Artemia bait preparation and feeding method for cynoglossus semilaevis larva bait transfer period

Abstract

The invention relates to the technical field of aquaculture, and discloses an artemia bait preparation and feeding method for cynoglossus semilaevis larvae in the bait transfer period, and the method comprises the following steps: constructing a basic artemia suspension; putting the artemia into an interface induction pretreatment solution containing soybean lecithin and taurine, and stirring at constant temperature under low-temperature and micro-inflation conditions, so that the artemia forms an induction adsorption layer and reaches pre-balance; then raising the temperature and adding microparticle compound feed in batches to carry out gradient competitive enhancement, so as to prepare enhanced artemia bait; and finally, carrying out collaborative feeding according to a preset strategy after cleaning. According to the method, interface induction and physiodynamic regulation are utilized, wrapping of the micropellet feed on the body surface of artemia and filling of the micropellet feed in the intestinal tract are achieved, the bait loading efficiency is remarkably improved, the problems that larvae and juveniles refer to feed and are insufficient in nutrition intake in the bait transfer period are effectively solved, the survival rate is increased, and water pollution is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aquaculture, in particular to a method for preparing and feeding Artemia as feed for juvenile Cynoglossus semilaevis during the transition period. BACKGROUND

[0002] Cynoglossus semilaevis is an important marine economic fish in China. The transition period during the process of its breeding, i.e. the period from Artemia and other biological feed to artificial compound feed, is a key period for determining the survival rate and growth quality of the seed. During this period, the digestive system of the larvae is not fully developed, and the behavior habit is strongly dependent on visual predation of moving objects. The acceptance of artificial micro-particle feed which is static and lacks specific biological odor is very low, and phenomena such as refusal to eat, uneven feeding and cannibalism are prone to occur.

[0003] In the prior art, the transition is usually carried out by directly feeding micro-particle feed or simple biological reinforcement. However, the direct feeding method is difficult to stimulate the feeding instinct of the larvae due to the lack of feeding attraction and movement stimulation of the artificial feed, resulting in a large amount of feed sinking to the bottom or suspended in the water. This not only causes waste of feed, but also causes rapid dissolution and corruption of the un-eaten feed in the water, leading to a sharp increase in ammonia nitrogen, which seriously deteriorates the water environment and causes stress death of the seed. On the other hand, the traditional biological reinforcement technology mainly relies on the non-selective filtering action of Artemia on nutritional emulsion or suspension to fill the nutritional substances in the intestinal tract of Artemia. This method has the problems of low reinforcement efficiency and short retention time of nutrients. Due to the lack of precise regulation of the physiological state of Artemia, the metabolism of Artemia is vigorous during the reinforcement process, and the ingested nutrients are easily metabolized or excreted. At the same time, simple physical mixing cannot form a stable combination layer on the surface of Artemia, and the micro-particle feed is difficult to effectively adhere, resulting in the "carrier" effect being limited to the inside of the intestinal tract, which limits the effective load of artificial compound feed per Artemia. In addition, the existing reinforcement process ignores the feeding kinetics characteristics of Artemia under different temperatures and chemical environments, and it is difficult to achieve rapid accumulation of feed particles in Artemia and stable coating on the surface of Artemia, which cannot meet the dual requirements of nutritional comprehensiveness and water quality stability of Cynoglossus semilaevis larvae during the transition period. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a method for preparing and feeding Artemia as feed for Cynoglossus semilaevis larvae during the transition period, which solves the problems of direct feeding leading to refusal to eat and water quality deterioration in the prior art of Cynoglossus semilaevis larvae transition, and the low load and poor stability of micro-particle feed caused by the lack of physiological kinetics regulation in traditional biological reinforcement.

