Live bait feeding method for improving survival rate of Hualong hybrid spotted fry

Abstract

The invention discloses a live bait feeding method for improving the survival rate of Hualong hybrid spotted fry, and relates to the technical field of fish culture. Comprising the following steps: (1) feeding composite coated seaweed bait at the age of 1-10 days; (2) feeding compound coated seaweed bait, live earthworms and anesthetized earthworms at the age of 11-20 days, and feeding pretreated moina at the same time; (3) feeding compound coated seaweed bait, live earthworms and anesthetized earthworms at the age of 21-35 days, and feeding pretreated moina at the same time; (4) feeding compound coated seaweed bait, live earthworms and anesthetized earthworms at the age of 36-50 days, and feeding pretreated moina at the same time. According to the method, the requirements of the fry in different growth periods for nutritional ingredients are met by feeding the baits in different proportions in stages, the nutritional ingredients are reasonable in configuration, the problems that at present, the baits for the Hualong hybrid spotted fish are single in variety, unbalanced in nutrition and low in survival rate are solved, and the method has important significance on the large-scale breeding technology of the Hualong hybrid spotted fish.

Description

Technical Field

[0001] The invention relates to the technical field of fish breeding, and in particular to a live bait feeding method for improving the survival rate of hybrid grouper fry. Background Art

[0002] Grouper is a world-famous precious marine fish, belonging to the order Perciformes, suborder Percoidei, family Epinephelidae. There are more than 160 species of grouper recorded worldwide, mainly distributed in tropical and subtropical waters. There are many species of grouper, each with its own characteristics. There are about 46 species distributed along the coast of the mainland, providing rich parental materials for distant hybrid breeding of grouper.

[0003] The Hualong hybrid spot, also known as the dragon rat spot, has a beautiful body shape, a flat body, a long snout, a head shaped like a mouse, bright colors, spots all over the sides of the body, and three obvious vertical stripes on the back of the body. It can adjust its skin color according to the environment. The Hualong hybrid spot is a product of the humpback bass ( Chromileptes altivelis ) is the female parent, Epinephelus saddlebackus ( Epinephelus lanceolatus ) as the male parent, and develop distant hybrid breeding research, thereby screening out high-quality hybrid combinations to add new varieties to grouper farming. The growth rate of Hualong hybrid grouper is significantly better than that of the female parent, and the meat quality is better than that of the male parent, which has good development prospects.

[0004] During the artificial breeding of hybrid grouper, the fry of hybrid grouper are prone to discomfort due to unreasonable bait ratio and feeding method, resulting in slow growth, weak resistance and susceptibility to diseases. Especially in the process of newly hatched fry to grow into young fish, the fry have weak environmental adaptability, low survival rate and weight gain rate, and are even prone to large-scale death. At the same time, there are few introductions on the method of using live bait to feed hybrid grouper fry to improve the survival rate of fry. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the present invention proposes a live bait feeding method for improving the survival rate of hybrid grouper fry of Hualong fish, so as to solve the problems raised by the above-mentioned background technology.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: A live bait feeding method for improving the survival rate of hybrid grouper fry, comprising the following steps: (1) From 1 to 10 days old, feed 30-50% composite coated seaweed feed and the rest as basic feed; (2) At 11-20 days of age, feed them 20-30% composite coated seaweed bait, 2-7% live earthworms, 5-10% anesthetized earthworms, and 20-30% pre-treated Moina, with the rest as base bait; (3) At 21-35 days of age, feed them with 10-15% composite coated seaweed bait, 10-20% live earthworms, 10-25% anesthetized earthworms, and 15-25% pre-treated Moina, and the rest as basic bait; (4) At 36-50 days of age, feed 5-10% composite coated seaweed bait, 20-30% live earthworms, 5-12% anesthetized earthworms, and 20-30% pre-treated Moina, and the rest as basic bait; The composite coated seaweed bait comprises 20-60% of Dictyophora staghornii ( Dictyota cervicornis )、20~30% Gracilaria slenderis( Gracilaria tenuistipitata )、10~15% Kappaphycus longicornis( Kappaphycus alvarezii )、8~15% Qiongzhi( Betaphycus gelatinus ) and 2~10% creeping sargassum ( Sargassum polycystum ); The pretreatment of Moina is obtained by soaking Moina in a pretreatment solution, wherein the pretreatment solution comprises the following components by weight: 12 to 25 parts of Psoralea gracilis (a plant of the Rhamnaceae family); Sageretia slender JR Drumm.&Sprague's young branches and leaves), 10-30 portions of flat buds (Gentianaceae flat buds ( Gentianopsis barbata ) or the dried whole herb of G. barbata (Froel.) Ma var.ovatodelt-oidea (Burk.) Ma), 10-18 parts of palmate orchid (a plant of the Orchidaceae family Dactylorhiza hatagirea (D. Don) So tubers), 8-15 portions of Piper longum ( Fruit Long Peppers Piper longum Long pepper L.) and 5-12 rib flowers (Gentianaceae rib flowers ( Lomatogonium carinthiacum (Wulfen) A.Braun dried whole herb).

