A salt-tolerant functional feed for rainbow trout and a preparation method and use method thereof

Abstract

The present application relates to a kind of rainbow trout salt-tolerant functional feed and its preparation method and use method, belong to aquaculture technical field.To solve the problems such as long feeding cycle, need light pre-adaptation treatment and high domestication cost of existing rainbow trout salt-tolerant functional feed, the present application provides a kind of rainbow trout salt-tolerant functional feed, component includes fish meal, cottonseed protein concentrate, wheat flour, fermented soybean meal, fish oil, choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, proline, phenylalanine, glycine, sorbitol, vitamin C and Chinese herbal medicine extract.The present application significantly improves the osmotic regulation ability and antioxidant defense ability of rainbow trout fry, compared with prior art, the present application feeding cycle is shortened from 45 days to 40 days, fish meal addition amount is reduced from 30% to 25%, under the premise of guaranteeing salt-tolerant domestication effect, shorten domestication cycle, simplify operation process and reduce feed cost.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, and in particular relates to a salt-tolerant functional feed for rainbow trout and its preparation and application methods. Background Technology

[0002] Rainbow trout, with its tender meat and rich nutrition, is highly favored by consumers. Since its introduction to my country in the 1950s, it has been widely cultivated in more than 20 inland provinces in Northeast, Northwest, and Southwest my country, becoming one of the most important cold-water fish species farmed in the country. Currently, the annual consumption of rainbow trout in China exceeds 140,000 tons, of which more than 60% relies on imports. Existing farmed production is far from meeting the growing market demand. At the same time, due to limitations in land and cold-water resources, inland aquaculture capacity is approaching saturation. In recent years, with the discovery of the Yellow Sea cold water mass and the continuous upgrading of deep-sea aquaculture equipment, deep-sea rainbow trout aquaculture, mainly based on the land-sea relay aquaculture model, has gradually taken shape and become an important direction for expanding aquaculture space. Under this model, large-sized seedlings must be acclimatized to salinity before being released into the sea for aquaculture. However, the osmotic pressure imbalance and oxidative stress caused by sudden changes in salinity in a short period of time are the main reasons for the high mortality rate of seedlings. In addition, rainbow trout seedlings in my country are mainly cultivated in inland flowing water systems. Due to limitations in site and facilities, it is difficult to carry out large-scale seedling domestication using the traditional step-by-step salinity domestication method, which seriously restricts the development of the rainbow trout deep-sea aquaculture industry.

[0003] In recent years, strategies for regulating fish salinity adaptation through nutritional means have received widespread attention. Existing studies have shown that adding functional additives to feed can improve the osmotic regulation and antioxidant defense capabilities of rainbow trout, effectively alleviating physiological damage caused by salinity stress.

[0004] Patent application CN119054844A discloses a technical solution for extending the light exposure time in freshwater aquaculture and supplementing it with functional feed, enabling rainbow trout fry to be directly introduced into the sea for aquaculture. However, this technical solution requires pre-acclimatization treatment of the fry before feeding, making the process cumbersome; the continuous feeding cycle is as long as 45 days, and the acclimatization efficiency needs improvement; moreover, the fishmeal content in the feed is as high as 30%, making it heavily reliant on imported fishmeal and resulting in high costs. These shortcomings, to some extent, restrict the widespread application of this technology in large-scale land-sea relay aquaculture production. Therefore, developing a functional feed that can significantly improve the salt tolerance of rainbow trout fry, reduce feed costs, and simplify the operation process within a shorter feeding cycle is of great significance for promoting the sustainable development of the rainbow trout deep-sea aquaculture industry. Summary of the Invention

[0005] To address the problems of long feeding cycles, the need for light pre-acclimatization treatment, and high acclimatization costs associated with existing salt-tolerant functional feeds for rainbow trout, this invention provides a salt-tolerant functional feed for rainbow trout, along with its preparation and application methods.

[0006] The technical solution of this invention:

[0007] A salt-tolerant functional feed for rainbow trout, comprising the following components in parts by weight: 250 parts fish meal, 200 parts cottonseed protein concentrate, 156 parts wheat flour, 120 parts fermented soybean meal, 180 parts fish oil, 3 parts choline chloride, 10 parts vitamin and mineral premix, 3 parts butylated hydroxytoluene, 4 parts betaine, 30 parts sodium chloride, 2 parts sodium alginate, 10 parts glutamine, 5 parts proline, 8 parts phenylalanine, 2 parts glycine, 2 parts sorbitol, 5 parts vitamin C, and 10 parts traditional Chinese medicine extract.

