A kind of eel seedling starter bait and preparation method thereof

Abstract

The invention discloses a juvenile eel bait and a preparation method thereof. The juvenile eel bait comprises the following raw materials in parts by weight: 60-70 parts of dried black soldier flies larvae, 10-20 parts of dried shrimp and crab shells, 15-25 parts of raw eggs and 0.1-0.2 parts of Mucor koji powder. The juvenile eel bait has a special smell by using Mucor fermentation, thereby increasing the juvenile eel opening rate. The feed produced by the juvenile eel has a dark red color, which is similar to the color of water earthworms. After being shaped, the filamentous shape is similar to the natural juvenile eel bait water earthworms. The juvenile eel bait is rich in various nutrients such as astaxanthin, can enhance the disease resistance of young eels, has simple components, is rich in nutrition, is more naturally antiseptic, and can better meet the nutritional needs of the juvenile eel. The juvenile eel bait is filamentous after being shaped by a shaped device and then boiled in hot water for a period of time, so that the juvenile eel bait finally formed has strong stability and can be kept in water for 2-3 hours without being dispersed.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture, and in particular to a bait for yellow eel seedlings and a preparation method thereof. Background Art

[0002] Yellow eel is a bottom-dwelling fish that likes to live in rivers, lakes, ditches and rice fields. It is an omnivorous fish that mainly feeds on animals. It is greedy and likes to eat fresh bait. Under natural conditions, it mainly preys on tadpoles, young frogs, snails, clams, small fish, shrimps and other aquatic and terrestrial insects and larvae. Yellow eel growth is mainly concentrated in summer and autumn, and grows slowly in winter and spring. Yellow eel seedlings rely on natural reproduction, and the source of eel seedlings is wild capture from all over the country; when artificially cultivated, they need to be trained to eat to promote the opening of the mouth of the yellow eel seedlings.

[0003] The cultivation of young eels is a major problem in artificial breeding at present. Whether it is natural or artificial, its survival rate is very low, generally 35% to 40%. In the process of yellow eel breeding, the starting feed for young eels can generally only be water earthworms, cladocerans, and natural copepods. However, since such baits are expensive, difficult to store, and difficult to use at any time, the cost of yellow eel breeding is greatly increased, and the intensive and large-scale breeding needs cannot be met. At the same time, since young eels like to eat fresh baits, but artificial feeds are mostly granular, and the main components are not nutritious enough, more artificial additives are added, and they float on the water surface after puffing, and the palatability is poor, the attractant effect is not good, resulting in waste of bait and water pollution. Therefore, the lack of artificial starting feed for yellow eels has become a technical bottleneck in the ecological breeding technology of yellow eels. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a bait for juvenile eels and a preparation method thereof, so as to solve the problems raised in the background technology.

[0005] The present invention solves the above technical problems and adopts the following technical scheme: a kind of eel seedling starter bait, which comprises the following raw materials in parts by weight: 60-70 parts of dried black soldier fly larvae, 10-20 parts of dried shrimp and crab shells, 15-25 parts of raw eggs and 0.1-0.2 parts of Mucor powder.

[0006] Preferably, the dried shrimp and crab shells include shrimp shells and crab shells, the shrimp shells include one or a combination of shrimp, river shrimp, Procambarus clarkii, and mantis shrimp, and the crab shells include one or a combination of Chinese mitten crab, swimming crab, and mud crab.

[0007] Preferably, the dried black soldier fly larvae are 65 parts, dried shrimp and crab shells are 15 parts, raw eggs are 10 parts and Mucor powder is 0.16 parts.

