A method for directional breeding of active bait for enhancing the stress resistance of east star open seedlings

Abstract

This invention relates to a method for the targeted cultivation of live feed to enhance the stress resistance of grouper fry, specifically a method for the targeted cultivation of grouper fry and its live feed. The live feed includes artichoke culture and rotifer culture. The targeted cultivation of the artichoke culture includes the following steps: placing artichokes in seawater, adding *Cryptospira spp.* powder, *Spirulina* powder, arginine, and *Cinnamomum camphora* oil for cultivation to obtain the artichoke culture; the targeted cultivation of the rotifer culture includes the following steps: placing rotifers in seawater, adding *Nyctaginus* pink bacteria. Natrialba pink Rotifer cultures were obtained by cultivating bacterial powder, spirulina powder, methionine, and sunflower oil. This method, through targeted cultivation of live feed, enriches the live feed with corresponding functional components. After feeding it to newly hatched juvenile scorpion, it can significantly improve the stress resistance of the juveniles and increase their survival rate, thus solving the industry pain points of slow development, low survival rate, and poor stress resistance of newly hatched scorpion scorpion.

Description

Technical Field

[0001] This invention relates to the field of fish fry cultivation technology, specifically to a method for targeted cultivation of live feed to enhance the stress resistance of newly hatched grouper fry. Background Technology

[0002] The Eastern Star Grouper, also known as the Seven-Star Grouper, is scientifically named Leopard Gill Spinosaurus. Plectropomus leopardus It belongs to the genus *Scoidea* and is a warm-water carnivorous fish. Its flesh is tender, nutritious, and of high economic value, making it a prized edible fish and highly favored by consumers.

[0003] Currently, the traditional live feed for grouper fry during the rearing period consists of algae, rotifers, artichokes, and copepods. Newly hatched fry are typically fed S-type rotifers as their first food, while the diet of larvae and juveniles changes continuously as they grow, progressing from rotifers and artichoke nauplii to copepods and finally adult artichokes. Rotifers, artichokes, and copepods are usually fortified with fish liver oil or algae. This traditional method requires multiple changes of live feed within a short period of 1-2 months. Furthermore, due to unstable nutritional transitions and a mismatch between the feed and the grouper's developmental stage, it takes over 40 days for grouper to develop from fry to juvenile. During this metamorphosis, they are prone to stress and have weak resistance to environmental changes, significantly reducing the survival rate of the fry. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for targeted cultivation of active feed to enhance the stress resistance of newly hatched grouper seedlings. Through targeted cultivation, the active feed accumulates specific nutrients and functional components, which can directly improve the stress resistance of newly hatched grouper seedlings after feeding. This method simplifies the seedling cultivation process and improves the survival rate and growth rate of seedlings without the need to change the type of feed multiple times.

[0005] Fish fry are in a rapid development stage, and their immune systems are not yet fully developed, making them much less resistant to various diseases than adult fish. The initial feeding stage, where fish transition from endogenous to exogenous nutrition, is a crucial factor in determining the success of fry rearing and is also one of the peak mortality periods. Therefore, the scientific and appropriateness of the initial feed is paramount. The subsequent metamorphosis stage of larvae is the second peak mortality period for fry. Ensuring the rationality of the feed's nutrition and meeting the material requirements for metamorphosis will greatly improve the survival rate of fry. Therefore, it is also very important to cultivate bioactive feed for larvae to perfectly match the individual development of the grouper, thereby promoting fry growth, improving stress resistance, and increasing survival rate.

[0006] Based on years of observation and experience in seedling cultivation and aquaculture, and combined with extensive experimental screening, the applicant has finally determined the optimal live feed cultivation program, which includes the following key technical points: A method for targeted cultivation of active feed to enhance the stress resistance of newly hatched seedlings of the Chinese starfish, wherein the active feed includes culture of Artemia pilosa and culture of Rotifers; The directed cultivation of the brine shrimp culture includes the following steps: placing brine shrimp in seawater and adding Cryptorhizium anisopliae. Natrinema pellirubrum Artemia culture was obtained by cultivating bacterial powder, spirulina powder, arginine, and *Cinnamomum camphora* oil. The directed cultivation of the rotifer culture included the following steps: placing rotifers in seawater and adding pink *Nalva* bacteria. Natrialba pink Rotifer cultures were obtained by cultivating bacterial powder, spirulina powder, methionine, and sunflower oil.

