion ratio.

[0010] A second aspect of the invention is to provide the use of lanosterols or their feed-acceptable esters in the preparation of crustacean feed additives for maintaining the physiological health of crustaceans.

[0011] According to a preferred embodiment of the present invention, maintaining the physiological health of crustaceans includes regulating the lipid metabolism of crustaceans, improving the antioxidant capacity of crustaceans, and / or improving the digestive enzyme activity of crustaceans.

[0012] According to a preferred embodiment of the present invention, lipid metabolism in crustaceans is regulated and lipid metabolism disorders are improved, specifically by reducing the levels of total cholesterol, triglycerides and / or low-density lipoprotein cholesterol in the hemolymph and promoting the transport and storage of lipids in tissues such as the liver and pancreas.

[0013] According to a preferred embodiment of the present invention, improving the antioxidant capacity of crustaceans enhances the body's antioxidant defense capabilities and alleviates oxidative stress damage. Specifically, this is manifested in the increase of superoxide dismutase activity and / or total antioxidant capacity in the hepatopancreas, and / or the decrease of malondialdehyde content in the hepatopancreas.

[0014] According to a preferred embodiment of the present invention, improving the digestive enzyme activity of crustaceans involves specifically enhancing digestive enzyme activity and optimizing the digestion and absorption pattern of nutrients. Specifically, this is manifested in the enhancement of lipase and protease activity and the decrease of amylase activity. Through the shift in energy metabolism preference, the digestion and absorption of nutrients are effectively improved.

[0015] According to a preferred embodiment of the present invention, the crustacean is any one of the following: Litopenaeus vannamei, Penaeus monodon, Penaeus sinensis, Eriocheir sinensis, Procambarus clarkii, Muscovy crab, and Portunus trituberculatus.

[0016] The above two aspects are applied in the preparation of crustacean feed additives, especially for shrimp, including Litopenaeus vannamei, Penaeus monodon, and Penaeus sinensis.

[0017] According to a preferred embodiment of the present invention, the content of animal protein source in the feed is not higher than 30%, preferably not higher than 26%. The application of the above two aspects in the preparation of crustacean feed additives is mainly aimed at feeds that lack cholesterol due to the substitution of some animal protein source by plant protein source or other protein source, resulting in a low content of animal protein source.

[0018] The animal protein content in the feed is 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or any value between them.

[0019] Preferably, the animal protein source in the feed includes fishmeal, with the fishmeal content not exceeding 25%, and more preferably not exceeding 20%. The application of the above two aspects in the preparation of crustacean feed additives is mainly aimed at feeds lacking cholesterol due to the substitution of some fishmeal by plant protein sources or other protein sources, resulting in low fishmeal content.

[0020] The fishmeal content in the feed is 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, or any value between them.

[0021] According to a preferred embodiment of the present invention, lanosterols include one or more of lanosterol, dihydrolanosterol, 24-methylenedihydrolanosterol, and parkol.

[0022] According to a preferred embodiment of the present invention, feed-acceptable esters of lanosterols include esterification products obtained by combining lanosterols with fatty acids of any form, or mixtures of lanosterols with partially esterified products. The aforementioned fatty acids of any form include single fatty acids or mixed fatty acids.

[0023] The esters of lanosterols that are acceptable in feed include, but are not limited to, one or more of the following: lanosterol formate, lanosterol acetate, lanosterol oleate, lanosterol palmitate, and lanosterol laurate.

[0024] The lanosterols are preferably a mixture of lanosterol and dihydrolanosterol, the structural formulas of which are shown in formula (I) and formula (II), respectively.

[0025] (I) (II) The mass ratio of lanosterol to dihydrolanosterol is (0.5~5):1, preferably (1~3):1. The mass ratio of lanosterol to dihydrolanosterol is 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1 or any value between them.

[0026] Preferably, the mass ratio of lanosterol to dihydrolanosterol is 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, or any value between them.

[0027] According to a preferred embodiment of the present invention, the amount of lanosterols or their feed-acceptable esters added to the feed is 0.02% to 0.4%, preferably 0.05% to 0.1% or 0.1% to 0.2%.

[0028] The addition of lanosterols or their feed-acceptable esters to feed is 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, or any value between them.