[0008] Furthermore, the raw materials of the herbal extract are composed of the following components in parts by weight: 10 parts of Acanthopanax senticosus, 15 parts of licorice, 10 parts of Schisandra chinensis, and 10 parts of Cornus officinalis.

[0009] Furthermore, each kilogram of the vitamin and mineral premix contains: Vitamin A: 150 mg; Vitamin B1: 300 mg; Vitamin B2: 300 mg; Vitamin B6: 280 mg; Vitamin D3: 6 mg; Vitamin E: 1200 mg; Vitamin K3: 140 mg; Vitamin C: 4500 mg; D-calcium pantothenate: 800 mg; Nicotinamide: 1500 mg; Manganese sulfate: 10000 mg; Ferrous sulfate: 10000 mg; Zinc oxide: 6000 mg; Copper sulfate: 4000 mg; Sodium selenite: 100 mg; Magnesium sulfate: 100000 mg; and Potassium iodide: 500 mg.

[0010] A method for preparing a salt-tolerant functional feed for rainbow trout includes the following steps:

[0011] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0012] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, proline, phenylalanine, glycine, sorbitol, and vitamin C. Mix them thoroughly to obtain the premixed additive.

[0013] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil to the mixed powder and mix evenly. Then add the herbal extract and water and continue mixing until evenly mixed to obtain a wet mixture.

[0014] Step 4: Put the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3-5 mm. After drying, the rainbow trout salt-tolerant functional feed is obtained.

[0015] Furthermore, the herbal extract described in step three is prepared using the following method: Weigh 10 parts of Acanthopanax senticosus, 15 parts of Glycyrrhiza uralensis, 10 parts of Schisandra chinensis, and 10 parts of Cornus officinalis by weight. Add distilled water at a ratio of 1g:10mL and soak for 30 minutes. Then, bring to a boil over high heat and simmer over low heat for 30-60 minutes. Filter out the liquid. Add distilled water to the remaining dregs at a ratio of 1g:5mL and decoct again. Combine the two liquids and concentrate under vacuum at 80℃ to a relative density of 1.15. Store at 4℃.

[0016] Furthermore, the sieving described in step one is sieving through a 60-mesh sieve.

[0017] Furthermore, the drying process described in step four involves drying in a 60°C forced-air drying oven until the moisture content is below 10%.

[0018] A method for using a salt-tolerant functional feed for rainbow trout involves selecting rainbow trout fry weighing 100–400g; directly feeding the salt-tolerant functional feed while providing continuous light with an intensity of 800–1000 Lux; feeding continuously for 40 days, 2–4 times a day, with a daily feed amount of 2% of the fish's body weight; after the feeding period ends, the rainbow trout fry are directly transferred to seawater for aquaculture.

[0019] Furthermore, the light period of the continuous illumination is L24:D0.

[0020] Furthermore, the rainbow trout includes landlocked rainbow trout, as well as triploid rainbow trout and all-female rainbow trout obtained from the landlocked rainbow trout.

[0021] The beneficial effects of this invention are:

[0022] This invention optimizes feed formulation, reducing the amount of fishmeal added while compounding an amino acid combination consisting of glutamine, proline, phenylalanine, and glycine, and adding functional components such as sorbitol, vitamin C, and traditional Chinese medicine extracts. This significantly enhances the osmotic regulation and antioxidant defense capabilities of rainbow trout fry, effectively alleviating physiological damage caused by sudden changes in salinity. It solves the problems of long feeding cycles, the need for light pre-acclimatization treatment, and high dependence on fishmeal in existing technologies, and achieves the technical effect that large-sized rainbow trout fry can be directly introduced into the sea for aquaculture after 40 days of feeding with a significantly improved survival rate.

[0023] Experimental data show that triploid rainbow trout fed with the feed of this invention achieved a 100% survival rate after 14 days of salinity stress. Compared with existing technologies, this invention shortens the feeding cycle from 45 days to 40 days, increasing acclimatization efficiency by approximately 11%; the amount of fishmeal added is reduced from 30% to 25%, significantly lowering feed costs; and the pre-feeding light acclimatization step is eliminated, requiring only continuous light exposure during the feeding period to achieve ideal acclimatization results, greatly simplifying the operation process.