[0007] Preferably, the inoculation density of Artemia or Rotifers in seawater is 300-400 cells / mL.

[0008] Preferably, during the directed cultivation of Artemia var. sarcodactylus, Cryptorhizium anisopliae is added to the seawater. Natrinema pellirubrum Bacterial powder 0.8~1.0g / L, Spirulina powder 0.4~0.55g / L, Arginine 0.1~0.2g / L, and Rosa rugosa oil 1.5~3.0mL / L.

[0009] Preferably, during the directed cultivation of rotifer cultures, pink bacteria of the genus *Nalva* in seawater are used. Natrialba pink Bacterial powder 0.8~1.0g / L, spirulina powder 0.4~0.55g / L, methionine 0.1~0.2g / L, sunflower oil 1.5~3.0 mL / L.

[0010] Preferably, the targeted cultivation time is no less than 24 hours.

[0011] More preferably, the targeted cultivation time is 24-36 hours.

[0012] Preferably, the *Cinnamomum camphora* oil is an oil extracted from the stems and leaves of *Cinnamomum camphora*, and the *Sunflower* oil is an oil extracted from the stems and leaves of *Sunflower*. The extraction method of the oil is to weigh the dry powder of stems and leaves, add 150-300 ml of petroleum ether to every 50-100 g of dry powder of stems and leaves, reflux extract for 6-8 hours, and recover the solvent at 40-50℃ to obtain crude oil.

[0013] The present invention further relates to the active feed obtained by the active feed directional cultivation method and its application in improving the stress resistance of seedlings of the Chinese star bream or promoting the development of seedlings of the Chinese star bream.

[0014] Preferred application method: Feed newly hatched fry with rotifer culture before 15 days of age, 4 times a day, each time with rotifer culture accounting for 3% to 5% of the seedling seawater. Feed with artichoke culture from 15 to 45 days of age, 3 times a day, each time with rotifer culture accounting for 3% to 5% of the seedling seawater.

[0015] The beneficial effects of this invention are: This invention involves targeted cultivation of rotifers and artemia, allowing the effective components of Cryptorhizium anisopliae, pink bacteriums of the genus Nephrolepis, and oils from Rhododendron simsii and Senna alexandrina to be concentrated in or utilized by the active feed. After feeding, the seedlings of the Oriental Star Spotted Leptospira can effectively enhance their resistance to environmental fluctuations and pathogen invasion, reduce the probability of stress reactions, and ensure a stable nutrient supply to meet the growth needs of seedlings at different developmental stages. This eliminates the need for frequent changes in feed type, simplifies seedling cultivation, and ultimately improves the survival rate of seedlings, accelerates seedling growth, and enhances the overall efficiency of seedling cultivation. Detailed Implementation

[0016] To facilitate a clearer understanding of the technical content of this invention by those skilled in the art, the invention will be further described below in conjunction with specific embodiments.

[0017] Unless otherwise specified, the experimental methods described in the following examples are conventional methods.

[0018] The oil from the rosy bud flower ( ) is derived from the rosy bud flower ( ) Calliandra haematocephala The oil extracted from the stems and leaves of *Hassk.*, said sunflower oil is derived from the sunflower (*Hassk.*). Portulaca grandiflora Oil extracted from the stems and leaves of Hook. The extraction method is as follows: weigh the dried stem and leaf powder, add 150-300ml of organic solvent (petroleum ether) to every 50-100g of dried stem and leaf powder, reflux for 6-8 hours (temperature controlled at the boiling point of the solvent), and recover the solvent at 40-50℃ to obtain crude oil.

[0019] Example 1: Targeted Cultivation Method of Active Feed for Enhancing the Stress Resistance of Orientia zebrina Seedlings The live bait includes brine shrimp cultures and rotifer cultures, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. The specific steps are as follows: Artemia were placed in seawater (salinity 32-33‰) at a density of 300 cells / mL, with dissolved oxygen in the water controlled at no less than 5.0 mg / L, and Cryptorhizium anisopliae were added. Natrinema pellirubrum (CCTCC AB 2012854) Artemia culture was obtained by culturing 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of arginine, and 1.5 mL / L of *Cinnamomum camphora* oil for 24 hours. The bacterial content in the bacterial powder was not less than 10. 9 cfu / g.