[0029] A third aspect of the present invention is to provide a crustacean feed comprising the aforementioned lanosterols or feed-acceptable esters thereof.

[0030] According to a preferred embodiment of the present invention, crustacean feed, based on dry weight, comprises the following components: (1) Animal protein source 15%~40%; (2) Plant protein source 20%~50%; (3) Carbohydrates 5%~30%; (4) Fat 0%~10%; (5) Nutritional supplements and excipients 1% to 15%, including lanosterols or their feed-acceptable esters.

[0031] According to a preferred embodiment of the present invention, crustacean feed, based on dry weight, comprises the following components: (1) Animal protein source 20%~30%; (2) Plant protein source 30%~40%; (3) Carbohydrates 20%~30%; (4) Fat 1%~5%; (5) 5% to 10% of nutritional supplements and excipients, including lanosterols or their feed-acceptable esters, wherein the amount of lanosterols or their feed-acceptable esters added to the feed is 0.02% to 0.4%, preferably 0.05% to 0.1%.

[0032] The present invention has the following beneficial effects: (1) The application of lanosterols or their feed-acceptable esters in the preparation of crustacean feed additives in this invention provides an effective alternative or supplementary solution for cholesterol addition in feed, thereby reducing feed costs and having the potential for cost optimization. It provides feed production enterprises with a new option to reduce formulation costs while maintaining the performance of high-end products.

[0033] (2) The addition of lanosterols or their feed-acceptable esters to feed can significantly improve the growth performance and feed utilization of crustaceans under low fishmeal feed conditions.

[0034] (3) The addition of lanosterols or their feed-acceptable esters to the feed can systematically regulate the lipid metabolism, digestive function and antioxidant capacity of crustaceans, and maintain their physiological health. Attached Figure Description

[0035] Figure 1 The images show hepatopancreatic tissue sections of Litopenaeus vannamei from each group in the examples. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0037] Unless otherwise specified, the raw materials and equipment used in the following embodiments of the present invention are commercially available.

[0038] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this invention are based on weight, unless being based on weight would not be in accordance with the common understanding of those skilled in the art.

[0039] The "range" disclosed herein is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that the ranges of 60-110 and 80-120 will also be understood. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers.

[0040] Unless otherwise specified in this application, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0041] Unless otherwise specified, all technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0042] In this application, unless otherwise specified, the terms "comprising" and "including" as used herein are open-ended or closed-ended. For example, "comprising" and "including" may mean that other components not listed may also be included, or that only the listed components may be included.

[0043] In this description, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0044] This invention discloses a method for applying lanosterols or their feed-acceptable esters in low-fishmeal feeds for crustaceans, such as Litopenaeus vannamei. Specifically, by exogenously adding a specific dosage range of lanosterols or their feed-acceptable esters to a low-fishmeal (e.g., 15% fishmeal) feed, an effective supplementation or replacement of cholesterol is achieved, systematically solving a series of growth and health problems caused by reduced fishmeal intake.

[0045] The overall implementation path of the plan is as follows: First, a 15% fishmeal-based feed with soybean meal, peanut meal, etc. as the main protein source is formulated; then, through a step-by-step mixing feed processing technology, precisely measured lanosterol is evenly added to the feed to make pelleted feed; finally, by feeding this specific feed, the growth performance, lipid metabolism, antioxidant defense system and digestive function of Litopenaeus vannamei are measured and analyzed.

[0046] 1. Test materials

[0047] Experimental animals: Litopenaeus vannamei ( Litopenaeus vannamei Juvenile shrimp (also known as whiteleg shrimp) have an initial weight of about 0.80 g.

[0048] Test substance: Lanosterol product (purity ≥90.4%), provided by Zhejiang Garden Biomedical Co., Ltd. This lanosterol product is a mixture of lanosterol and dihydrolanosterol, with a content ratio of (2±0.2):1.

[0049] Feed formulation: An isonitrogenous and lipid-based feed is used, with the basal feed being a low-fishmeal feed (fishmeal content of 15%), and a portion of the fishmeal is replaced by a mixed plant protein source (soybean meal, peanut meal, and wheat gluten).