[0024] With the rapid development of the rainbow trout deep-sea aquaculture industry, the market demand for efficient and low-cost salinity acclimatization technology for large-scale seedlings is becoming increasingly urgent. This invention provides reliable technical support for the land-sea relay aquaculture model, and has good prospects for promotion and application and significant economic benefits. Attached Figure Description

[0025] Figure 1 Comparison of survival rates of triploid rainbow trout fed with control diets 1 to 5 after 14 days of salinity stress;

[0026] Figure 2 A comparison of the survival rates of triploid rainbow trout fed with Example 1, Comparative Examples 5 to 8 after 14 days of salinity stress.

[0027] Figure 3 The graph shows a comparison of serum osmolality, total antioxidant capacity, and malondialdehyde (MDA) content in triploid rainbow trout fed with the diets of Example 1, Comparative Examples 5 to 8. A represents serum osmolality, B represents total antioxidant capacity, and C represents MDA content. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention. In the following embodiments, the process equipment or apparatus not specifically specified are all conventional equipment or apparatus in the art. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commercially available; unless otherwise specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0029] Example 1

[0030] This embodiment provides a salt-tolerant functional feed for rainbow trout, wherein every 1000 parts by weight of the feed contains the following components:

[0031] Fish meal 250 parts, cottonseed protein concentrate 200 parts, wheat flour 156 parts, fermented soybean meal 120 parts, fish oil 180 parts, choline chloride 3 parts, vitamin and mineral premix 10 parts, butylated hydroxytoluene 3 parts, betaine 4 parts, sodium chloride 30 parts, sodium alginate 2 parts, glutamine 10 parts, proline 5 parts, phenylalanine 8 parts, glycine 2 parts, sorbitol 2 parts, vitamin C 5 parts, and traditional Chinese medicine extract 10 parts.

[0032] In this embodiment, each kilogram of vitamin and mineral premix contains: Vitamin A: 150 mg; Vitamin B1: 300 mg; Vitamin B2: 300 mg; Vitamin B6: 280 mg; Vitamin D3: 6 mg; Vitamin E: 1200 mg; Vitamin K3: 140 mg; Vitamin C: 4500 mg; D-calcium pantothenate: 800 mg; Nicotinamide: 1500 mg; Manganese sulfate: 10000 mg; Ferrous sulfate: 10000 mg; Zinc oxide: 6000 mg; Copper sulfate: 4000 mg; Sodium selenite: 100 mg; Magnesium sulfate: 100000 mg; and Potassium iodide: 500 mg.

[0033] In this embodiment, the herbal extract was prepared by the following method: 10 parts of Acanthopanax senticosus, 15 parts of Glycyrrhiza uralensis, 10 parts of Schisandra chinensis, and 10 parts of Cornus officinalis were weighed according to the weight ratio of 1g:10mL and soaked in distilled water for 30min. Then, the mixture was brought to a boil over high heat and then simmered over low heat for 30-60min. The liquid was filtered out, and the remaining dregs were added to distilled water at a ratio of 1g:5mL and decocted a second time. The two liquids were combined and concentrated under vacuum at 80℃ to a relative density of 1.15. The mixture was then stored at 4℃.

[0034] The preparation method of the salt-tolerant functional feed for rainbow trout in this embodiment is as follows:

[0035] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0036] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, proline, phenylalanine, glycine, sorbitol, and vitamin C. Mix them thoroughly to obtain the premixed additive.

[0037] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil to the mixed powder and mix evenly. Then add the herbal extract and water and continue mixing until evenly mixed to obtain a wet mixture.

[0038] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0039] Comparative Example 1

[0040] This comparative example provides a rainbow trout feed, which contains the following components in parts by weight per 1000 parts by weight: 250 parts fish meal, 200 parts cottonseed protein concentrate, 173 parts wheat flour, 120 parts fermented soybean meal, 180 parts fish oil, 3 parts choline chloride, 10 parts vitamin and mineral premix, 3 parts butylated hydroxytoluene, 4 parts betaine, 30 parts sodium chloride, 2 parts sodium alginate, 10 parts glutamine, and 15 parts alanine.

[0041] The formulation of vitamins and minerals in this comparative vitamin and mineral premix is ​​the same as that in Example 1.