[0007] Preferably, the method for preparing the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 1.5×10 10 ~5.0×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 1.0×10- ... 8 ~4.5×10 9The seaweed liquid containing cells / mL is the composite seaweed bait; 3) According to weight, weigh 10-20 parts of soybean flour, 10-15 parts of soybean oil, 5-8 parts of xanthan gum and 40-60 parts of water, mix and boil at 96-100°C for 3-5 minutes, and cool to 20-26°C to obtain a coating solution; 4) Mix the composite seaweed bait obtained in step 2) and the coating solution obtained in step 3), and stir for 10 to 20 minutes to obtain the composite coated seaweed bait.

[0008] Preferably, in step 4), the composite seaweed bait and the coating liquid are mixed in a volume ratio of 1:(1.5-2.5).

[0009] Preferably, the basic bait comprises, by weight, 12 to 20 parts of fish meal, 10 to 15 parts of soybeans, 8 to 12 parts of rapeseed meal, 5 to 9 parts of corn, and 1 to 3 parts of fine rice bran.

[0010] Preferably, the method for preparing the anesthetized earthworms is to add the earthworms to a eugenol ethanol solution with a volume concentration of 20-30 mg / L and soak them for 15-25 minutes to obtain the anesthetized earthworms.

[0011] Preferably, the preparation method of pre-treated Moina comprises the following steps: S1. Mix slender pyracantha vine, flat bud, palmate orchid, Piper longum and rib column flower to obtain a mixture; S2, adding 3 to 5 times the weight of the mixture of distilled water to the mixture, soaking for 10 to 20 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding 2 to 4 times the weight of distilled water to the first drug residue, heating and boiling for 30 minutes, filtering to obtain a second drug solution; then combining the first drug solution and the second drug solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak it for 60 to 80 minutes to obtain the pretreated moina.

[0012] Preferably, in step (1), the total feeding amount of the composite coated seaweed bait and the basic bait is 1-3% of the body weight of the fry, and the feeding frequency is 4-6 times a day.

[0013] Preferably, in step (2), the total feeding amount of the composite coated seaweed bait, live earthworms, anesthetized earthworms, pretreated Moina and basic bait is 4-6% of the body weight of the fry, and the feeding frequency is 3-5 times a day.

[0014] Preferably, in step (3), the total feeding amount of the composite coated seaweed bait, live earthworms, anesthetized earthworms, pretreated Moina and basic bait is 7-9% of the body weight of the fry, and the feeding frequency is 2-4 times a day.

[0015] Preferably, in step (4), the total feeding amount of the composite coated seaweed bait, live earthworms, anesthetized earthworms, pretreated Moina and basic bait is 10-15% of the body weight of the fry, and the feeding frequency is 2-4 times a day.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention meets the nutritional requirements of fry at different growth stages by feeding different proportions of bait in different stages. The nutritional components of the present invention are reasonably configured, which solves the problems of single bait type, nutritional imbalance and low survival rate of hybrid grouper fry, and has important significance for large-scale breeding technology of hybrid grouper fry. (2) The coating liquid prepared by the present invention is prepared from soybean powder, soybean oil, xanthan gum and water. The ingredients are simple and easy to obtain, and the amount of the coated content is large, which is conducive to the composite seaweed bait not being easy to disperse when entering the water, thereby enhancing the stability of the bait and being easy to be caught by fish fry. The algae contain rich natural plant ingredients and can emit an odor that fish like, thereby improving the feeding appeal, attracting more fish fry to eat, and obtaining the required algae nutrition; (3) The live baits that can be stably provided on the market are difficult to be fully ingested by the fry, but if all dead baits are provided, it will have the problem of poor palatability and easy to be vomited out. The present application combines live earthworms and anesthetized earthworms as part of the bait. The earthworms move slowly and are easy to be ingested by the fry. At the same time, after the anesthetized earthworms are ingested by the fry, the earthworms struggle in the mouth of the fry, making the fry feel that they are eating live bait, thus solving the problem of low bait ingestion rate. In addition, part of the earthworms are anesthetized, and the transportation cost of the bait is reduced; (4) The pretreatment solution not only kills the parasites that the Moina carries, thus preventing them from being carried to the fry and causing a decrease in the survival rate of the fry, but also contains active ingredients in traditional Chinese medicine that are beneficial to promoting intestinal peristalsis of the fry, enhancing intestinal metabolic activity, and increasing the feeding rate of the fry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is 20-day-old hybrid fish fry; Figure 2 It is 30-day-old hybrid fish fry; Figure 3 It is 50-day-old hybrid fish fry; Figure 4 It is a 60-day-old hybrid fish of Hualong; Figure 5 This is a 120-day-old hybrid fish. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.