[0050] 2. Experimental Design

[0051] Experimental group: HF group: High fish meal control group (25% fish meal, 0% lanosterol product).

[0052] LF group: Low fish meal control group (15% fish meal, 0% lanosterol product).

[0053] Group L0.05: Low fish meal + 0.05% lanosterol product.

[0054] Group L0.1: Low fish meal + 0.1% lanosterol product.

[0055] Group L0.2: Low fish meal + 0.2% lanosterol product.

[0056] Group L0.4: Low fish meal + 0.4% lanosterol product.

[0057] The specific feed formulations for each experimental group, including those with high fishmeal and low fishmeal content, are shown in Table 1.

[0058] Table 1

[0059] Culture conditions: Indoor recirculating aquaculture system, culture cycle 56 days. Water temperature (28±0.5)℃, salinity (32±0.5)‰.

[0060] Indicator measurements: growth indicators (final average weight, weight gain rate, specific growth rate, feed conversion ratio), body composition, blood and lymph physiological and biochemical indicators, lipid metabolism indicators, antioxidant indicators, and digestive enzyme indicators.

[0061] 3. Results and Analysis

[0062] 3.1 Growth performance

[0063] The initial average weight, final average weight, weight gain rate, and specific growth rate of Litopenaeus vannamei in each group were measured.

[0064]

[0065] W t The average body weight of Litopenaeus vannamei at the end of the experiment (unit: g / tail). W0 represents the average body weight of Litopenaeus vannamei at the start of the experiment (unit: g / tail). t is the test period (unit: days); M represents the total weight of the feed given (in g). n is the number of Litopenaeus vannamei shrimp used in the experiment (unit: shrimp).

[0066] As shown in Table 2, the low fishmeal group resulted in slow growth, significantly reduced weight gain and specific growth rate of Litopenaeus vannamei, and low feed utilization efficiency (increased feed conversion ratio).

[0067] Adding lanosterol to low-fishmeal feed improved the average final weight, weight gain, and specific growth rate of Litopenaeus vannamei. Specifically, adding 0.05%-0.1% lanosterol to the low-fishmeal feed significantly improved these parameters, restoring them to levels indistinguishable from the high-fishmeal group (25% fishmeal). The addition of lanosterol enhanced growth performance and improved feed conversion efficiency.

[0068] Meanwhile, the feed conversion ratio (FCR) is showing a decreasing trend. A lower FCR means less undigested nutrient discharge, which helps reduce the pollution load on aquaculture water bodies, aligns with the concept of environmentally friendly sustainable development, and contributes to the improvement of the aquaculture environment.

[0069] Table 2. Effects of lanosterol on the growth performance of Litopenaeus vannamei.

[0070] Note: Data are mean ± standard error. Different letters in the same row indicate significant differences. P <0.05).

[0071] FW, final average weight; WGR, weight gain rate; SGR, specific growth rate; FCR, feed conversion ratio.

[0072] 3.2 Body Composition

[0073] As shown in Table 3, the addition of lanosterol products had no significant effect on the moisture, crude fat, and crude ash content of whole Litopenaeus vannamei. Under low fishmeal feed conditions, the addition of 0.1%-0.2% lanosterol products significantly increased the crude protein content of whole shrimp, and there was no significant difference compared with the high fishmeal group (HF group).

[0074] Table 3. Effects of lanosterol on body composition (%, wet weight) of Litopenaeus vannamei

[0075] Note: Data are mean ± standard error. Different letters in the same row indicate significant differences. P <0.05).

[0076] 3.3 Serum biochemical indicators

[0077] As shown in Table 4, the addition of lanosterol products had no significant effect on the serum biochemical indicators of Litopenaeus vannamei.

[0078] Table 4. Effects of lanosterol on serum biochemical parameters of Litopenaeus vannamei.

[0079] Note: Data are mean ± standard error. ALT, alanine aminotransferase; AST, aspartate aminotransferase; TP, total protein; ALB, albumin; GLB, globulin; GLU, glucose.

[0080] 3.4 Digestive enzyme activity

[0081] As shown in Table 5, low fishmeal diets lead to a significant decrease in the activity of lipase and trypsin in Litopenaeus vannamei, resulting in low efficiency in the digestion and absorption of nutrients (especially fats and proteins).