[0008] In addition, the present invention also discloses a method for preparing the above-mentioned eel seedling starter bait, which comprises the following steps:

[0009] Step 1: Place the dried shrimp and crab shells in water and heat them for a period of time, take out the shrimp and crab shells, dry them, place them in a grinder, and then sieve them;

[0010] Step 2: Pulverize the dried black soldier fly larvae in a grinder, sieve, mix the dried black soldier fly larvae powder and dried shrimp and crab shell powder in a blender, and add water while stirring until the water content of the mixture reaches 60-70%;

[0011] Step 3: Mix the mixture obtained in step 2 with the Mucor koji powder, put them into a container and place them in a fermentation box, control the temperature of the fermentation box at 25-28° C., and ferment for 3-7 days. After the white Mucor grows all over the surface of the mixture, take out the fermented product, dry it, and crush it in a grinder. After the crushing is completed, sieve it and put it into a sealed bag for storage.

[0012] Step 4. Add raw eggs to the mixture in step 3 and stir thoroughly into a paste. Then pass the bait through a shaping device to make it into filaments. After boiling it in hot water for a while, scoop it out with a strainer and set it aside after cooling.

[0013] Preferably, step one is specifically as follows: placing the dried shrimp and crab shells in 100° C. water and heating them for 5 minutes, taking out the shrimp and crab shells, drying them, and crushing them in a grinder, placing the powder in a 50-mesh sieve, and then sieving.

[0014] Preferably, step 2 is specifically as follows: crushing the dried black soldier fly larvae in a grinder, placing the powder in a 50-mesh sieve, sieving, mixing the dried black soldier fly larvae powder and the dried shrimp and crab shell powder in a blender at a mass ratio of 6:1, and adding water while stirring until the moisture content of the mixture reaches 65%.

[0015] Preferably, step three is specifically as follows: the mixture obtained in step two and the Mucor koji powder are mixed in a mass ratio of 500:1, loaded into a container and placed in a fermentation box, the temperature of the fermentation box is controlled at 25-28°C, and fermented for 3-7 days. After the white Mucor grows all over the surface of the mixture, the fermented product is taken out and dried, and crushed in a grinder. After the crushing is completed, it is sieved with a 50-mesh sieve, and then stored in a sealed bag.

[0016] Preferably, the container in step three is a cubic container with a length of 60 cm, a width of 50 cm and a height of 5 cm.

[0017] Preferably, the shaping device in step four includes a pressurized cylinder, the top of which is open, and the bottom is fixedly connected to the sieve plate, the sieve holes of the sieve plate are fixedly connected to the end of the shaping tube, the inside of the pressurized cylinder is slidably matched with the piston, the top of the piston is fixedly connected to the bottom of the piston rod, and the top of the piston rod is fixedly connected to the push-pull rod; a filter scoop is provided under the shaping tube, the outer periphery of the filter scoop is placed on the top of the constant temperature pot, and a cooling pot is provided on one side of the constant temperature pot.

[0018] Preferably, step four is specifically as follows: add raw eggs to the mixture in step three, stir thoroughly into a paste, load the bait into the pressurized cylinder of the shaping device first, then install the piston, push the push-pull rod downward to extrude the bait, and let the bait extruded into filaments pass through the sieve holes of the sieve plate and be discharged from the shaping tube to form filaments with a length of 2-3 cm. The filaments then fall into a 40-mesh filter scoop below, and then boil in 75°C hot water in a constant temperature pot for one minute, remove the filter scoop, place it in a cooling pot, cool it in 4-5°C cold water in the cooling pot and set it aside.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention utilizes Mucor fermentation to give the bait a special smell, thereby increasing the opening rate of eel fry. The color of the feed produced is dark red, which is similar to the color of water earthworms, and after shaping, the filamentous shape is similar to the natural opening bait water earthworms. The bait of the present invention is rich in various nutrients such as astaxanthin, which can enhance the disease resistance of young eels. The present invention has simple components, rich nutrition, more natural antiseptic, and can better meet the nutritional needs of yellow eels.

[0021] 2. After the bait in the present invention is made into filaments by a shaping device, it is boiled in hot water for a period of time. The bait finally formed in this way has strong stability and can remain in water for 2 to 3 hours without dispersing.