[0019] Example 1 A live bait feeding method for improving the survival rate of hybrid grouper fry, comprising the following steps: (1) From 1 to 10 days old, feed 30% composite coated seaweed feed and the rest as basic feed; the total feed amount is 1% of the fry body weight, and the feeding frequency is 4 times a day; (2) At 11-20 days of age, feed the fish with 20% composite coated seaweed bait, 2% live earthworms, 5% anesthetized earthworms, and 20% pre-treated Moina, and the rest as basic bait; the total feeding amount is 4% of the fry body weight, and the feeding frequency is 3 times a day; (3) At 21 to 35 days of age, feed the fish with 10% composite coated seaweed feed, 10% live earthworms, 10% anesthetized earthworms, 15% pre-treated Moina, and the rest as basic feed; the total feed amount is 7% of the fry body weight, and the feeding frequency is twice a day; (4) At 36 to 50 days of age, feed the fry with 5% composite coated seaweed bait, 20% live earthworms, 5% anesthetized earthworms, and 20% pre-treated Moina, and the rest as basic bait; the total feeding amount is 10% of the fry body weight, and the feeding frequency is twice a day.

[0020] The basic bait comprises, by weight, 12 parts of fish meal, 10 parts of soybeans, 8 parts of rapeseed meal, 5 parts of corn, and 1 part of fine rice bran.

[0021] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara striata and Sargassum stoloniferum were cultured in a photobioreactor to obtain a density of 1.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 1.0×10- ... 8 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 10 parts of soybean flour, 10 parts of soybean oil, 5 parts of xanthan gum and 40 parts of water by weight, mix and boil at 96°C for 3 minutes, and cool to 20°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed at a volume ratio of 1:1.5, and stirred for 10 minutes to obtain the composite coated seaweed bait.

[0022] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 20 mg / L and soak them for 15 minutes to obtain the anesthetized earthworms.

[0023] The preparation method of pre-treating Moina comprises the following steps: S1, mix 2 parts of slender pyracantha vine, 10 parts of flat bud, 10 parts of palmately split orchid, 8 parts of Piper longum and 5 parts of rib column flower to obtain a mixture; S2, adding 3 times the weight of the mixture of distilled water to the mixture, soaking for 10 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first liquid medicine and a first residue; S3, adding distilled water twice the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 60 minutes to obtain the pretreated moina.

[0024] Example 2 A live bait feeding method for improving the survival rate of hybrid grouper fry of Hualong fish comprises the following steps: (1) From 1 to 10 days old, feed 50% of the compound coated seaweed feed and the rest of the feed as basic feed; the total feed amount is 3% of the fry body weight, and the feeding frequency is 6 times a day; (2) At 11-20 days of age, feed 30% composite coated seaweed bait, 7% live earthworms, 10% anesthetized earthworms, and 30% pre-treated Moina, and the rest is basic bait; the total feeding amount is 6% of the fry body weight, and the feeding frequency is 5 times a day; (3) From 21 to 35 days old, feed the fish with 15% composite coated seaweed bait, 20% live earthworms, 25% anesthetized earthworms, and 25% pre-treated Moina, and the rest as basic bait; the total feeding amount is 9% of the fry body weight, and the feeding frequency is 4 times a day; (4) At 36 to 50 days of age, feed the fry with 10% composite coated seaweed bait, 30% live earthworms, 12% anesthetized earthworms, and 30% pre-treated Moina, with the rest as base bait; the total feed amount is 15% of the fry body weight, and the feeding frequency is 4 times a day.

[0025] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora staghornsis, Gracilaria tenuifolia, Kappaphycus longicornis, Agara striata and Sargassum creeping were cultured in a photobioreactor to obtain a density of 5.0×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 4.5×10- 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 20 parts of soybean flour, 15 parts of soybean oil, 8 parts of xanthan gum and 60 parts of water by weight, mix and boil at 100°C for 5 minutes, and cool to 26°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed at a volume ratio of 1:2.5, and stirred for 20 minutes to obtain a composite coated seaweed bait.

[0026] The basic bait comprises, by weight, 20 parts of fish meal, 15 parts of soybeans, 12 parts of rapeseed meal, 9 parts of corn, and 3 parts of fine rice bran.

[0027] The preparation method of the anesthetic earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 30 mg / L and soak them for 25 minutes to obtain the anesthetic earthworms.

[0028] The preparation method of the pretreated Moina comprises the following steps: S1, mixing 25 parts of slender pyracantha vine, 30 parts of flat bud, 18 parts of palmately split orchid, 15 parts of Piper longum and 12 parts of rib column flower to obtain a mixture; S2, adding 5 times the weight of the mixture of distilled water to the mixture, soaking for 20 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding distilled water 4 times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 80 minutes to obtain the pretreated moina.