[0020] Rotifers were placed in seawater (salinity 32-33‰) at a density of 300 rotifers / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L, and pink bacterium of the genus *Neuroglobulus* was added. Natrialba pink (CCTCC AB 2013111) Rotifer cultures were obtained by incubating 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of methionine, and 1.5 mL / L of sunflower oil for 24 hours. The bacterial powder contained no less than 10% bacteria. 9 cfu / g.

[0021] Example 2: Targeted Cultivation Method Using Active Feed to Enhance the Stress Resistance of Orientia zebrina Seedlings The live bait includes brine shrimp cultures and rotifer cultures, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. The specific steps are as follows: According to density 400 Place brine shrimp in seawater (salinity 32-33‰) at a concentration of / mL, ensuring dissolved oxygen in the water is not lower than 5.0 mg / L, and add Cryptorhizium anisopliae. Natrinema pellirubrum (CCTCC AB 2012854) Artemia culture was obtained by culturing 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of arginine, and 1.5 mL / L of *Cinnamomum camphora* oil for 24 hours. The bacterial content in the bacterial powder was not less than 10. 9 cfu / g.

[0022] According to density 400 Place rotifers in seawater (salinity 32-33‰) at a concentration of / mL, ensuring dissolved oxygen in the water is not lower than 5.0 mg / L, and add pink bacterium of the genus *Neoplasmium*. Natrialba pink (CCTCC AB 2013111) Rotifer cultures were obtained by incubating 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of methionine, and 1.5 mL / L of sunflower oil for 24 hours. The bacterial powder contained no less than 10% bacteria. 9 cfu / g.

[0023] Example 3: Targeted Cultivation Method of Active Feed for Enhancing the Stress Resistance of Orientia zebrina Seedlings The live bait includes brine shrimp cultures and rotifer cultures, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. The specific steps are as follows: Artemia were placed in seawater (salinity 32-33‰) at a density of 300 cells / mL, with dissolved oxygen in the water controlled at no less than 5.0 mg / L, and Cryptorhizium anisopliae were added. Natrinema pellirubrum(CCTCC AB 2012854) Artemia culture was obtained by incubating 1 g / L of bacterial powder, 0.55 g / L of spirulina powder, 0.2 g / L of arginine, and 3.0 mL / L of *Cinnamomum camphora* oil for 24 hours. The bacterial content in the bacterial powder was not less than 10. 9 cfu / g.

[0024] Rotifers were placed in seawater (salinity 32-33‰) at a density of 300 rotifers / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L, and pink bacterium of the genus *Neuroglobulus* was added. Natrialba pink (CCTCC AB 2013111) Rotifer cultures were obtained by incubating 1.0 g / L of bacterial powder, 0.55 g / L of spirulina powder, 0.2 g / L of methionine, and 3.0 mL / L of sunflower oil for 24 hours. The bacterial powder contained no less than 10% bacteria. 9 cfu / g.

[0025] Example 4: Targeted Cultivation Method of Active Feed for Enhancing the Stress Resistance of Orientia zebrina Seedlings The live bait includes brine shrimp cultures and rotifer cultures, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. The specific steps are as follows: Artemia were placed in seawater (salinity 32-33‰) at a density of 300 cells / mL, with dissolved oxygen in the water controlled at no less than 5.0 mg / L, and Cryptorhizium anisopliae were added. Natrinema pellirubrum (CCTCC AB 2012854) The bacteria were cultivated using 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of arginine, and 1.5 mL / L of *Corydalis yanhusuo* oil. 36h Artemia culture was obtained. The bacterial content in the bacterial powder was not less than 10. 9 cfu / g.

[0026] Rotifers were placed in seawater (salinity 32-33‰) at a density of 300 rotifers / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L, and pink bacterium of the genus *Neuroglobulus* was added. Natrialba pink (CCTCC AB 2013111) The bacteria were cultivated using 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of methionine, and 1.5 mL / L of sunflower oil. 36h， Rotifer cultures were obtained. The bacterial powder contained a bacterial count of not less than 10⁻⁶. 9 cfu / g.