[0005] To achieve the above purpose, the present application is implemented by the following technical scheme: a method for preparing and feeding Artemia as feed for Cynoglossus semilaevis larvae during the transition period, comprising the following steps: S1, base suspension construction: collect and clean the hatched Artemia nauplii, adjust the density, and prepare the base Artemia suspension; S2, interface-induced pre-equilibrium treatment: prepare an interface-induced pre-treatment solution containing soybean lecithin and taurine; place the base Artemia suspension in the interface-induced pre-treatment solution, and perform constant temperature stirring treatment under low temperature and micro-aeration conditions to form an induced adsorption layer on the body surface and digestive tract of the Artemia nauplii, achieving a pre-equilibrium state of physiology and interface; S3, gradient competitive reinforcement: under the condition of maintaining stirring, add micro-particle compound feed to the system after step S2 in batches, and increase the system temperature to the reinforcement temperature to perform biological coating reinforcement, thereby preparing the reinforced Artemia bait; S4, collaborative feeding: collect and clean the reinforced Artemia bait to remove residues, and then feed the reinforced Artemia bait to the C. semilaevis juvenile fish in collaboration with the micro-particle compound feed according to a preset bait switching strategy.

[0006] Preferably, the specific formulation of the interface-induced pre-treatment solution in step S2 is as follows: the concentration of soybean lecithin is 0.5-0.8 g / L, the concentration of taurine is 0.2-0.4 g / L, and the solvent is seawater with a salinity of 20%-22%.

[0007] Preferably, the low temperature and micro-aeration condition in step S2 is as follows: the temperature is controlled at 18-20℃, and the aeration amount is controlled at 0.1-0.2 L / min·L; the time of the constant temperature stirring treatment is 30-45 minutes.

[0008] Preferably, the reinforcement temperature in step S3 is controlled at 24-26℃, which is 6-8℃ higher than the low temperature in step two, so as to stimulate the feeding activity of the Artemia nauplii by using the temperature difference.

[0009] Preferably, the batch addition of the micro-particle compound feed in step S3 specifically includes: adding 30% of the total amount at the beginning of the reinforcement, adding 30% of the total amount when the reinforcement is performed to 1 / 3 of the total time, and adding the remaining 40% when the reinforcement is performed to 2 / 3 of the total time; maintaining the feed concentration gradient in the system.

[0010] Preferably, the total amount of the micro-particle compound feed added in step S3 is 1.5-2.0 times the wet weight of the Artemia nauplii, and the particle size of the micro-particle compound feed ranges from 50 to 100 μm.

[0011] Preferably, the total length of the biological coating reinforcement in step S3 is 4-6 hours, and the termination standard is that the intestinal fullness of the Artemia nauplii reaches more than 85%.

[0012] Preferably, the cleaning in step S4 removes the residues, specifically by filtering with a 120-mesh silk screen and rinsing with fresh seawater having a salinity of 28%-30% until the rinsing liquid is clear to remove unbound micro-particle compound feed and interface-induced pre-treatment liquid components.

[0013] Preferably, the preset bait switching strategy in step S4 is specifically: At 18-20 days of age of the C. semilaevis larvae, 100% of the enhanced Artemia bait is fed; At 21-22 days of age, 70% of the enhanced Artemia bait and 30% of the micro-particle compound feed are fed; At 23-24 days of age, 30% of the enhanced Artemia bait and 70% of the micro-particle compound feed are fed; At 25 days of age and later, the micro-particle compound feed is completely fed.

[0014] Preferably, during the mixed feeding stage at 21-24 days of age, the interval feeding mode is adopted, the micro-particle compound feed is first fed, and the enhanced Artemia bait is fed after an interval of 20-30 minutes.

[0015] The present application provides a method for preparing and feeding Artemia bait for C. semilaevis larvae during the bait switching period. The method has the following beneficial effects: 1. The present application discards the traditional extensive mixing, controls the temperature difference and flow field state during the pre-treatment and enhancement stages, and artificially controls the physiological rhythm of Artemia. The process control based on physiological kinetics ensures the consistency of the enhanced Artemia bait prepared in different batches in terms of nutritional uniformity and vitality, which is beneficial to large-scale production and application.

[0016] 2. The present application uses the feeding induction of taurine combined with a low-temperature environment to make Artemia in a metastable state of metabolic inhibition but appetite activation through the interface-induced pre-equilibrium treatment step; combined with the modification effect of soybean lecithin on the interface, the compensatory feeding behavior of Artemia is stimulated when the temperature is raised to enter the enhancement stage, so that the filling degree of the micro-particle feed in the intestinal tract of Artemia and the attachment amount on the body surface are significantly higher than those of the conventional direct feeding method.