[0042] The preparation method of this comparative rainbow trout feed is as follows:

[0043] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0044] Step 2: Weigh out choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate and glutamine according to the formula, mix them evenly to obtain the premixed additive;

[0045] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil to the mixed powder and mix evenly. Then add the herbal extract and water to obtain a wet mixture.

[0046] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0047] Comparative Example 2

[0048] This comparative example provides a rainbow trout feed, wherein every 1000 parts by weight of the feed contains the following components:

[0049] Fish meal 250 parts, cottonseed protein concentrate 200 parts, wheat flour 173 parts, fermented soybean meal 120 parts, fish oil 180 parts, choline chloride 3 parts, vitamin and mineral premix 10 parts, butylated hydroxytoluene 3 parts, betaine 4 parts, sodium chloride 30 parts, sodium alginate 2 parts, glutamine 10 parts, alanine 2 parts, proline 5 parts, and phenylalanine 8 parts.

[0050] The formulation of vitamins and minerals in this comparative vitamin and mineral premix is ​​the same as that in Example 1.

[0051] The preparation method of this comparative rainbow trout feed is as follows:

[0052] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0053] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, alanine, proline, and phenylalanine. Mix them thoroughly to obtain the premixed additive.

[0054] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil and water to the mixed powder and continue mixing until even to obtain a wet mixture.

[0055] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0056] Comparative Example 3

[0057] This comparative example provides a rainbow trout feed, wherein every 1000 parts by weight of the feed contains the following components:

[0058] Fish meal 250 parts, cottonseed protein concentrate 200 parts, wheat flour 173 parts, fermented soybean meal 120 parts, fish oil 180 parts, choline chloride 3 parts, vitamin and mineral premix 10 parts, butylated hydroxytoluene 3 parts, betaine 4 parts, sodium chloride 30 parts, sodium alginate 2 parts, glutamine 10 parts, alanine 8 parts, proline 5 parts, and glycine 2 parts.

[0059] The formulation of vitamins and minerals in this comparative vitamin and mineral premix is ​​the same as that in Example 1.

[0060] The preparation method of this comparative rainbow trout feed is as follows:

[0061] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0062] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, alanine, proline, and glycine. Mix them thoroughly to obtain the premixed additive.

[0063] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil and water to the mixed powder and continue mixing until even to obtain a wet mixture.

[0064] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0065] Comparative Example 4

[0066] This comparative example provides a rainbow trout feed, wherein every 1000 parts by weight of the feed contains the following components:

[0067] Fish meal 250 parts, cottonseed protein concentrate 200 parts, wheat flour 173 parts, fermented soybean meal 120 parts, fish oil 180 parts, choline chloride 3 parts, vitamin and mineral premix 10 parts, butylated hydroxytoluene 3 parts, betaine 4 parts, sodium chloride 30 parts, sodium alginate 2 parts, glutamine 10 parts, alanine 5 parts, phenylalanine 8 parts, and glycine 2 parts.

[0068] The formulation of vitamins and minerals in this comparative vitamin and mineral premix is ​​the same as that in Example 1.

[0069] The preparation method of this comparative rainbow trout feed is as follows:

[0070] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0071] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, alanine, phenylalanine and glycine, mix them evenly to obtain the premixed additive.

[0072] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil and water to the mixed powder and continue mixing until even to obtain a wet mixture.

[0073] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0074] Comparative Example 5

[0075] This comparative example provides a rainbow trout feed, wherein every 1000 parts by weight of the feed contains the following components:

[0076] Fish meal 250 parts, cottonseed protein concentrate 200 parts, wheat flour 173 parts, fermented soybean meal 120 parts, fish oil 180 parts, choline chloride 3 parts, vitamin and mineral premix 10 parts, butylated hydroxytoluene 3 parts, betaine 4 parts, sodium chloride 30 parts, sodium alginate 2 parts, glutamine 10 parts, proline 5 parts, phenylalanine 8 parts and glycine 2 parts.

[0077] The formulation of vitamins and minerals in this comparative vitamin and mineral premix is ​​the same as that in Example 1.

[0078] The preparation method of this comparative rainbow trout feed is as follows:

[0079] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0080] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, proline, phenylalanine and glycine, mix them evenly to obtain the premixed additive.

[0081] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil and water to the mixed powder and continue mixing until even to obtain a wet mixture.