[0027] Comparative Example 1: Targeted Cultivation Method Using Live Feed The active bait includes brine shrimp culture and rotifer culture, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. The rotifer cultures and artichoke cultures in this comparative example were cultured using the same method. The specific steps are as follows: Artemia or rotifers were placed in seawater (salinity 32-33‰) at a density of 300 cells / mL, with dissolved oxygen in the water controlled at no less than 5.0 mg / L, and Cryptorhizium anisopliae were added. Natrinema pellirubrum (CCTCC AB 2012854) A culture of Artemia or rotifers was obtained by incubating 0.8 g / L of bacterial powder, 0.4 g / L of Spirulina powder, 0.1 g / L of arginine, and 1.5 mL / L of *Cinnamomum camphora* oil for 24 hours. The bacterial powder contained no less than 10... 9 cfu / g.

[0028] Comparative Example 2: Targeted Cultivation Method Using Live Feed The active bait includes brine shrimp culture and rotifer culture, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. The rotifer cultures and artichoke cultures in this comparative example were cultured using the same method. The specific steps are as follows: Arsenic worms or rotifers were placed in seawater (salinity 32-33‰) at a density of 300 worms / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L, and pink bacterium of the genus *Nalva* was added. Natrialba pink (CCTCC AB 2013111) A culture of Artemia or rotifers was obtained by incubating 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of methionine, and 1.5 mL / L of sunflower oil for 24 hours. The bacterial powder contained no less than 10% bacteria. 9 cfu / g.

[0029] Comparative Example 3: Targeted Cultivation Method of Live Feed The active bait includes brine shrimp culture and rotifer culture, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. In this comparative example, artichokes were bred using sunflower oil, and rotifers were bred using redbud oil. The specific steps are as follows: Artemia were placed in seawater (salinity 32-33‰) at a density of 300 cells / mL, with dissolved oxygen in the water controlled at no less than 5.0 mg / L, and Cryptorhizium anisopliae were added. Natrinema pellirubrum (CCTCC AB 2012854) Bacterial powder 0.8 g / L, Spirulina powder 0.4 g / L, Arginine 0.1 g / L Sunflower oil The culture of artichokes was obtained by incubating at 1.5 mL / L for 24 hours. The bacterial count in the mycelium powder was not less than 10. 9 cfu / g.

[0030] Rotifers were placed in seawater (salinity 32-33‰) at a density of 300 rotifers / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L, and pink bacterium of the genus *Neuroglobulus* was added. Natrialba pink (CCTCC AB 2013111) Bacterial powder 0.8 g / L, Spirulina powder 0.4 g / L, Methionine 0.1 g / L Red tassel flower oilRotifer cultures were obtained by incubating at 1.5 mL / L for 24 hours. The bacterial count in the bacterial powder was not less than 10. 9 cfu / g.

[0031] Comparative Example 4: Targeted Cultivation Method Using Live Feed The active bait includes brine shrimp culture and rotifer culture, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. In this comparative example, the strains of bacteria used in the cultivation of rotifers and artichokes are different. The specific steps are as follows: Artemia were placed in seawater (salinity 32-33‰) at a density of 300 Artemia / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L. Pink fungus of the genus Naberezula Natrialba pink (CCTCC AB 2013111) Artemia culture was obtained by incubating 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of arginine, and 1.5 mL / L of *Cinnamomum camphora* oil for 24 hours. The bacterial powder contained no less than 10% bacteria. 9 cfu / g.

[0032] Rotifers were placed in seawater (salinity 32-33‰) at a density of 300 rotifers / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L. Cryptorhizium alkaline fungus Natrinema pellirubrum (CCTCC AB 2012854) Rotifer cultures were obtained by incubating 0.8 g / L of bacterial powder, 0.4 g / L of spirulina powder, 0.1 g / L of methionine, and 1.5 mL / L of sunflower oil for 24 hours. The bacterial powder contained no less than 10% bacteria. 9 cfu / g.