[0017] 3. The present application forms an induced adsorption layer on the body surface of Artemia nauplii by using the amphiphilic characteristics of lecithin in the pre-treatment liquid; this makes the micro-particle feed not only be ingested into the intestinal tract, but also be adsorbed on the appendages and body surface of Artemia by means of interfacial tension, thereby greatly increasing the effective biomass of the unit Artemia bait for transmitting artificial compound feed to C. semilaevis larvae. DETAILED DESCRIPTION

[0018] All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts fall within the scope of protection of the present application.

[0019] Embodiment: Embodiment 1: The embodiment provides a method for preparing and feeding Artemia bait for Cynoglossus semilaevis juvenile fish during the transition period, and the specific steps are as follows: Construction of a basic suspension Collect fresh Artemia nauplii after hatching, rinse them with sterilized seawater, adjust the density of the Artemia nauplii to 2500 per mL, and obtain a basic Artemia suspension.

[0020] Interface-induced pre-equilibrium treatment Prepare an interface-induced pre-treatment solution: use seawater with a salinity of 21% as the solvent, add soybean lecithin to a concentration of 0.65 g / L, add taurine to a concentration of 0.3 g / L, and add vitamin C to a concentration of 0.075 g / L.

[0021] Place the basic Artemia suspension obtained by constructing a basic suspension in the interface-induced pre-treatment solution, control the system temperature to be constant at 19°C, turn on the micro-aeration device, set the aeration amount to 0.15 L / min·L, and set the stirring speed to 40 r / min. Under these conditions, constant temperature stirring treatment is carried out for 38 minutes to make the Artemia nauplii complete physiological and interface pre-equilibrium.

[0022] Gradient competitive reinforcement Keep the stirring state, and increase the system temperature to the reinforcement temperature of 25°C at a rate of 1°C / 10 min. Weigh the micro-particle compound feed at 1.75 times the wet weight of the Artemia nauplii, and add it in batches: When the system temperature reaches 25°C, add 30% of the total amount of feed; After 1.5 hours of reinforcement, add 30% of the total amount of feed; After 3.5 hours of reinforcement, add 40% of the total amount of feed. The total duration of the entire reinforcement process is maintained for 5 hours, and after the end, the Artemia gut fullness is observed to be more than 90% by microscopy, and the reinforced Artemia bait is prepared.

[0023] Synergistic feeding Collect the above-mentioned reinforced Artemia bait with a 120-mesh silk screen, and rinse it with fresh seawater with a salinity of 29% until the filtrate is clear.

[0024] The following transition feeding strategy is performed for 18-35 day-old Cynoglossus semilaevis juvenile fish: 18-20 days old: feed 100% of the reinforced Artemia bait, 6 times a day.

[0025] 21-22 days old: feed the reinforced Artemia bait and the micro-particle compound feed at a mass ratio of 7:3; adopt interval feeding, first feed the micro-particle feed, and then feed the reinforced Artemia after an interval of 25 minutes.

[0026] 23-24 days old: feeding with the enhanced Artemia prey and the micro-particle compound feed at a mass ratio of 3:7; keeping interval feeding.

[0027] 25 days old and later: feeding with the micro-particle compound feed completely.

[0028] Example 2: The present example provides a method for preparing and feeding Artemia prey for Cynoglossus semilaevis larvae during the weaning period, and the specific steps are as follows: Construction of the basic suspension: Collect the hatched Artemia nauplii and wash them, adjust the density to 2000 pieces / mL to obtain the basic Artemia suspension.

[0029] Interface-induced pre-equilibration treatment: Prepare the interface-induced pre-treatment solution: use seawater with a salinity of 20% as the solvent, add soybean lecithin to a concentration of 0.5 g / L, add taurine to a concentration of 0.2 g / L, and add vitamin C to a concentration of 0.05 g / L.

[0030] Place the basic Artemia suspension in the interface-induced pre-treatment solution, control the system temperature to be constant at 18°C, set the aeration amount to be 0.1 L / min·L, and set the stirring speed to be 30 r / min. Under this condition, constant temperature stirring treatment is carried out for 30 minutes to establish a preliminary induced adsorption layer.