[0022] 3. The dried black soldier fly larvae of the present invention can produce a synergistic effect with Mucor, shrimp shells and crab shells: Mucor decomposes the macromolecular fat in the dried black soldier fly larvae into small molecules, and the small molecule fat can increase the stability of astaxanthin in shrimp shells and crab shells, and can promote the absorption of astaxanthin by eels; astaxanthin can promote the growth of Mucor, enhance the fermentation ability of Mucor, and improve the utilization rate of the dried black soldier fly larvae.

[0023] 4. The dried larvae of black soldier flies in the feed formula of the present invention have high nutritional value and contain multiple amino acids and vitamins required for the growth of yellow eel; since shrimp shells and crab shells (including mud shrimp, river shrimp, Procambarus clarkii, slipper shrimp, Chinese mitten crab, swimming crab, mud crab, etc.) are rich in calcium and astaxanthin, the ground shrimp shells and crab shells can be used as calcium supplements for yellow eel to enrich the calcium content of water bodies; in addition, astaxanthin makes the bait red and has the effect of enhancing immunity, which can not only simulate the color of water earthworms and enhance its food attractant effect, but also improve the disease resistance of yellow eel seedlings.

[0024] 5. The feed of the present invention adopts Mucor for fermentation, which can decompose the macromolecular proteins, polysaccharides, ribose and the like in black soldier fly larvae, shrimp shells and crab shells (including mud shrimp, river shrimp, Procambarus clarkii, mantis shrimp, Chinese mitten crab, swimming crab, mud crab, etc.) into small molecular amino acids, glucose and the like, thereby improving the nutritional value of the bait and facilitating the absorption of nutrients by the eel seedlings. At the same time, the bait after fermentation has a unique insect fragrance, which can enhance its feeding effect. Moreover, the feed fermented by Mucor has a natural antiseptic effect, which is beneficial to the storage of the feed.

[0025] 6. The steps of the present invention are simple to operate, with few additives and no preservatives, which reduces the phenomenon of bioaccumulation, is safer and more natural, and can reduce production costs, meet the growth needs of eels, and can also meet the needs of humans for eels.

[0026] 7. The present invention utilizes raw eggs as adhesives, which are conducive to bait shaping after high-temperature cooking and are not easily dispersed in water, thereby reducing feed waste, reducing water pollution caused by dissolved feed, and increasing the nutrition of bait.

[0027] 8. The shaping device involved in the present invention can quickly prepare bait in the form of threads, thus greatly improving the preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the shaping device used in the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0030] A bait for yellow eel seedlings comprises the following raw materials in parts by weight: 60-70 parts of dried black soldier fly larvae, 10-20 parts of dried shrimp and crab shells, 15-25 parts of raw eggs and 0.1-0.2 parts of mucor koji powder.

[0031] Preferably, the dried shrimp and crab shells include shrimp shells and crab shells, the shrimp shells include one or a combination of shrimp, river shrimp, Procambarus clarkii, and mantis shrimp, and the crab shells include one or a combination of Chinese mitten crab, swimming crab, and mud crab.

[0032] Preferably, the dried black soldier fly larvae are 65 parts, dried shrimp and crab shells are 15 parts, raw eggs are 10 parts and Mucor powder is 0.16 parts.

[0033] In addition, the present invention also discloses a method for preparing the above-mentioned eel seedling starter bait, which comprises the following steps:

[0034] Step 1: Place the dried shrimp and crab shells in water and heat them for a period of time, take out the shrimp and crab shells, dry them, place them in a grinder, and then sieve them;

[0035] Step 2: Pulverize the dried black soldier fly larvae in a grinder, sieve, mix the dried black soldier fly larvae powder and dried shrimp and crab shell powder in a blender, and add water while stirring until the water content of the mixture reaches 60-70%;

[0036] Step 3: Mix the mixture obtained in step 2 with the Mucor koji powder, put them into a container and place them in a fermentation box, control the temperature of the fermentation box at 25-28° C., and ferment for 3-7 days. After the white Mucor grows all over the surface of the mixture, take out the fermented product, dry it, and crush it in a grinder. After the crushing is completed, sieve it and put it into a sealed bag for storage.