[0029] Example 3 A live bait feeding method for improving the survival rate of hybrid grouper fry of Hualong fish comprises the following steps: (1) From 1 to 10 days old, feed 40% of the composite coated seaweed feed and the rest as basic feed; the total feed amount is 2% of the fry body weight, and the feeding frequency is 5 times a day; (2) At 11-20 days of age, feed the fish with 25% composite coated seaweed bait, 5% live earthworms, 8% anesthetized earthworms, and 25% pre-treated Moina, and the rest as basic bait; the total feeding amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed the fish with 12% composite coated seaweed bait, 18% live earthworms, 20% anesthetized earthworms, 22% pre-treated Moina, and the rest as basic bait; the total feeding amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry with 8% composite coated seaweed bait, 27% live earthworms, 10% anesthetized earthworms, and 26% pre-treated Moina, with the rest as base bait; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0030] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 4.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 3.0×10-10 according to the mass ratio of 50% Dictyophora stagna, 20% Gracilaria tenuifolia, 10% Kappaphycus longicornis, 12% Agarwood and 8% Sargassum creeping. 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 15 parts of soybean flour, 12 parts of soybean oil, 6 parts of xanthan gum and 50 parts of water by weight, mix and boil at 98°C for 4 minutes, and cool to 25°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed in a volume ratio of 1:2, and stirred for 15 minutes to obtain the composite coated seaweed bait.

[0031] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0032] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 25 mg / L and soak them for 20 minutes to obtain the anesthetized earthworms.

[0033] The preparation method of the pretreated Moina comprises the following steps: S1, mixing 20 parts of slender pyracantha vine, 20 parts of flat bud, 15 parts of palmately split orchid, 10 parts of Piper longum and 10 parts of rib column flower to obtain a mixture; S2, adding distilled water 4 times the weight of the mixture to the mixture, soaking for 15 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding distilled water three times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 70 minutes to obtain the pretreated moina.

[0034] Comparative Example 1 The difference between this comparative example and Example 3 is that the composite coated seaweed bait is not subjected to coating treatment, and the other components and steps remain unchanged.

[0035] A live bait feeding method for improving the survival rate of hybrid grouper fry of Hualong fish comprises the following steps: (1) From 1 to 10 days old, feed 40% compound seaweed feed and the rest as basic feed; the total feed amount is 2% of the fry body weight, and the feeding frequency is 5 times a day; (2) At 11 to 20 days of age, feed the fish with 25% compound seaweed feed, 5% live earthworms, 8% anesthetized earthworms, 25% pre-treated Moina, and the rest as basic feed; the total feed amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed the fish with 12% compound seaweed feed, 18% live earthworms, 20% anesthetized earthworms, 22% pre-treated Moina, and the rest as basic feed; the total feed amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry with 8% compound seaweed feed, 27% live earthworms, 10% anesthetized earthworms, and 26% pre-treated Moina, with the remainder as base feed; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0036] The preparation method of the composite seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 4.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 3.0×10-10 according to the mass ratio of 50% Dictyophora stagna, 20% Gracilaria tenuifolia, 10% Kappaphycus longicornis, 12% Agarwood and 8% Sargassum creeping. 9 The seaweed liquid with cells / mL is the composite seaweed bait.

[0037] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0038] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 25 mg / L and soak them for 20 minutes to obtain the anesthetized earthworms.

[0039] The preparation method of the pretreated Moina comprises the following steps: S1, mixing 20 parts of slender pyracantha vine, 20 parts of flat bud, 15 parts of palmately split orchid, 10 parts of Piper longum and 10 parts of rib column flower to obtain a mixture; S2, adding distilled water 4 times the weight of the mixture to the mixture, soaking for 15 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding distilled water three times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 70 minutes to obtain the pretreated moina.

[0040] Comparative Example 2 The difference between this comparative example and Example 3 is that no composite coated seaweed bait is added, and the other ingredients and steps remain unchanged.

[0041] A live bait feeding method for improving the survival rate of hybrid grouper fry, comprising the following steps: (1) From 1 to 10 days old, feed the basal feed; the total feeding amount is 2% of the fry's body weight, and the feeding frequency is 5 times a day; (2) At 11 to 20 days of age, feed 5% live earthworms, 8% anesthetized earthworms, 25% pre-treated Moina, and the rest as basic bait; the total feeding amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed the fish with 18% live earthworms, 20% anesthetized earthworms, 22% pre-treated Moina, and the rest as basic bait; the total feed amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry with 27% live earthworms, 10% anesthetized earthworms, 26% pre-treated Moina, and the rest as base bait; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0042] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0043] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 25 mg / L and soak them for 20 minutes to obtain the anesthetized earthworms.

[0044] The preparation method of the pretreated Moina comprises the following steps: S1, mixing 20 parts of slender pyracantha vine, 20 parts of flat bud, 15 parts of palmately split orchid, 10 parts of Piper longum and 10 parts of rib column flower to obtain a mixture; S2, adding 4 times the weight of the mixture of distilled water to the mixture, soaking for 15 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first liquid medicine and a first residue; S3, adding distilled water three times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 70 minutes to obtain the pretreated moina.

[0045] Comparative Example 3 The difference between this comparative example and Example 3 is that the anesthetized earthworms are replaced with live earthworms, and the other ingredients and steps remain unchanged.