[0031] Gradient competitive enhancement: Keep the stirring state, and raise the system temperature to the enhancement temperature of 24°C.

[0032] Take the micro-particle compound feed at 1.5 times the wet weight of the Artemia nauplii, and add it in batches: When the system temperature reaches 24°C at the beginning, add 30% of the total amount of feed; When the enhancement is carried out for 1 hour and 20 minutes, add 30% of the total amount of feed; When the enhancement is carried out for 2 hours and 40 minutes, add 40% of the total amount of feed. The total duration of the enhancement process is maintained for 4 hours to prepare the enhanced Artemia prey.

[0033] Co-feeding: Collect the enhanced Artemia prey, and rinse it with seawater with a salinity of 28% to remove residues.

[0034] The feeding strategy is the same as in Example 1, except that during the mixed feeding stage of 21-24 days old, the feeding interval time of the micro-particle compound feed and the enhanced Artemia prey is controlled to be 20 minutes.

[0035] Example 3: The embodiment provides a method for preparing and feeding Artemia bait for Cynoglossus semilaevis fry in a weaning period, and the specific steps are as follows. Construction of a basic suspension: Collect the hatched Artemia nauplii and wash them, and adjust the density to 3000 / mL to obtain a basic Artemia suspension.

[0036] Interface induction pre-equilibration treatment: Prepare an interface induction pretreatment solution: use seawater with a salinity of 22% as a solvent, add soybean lecithin to make the concentration 0.8 g / L, add taurine to make the concentration 0.4 g / L, and add vitamin C to make the concentration 0.1 g / L.

[0037] Place the basic Artemia suspension in the interface induction pretreatment solution, control the system temperature to be constant at 20℃, set the aeration amount to be 0.2 L / min·L, and set the stirring speed to be 50 r / min. Under this condition, constant temperature stirring treatment is performed for 45 minutes to form a relatively thick induced adsorption layer and fully stimulate potential appetite.

[0038] Gradient competitive reinforcement: Keep the stirring state, and raise the system temperature to the reinforcement temperature 26℃.

[0039] Take 2.0 times of the wet weight of the Artemia nauplii micro-particle compound feed, and add it in batches: When the system temperature reaches 26℃, 30% of the total amount of feed is added; After 2 hours of reinforcement, 30% of the total amount of feed is added; After 4 hours of reinforcement, 40% of the total amount of feed is added. The total time of the whole reinforcement process is maintained for 6 hours to ensure sufficient feeding and coating under high feeding rate, and the reinforced Artemia bait is prepared.

[0040] Synergistic feeding: Collect the reinforced Artemia bait, and wash it with seawater with a salinity of 30% to remove residues.

[0041] The feeding strategy is the same as that in Example 1, and in the mixed feeding stage of 21-24 days old, the feeding interval time of the micro-particle compound feed and the reinforced Artemia bait is controlled to be 30 minutes, so that the fry has more sufficient passive adaptation time.

[0042] Comparative Example 1: Compared with Example 1, the difference lies in that soybean lecithin and taurine are not added in the interface induction pretreatment solution, and only an equal volume of seawater with a salinity of 21% is used to replace them; the rest of the steps and parameters are the same as those in Example 1.

[0043] Comparative Example 2: The difference compared with Example 1 is that no soybean lecithin is added in the interface-induced pre-treatment solution, and the rest of the components and steps are the same as Example 1.

[0044] Comparative Example 3: The difference compared with Example 1 is that no taurine is added in the interface-induced pre-treatment solution, and the rest of the components and steps are the same as Example 1.

[0045] Comparative Example 4: The difference compared with Example 1 is that the interface-induced pre-equilibrium treatment is omitted, the basic Artemia suspension solution is directly heated to 25℃, and the gradient competitive reinforcement feeding operation is directly performed without low-temperature pre-equilibrium treatment; the rest are the same as Example 1.

[0046] Comparative Example 5: The difference compared with Example 1 is that the treatment temperature in the interface-induced pre-equilibrium treatment is adjusted to 25℃, that is, the interface-induced pre-equilibrium treatment and the gradient competitive reinforcement are carried out at the same reinforcement temperature, and there is no temperature gradient of low-temperature pre-equilibrium temperature reinforcement; the rest are the same as Example 1.