[0037] Step 4. Add raw eggs to the mixture in step 3 and stir thoroughly into a paste. Then pass the bait through a shaping device to make it into filaments. After boiling it in hot water for a while, scoop it out with a strainer and set it aside after cooling.

[0038] Preferably, step one is specifically as follows: placing the dried shrimp and crab shells in 100° C. water and heating them for 5 minutes, taking out the shrimp and crab shells, drying them, and crushing them in a grinder, placing the powder in a 50-mesh sieve, and then sieving.

[0039] Preferably, step 2 is specifically as follows: crushing the dried black soldier fly larvae in a grinder, placing the powder in a 50-mesh sieve, sieving, mixing the dried black soldier fly larvae powder and the dried shrimp and crab shell powder in a blender at a mass ratio of 6:1, and adding water while stirring until the moisture content of the mixture reaches 65%.

[0040] Preferably, step three is specifically as follows: the mixture obtained in step two and the Mucor koji powder are mixed in a mass ratio of 500:1, loaded into a container and placed in a fermentation box, the temperature of the fermentation box is controlled at 25-28°C, and fermented for 3-7 days. After the white Mucor grows all over the surface of the mixture, the fermented product is taken out and dried, and crushed in a grinder. After the crushing is completed, it is sieved with a 50-mesh sieve, and then stored in a sealed bag.

[0041] Preferably, the container in step three is a cubic container with a length of 60 cm, a width of 50 cm and a height of 5 cm.

[0042] Preferably, if Figure 1 As shown, the shaping device in step 4 includes a pressurized cylinder 1, the top of which is open, and the bottom is fixedly connected to a sieve plate 2, the sieve holes of the sieve plate 2 are fixedly connected to the end of a shaping tube 3, the inside of the pressurized cylinder 1 is slidably matched with a piston 4, the top of the piston 4 is fixedly connected to the bottom of a piston rod 5, and the top of the piston rod 5 is fixedly connected to a push-pull rod 6; a filter scoop 7 is provided below the shaping tube 3, the outer periphery of the filter scoop 7 is placed on the top of a thermostatic pot 8, and a cooling pot 9 is provided on one side of the thermostatic pot 8. Through this shaping device, filamentous bait can be quickly prepared, which greatly improves the preparation efficiency.

[0043] Preferably, step four is specifically as follows: add raw eggs to the mixture in step three, stir thoroughly into a paste, first load the bait into the pressurized cylinder 1 of the shaping device, then install the piston 4, push the push-pull rod 6 downward, and extrude the bait, the bait extruded into filaments passes through the sieve holes of the sieve plate 2, and is discharged from the shaping tube 3 to form filamentary bait with a filament length of 2-3 cm, and then the filamentary bait falls into the 40-mesh filter scoop 7 below, and then is boiled in 75°C hot water in the constant temperature pot 8 for one minute, then the filter scoop 7 is taken out and placed in the cooling pot 9, and cooled in 4-5°C cold water in the cooling pot 9 for use.

[0044] Example 1: 65 parts of dried black soldier fly larvae, 15 parts of dried shrimp and crab shells, 10 parts of raw eggs and 0.16 parts of Mucor koji powder.

[0045] The preparation method is as follows:

[0046] Step 1: Place the dried shrimp and crab shells in 100°C water and heat for 5 minutes, take out the shrimp and crab shells, dry them, and grind them in a grinder, place the powder in a 50-mesh sieve, and then sieve;

[0047] Step 2: grind the dried black soldier fly larvae in a grinder, put the powder in a 50-mesh sieve, sieve, mix the dried black soldier fly larvae powder and dried shrimp and crab shell powder in a blender at a mass ratio of 6:1, and add water while stirring until the water content of the mixture reaches 65%;

[0048] Step 3: Mix the mixture obtained in step 2 and the Mucor koji powder in a mass ratio of 500:1, put them into a container and place them in a fermentation box, control the temperature of the fermentation box to 25-28° C., ferment for 3-7 days, take out the fermented product after the white Mucor grows all over the surface of the mixture, dry it, and crush it in a grinder. After the crushing is completed, sieve it with a 50-mesh sieve, and then put it into a sealed bag for storage.