[0082] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0083] Comparative Example 6

[0084] This comparative example provides a rainbow trout feed, wherein every 1000 parts by weight of the feed contains the following components:

[0085] Fish meal 250 parts, cottonseed protein concentrate 200 parts, wheat flour 166 parts, fermented soybean meal 120 parts, fish oil 180 parts, choline chloride 3 parts, vitamin and mineral premix 10 parts, butylated hydroxytoluene 3 parts, betaine 4 parts, sodium chloride 30 parts, sodium alginate 2 parts, glutamine 10 parts, proline 5 parts, phenylalanine 8 parts, glycine 2 parts, sorbitol 2 parts, and vitamin C 5 parts.

[0086] The formulation of vitamins and minerals in this comparative vitamin and mineral premix is ​​the same as that in Example 1.

[0087] The preparation method of this comparative rainbow trout feed is as follows:

[0088] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0089] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, proline, phenylalanine, glycine, sorbitol, and vitamin C. Mix them thoroughly to obtain the premixed additive.

[0090] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil and water to the mixed powder and continue mixing until even to obtain a wet mixture.

[0091] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0092] Comparative Example 7

[0093] This comparative example provides a rainbow trout feed, wherein every 1000 parts by weight of the feed contains the following components:

[0094] 250 parts fish meal, 200 parts cottonseed protein concentrate, 158 parts wheat flour, 120 parts fermented soybean meal, 180 parts fish oil, 3 parts choline chloride, 10 parts vitamin and mineral premix, 3 parts butylated hydroxytoluene, 4 parts betaine, 30 parts sodium chloride, 2 parts sodium alginate, 10 parts glutamine, 5 parts proline, 8 parts phenylalanine, 2 parts glycine, 5 parts vitamin C, and 10 parts traditional Chinese medicine extract.

[0095] The formulation of vitamins and minerals in this comparative vitamin and mineral premix, as well as the preparation method of the herbal extract, are the same as in Example 1.

[0096] The preparation method of this comparative rainbow trout feed is as follows:

[0097] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0098] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, proline, phenylalanine, glycine, and vitamin C. Mix them thoroughly to obtain the premixed additive.

[0099] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil to the mixed powder and mix evenly. Then add the herbal extract and water and continue mixing until evenly mixed to obtain a wet mixture.

[0100] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0101] Comparative Example 8

[0102] This comparative example provides a rainbow trout feed, wherein every 1000 parts by weight of the feed contains the following components:

[0103] Fish meal 250 parts, cottonseed protein concentrate 200 parts, wheat flour 161 parts, fermented soybean meal 120 parts, fish oil 180 parts, choline chloride 3 parts, vitamin and mineral premix 10 parts, butylated hydroxytoluene 3 parts, betaine 4 parts, sodium chloride 30 parts, sodium alginate 2 parts, glutamine 10 parts, proline 5 parts, phenylalanine 8 parts, glycine 2 parts, sorbitol 2 parts, and traditional Chinese medicine extract 10 parts.

[0104] The formulation of vitamins and minerals in this comparative vitamin and mineral premix, as well as the preparation method of the herbal extract, are the same as in Example 1.

[0105] The preparation method of this comparative rainbow trout feed is as follows:

[0106] Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder.

[0107] Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, proline, phenylalanine, glycine, and sorbitol. Mix them thoroughly to obtain the premixed additive.

[0108] Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil to the mixed powder and mix evenly. Then add the herbal extract and water and continue mixing until evenly mixed to obtain a wet mixture.

[0109] Step 4: Feed the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3mm. Place the pellets in a 60℃ forced-air drying oven and dry them until the moisture content is less than 10%. After cooling, store them in a -20℃ refrigerator for later use.

[0110] The methods and results for testing feed quality and breeding effects are as follows:

[0111] I. Feed nutrient composition testing

[0112] The crude protein, crude fat, crude ash, and moisture content of the feeds in Example 1 and Comparative Examples 1-8 were tested, and the results are shown in Table 1.

[0113] Table 1

[0114]

[0115] Table 1 shows that the crude protein content of each group of feeds was 41.13%–41.20%, and the crude fat content was 20.26%–20.35%. The nutritional composition was basically the same, and all of them were isonitrogenous and islipid-free feeds. This eliminated the influence of differences in basic nutritional levels on the results of subsequent breeding experiments and ensured the comparability of experimental data between each comparative ratio and the example.