[0033] Comparative Example 5: Targeted Cultivation Method of Live Feed The active bait includes brine shrimp culture and rotifer culture, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. In this comparative example, the proportions of the cultivation materials are different. The specific steps are as follows: Artemia were placed in seawater (salinity 32-33‰) at a density of 300 cells / mL, with dissolved oxygen in the water controlled at no less than 5.0 mg / L, and Cryptorhizium anisopliae were added. Natrinema pellirubrum (CCTCC AB 2012854) Bacterial powder 0.8 g / L, Spirulina powder 0.4 g / L Arginine 0.5 g / L, Rosa rugosa oil 1.0 mL / L After culturing for 24 hours, an artemisia culture is obtained. The bacterial count in the mycelium powder is not less than 10. 9 cfu / g.

[0034] Rotifers were placed in seawater (salinity 32-33‰) at a density of 300 rotifers / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L, and pink bacterium of the genus *Neuroglobulus* was added. Natrialba pink (CCTCC AB 2013111) Bacterial powder 0.8 g / L, Spirulina powder 0.4 g / L, Methionine 0.3 g / L, sunflower oil 1.0 mL / L After 24 hours of cultivation, a rotifer culture is obtained. The bacterial content in the mycelium powder is not less than 10. 9cfu / g.

[0035] Comparative Example 6: Targeted Cultivation Method of Live Feed The active bait includes brine shrimp culture and rotifer culture, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. In this comparative example, no microorganisms were added during the directional culture process. The specific steps are as follows: Artemia were placed in seawater (salinity 32-33‰) at a density of 300 Artemia / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L. Spirulina powder 0.4 g / L, arginine 0.1 g / L, and rosary pea oil 1.5 mL / L were added and cultured for 24 h to obtain Artemia culture.

[0036] Rotifers were placed in seawater (salinity 32-33‰) at a density of 300 rotifers / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L. Spirulina powder 0.4 g / L, methionine 0.1 g / L, and sunflower oil 1.5 mL / L were added and cultured for 24 h to obtain rotifer culture.

[0037] The bioactive feed obtained through the above examples or comparative methods was directly used for the rearing of grouper fry. Artemia culture and rotifer culture were added to the grouper fry rearing pond at a volume ratio of 3%–5% as bio-feed for the grouper fry. The specific feeding method is as follows: Newly hatched fry should be fed rotifer culture 4 times a day until they are 15 days old, at a volume ratio of 3% (rotifer culture: seedling seawater) each time. From 15 to 45 days old, they should be fed artichoke culture 3 times a day, at a volume ratio of 5% (artichoke culture: seedling seawater) each time.

[0038] Comparative Example 7: Targeted Cultivation Method of Live Feed The active bait includes brine shrimp culture and rotifer culture, with the size of the brine shrimp and rotifers selected according to the size of the grouper's mouth opening. In this comparative example, no microorganisms were added during the cultivation of live feed, but the microorganisms were introduced during the fry cultivation process. Use The specific steps are as follows: Artemia were placed in seawater (salinity 32-33‰) at a density of 300 Artemia / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L. Spirulina powder 0.4 g / L, arginine 0.1 g / L, and rosary pea oil 1.5 mL / L were added and cultured for 24 h to obtain Artemia culture.

[0039] Rotifers were placed in seawater (salinity 32-33‰) at a density of 300 rotifers / mL, with dissolved oxygen in the water controlled to be no less than 5.0 mg / L. Spirulina powder 0.4 g / L, methionine 0.1 g / L, and sunflower oil 1.5 mL / L were added and cultured for 24 h to obtain rotifer culture.

[0040] The specific feeding method is as follows: Newly hatched fry should be fed rotifer culture and pink fungi of the genus *Narcote* until 15 days of age. Natrialba pink (CCTCC AB 2013111) Bacterial powder, feed 4 times a day, each time at 24 mg / L, and feed rotifer culture at a volume ratio of 3% (rotifer culture: seedling seawater); feed Artemia culture and Cryptorhizium anisopliae from 15 to 45 days old. Natrinema pellirubrum (CCTCC AB 2012854) Bacterial powder, feed 3 times a day, each time at 24mg / L of bacterial powder, and feed Artemia culture at a volume ratio of 5% (Artemia culture: seedling seawater).

[0041] The bacterial powder contains no less than 10 bacteria. 9 cfu / g.