[0049] Step 4. Add raw eggs to the mixture in step 3, stir thoroughly into a paste, pass the bait through a shaping device to make it into filaments with a length of 2-3 cm, then boil it in 75°C hot water for one minute, scoop it out with a 40-mesh strainer, and set it aside after cooling.

[0050] The appropriate amount of bait prepared in the above steps can be used to directly feed young eels with a body length of 5-6 cm. Three feeding basins are placed, and 20 young eels with a body length of 5-6 cm are placed in each feeding basin. Water earthworms are fed once a day, and the feeding amount is about 10% of the body weight. The survival rate, body length and weight gain of the eels are compared after 30 days.

[0051] Embodiment 2:

[0052] Water earthworms were directly used as the starter feed for young eels and placed in feeding basins. Three feeding basins were placed, with 20 young eels with a body length of 5-6 cm in each basin. Water earthworms were fed once a day, and the feeding amount was about 10% of the body weight. The survival rate, body length and weight gain of the eels were compared after 30 days.

[0053] Embodiment 3:

[0054] 65 parts of dried black soldier fly larvae, 15 parts of dried shrimp and crab shells, and 20 parts of raw eggs.

[0055] The preparation method is as follows:

[0056] Step 1: Place the dried shrimp and crab shells in 100°C water and heat for 5 minutes, take out the shrimp and crab shells, dry them, and grind them in a grinder, place the powder in a 50-mesh sieve, and then sieve;

[0057] Step 2: grind the dried black soldier fly larvae in a grinder, put the powder in a 50-mesh sieve, sieve, mix the dried black soldier fly larvae powder and dried shrimp and crab shell powder in a blender at a mass ratio of 6:1, and add water while stirring until the water content of the mixture reaches 65%;

[0058] Step 3: directly drying the mixture obtained in step 2, and crushing it in a crusher. After the crushing is completed, sieving it with a 50-mesh sieve, and then storing it in a sealed bag.

[0059] Step 4. Add raw eggs to the mixture in step 3, stir thoroughly into a paste, pass the bait through a shaping device to make it into filaments with a length of 2-3 cm, then boil it in 75°C hot water for one minute, scoop it out with a 40-mesh strainer, and set it aside after cooling.

[0060] The appropriate amount of bait prepared in the above steps can be used to directly feed young eels with a body length of 5-6 cm. Three feeding basins are placed, and 20 young eels with a body length of 5-6 cm are placed in each feeding basin. Water earthworms are fed once a day, and the feeding amount is about 10% of the body weight. The survival rate, body length and weight gain of the eels are compared after 30 days.

[0061] Result analysis:

[0062] The data of Example 1 and Example 2 are shown in Table 1 below:

[0063] Table 1 Various indicators of eel seedlings raised in Example 1 and Example 2

[0064]

[0065] The data of Example 1 and Example 3 are shown in Table 2 below:

[0066] Table 2 Various indicators of eel seedlings raised in Example 1 and Example 3

[0067] Through the above comparison, it can be seen that Example 1 of the present invention can effectively improve the survival rate, body length growth rate and weight gain rate of yellow eel seedlings compared with the traditional bait water earthworms in Example 2, and the present invention is no different from water earthworms in palatability and feeding effect, and all indicators are higher than yellow eel seedlings with water earthworms as the starting bait, and the survival rate is above 80%. At the same time, compared with the unfermented bait in Example 3, the bait fermented by Mucor in Example 1 of the present invention can have a significant feeding effect on yellow eel seedlings, and has obvious advantages in opening rate and initial feeding time.

[0068] The amino acid and fatty acid analysis table of the fermented open-mouthed bait of Example 1 of the present invention is as follows in Table 3:

[0069] Table 3 Analysis of amino acids and fatty acids in the eel's diet It can be seen that after fermentation with Mucor koji powder in step three of the present invention, a large amount of short peptides and fatty acids can be produced, which makes the bait have a unique smell. The aspartic acid, glutamic acid, cysteine ​​and methionine in the short peptides and the oleic acid and stearic acid in the fatty acids are the main sources of the unique smell, which has a significant feeding effect on eel seedlings.