[0046] A live bait feeding method for improving the survival rate of hybrid grouper fry, comprising the following steps: (1) From 1 to 10 days old, feed 40% of the composite coated seaweed feed and the rest as basic feed; the total feed amount is 2% of the fry body weight, and the feeding frequency is 5 times a day; (2) At 11-20 days of age, feed the fry with 25% composite coated seaweed feed, 13% live earthworms, and 25% pre-treated Moina, and the rest is the basic feed; the total feed amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed the fish with 12% composite coated seaweed feed, 38% live earthworms, 22% pre-treated Moina, and the rest as basic feed; the total feed amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry with 8% composite coated seaweed feed, 37% live earthworms, 26% pre-treated Moina, and the rest as basic feed; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0047] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 4.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 3.0×10-10 according to the mass ratio of 50% Dictyophora stagna, 20% Gracilaria tenuifolia, 10% Kappaphycus longicornis, 12% Agarwood and 8% Sargassum creeping. 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 15 parts of soybean flour, 12 parts of soybean oil, 6 parts of xanthan gum and 50 parts of water by weight, mix and boil at 98°C for 4 minutes, and cool to 25°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed in a volume ratio of 1:2, and stirred for 15 minutes to obtain the composite coated seaweed bait.

[0048] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0049] The preparation method of the pretreated Moina comprises the following steps: S1, mixing 20 parts of slender pyracantha vine, 20 parts of flat bud, 15 parts of palmately split orchid, 10 parts of Piper longum and 10 parts of rib column flower to obtain a mixture; S2, adding distilled water 4 times the weight of the mixture to the mixture, soaking for 15 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding distilled water three times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 70 minutes to obtain the pretreated moina.

[0050] Comparative Example 4 The difference between this comparative example and Example 3 is that the live earthworms are replaced with anesthetized earthworms, and the other ingredients and steps remain unchanged.

[0051] A live bait feeding method for improving the survival rate of hybrid grouper fry, comprising the following steps: (1) From 1 to 10 days old, feed 40% of the composite coated seaweed feed and the rest as basic feed; the total feed amount is 2% of the fry body weight, and the feeding frequency is 5 times a day; (2) At 11 to 20 days of age, feed the fish with 25% composite coated seaweed feed, 13% anesthetized earthworms, 25% pre-treated Moina, and the rest as basic feed; the total feed amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed the fish with 12% composite coated seaweed feed, 38% anesthetized earthworms, 22% pre-treated Moina, and the rest as basic feed; the total feed amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry 8% composite coated seaweed feed, 37% anesthetized earthworms, 26% pre-treated Moina, and the rest as basic feed; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0052] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 4.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 3.0×10-10 according to the mass ratio of 50% Dictyophora stagna, 20% Gracilaria tenuifolia, 10% Kappaphycus longicornis, 12% Agarwood and 8% Sargassum creeping. 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 15 parts of soybean flour, 12 parts of soybean oil, 6 parts of xanthan gum and 50 parts of water by weight, mix and boil at 98°C for 4 minutes, and cool to 25°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed in a volume ratio of 1:2, and stirred for 15 minutes to obtain the composite coated seaweed bait.

[0053] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0054] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 25 mg / L and soak them for 20 minutes to obtain the anesthetized earthworms.

[0055] The preparation method of the pretreated Moina comprises the following steps: S1, mixing 20 parts of slender pyracantha vine, 20 parts of flat bud, 15 parts of palmately split orchid, 10 parts of Piper longum and 10 parts of rib column flower to obtain a mixture; S2, adding distilled water 4 times the weight of the mixture to the mixture, soaking for 15 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding distilled water three times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 70 minutes to obtain the pretreated moina.

[0056] Comparative Example 5 The difference between this comparative example and Example 3 is that the moina was not pretreated, and the other components and steps remained unchanged.

[0057] A live bait feeding method for improving the survival rate of hybrid grouper fry of Hualong fish comprises the following steps: (1) From 1 to 10 days old, feed 40% of the composite coated seaweed feed and the rest as basic feed; the total feed amount is 2% of the fry body weight, and the feeding frequency is 5 times a day; (2) At 11-20 days of age, feed 25% composite coated seaweed bait, 5% live earthworms, 8% anesthetized earthworms, and 25% Moina, and the rest is basic bait; the total feeding amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed the fry with 12% composite coated seaweed bait, 18% live earthworms, 20% anesthetized earthworms, 22% Moina, and the rest as basic bait; the total feeding amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry with 8% composite coated seaweed bait, 27% live earthworms, 10% anesthetized earthworms, and 26% Moina, with the rest as base bait; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0058] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 4.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 3.0×10-10 according to the mass ratio of 50% Dictyophora stagna, 20% Gracilaria tenuifolia, 10% Kappaphycus longicornis, 12% Agarwood and 8% Sargassum creeping. 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 15 parts of soybean flour, 12 parts of soybean oil, 6 parts of xanthan gum and 50 parts of water by weight, mix and boil at 98°C for 4 minutes, and cool to 25°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed in a volume ratio of 1:2, and stirred for 15 minutes to obtain the composite coated seaweed bait.