[0047] Comparative Example 6: The difference compared with Example 1 is that the addition method of the micro-particle compound feed in the gradient competitive reinforcement is adjusted to be added all at once at the beginning of the reinforcement, without using batch gradient addition; the rest are the same as Example 1.

[0048] Test Example 1: Evaluation of the Biological Characteristics and Loading Efficiency of Reinforced Artemia Bait Experimental Steps: Sampling: 50 mL of uniformly mixed liquid was randomly taken from the reinforced system after Step Three in Example 1 to Example 3, and Comparative Example 1 to Comparative Example 6, using a pipette, and 3 parallel groups were set for each example and comparative example.

[0049] Survival rate determination: the samples taken were placed in a glass culture dish, and the total number of Artemia in the samples was counted under a dissecting microscope and the number of dead individuals . The criterion for determining a dead individual is that the antennae and appendages stop swinging for more than 15 seconds in a stationary state. The survival rate calculation formula is: .

[0050] Full individual rate determination: 100 individuals were randomly selected from the above live samples and observed under an optical microscope. The number of individuals with micro-particle feed filling length in the intestine exceeding 80% of the total length of the intestine and micro-particle attachments on the body surface was recorded. The full individual rate calculation formula is: .

[0051] Monol load determination: The remaining enhanced artemia in each group was collected with a 120 mesh nylon screen, and rinsed with distilled water for 3 times to remove unbound free feed. The rinsed artemia was dried to constant weight in a constant temperature oven at 60°C, and the total dry weight was weighed . The total number of individuals of the dried artemia was counted at the same time . Another batch of non-enhanced nauplii artemia was taken, and the average dry weight of individual blank artemia was determined according to the same procedure . The monol load calculation formula is: .

[0052] Experimental data: Table 1: Biological indicators and monol load determination results of the enhanced artemia bait in each experimental group

[0053] Result analysis: The data in Table 1 shows that the monol load of Examples 1 to 3 is significantly higher than that of Comparative Examples 1 to 3. By comparing the data of Comparative Example 1 and Comparative Example 2, it can be seen that in the absence of soy lecithin, the monol load of artemia decreases, indicating that the presence of soy lecithin in the interface pretreatment liquid promotes the physical adsorption or adhesion of micro-particle feed on the surface of artemia, increasing the amount of bait carried other than intestinal feeding. By comparing the data of Comparative Example 1 and Comparative Example 3, the lack of taurine leads to a decrease in the full individual rate and monol load, indicating that the combination of taurine and low-temperature pretreatment conditions triggers the concentrated feeding behavior of artemia on micro-particle feed during the subsequent warming stage, improving the feeding efficiency per unit time.

[0054] By comparing the data of Comparative Example 1 and Comparative Example 4 and Comparative Example 5, artemia that has not been subjected to low-temperature pretreatment or is in a constant temperature throughout the process has lower full individual rate and survival rate than Example 1. The low-temperature pretreatment combined with subsequent warming operation used in Example 1 establishes a temperature gradient field. The data shows that the presence of this temperature gradient allows artemia to maintain a low metabolic state at low temperature, and when the temperature rises to the enhancement temperature, the change in metabolic rate matches the feeding time, thereby synchronizing the feeding behavior. Since there is no temperature change to stimulate the feeding activity of artemia under constant temperature in Comparative Example 5, the feeding activity is randomly distributed, and the full state cannot reach the high proportion of Example 1.

[0055] Comparing the data of Example 1 and Comparative Example 6, the process of adding micro-particle feed in batches is superior to adding all at once in terms of survival rate and full individual rate. In Comparative Example 6, the addition of excess micro-particle feed all at once causes the concentration of suspended particles in the water body to be too high instantaneously, exceeding the filter-feeding threshold of Artemia, which causes mechanical damage to Artemia or deterioration of the local micro-environment of the water body, resulting in a decrease in survival rate. Example 1 maintains a dynamic balance of feed concentration in the system by adding feed in batches, keeping the feed concentration within the effective filter-feeding range of Artemia, ensuring a continuous and efficient feeding and loading process.