[0082] Adding 0.05%-0.2%, especially 0.05%-0.1% lanosterol to low-fishmeal feed significantly increased the activity of lipase and trypsin in Litopenaeus vannamei, while significantly reducing amylase activity, indicating that it can effectively improve the digestion and absorption of nutrients.

[0083] Specifically, the addition of lanosterol products leads to a shift in energy metabolism preferences and an increase in the activity of lipases and proteases. This means that the body's ability to digest fats and proteins is enhanced, allowing fats and proteins to be used more efficiently as energy and growth raw materials. Correspondingly, the body's dependence on carbohydrates decreases, manifested as a decline in amylase activity.

[0084] Table 5. Effects of lanosterol on the digestive enzyme activity of Litopenaeus vannamei.

[0085] Note: Data are mean ± standard error. Different letters in the same row indicate significant differences. P <0.05).

[0086] 3.5 Lipid Metabolism

[0087] As shown in Table 6, low fishmeal diets led to abnormally high levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) in the hemolymph of Litopenaeus vannamei, indicating impaired lipid transport and utilization and posing a health risk.

[0088] Compared to the LF group, the addition of lanosterol to the low-fishmeal diet reduced the levels of total cholesterol (TC), low-dose lipoprotein cholesterol (LDL-C), and triglycerides (TG) in the hemolymph. In particular, the addition of 0.1%-0.2% lanosterol significantly reduced TC, LDL-C, and TG levels in the hemolymph, restoring them to normal ranges. This indicates that lanosterol can alleviate lipid metabolism disorders and promote lipid transport and storage in tissues such as the hepatocellular carcinoma and pancreas. The addition of lanosterol did not significantly alter the level of high-density lipoprotein cholesterol (HDL-C) in the hemolymph.

[0089] By adding lanosterol products to low-fishmeal feed, lipid metabolism in Litopenaeus vannamei can be systematically regulated, thus improving lipid metabolism disorders induced by low-fishmeal feed.

[0090] Table 6. Effects of lanosterol on lipid metabolism in Litopenaeus vannamei.

[0091] Note: Data are mean ± standard error. Different letters in the same row indicate significant differences. P <0.05).

[0092] TC, total cholesterol; TG, triglycerides; LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol.

[0093] 3.6 Antioxidant

[0094] As shown in Table 7, low fishmeal diets lead to a decrease in total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity in the hepatopancreas of Litopenaeus vannamei, and an increase in the content of malondialdehyde (MDA), the end product of lipid peroxidation, indicating that the body is under oxidative stress.

[0095] The addition of lanosterol products may significantly affect the antioxidant capacity of Litopenaeus vannamei by enhancing the activity of antioxidant enzymes. Compared with the LF group, the addition of lanosterol products to the low fishmeal diet increased hepatopancreatic SOD activity and T-AOC, and decreased hepatopancreatic MDA content. In particular, the addition of 0.1%-0.2% lanosterol products to the diet significantly reduced hepatopancreatic MDA content. SOD activity reached its highest level when 0.1% lanosterol products were added to the diet. The addition of 0.05%-0.1% lanosterol products to the diet significantly increased hepatopancreatic T-AOC. The addition of lanosterol products did not result in significant differences in antioxidant performance parameters compared with the HF group.

[0096] Table 7. Effects of lanosterol on the antioxidant capacity of Litopenaeus vannamei.

[0097] Note: Data are mean ± standard error. Different letters in the same row indicate significant differences. P <0.05).

[0098] MDA, malondialdehyde; SOD, superoxide dismutase; T-AOC, total antioxidant capacity.

[0099] 3.7 Hepatopancreatic tissue sections

[0100] like Figure 1 As shown, morphological studies of hepatopancreatic tissue revealed that in the HF group, the hepatic tubules were tightly packed, the cell shapes were more regular, the basement membrane structure was more intact, and the lumen exhibited a regular star shape. In the LF group, the hepatic tubules were more loosely packed. After adding lanosterol to the feed, the hepatic tubules became more tightly packed, and the basement membrane became clearer. Overall, the addition of lanosterol to the feed did not cause significant liver damage or morphological changes, and it effectively improved the liver morphological changes caused by low fishmeal diets.