[0059] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0060] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 25 mg / L and soak them for 20 minutes to obtain the anesthetized earthworms.

[0061] Comparative Example 6 The difference between this comparative example and Example 3 is that the moina is replaced by rotifer, and the other components and steps remain unchanged.

[0062] A live bait feeding method for improving the survival rate of hybrid grouper fry of Hualong fish comprises the following steps: (1) From 1 to 10 days old, feed 40% of the composite coated seaweed feed and the rest as basic feed; the total feed amount is 2% of the fry body weight, and the feeding frequency is 5 times a day; (2) At 11 to 20 days of age, feed 25% composite coated seaweed bait, 5% live earthworms, 8% anesthetized earthworms, and 25% pre-treated rotifers, and the rest as basic bait; the total feeding amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed 12% composite coated seaweed bait, 18% live earthworms, 20% anesthetized earthworms, 22% pre-treated rotifers, and the rest as basic bait; the total feeding amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry with 8% composite coated seaweed bait, 27% live earthworms, 10% anesthetized earthworms, and 26% pre-treated rotifers, with the remainder as base bait; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0063] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 4.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 3.0×10-10 according to the mass ratio of 50% Dictyophora stagna, 20% Gracilaria tenuifolia, 10% Kappaphycus longicornis, 12% Agarwood and 8% Sargassum creeping. 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 15 parts of soybean flour, 12 parts of soybean oil, 6 parts of xanthan gum and 50 parts of water by weight, mix and boil at 98°C for 4 minutes, and cool to 25°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed in a volume ratio of 1:2, and stirred for 15 minutes to obtain the composite coated seaweed bait.

[0064] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0065] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 25 mg / L and soak them for 20 minutes to obtain the anesthetized earthworms.

[0066] The preparation method of the pretreated rotifer comprises the following steps: S1, mixing 20 parts of slender pyracantha vine, 20 parts of flat bud, 15 parts of palmately split orchid, 10 parts of Piper longum and 10 parts of rib column flower to obtain a mixture; S2, adding distilled water 4 times the weight of the mixture to the mixture, soaking for 15 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding distilled water three times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add rotifers to the pretreatment solution and soak for 70 minutes to obtain pretreated rotifers.

[0067] Comparative Example 7 The difference between this comparative example and Example 3 is that the slender pyracantha vine in the pretreatment solution is replaced with scutellaria baicalensis, and the other ingredients and steps remain unchanged.

[0068] A live bait feeding method for improving the survival rate of hybrid grouper fry of Hualong fish comprises the following steps: (1) From 1 to 10 days old, feed 40% of the composite coated seaweed feed and the rest as basic feed; the total feed amount is 2% of the fry body weight, and the feeding frequency is 5 times a day; (2) At 11-20 days of age, feed the fish with 25% composite coated seaweed bait, 5% live earthworms, 8% anesthetized earthworms, and 25% pre-treated Moina, and the rest as basic bait; the total feeding amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed the fish with 12% composite coated seaweed bait, 18% live earthworms, 20% anesthetized earthworms, 22% pre-treated Moina, and the rest as basic bait; the total feeding amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry with 8% composite coated seaweed bait, 27% live earthworms, 10% anesthetized earthworms, and 26% pre-treated Moina, with the rest as base bait; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0069] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 4.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 3.0×10-10 according to the mass ratio of 50% Dictyophora stagna, 20% Gracilaria tenuifolia, 10% Kappaphycus longicornis, 12% Agarwood and 8% Sargassum creeping. 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 15 parts of soybean flour, 12 parts of soybean oil, 6 parts of xanthan gum and 50 parts of water by weight, mix and boil at 98°C for 4 minutes, and cool to 25°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed in a volume ratio of 1:2, and stirred for 15 minutes to obtain the composite coated seaweed bait.

[0070] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0071] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 25 mg / L and soak them for 20 minutes to obtain the anesthetized earthworms.

[0072] The preparation method of the pretreated Moina comprises the following steps: S1, mixing 20 parts of Cistanche deserticola, 20 parts of Flat Bud, 15 parts of Orchidaceae, 10 parts of Piper longum and 10 parts of Corydalis serrata to obtain a mixture; S2, adding 4 times the weight of the mixture of distilled water to the mixture, soaking for 15 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first liquid medicine and a first residue; S3, adding distilled water three times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 70 minutes to obtain the pretreated moina.

[0073] Comparative Example 8 The difference between this comparative example and Example 3 is that the number of flat buds is increased in the pretreatment solution, and the other ingredients and steps remain unchanged.