[0056] Test Example 2: Monitoring of the Environmental Stability of the Aquaculture Water Body Experimental Steps: Monitoring Time Point Selection: The test was conducted when the C. semilaevis larvae were cultured to 22 days old. At this time, each experimental group was in the mixed feeding stage of intensive Artemia bait and micro-particle compound feed, and the feeding strategy was implemented according to the corresponding operations described in Examples 1 to 3 and Comparative Examples 1 to 6.

[0057] Feeding and Sampling: Feeding was performed at 08:00 in the morning. Before feeding, the water circulation system of the culture tank was closed to make the water body static. The bait was evenly sprayed into the culture tank according to the set feeding amount of each group. After feeding, the water was left still for 2 hours without suction or water change during this period. After 2 hours, water samples were collected at 10 cm below the water surface using a siphon, 500 mL from each culture tank, and 3 parallel sampling points were set for each group.

[0058] Ammonia Nitrogen Concentration Determination: 10 mL of water sample was taken, potassium sodium tartrate solution and Nash reagent were added for color development reaction, and after standing for 10 minutes, the absorbance was measured at 420 nm wavelength using a UV-visible spectrophotometer, and the ammonia nitrogen concentration in the water body was calculated according to the standard curve.

[0059] Water Turbidity Determination: 20 mL of water sample was placed in a sample tube and detected using a scattering turbidimeter, and the reading was recorded. The turbidity value was used to represent the content of un-ingested and suspended micro-particle feed and organic debris in the water body.

[0060] Experimental Data: Table 2: Monitoring Results of Ammonia Nitrogen Concentration and Turbidity in the Aquaculture Water Body after 2 Hours of Feeding

[0061] Result Analysis: The data in Table 2 shows that the ammonia nitrogen concentration and turbidity values of the water bodies in Examples 1 to 3 are at a relatively low level. Comparing the data of Comparative Example 1 and Comparative Example 2, after removing the soy lecithin component, the ammonia nitrogen concentration of the water body increased from 0.124 mg / L to 0.415 mg / L, and the turbidity also increased significantly. The data shows that after the intervention of soy lecithin in the pretreatment stage, an interface layer with certain binding force is formed on the surface of Artemia nauplii. This interface layer can maintain the stability of micro-particle feed adhesion on the surface of Artemia during the subsequent intensification and feeding process, reducing the shedding and loss of feed particles in the time window from feeding to being eaten by fish.

[0062] Comparing the data of Comparative Example 1 and Comparative Examples 4 and 5, the experimental groups lacking low-temperature pre-equilibration treatment or temperature gradient control have higher water pollution indicators. Example 1 establishes a competitive intensification mechanism based on the biological rhythm of organisms through pre-equilibration treatment in a low-temperature environment and subsequent temperature increase and gradient feeding. This mechanism ensures that micro-particle feed is efficiently locked in the form of intestinal filling and surface adsorption of Artemia. In contrast, due to the lack of the above kinetic control, micro-particle feed fails to form a close binding state with Artemia, resulting in a large amount of free feed directly entering the water and dissolving or suspending, causing an increase in ammonia nitrogen and turbidity.

[0063] Comparing the data of Example 1 and Comparative Example 1, Comparative Example 1 uses a direct mixing and feeding method of non-intensified Artemia and micro-particle feed, which has the highest ammonia nitrogen concentration and turbidity in the water body. This confirms that the preparation method described in Example 1 changes the form of feed entering the water by preloading micro-particle feed on the carrier of Artemia. The micro-particle feed changes from a free and scattered state to a state of being wrapped or carried by a biological carrier. This change in physical form reduces the direct contact area and contact time between feed components and water, thereby inhibiting the leaching of nutrients and the deterioration of water quality.

[0064] Test Example 3: Test of weaning effect and growth performance of C. semilaevis larvae Experimental steps: Experimental fish grouping: Select 18-day-old C. semilaevis larvae of the same batch, healthy and uniform in size as experimental subjects. The initial average length is 10.5 ± 0.5 mm. Randomly allocate the larvae to 9 groups, with 3 parallel repeats in each group, and use 300L round glass steel aquaculture tanks for each repeat, with a stocking density of 2000 individuals per tank.