[0116] II. Aquaculture Experiments and Growth Performance Testing

[0117] (1) Healthy triploid rainbow trout with consistent genetic background and uniform weight were selected and five kinds of isonitrogenous and isolipid feeds prepared by comparative example 1 to comparative example 5 were used to carry out aquaculture experiments in the indoor recirculating aquaculture system of Heilongjiang Fisheries Research Institute.

[0118] Before the formal aquaculture experiment began, all experimental fish were fed commercial feed for two weeks to adapt to the laboratory aquaculture environment. During the aquaculture period, the photoperiod was L12:D12, the water temperature was maintained at (14±0.5)℃, the oxygen content in the water was maintained above 9mg / L, the carbon dioxide concentration was not higher than 15mg / L, and the ammonia nitrogen and nitrite content were not higher than 0.1 mg / L.

[0119] The formal aquaculture experiment lasted for 40 days. During the aquaculture period, experimental feed was administered at 2% of the fish's body weight, twice a day (8:00 and 16:00). The water quality conditions were kept consistent with those during the temporary rearing period, and the photoperiod was L24:D0. After the aquaculture experiment, the fish were fasted for 24 hours, and growth indicators were collected. Twenty fish were randomly selected from each aquaculture tank, anesthetized, weighed, and then directly transferred to 30ppt artificial seawater to observe their survival rate for 14 days.

[0120] The experimental data were expressed as mean ± standard deviation. One-way ANOVA was performed using SPSS 23.0 software. Duncan's multiple range test was used for pairwise comparisons between groups. P < 0.05 was considered statistically significant.

[0121] The initial weight, final weight, weight gain rate, specific growth rate, and feed conversion ratio of each group of fish fry are shown in Table 2. The survival rate after salinity acclimatization is shown in Table 2. Figure 1 As shown.

[0122] Table 2

[0123]

[0124] As shown in Table 2, the final body weight, weight gain rate, and specific growth rate of Comparative Examples 2-5 were significantly higher than those of Comparative Example 1 (P < 0.05), while the feed conversion ratio was significantly lower than that of Comparative Example 1 (P < 0.05). Among them, the weight gain rate and specific growth rate of Comparative Example 5 were significantly higher than those of other treatment groups, while the feed conversion ratio was significantly lower than that of Comparative Examples 2 and 3 (P < 0.05).

[0125] Depend on Figure 1 It can be seen that different feed acclimatizations altered the survival rate of triploid rainbow trout after 14 days of high salinity stress. Compared with Comparative Example 1, functional additives improved the survival rate after salinity stress to varying degrees. Among them, Comparative Example 5 had the highest survival rate (90%), which was 26.67% higher than that of Comparative Example 1.

[0126] (2) Healthy triploid rainbow trout with consistent genetic background and uniform weight were selected and five kinds of isonitrogenous and isolipid feeds prepared by Example 1, Comparative Examples 5-8 were used to carry out aquaculture experiments in the indoor recirculating aquaculture system of Heilongjiang Fisheries Research Institute.

[0127] Before the formal aquaculture experiment began, all experimental fish were fed commercial feed for two weeks to adapt to the laboratory aquaculture environment. During the aquaculture period, the photoperiod was L12:D12, the water temperature was maintained at (14±0.5)℃, the oxygen content in the water was maintained above 9mg / L, the carbon dioxide concentration was not higher than 15mg / L, and the ammonia nitrogen and nitrite content were not higher than 0.1 mg / L.

[0128] The formal aquaculture experiment lasted for 40 days. During the aquaculture period, experimental feed was administered at 2% of the fish's body weight, twice daily (8:00 and 16:00). The water quality conditions remained consistent with those during the temporary rearing period, with a photoperiod of L24:D0 and a light intensity of 800–1000 Lux. After the aquaculture experiment, the fish were fasted for 24 hours, and growth indicators were collected. Twenty fish were randomly selected from each tank, anesthetized, weighed, and then directly transferred to 30 ppt of artificial seawater for observation of their survival rate over 14 days.

[0129] The experimental data were expressed as mean ± standard deviation. One-way ANOVA was performed using SPSS 23.0 software, followed by pairwise comparisons between groups using Duncan's multiple range test. P < 0.05 was considered statistically significant.

[0130] The initial weight, final weight, weight gain rate, specific growth rate, and feed conversion ratio of each group of fish fry are shown in Table 3. The survival rate after salinity acclimatization is shown in Table 3. Figure 2 As shown.