[0101] In summary, lanosterol products, as functional additives in low-fishmeal feeds, have a significant promoting effect on improving the growth performance and maintaining the physiological health of Litopenaeus vannamei. The addition dosage in low-fishmeal Litopenaeus vannamei feed is 0.05%-0.4%, preferably 0.05%-0.1% or 0.1%-0.2%.

[0102] Adding 0.05%-0.1% lanosterol to low-fishmeal feed significantly improved the average weight, weight gain, and specific growth rate of Litopenaeus vannamei. Furthermore, adding 0.1%-0.2% lanosterol to low-fishmeal feed significantly increased the crude protein content of whole shrimp. Adding lanosterol to the feed had no significant effect on the serum biochemistry of Litopenaeus vannamei.

[0103] Adding lanosterol to low-fishmeal feeds can improve the digestion and absorption of nutrients by increasing trypsin and lipase activity.

[0104] Adding lanosterol to feed can effectively reduce blood lipid levels by lowering total cholesterol, triglycerides, and low-density lipoprotein levels in the hemolymph and promoting cholesterol transport to the liver and pancreas.

[0105] Adding lanosterol to low-fishmeal feeds may enhance the body's antioxidant capacity by significantly increasing the activity of antioxidant enzymes. Due to the enhanced antioxidant capacity and improved hepatopancreatic health, feeding the feed of this invention results in a stronger ability to cope with environmental stresses, such as sudden temperature changes, salinity variations, or hypoxia, contributing to a potential increase in stress resistance.

[0106] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. The use of lanosterols or their feed-acceptable esters in the preparation of crustacean feed additives, characterized in that, Used to improve the growth performance of crustaceans.

2. The use of lanosterols or their feed-acceptable esters in the preparation of crustacean feed additives, characterized in that, Used to maintain the physiological health of crustaceans.

3. The application according to claim 2, characterized in that, It is used to regulate lipid metabolism in crustaceans, enhance antioxidant capacity in crustaceans, and / or improve digestive enzyme activity in crustaceans.

4. The application according to any one of claims 1-3, characterized in that, The crustaceans mentioned are any one of the following: Litopenaeus vannamei, Penaeus monodon, Penaeus sinensis, Procambarus clarkii, Eriocheir sinensis, Muscovy crab, and Portunus trituberculatus.

5. The application according to any one of claims 1-3, characterized in that, The content of animal protein sources in feed shall not exceed 30%.

6. The application according to claim 5, characterized in that, The animal protein source in the feed includes fishmeal, and the fishmeal content is no more than 25%.

7. The application according to claim 6, characterized in that, The fishmeal content is no higher than 20%.

8. The application according to any one of claims 1-3, characterized in that, The lanosterols include one or more of lanosterol, dihydrolanosterol, 24-methylenedihydrolanosterol, and parkol; The amount of the lanosterol or its feed-acceptable ester added to the feed is 0.02% to 0.4%.

9. The application according to claim 8, characterized in that, The amount of the lanosterol or its feed-acceptable ester added to the feed is 0.05%~0.1% or 0.1%~0.2%.

10. The application according to claim 8, characterized in that, The lanosterols include lanosterol and dihydrolanosterol, with a mass ratio of lanosterol to dihydrolanosterol of (0.5~5):

1.

11. The application according to claim 10, characterized in that, The mass ratio of lanosterol to dihydrolanosterol is (1~3):

1.

12. A crustacean feed, characterized in that, The substance includes any one of the lanosterols or their feed-acceptable esters as claimed in claims 1-3, wherein the amount of the lanosterols or their feed-acceptable esters added is 0.02% to 0.4%.

13. The feed according to claim 12, characterized in that, The amount of the lanosterol or its feed-acceptable ester added is 0.05%~0.1% or 0.1%~0.2%.

14. The feed according to claim 12, characterized in that, The feed, based on its dry weight, comprises the following components: (1) Animal protein source 15%~40%; (2) Plant protein source 20%~50%; (3) Carbohydrates 5%~30%; (4) Fat 0%~10%; (5) Nutritional supplements and excipients, 1% to 15%, including the lanosterols or their feed-acceptable esters.

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