[0065] Cultivation management: The experimental period is 17 days. Each group obtains feed according to the preparation method described in its corresponding example or comparative example, and strictly implements the feeding strategy specified therein. During the cultivation period, the water temperature is controlled at 23 ± 1°C, the salinity is 28%-30%, and the dissolved oxygen is maintained above 6 mg / L. The bottom is cleaned twice a day to remove residual feed and feces.

[0066] Data collection: Survival rate: At the end of the experiment, count the number of surviving fish fry remaining in each tank.

[0067] Specific growth rate: At the beginning and end of the experiment, 50 fish fry were randomly selected from each tank to measure their wet weight. ,in For final equal weight As the initial average weight, This refers to the number of days in the experiment.

[0068] Coefficient of variation in total length: At the end of the experiment, the total length of the sample fish fry was measured, and the ratio of the standard deviation to the mean was calculated. This indicator is used to characterize the uniformity of fish fry size.

[0069] Success rate of transitioning to a new diet: On day 35 of the experiment, feeding of artichokes was stopped, and only micro-particle formulated feed was given. The proportion of fry that showed obvious feeding behavior and whose abdomens were visibly filled with feed within 10 minutes of feeding was observed and counted.

[0070] Experimental data: Table 3: Statistics on growth performance and feeding effectiveness of juvenile and semi-smooth tongue sole during the feeding transition period

[0071] Results analysis: Table 3 shows that Examples 1 to 3 significantly outperformed the comparative examples in terms of survival rate and specific growth rate. Comparing the data of Example 1 with Comparative Examples 1 and 4, Example 1, through interface-induced pre-equilibrium treatment combined with a gradient competitive enhancement process, enabled the efficient uptake and adsorption of micro-particle feed by Artemia. When this Artemia loaded with highly nutritious artificial feed was preyed upon by larvae, the Artemia acted as a biological carrier, achieving passive nutrient transfer. This transfer mechanism compensated for the nutritional imbalance inherent in single-feeding of Artemia and also avoided the problem of insufficient feed intake caused by poor palatability when larvae directly ingested micro-particle feed. Comparative Example 4, lacking a pre-equilibrium step, exhibited unstable feed loading efficiency of Artemia, resulting in reduced actual nutrient input for the fry and thus a lower growth rate.

[0072] The coefficient of variation of the full length reflects the synchronicity of the population growth. The CV value of Example 1 is significantly lower than that of Comparative Example 6 and Comparative Example 1. The batch-wise gradient feeding strategy adopted in Example 1, combined with the physiological synchronicity established in the pretreatment stage, ensures the uniformity of Artemia population in the enrichment process. This homogenized feed supply allows different individual sizes of fry to obtain sufficient nutrition, reducing the cannibalism caused by excessive individual growth differences. On the contrary, due to the lack of concentration gradient control in the enrichment process of Comparative Example 6, the Artemia individuals have large differences in fullness, leading to uneven nutrition intake by fry, and further exacerbating the size differentiation and survival rate decline.

[0073] Example 1 shows a significant advantage in terms of successful weaning rate. In the preparation process, Example 1 uses soy lecithin and specific process parameters to construct an induced adsorption layer on the surface of Artemia. This structure allows micro-particles to be wrapped in the Artemia surface, and at the moment when the fry prey on Artemia, the chemical signal of the micro-particle feed is first contacted by the taste and tactile receptors of the fry. Through this accompanying feeding, the fry establishes a taste adaptation memory for micro-particle feed during the weaning period. Comparative Example 2 lacks an interfacial modification component, making it difficult for micro-particle feed to effectively adhere to the surface of Artemia. This results in the fry being unable to establish a sensory association with artificial feed while feeding on live prey, and thus showing a higher refusal rate after completely discontinuing live prey.

