Method for efficiently promoting chlamys farreri larva attachment and metamorphosis through noradrenaline

Abstract

The invention belongs to the field of shellfish culture, and particularly relates to a method for efficiently promoting chlamys farreri larva attachment and metamorphosis through noradrenaline. Aiming at the problem of low attachment and metamorphosis rate in the current chlamys farreri breeding process, the invention provides the method for efficiently promoting the attachment and metamorphosis of the chlamys farreri larvae by using the chemical inducer noradrenaline, and a technical support is provided for improving the attachment and metamorphosis rate in the chlamys farreri seedling production process.

Description

Technical Field

[0001] This invention belongs to the field of shellfish aquaculture, specifically relating to a method for efficiently promoting the attachment and metamorphosis of scallop larvae using norepinephrine. Background Technology

[0002] The scallop (Scallop spp.) belongs to the phylum Mollusca, class Bivalvia, and is an important farmed shellfish in my country with extremely high economic value. However, the large-scale production of scallop seedlings has long been constrained by high mortality rates caused by the incomplete metamorphosis of larvae. Scallop larvae enter the attachome stage after developing into eyespot larvae. During this stage, the larvae shed their vesicles and develop a foot and secondary shell. However, due to unexplained reasons, delayed metamorphosis and eventual death of scallop larvae are common, with mortality rates reaching over 80%. Therefore, improving the metamorphosis rate of scallop larvae is crucial for ensuring the large-scale production of scallop seedlings. To date, however, no method has been found to solve the problem of low metamorphosis rates in scallop larvae.

[0003] Metamorphosis in bivalve larvae can be induced by a variety of factors. For example, studies on metamorphosis in Pacific oysters have shown that when the larvae are in a suitable environment, they secrete norepinephrine, activating the morphogenesis pathway. In species such as the purple mussel, norepinephrine has been shown to promote larval recognition of attachment substrates. Experiments on bivalve clams such as bay scallops and mud clams have also confirmed that norepinephrine... + Ca 2+ Metal cations have a significant inducing effect on bivalve larvae, but there are currently no studies on the use of norepinephrine to induce metamorphosis in scallop larvae. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for increasing the metamorphosis rate of scallop larvae using norepinephrine. When the number of eye-spot larvae in the scallop reaches 60%, the larvae are collected to a density five times that of the normal culture system, and then... -2 Norepinephrine solution was used to induce larvae of the comb-shaped scallop for 3-12 hours.

[0005] Furthermore, the induction time is 6 hours.

[0006] The present invention also provides a scallop larva inducer, comprising norepinephrine.

[0007] The present invention has the following beneficial effects:

[0008] Adding norepinephrine to the aquaculture water effectively increases the attachment metamorphosis rate of the scallop. When the eyespot larvae of the scallop reach 60%, use 10 -2A mmol / L norepinephrine solution induced larvae five times more than those in the normal culture system for 6 hours, resulting in an attachment metamorphosis rate as high as 83.33%, which was 56.25% higher than the control on average. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 Effects of norepinephrine treatment on metamorphosis of scallop larvae; C: control group; N: norepinephrine group. Detailed Implementation

[0011] Various exemplary embodiments of the present invention are now described in detail. Unless otherwise specified, the methods used in the embodiments are conventional methods, and the reagents used are commercially available reagents or reagents prepared using conventional methods. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and embodiments of the present invention.

[0012] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0013] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0014] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0015] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0016] Induction experiments were conducted at the Laizhou Seedling Farm in Yantai in April 2025. Using 10... -2 Norepinephrine at mmol / L was used to induce 6 hours of treatment in scallop larvae with an eyepoint larvae ratio of 60%, including the following steps:

[0017] 1. Experimental materials:

[0018] 1.1 Scallop larvae:

[0019] Scallop larvae with an eye spot larvae ratio of 60% were selected from the seedling farm in Laizhou City, Yantai in April 2025.

[0020] 1.2 Inducing reagent:

[0021] The norepinephrine used in this experiment was purchased from Shanghai Aladdin Company.

[0022] 2. Experimental methods:

[0023] 2.1 Preparation of norepinephrine solution: Prepare a 1 mmol / L stock solution of norepinephrine using clean seawater, and then dilute it to 10 mmol / L. -2 Working solution concentration: mmol / L. All solutions should be prepared fresh for each experiment.

[0024] 2.2 Induction of *Ctenopharynx scallop* larvae: *Ctenopharynx scallop* larvae with an eyepoint larval ratio of 60% were collected using 260-mesh silk and induced in the working solution of step (1) for 6 hours. Simultaneously, ordinary *Ctenopharynx scallop* larvae without norepinephrine induction solution were set as a control group, with three replicates in each group. The larval induction density was 20-25 larvae / ml, which is 5 times the larval density of the ordinary culture system. No feeding or water changes were performed during the induction period.

[0025] 2.3 Cultivation of *Scallop* larvae after induction; The larvae treated in step (2) were collected using a sieve, rinsed three times with filtered seawater, and placed in clean filtered seawater for continued aeration and cultivation. The larval density was 4-5 larvae / ml. After 1 hour of induced larval recovery, the larvae were introduced into the substrate. The culture feed was *Isochrysis galbana*, fed four times a day. The culture temperature was 19-20℃, and the water was changed twice a day, half of it each time.

[0026] 2.4 Observation Records: Eight days after the induction treatment, the larvae completed their attachment metamorphosis. The number of larvae attached to the top and bottom of the attachment substrate in each group was counted, and the final metamorphosis rate was calculated. Metamorphosis rate = (Number of metamorphosed individuals / Total number of individuals) × 100%.

[0027] 3. Results:

[0028] The results are shown in Table 1 and... Figure 1 As shown.

[0029] Table 1. Effects of norepinephrine treatment on metamorphosis of scallop larvae.

[0030]

[0031] According to the data from the embodiment, using 10 -2 Norepinephrine at mmol / L significantly increased the metamorphosis rate of scallop larvae in the experimental groups, with the highest metamorphosis rate reaching 83.33%, demonstrating a highly significant metamorphosis induction effect.

[0032] This invention selects norepinephrine, an important neurotransmitter for metamorphosis regulation, as a metamorphosis inducer. The induction is highly efficient and simple to operate. Furthermore, the use of a 1 / 5 normal culture volume further reduces costs. The optimal norepinephrine solution treatment conditions established in this invention can increase the metamorphosis rate of *Scallop scallop* larvae by an average of 56.25%, significantly higher than the control group. This method can be applied in large-scale production, reducing the problem of mass mortality of *Scallop scallop* larvae due to failure to complete the metamorphosis process, and improving the metamorphosis rate of *Scallop scallop scallop* larvae. This provides a stable and efficient metamorphosis induction scheme for the large-scale breeding of *Scallop scallop* seedlings, which is of great significance for improving seedling production efficiency.

[0033] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for increasing the metamorphosis rate of scallop larvae using norepinephrine, characterized in that, When the number of eye spot larvae in the scallop reaches 60%, collect the larvae to a density 5 times that of the normal culture system, and use 10 -2 Norepinephrine solution was used to induce larvae of the comb-shaped scallop for 3-12 hours, and the larvae were cultured normally after the induction was completed.

2. The method according to claim 1, characterized in that, When the number of eyedrop larvae reaches 60%, inducement treatment is performed.

3. The method according to claim 1, characterized in that, The larval density during induction was 5 times that of the ordinary culture system.

4. The method according to claim 1, characterized in that, The induction time is 6 hours.

5. A scallop larvae inducer, characterized in that, Including norepinephrine.

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