[0070] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A method for preparing a starter bait for yellow eel seedlings, characterized in that: The eel seedling starter bait comprises the following raw materials in parts by weight: 60-70 parts of dried black soldier fly larvae, 10-20 parts of dried shrimp and crab shells, 10-25 parts of raw eggs and 0.1-0.2 parts of mucor powder; the preparation method comprises the following steps: Step 1: Place the dried shrimp and crab shells in water and heat them for a period of time, take out the shrimp and crab shells, dry them, place them in a grinder, and then sieve them; Step 2: grind the dried black soldier fly larvae in a grinder, put the powder in a 50-mesh sieve, sieve, mix the dried black soldier fly larvae powder and dried shrimp and crab shell powder in a blender at a mass ratio of 6:1, and add water while stirring until the water content of the mixture reaches 65%; Step 3: Mix the mixture obtained in step 2 and the Mucor koji powder in a mass ratio of 500:1, put them into a container and place them in a fermentation box, control the temperature of the fermentation box at 25-28° C., and ferment for 3-7 days. After the white Mucor grows all over the surface of the mixture, take out the fermented product, dry it, and crush it in a grinder. After the crushing is completed, sieve it with a 50-mesh sieve, and then put it into a sealed bag for storage; Step 4: Add raw eggs to the mixture obtained in step 3, stir thoroughly into a paste, and then load the bait into the pressurized cylinder (1) of the shaping device, then install the piston (4), push the push-pull rod (6) downward to extrude the bait, and the bait extruded into filaments passes through the sieve holes of the sieve plate (2) and is discharged from the shaping tube (3) into filaments with a length of 2-3 cm. The filaments then fall into the 40-mesh filter scoop (7) below, and then boil in 75°C hot water in a constant temperature pot (8) for one minute, then remove the filter scoop (7), place it in a cooling pot (9), cool it in 4-5°C cold water in the cooling pot (9) and set it aside for later use; The shaping device in step 4 comprises a pressurized cylinder (1), the top of the pressurized cylinder (1) is open, the bottom is fixedly connected to the sieve plate (2), the sieve holes of the sieve plate (2) are fixedly connected to the end of the shaping tube (3), the inside of the pressurized cylinder (1) is slidably matched with the piston (4), the top of the piston (4) is fixedly connected to the bottom of the piston rod (5), and the top of the piston rod (5) is fixedly connected to the push-pull rod (6); a filter scoop (7) is provided below the shaping tube (3), the outer periphery of the filter scoop (7) is placed on the top of a constant temperature pot (8), and a cooling pot (9) is provided on one side of the constant temperature pot (8).

2. The method for preparing a starter bait for yellow eel seedlings according to claim 1, characterized in that: The dried shrimp and crab shells include shrimp shells and crab shells. The shrimp shells include one or several combinations of shrimp, river shrimp, Procambarus clarkii, and mantis shrimp. The crab shells include one or several combinations of Chinese mitten crab, swimming crab, and mud crab.

3. The method for preparing a starter bait for yellow eel seedlings according to claim 1, characterized in that: 65 parts of dried black soldier fly larvae, 15 parts of dried shrimp and crab shells, 10 parts of raw eggs and 0.16 parts of Mucor koji powder.

4. The method for preparing a starter bait for yellow eel seedlings according to claim 1, characterized in that: Step one is as follows: placing the dried shrimp and crab shells in 100°C water and heating them for 5 minutes, taking out the shrimp and crab shells, drying them, and crushing them in a grinder, placing the powder in a 50-mesh sieve, and then sieving.

5. The method for preparing a starter bait for yellow eel seedlings according to claim 1, characterized in that: The container in step three is a cubic container with a length of 60 cm, a width of 50 cm, and a height of 5 cm.

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