[0042] Comparative Example 8: Conventional live bait and its feeding method Choose cod liver oil (30 mL / m 3 Feed the animal with water-fortified feed that has been fortified for 12 hours.

[0043] Before feeding newly hatched grouper larvae, add 300,000 Chlorella cells / mL to the fry rearing seawater. After the larvae begin to eat, feed them rotifers fortified with cod liver oil for 12 hours daily, maintaining a rotifer density of 5-6 cells / mL. From 15-18 days old, maintain a rotifer density of 2-3 cells / mL and an Artemia nauplius density of 2-3 cells / mL. From 19-24 days old, feed them Artemia nauplius and copepods fortified with cod liver oil for 12 hours, maintaining a density of 2-3 cells / mL respectively. From 25-30 days old, feed them copepods fortified with cod liver oil for 12 hours, maintaining a density of 5-6 cells / mL. After 30 days old, feed them adult Artemia at 3% of their body weight. The appropriate size of the rotifers, Artemia, and other live food is selected according to the size of the grouper's mouth opening.

[0044] Experimental example: Newly hatched fry were raised at a density of approximately 600 fry per cubic meter of water in small indoor nurseries (1m×1m×0.8m). Nursery conditions included: water temperature 26℃~27℃, pH 7.3~7.5, dissolved oxygen above 5mg / L, and salinity 32~33‰. After one week of fry rearing, 5% of the water was changed every two days, increasing to 10% after one week. During the rearing process, the fry were fed the appropriate bioactive feed according to the methods described in the aforementioned examples and comparative studies. Three parallel experiments were conducted per group.

[0045] During the experiment, the number of dead fry was counted daily, the survival rate was calculated, the developmental status of the live fish was observed, and growth indicators such as body length and height were recorded. The results are shown in Table 1.

[0046] Table 1

[0047] In conventional seedling raising methods, grouper fry typically metamorphose into juveniles after 40 days of age. However, this invention rapidly promotes the growth and development of grouper larvae. Observations showed that in all embodiments, the larvae entered the juvenile stage at 30 days of age, reaching a body length of 21-25 mm and a body height of 9-11 mm, exhibiting robust body shape, high vitality, and excellent quality. In contrast, the control groups either failed to enter the juvenile stage at 30 days of age or only partially metamorphosed into juveniles, and experienced a peak in mortality during metamorphosis, with significantly lower survival rates at 30 days of age (P < 0.01) compared to the embodiments.

[0048] Among them, by comparing Comparative Examples 1-5 with Example 1, it can be seen that in the targeted cultivation of bait, the ratio of Cryptorhizium anisopliae and pink bacterium of the genus Nebulae, Spirulina powder, arginine, methionine, Rosa rugosa oil, and sunflower oil, as well as their application methods, have a significant impact on the bait cultivation effect.

[0049] Comparative Example 6, which did not add *Cryptospira erythrophagus* and *Nalcanthophytum* pink bacteria during the targeted breeding process, produced live feed that was unsuitable for the development of grouper fry, with all indicators showing poor results. This demonstrates that the aforementioned microorganisms play an important role in this invention. Comparative Example 7, which did not add microorganisms during feed breeding but transferred them to the fry breeding process, also showed satisfactory results, though not ideal. However, its effect was significantly better than Comparative Example 6, indicating that the aforementioned microorganisms have a direct effect on grouper fry. It is speculated that they may have interfered with the intestinal flora of grouper, thereby affecting the growth and development of grouper.

[0050] To further test the stress resistance of the grouper fry, 30-day-old grouper fry from each example and grouper fry from each comparative example were further cultured to a similar body length and height as the examples (21-25 mm in length and 9-11 mm in height) after 30 days of age. These fry were then rapidly transferred to new nurseries (at least 200 fry per group, with three parallel trials). The water temperature and pH in the nurseries were controlled to be higher than the pre-transfer conditions to create a rapidly changing adverse environment: a water temperature of 31-32°C, a pH of 7.9-8.1 (significantly higher than pre-transfer conditions), dissolved oxygen above 5 mg / L, and a salinity of 32-33‰. Survival rates were recorded two days after transfer. The results showed that after being transferred to the mutated environment, the survival rate of each example was 88%-93%, while the survival rate of each comparative example was below 76%, with comparative example 8 having the lowest survival rate (66%). The survival rates of the comparative examples were significantly lower (P < 0.01) than those of the examples. It is evident that the active feed prepared by this method can effectively improve the stress resistance of the starling.