[0131] Table 3

[0132]

[0133] As shown in Table 3, the final body weight of Comparative Examples 6-8 and Example 1 was significantly higher than that of Comparative Example 5 (P < 0.05). Among them, the final body weight, weight gain rate, and specific growth rate of Comparative Examples 7, 8 and Example 1 were significantly higher than those of Comparative Examples 5 and 6, while the feed conversion ratio was significantly lower than that of Comparative Examples 5 and 6 (P < 0.05).

[0134] Depend on Figure 2 It was found that different additive treatments altered the survival rate of triploid rainbow trout after 14 days of high salinity stress. Compared with Comparative Example 5, the functional additives improved the survival rate of rainbow trout to varying degrees. Among them, the survival rate of Example 1 was 100%, which was 11.67% higher than that of Comparative Example 5.

[0135] (3) Healthy triploid rainbow trout with consistent genetic background and uniform weight were selected and five kinds of isonitrogenous and isolipid feeds prepared by Example 1, Comparative Examples 5-8 were used to carry out aquaculture experiments in the indoor recirculating aquaculture system of Heilongjiang Fisheries Research Institute.

[0136] After a 24-hour fasting period following the end of the aquaculture trial, experimental fish were randomly selected from each experimental group. Blood was collected from the tail vein, and serum was separated by centrifugation after settling. Serum osmolality was measured using a freezing point osmometer; serum total antioxidant capacity was determined using the ABTS method with commercially available kits; and serum malondialdehyde (MDA) content was determined using the thiobarbituric acid (TBA) colorimetric method. All procedures were strictly performed according to the kit instructions. The experimental data are expressed as mean ± standard deviation. One-way ANOVA was performed using SPSS 23.0 software, and pairwise comparisons between groups were conducted using Duncan's multiple range test. A p-value < 0.05 was considered statistically significant. The results for serum osmolality, total antioxidant capacity, and MDA content are shown below. Figure 3 As shown.

[0137] Depend on Figure 3 It was found that different feed acclimatizations altered the serum osmolality and antioxidant indices of triploid rainbow trout after 14 days of high salinity stress. Compared with Comparative Example 5, the functional additives reduced the serum osmolality and malondialdehyde (MDA) content of rainbow trout to varying degrees, and increased the total antioxidant capacity of serum after salinity stress. Among them, the serum osmolality and MDA content of Example 5 were significantly lower than those of Comparative Example 5 (P < 0.05), and the total antioxidant capacity was significantly higher than that of Comparative Examples 6-8 (P < 0.05).

[0138] The data comparison above shows that this invention, through the synergistic combination of proline, phenylalanine, glycine, sorbitol, vitamin C, and traditional Chinese medicine extracts, achieves multi-target joint regulation of osmotic regulation and antioxidant defense systems during the salinity acclimatization of rainbow trout seedlings. The combined use of proline, phenylalanine, and glycine creates a complementary and enhancing effect across three dimensions: osmotic regulation, hormone synthesis, and antioxidation. Proline, as an osmotic regulator, maintains cellular osmotic pressure balance; phenylalanine, as an aromatic amino acid, participates in neuroendocrine regulation; and glycine helps alleviate oxidative damage. These three amino acids synergistically enhance the salinity adaptation ability of rainbow trout through different pathways. Based on this, sorbitol, vitamin C, and traditional Chinese medicine extracts were further added. These three components, through different mechanisms, form a multi-target joint regulation with amino acids. Sorbitol and proline synergistically maintain intracellular and extracellular ion balance and scavenge free radicals. Vitamin C directly scavenge free radicals and participates in maintaining the integrity of the gill tissue barrier structure. The active ingredients in the traditional Chinese medicine extract, such as Acanthopanax senticosus, licorice, Schisandra chinensis, and Cornus officinalis, can enhance the non-specific immune function of fish. When these three components are combined with amino acids, they form a synergistic effect through three pathways: osmotic regulation, antioxidant defense, and immune enhancement. This further increases the survival rate after salinity stress from 90% based on the amino acid combination to 100%, fully verifying that the above components have a significant synergistic effect in improving the salt tolerance of rainbow trout.