Claims

1. A method for preparing and feeding artemia during the transition period of juvenile and semi-smooth tongue sole, characterized in that, Includes the following steps: S1. Construction of basic suspension: Collect and wash the hatched Artemia nauplii, adjust the density, and prepare basic Artemia suspension. S2. Interface-induced preequilibrium treatment: Prepare an interface-induced pretreatment solution containing soybean lecithin and taurine; place the basic Artemia suspension in the interface-induced pretreatment solution and perform constant temperature stirring treatment under low temperature and micro-aeration conditions to form an induced adsorption layer on the surface and digestive tract of Artemia nauplii, thereby achieving a preequilibrium state of physiology and interface. S3. Gradient competitive enhancement: While maintaining stirring, micro-particle compound feed is added to the system treated in step S2 in batches, and the system temperature is raised to the enhancement temperature to carry out biological coating enhancement, thereby obtaining enhanced artichoke feed. S4. Co-feeding: Collect the enhanced brine shrimp bait and clean it to remove residues. Then, according to the preset feeding strategy, co-feed the enhanced brine shrimp bait with micro-particle compound feed to the larvae and juveniles of the tongue sole.

2. The method for preparing and feeding artichoke feed during the transition period of juvenile and semi-smooth tongue sole according to claim 1, characterized in that, The specific formulation of the interface-induced pretreatment solution in step S2 is as follows: the concentration of soybean lecithin is 0.5-0.8 g / L, the concentration of taurine is 0.2-0.4 g / L, and the solvent is seawater with a salinity of 20%-22%.

3. The method for preparing and feeding artichoke feed during the transition period of juvenile and semi-smooth tongue sole according to claim 1, characterized in that, The low temperature and micro-inflation conditions mentioned in step S2 are as follows: the temperature is controlled at 18-20℃, and the inflation volume is controlled at 0.1-0.2L / min·L; The constant temperature stirring treatment takes 30 to 45 minutes.

4. The method for preparing and feeding artemia during the transition period of juvenile and semi-smooth tongue sole according to claim 1, characterized in that, The enhanced temperature control in step S3 is 24-26°C, which is 6-8°C higher than the low temperature in step two, so as to stimulate the feeding activity of Artemia nauplii larvae by utilizing the temperature difference.

5. A method for preparing and feeding artichoke feed during the transition period of juvenile and semi-smooth tongue sole according to claim 1, characterized in that, The step S3 of adding micro-particle compound feed in batches specifically includes: Add 30% of the total amount at the beginning of the enhancement phase, add another 30% when the enhancement is 1 / 3 of the total time, and add the remaining 40% when the enhancement is 2 / 3 of the total time. Maintain the feed concentration gradient within the system.

6. A method for preparing and feeding artemia during the transition period of juvenile and semi-smooth tongue sole according to claim 1, characterized in that, The total amount of micro-particle compound feed added in step S3 is 1.5 to 2.0 times the wet weight of Artemia nauplii larvae, and the particle size range of the micro-particle compound feed is 50 to 100 μm.

7. A method for preparing and feeding artichoke feed during the transition period of juvenile and semi-smooth tongue sole according to claim 1, characterized in that, The total duration of biological encapsulation enhancement in step S3 is 4 to 6 hours, and the termination criterion is that the intestinal fullness of the Artemia nauplii reaches more than 85%.

8. A method for preparing and feeding artemia during the transition period of juvenile and semi-smooth tongue sole according to claim 1, characterized in that, The cleaning and removal of residues in step S4 specifically involves: The mixture was filtered through a 120-mesh silk screen and rinsed with fresh seawater with a salinity of 28%–30% until the rinse solution was clear, in order to remove unbound micro-particles from the compound feed and components of the interface induction pretreatment solution.

9. A method for preparing and feeding artemia during the transition period of juvenile and semi-smooth tongue sole according to claim 1, characterized in that, The preset bait-shifting strategy mentioned in step S4 is as follows: When the juvenile and fry of the tongue sole are 18 to 20 days old, feed them 100% fortified artichoke feed. At 21-22 days old, feed them 70% by weight of fortified artichoke feed and 30% by weight of micro-particle compound feed. At 23-24 days old, feed them 30% by weight of fortified artichoke feed and 70% by weight of micro-particle compound feed. From 25 days old onwards, feed only micro-particle compound feed.

10. A method for preparing and feeding artichoke feed during the transition period of juvenile and semi-smooth tongue sole according to claim 9, characterized in that, During the mixed feeding stage from 21 to 24 days of age, an intermittent feeding method is adopted. First, feed micro-particle compound feed, and then feed fortified artichoke feed after an interval of 20 to 30 minutes.

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