[0051] In summary, conventional methods typically use cod liver oil to nutritionally fortify bioactive feed. However, this invention selects other special plant oils, spirulina powder, and amino acids, and simultaneously cultivates them with microorganisms. This not only nutritionally fortifies the bioactive feed, but the fortified feed also aligns with the effects required for the growth, development, and metamorphosis of grouper fry. It effectively promotes rapid fry development and enhances their stress resistance. The microorganisms selected during feed cultivation not only promote the rapid absorption and utilization of plant extracts from the bioactive feed, but also improve the stress resistance of grouper fry during the rearing process. It is speculated that this is because the microorganisms play a role in regulating the intestinal flora structure of grouper, thereby enhancing their resistance to environmental changes.

[0052] The above description is only a partial embodiment of the technical solution of the present invention, intended to help those skilled in the art understand the core concept of the present invention, and is not an exhaustive list of all embodiments of the present invention. The scope of protection of the present invention shall be determined by the claims and their equivalents. Any equivalent substitutions, further optimizations and improvements to the technical features implemented based on the basic principles and concepts disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for targeted cultivation of live feed to enhance the stress resistance of newly hatched *Stropharia carinata* seedlings, characterized in that, The active bait includes culture of Artemia worms and culture of Rotifers; The directional cultivation of the Artemia culture includes the following steps: placing the Artemia in seawater, adding the Alginomarasmius sp Natrinema pellirubrum The Artemia culture is obtained by cultivating the Artemia with the bacterial powder, the spirulina powder, the arginine and the Salvia prionitis oil. The directional cultivation of the rotifer culture comprises the following steps: placing the rotifer in seawater, adding pink bacteria powder of Nautococcus Natrialba pink Rotifer culture is obtained by cultivating with bacteria powder, spirulina powder, methionine and sunflower oil.

2. The active bait directed breeding method according to claim 1, wherein, The inoculation density of Artemia or Rotifers in seawater is 300-400 per mL.

3. The active bait directed breeding method according to claim 1, wherein, During the directional cultivation of artemia culture, the halobacterium cryptic red base line is added in seawater Natrinema pellirubrum 0.8 ~1.0g / L of bacterial powder, 0.4~0.55g / L of spirulina powder, 0.1~0.2g / L of arginine, 1.5 ~3.0mL / L of salvia splendens oil.

4. The active bait directed breeding method of claim 1, wherein, In the directional cultivation of rotifer culture, the pink bacteria of naosphaera in seawater Natrialba pink 0.8~1.0g / L of bacteria powder, 0.4~0.55g / L of spirulina powder, 0.1~0.2g / L of methionine, and 1.5~3.0 mL / L of sunflower oil.

5. The active bait directed breeding method of claim 1, wherein, The targeted cultivation period shall not be less than 24 hours.

6. The active bait directed breeding method of claim 1, wherein, The targeted cultivation period is 24-36 hours.

7. The active bait directed breeding method of claim 1, wherein, The *Cinnamomum camphora* oil is an oil extracted from the stems and leaves of *Cinnamomum camphora*, and the *Sunflower* oil is an oil extracted from the stems and leaves of *Sunflower*. The extraction method of the oil is to weigh the dry powder of stems and leaves, add 150-300 ml of petroleum ether to every 50-100 g of dry powder of stems and leaves, reflux extract for 6-8 hours, and recover the solvent at 40-50℃ to obtain crude oil.

8. Active feed obtained by the active feed directional cultivation method according to any one of claims 1 to 7.

9. The use of the active feed according to claim 8 in improving the stress resistance of newly hatched juvenile scorpion seedlings or promoting the development of newly hatched juvenile scorpion seedlings.

10. Use according to claim 9, characterized in that, Newly hatched fry should be fed rotifer culture 4 times a day until they are 15 days old, with each feeding consisting of rotifer culture at a concentration of 3% to 5% of the seawater. From 15 to 45 days old, they should be fed artichoke culture 3 times a day, with each feeding consisting of artichoke culture at a concentration of 3% to 5% of the seawater.

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