Claims

1. A salt-tolerant functional feed for rainbow trout, characterized in that, The feed contains the following components in parts by weight: 250 parts fish meal, 200 parts cottonseed protein concentrate, 156 parts wheat flour, 120 parts fermented soybean meal, 180 parts fish oil, 3 parts choline chloride, 10 parts vitamin and mineral premix, 3 parts butylated hydroxytoluene, 4 parts betaine, 30 parts sodium chloride, 2 parts sodium alginate, 10 parts glutamine, 5 parts proline, 8 parts phenylalanine, 2 parts glycine, 2 parts sorbitol, 5 parts vitamin C, and 10 parts traditional Chinese medicine extract.

2. The salt-tolerant functional feed for rainbow trout according to claim 1, characterized in that, The raw materials of the herbal extract are composed of the following components in parts by weight: 10 parts Acanthopanax senticosus, 15 parts Glycyrrhiza uralensis, 10 parts Schisandra chinensis, and 10 parts Cornus officinalis.

3. The rainbow trout salt-tolerant functional feed according to claim 1, characterized in that, Each kilogram of the vitamin and mineral premix contains: Vitamin A: 150 mg; Vitamin B1: 300 mg; Vitamin B2: 300 mg; Vitamin B6: 280 mg; Vitamin D3: 6 mg; Vitamin E: 1200 mg; Vitamin K3: 140 mg; Vitamin C: 4500 mg; D-calcium pantothenate: 800 mg; Nicotinamide: 1500 mg; Manganese sulfate: 10000 mg; Ferrous sulfate: 10000 mg; Zinc oxide: 6000mg, copper sulfate: 4000mg, sodium selenite: 100mg, magnesium sulfate: 100000mg, and potassium iodide: 500mg.

4. A method for preparing a salt-tolerant functional feed for rainbow trout as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Grind the fish meal, cottonseed protein concentrate, and fermented soybean meal into powder and sieve them. Weigh the sieved fish meal, cottonseed protein concentrate, and fermented soybean meal according to the ratio and mix them evenly with wheat flour to obtain the base powder. Step 2: Weigh out the following ingredients according to the specified ratio: choline chloride, vitamin and mineral premix, butylated hydroxytoluene, betaine, sodium chloride, sodium alginate, glutamine, proline, phenylalanine, glycine, sorbitol, and vitamin C. Mix them thoroughly to obtain the premixed additive. Step 3: Add the premixed additive to the base powder and mix evenly to obtain a mixed powder. Add fish oil to the mixed powder and mix evenly. Then add the herbal extract and water and continue mixing until evenly mixed to obtain a wet mixture. Step 4: Put the wet mixture into a pellet mill and extrude it into pellets with a diameter of 3-5 mm. After drying, the rainbow trout salt-tolerant functional feed is obtained.

5. The preparation method according to claim 4, characterized in that, The herbal extract described in step three is prepared using the following method: Weigh 10 parts of Acanthopanax senticosus, 15 parts of Glycyrrhiza uralensis, 10 parts of Schisandra chinensis, and 10 parts of Cornus officinalis by weight. Add distilled water at a ratio of 1g:10mL and soak for 30 minutes. Then, bring to a boil over high heat and simmer over low heat for 30-60 minutes. Filter out the liquid. Add distilled water to the remaining dregs at a ratio of 1g:5mL and decoct again. Combine the two liquids and concentrate under vacuum at 80℃ to a relative density of 1.

15. Store at 4℃.

6. The preparation method according to claim 4 or 5, characterized in that, The sieving process described in step one involves passing the material through a 60-mesh sieve.

7. The preparation method according to claim 6, characterized in that, The drying process described in step four involves drying in a 60°C forced-air drying oven until the moisture content is below 10%.

8. A method of using the rainbow trout salt-tolerant functional feed as described in any one of claims 1-3, characterized in that, Select rainbow trout fry weighing 100-400g; feed them directly with the salt-tolerant functional feed, while providing continuous light with an intensity of 800-1000 Lux; feed them continuously for 40 days, 2-4 times a day, with a daily feed amount of 2% of the fish's body weight; after feeding, transfer the rainbow trout fry directly into seawater for culture.

9. The method of use according to claim 8, characterized in that, The photoperiod of the continuous illumination is L24:D0.

10. The method of use according to claim 8 or 9, characterized in that, The rainbow trout include landlocked rainbow trout, as well as triploid rainbow trout and all-female rainbow trout obtained from the landlocked rainbow trout.

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