[0074] A live bait feeding method for improving the survival rate of hybrid grouper fry, comprising the following steps: (1) From 1 to 10 days old, feed 40% of the composite coated seaweed feed and the rest as basic feed; the total feed amount is 2% of the fry body weight, and the feeding frequency is 5 times a day; (2) At 11-20 days of age, feed the fish with 25% composite coated seaweed bait, 5% live earthworms, 8% anesthetized earthworms, and 25% pre-treated Moina, and the rest as basic bait; the total feeding amount is 5% of the fry body weight, and the feeding frequency is 4 times a day; (3) From 21 to 35 days old, feed the fish with 12% composite coated seaweed bait, 18% live earthworms, 20% anesthetized earthworms, 22% pre-treated Moina, and the rest as basic bait; the total feeding amount is 8% of the fry body weight, and the feeding frequency is 3 times a day; (4) At 36 to 50 days of age, feed the fry with 8% composite coated seaweed bait, 27% live earthworms, 10% anesthetized earthworms, and 26% pre-treated Moina, with the rest as base bait; the total feed amount is 12% of the fry body weight, and the feeding frequency is 3 times a day.

[0075] The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 4.5×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 3.0×10-10 according to the mass ratio of 50% Dictyophora stagna, 20% Gracilaria tenuifolia, 10% Kappaphycus longicornis, 12% Agarwood and 8% Sargassum creeping. 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) Weigh 15 parts of soybean flour, 12 parts of soybean oil, 6 parts of xanthan gum and 50 parts of water by weight, mix and boil at 98°C for 4 minutes, and cool to 25°C to obtain a coating solution; 4) The composite seaweed bait obtained in step 2) and the coating solution obtained in step 3) are mixed in a volume ratio of 1:2, and stirred for 15 minutes to obtain the composite coated seaweed bait.

[0076] The basic bait, calculated by weight, includes 15 parts of fish meal, 12 parts of soybeans, 10 parts of rapeseed meal, 6 parts of corn, and 2 parts of fine rice bran.

[0077] The preparation method of the anesthetized earthworms is to add the earthworms into a eugenol ethanol solution with a volume concentration of 25 mg / L and soak them for 20 minutes to obtain the anesthetized earthworms.

[0078] The preparation method of the pretreated Moina comprises the following steps: S1, mixing 20 parts of slender pyracantha vine, 50 parts of flat bud, 15 parts of palmately split orchid, 10 parts of Piper longum and 10 parts of rib column flower to obtain a mixture; S2, adding distilled water 4 times the weight of the mixture to the mixture, soaking for 15 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding distilled water three times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering to obtain a second medicinal solution; then combining the first medicinal solution and the second medicinal solution to obtain a pretreatment solution; S4. Add the moina to the pretreatment solution and soak for 70 minutes to obtain the pretreated moina.

[0079] Test Example 1 Growth rate and survival rate of fry The methods of Examples 1 to 3 and Comparative Examples 1 to 8 were used to culture hybrid grouper fry, the number of stockings and the number of harvested fry were counted, and the survival rate was calculated, where the survival rate = the number of harvested fry / the number of stockings; the weight of the fry was tested for one month, 50 fry samples were tested for each feeding method, and the average value was taken to evaluate the growth rate of hybrid grouper fry; the application number CN201710683433.5, a method for breeding grouper, was used as conventional breeding, and the fry obtained was used as a control group; The statistical results are shown in Table 1: Table 1 Growth rate and survival rate of fry As can be seen from Table 1, the hybrid spotted fish fry cultured by different feeding methods have certain differences. The growth rate and survival rate of the fry in Example 3 are the highest. Through staged culture and the reasonable use of bait, the growth rate of the hybrid spotted fish fry of the present invention is accelerated, and no large-scale bacterial infection and death of the fry occurred during the culture period. Comparison between Example 3 and Comparative Examples 1 and 2 shows that it is very important to coat the composite coated seaweed bait, which is conducive to the composite seaweed bait not being easily dispersed when entering the water, enhancing the stability of the bait and having a strong palatability; comparison between Example 3 and Comparative Examples 4 shows that the survival status of earthworms directly affects the feeding rate of bait, which further affects the growth rate of fry. If the feeding rate is low, the growth rate is slow, and low immunity of fish can easily cause death; comparison between Example 3 and Comparative Examples 5 and 6 shows that for rotifers and naked Daphnia gracilis, hybrid spotted fish fry The fish prefer to eat Moina. After being treated with the pretreatment liquid, not only the parasites carried by Moina itself will be killed to avoid bringing the parasites to the fry, resulting in a lower survival rate of the fry, but also the active ingredients in the traditional Chinese medicine are beneficial to promote the peristalsis of the fry's intestines, enhance the metabolic activity of the intestine, increase the fry's feeding rate, and improve the fry's survival rate. By comparing Example 3 with Comparative Examples 7 and 8, it can be seen that in order to maintain a higher survival rate, it is necessary to increase the pretreatment step, and there are certain regulations on the types and numbers of the pretreatment components. If the specified value is not reached, the survival rate of the fry will be reduced, and the economic benefit is poor.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A live bait feeding method for improving the survival rate of hybrid grouper fry, characterized in that: The steps include: (1) From 1 to 10 days old, feed 30-50% composite coated seaweed feed and the rest as basic feed; (2) At 11-20 days of age, feed them 20-30% composite coated seaweed bait, 2-7% live earthworms, 5-10% anesthetized earthworms, and 20-30% pre-treated Moina, with the rest as base bait; (3) At 21-35 days of age, feed them with 10-15% composite coated seaweed bait, 10-20% live earthworms, 10-25% anesthetized earthworms, and 15-25% pre-treated Moina, and the rest as basic bait; (4) At 36-50 days of age, feed 5-10% composite coated seaweed bait, 20-30% live earthworms, 5-12% anesthetized earthworms, and 20-30% pre-treated Moina, and the rest as basic bait; The composite coated seaweed bait comprises 20-30% of Dictyota staghornis, 20-30% of Gracilaria tenuifolia, 10-15% of Kappaphycus longicornis, 8-15% of Agarwood and 2-10% of Sargassum creeping; The pre-treated moina is obtained by soaking the moina in a pre-treatment solution, wherein the pre-treatment solution comprises the following components by weight: 12-25 parts of slender spatholobi, 10-30 parts of flat buds, 10-18 parts of palmately split orchids, 8-15 parts of longan and 5-12 parts of rib column flowers.

2. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 1 is characterized in that, The preparation method of the composite coated seaweed bait comprises the following steps: 1) The algae species of Dictyophora serrata, Gracilaria tenuifolia, Kappaphycus longicornis, Agara sphaeroides and Sargassum sphaeroides were cultured in a photobioreactor to obtain a density of 1.5×10 10 ~5.0×10 10 cells / mL of algae liquid; 2) The total density of the mixture was 1.0×10-10 according to the mass ratio of 20-60% of Dictyophora stagna, 20-30% of Gracilaria tenuifolia, 10-15% of Kappaphycus longicornis, 8-15% of Agarwood and 2-10% of Sargassum creeping. 8 ~4.5×10 9 The seaweed liquid containing cells / mL is the composite seaweed bait; 3) According to weight, weigh 10-20 parts of soybean flour, 10-15 parts of soybean oil, 5-8 parts of xanthan gum and 40-60 parts of water, mix and boil at 96-100°C for 3-5 minutes, and cool to 20-26°C to obtain a coating solution; 4) Mix the composite seaweed bait obtained in step 2) and the coating solution obtained in step 3), and stir for 10 to 20 minutes to obtain the composite coated seaweed bait.

3. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 2 is characterized in that, In step 4), the composite seaweed bait and the coating liquid are mixed in a volume ratio of 1:(1.5-2.5).

4. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 1 is characterized in that, The basic bait comprises, by weight, 12 to 20 parts of fish meal, 10 to 15 parts of soybeans, 8 to 12 parts of rapeseed meal, 5 to 9 parts of corn, and 1 to 3 parts of fine rice bran.

5. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 1 is characterized in that, The preparation method of the anesthetized earthworms comprises adding the earthworms into a eugenol ethanol solution with a volume concentration of 20-30 mg / L and soaking the solution for 15-25 minutes to obtain the anesthetized earthworms.

6. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 1 is characterized in that, The preparation method of the pretreated Moina comprises the following steps: S1. Mix slender pyracantha vine, flat bud, palmate orchid, Piper longum and rib column flower to obtain a mixture; S2, adding 3 to 5 times the weight of the mixture of distilled water to the mixture, soaking for 10 to 20 minutes, heating and boiling for 30 minutes, filtering, and obtaining a first medicinal solution and a first medicinal residue; S3, adding distilled water 2 to 4 times the weight of the first medicinal residue to the first medicinal residue, heating and boiling for 30 minutes, filtering, and obtaining a second medicinal solution; Then the first liquid and the second liquid are combined to form a pretreatment liquid; S4. Add the moina to the pretreatment solution and soak it for 60 to 80 minutes to obtain the pretreated moina.

7. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 1 is characterized in that, The total feeding amount of the composite coated seaweed bait and the basic bait in step (1) is 1-3% of the body weight of the fry, and the feeding frequency is 4-6 times a day.

8. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 1 is characterized in that, In step (2), the total feeding amount of the composite coated seaweed bait, live earthworms, anesthetized earthworms, pre-treated Moina and basic bait is 4-6% of the body weight of the fry, and the feeding frequency is 3-5 times a day.

9. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 1 is characterized in that, In step (3), the total feeding amount of the composite coated seaweed bait, live earthworms, anesthetized earthworms, pre-treated Moina and basic bait is 7-9% of the body weight of the fry, and the feeding frequency is 2-4 times a day.

10. The live bait feeding method for improving the survival rate of Hualong hybrid grouper fry according to claim 1 is characterized in that: In step (4), the total feeding amount of the composite coated seaweed bait, live earthworms, anesthetized earthworms, pre-treated Moina and basic bait is 10-15% of the body weight of the fry, and the feeding frequency is 2-4 times a day.

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