Cultivation method of new Fujian oyster strain with white thin shell and high meat yield

Abstract

The invention provides a method for cultivating a new strain of Fujian oysters with white thin shells and high meat yield, and belongs to the technical field of aquaculture. Class groups with white shell color, shell thickness of 0.8-1.5 mm, shell depth of more than 2cm and high meat yield are preliminarily screened as core groups; preferably selecting 10% of Fujian oyster groups with white shells, the shell thickness of 0.8-1.5 mm, the shell depth of more than 2cm and the meat percentage of more than 20% by adopting a head cutting selection method, so as to obtain a new Fujian oyster strain with white thin shells and high meat percentage; further purifying the characters of white shell color, shell thickness of 0.8-1.5 mm and high meat yield in a family breeding mode to form a second-generation breeding family; and finally, a new strain with stable characters is obtained through several generations of continuous purification. The new strain of the Fujian oysters with white shells, thin shells and high meat yield has the advantages of stable inheritance, high meat yield, extremely high commodity value and the like, and has huge popularization and breeding prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for breeding oysters, in particular to a method for breeding a new strain of Fujian oysters with white shells, thin shells and high meat yield, and belongs to the technical field of aquaculture. BACKGROUND

[0002] Oysters are one of the most recognized marine delicacies in the world. Since artificial breeding of Fujian oysters began, there has been a lack of systematic and effective breeding work. The parent oysters used for breeding are from wild populations that have not undergone genetic improvement. In particular, the genetic background and quality of the parent oysters bred by most breeding farms have not been selected, often leading to a decrease in genetic diversity and degradation of germplasm. In recent years, this has been highlighted by the frequent mass mortality of farmed oysters, as well as the economic traits of small size, irregular shell shape, low meat yield, and poor appearance. The thickness of the oyster shell also severely affects the meat yield and growth rate of oysters, hindering the sustainable development of the oyster farming industry.

[0003] To overcome the difficulties of high quantity and low efficiency in the oyster farming industry, it is imperative to improve the quality of oyster products. The core problem and key issue is to breed a new oyster strain with an attractive shell shape, thin shell, soft body, and good quality. SUMMARY

[0004] To address the lack of new oyster strains, particularly those with regular shell shape, thin shell, and high meat yield, the present application aims to provide a method for breeding a new strain of Fujian oysters with white shells and high meat yield. This method is designed to breed new oyster strains with good quality and attractive shell shape to meet market demand, improve the quality and appearance of farmed oysters, and enhance the quality of Fujian oysters, thereby addressing the shortcomings of existing technologies.

[0005] The present application takes into account the differences in shell thickness among different production areas of Fujian oysters, as well as the biological characteristics of shell thickness polymorphism in the same production area. According to the principle of negative correlation between shell thickness and meat yield, thinner shells have lower weight, and under the same soft body weight, they have higher meat yield. By selecting different shell thicknesses from different production areas, combined with the height of meat yield and the shell color, and through continuous multi-generation selection, a new strain of Fujian oysters with white shells and high meat yield is bred to overcome the lack of existing technologies.

[0006] To achieve the above-mentioned objectives, the specific technical solutions adopted by the present application are as follows: A method for breeding a new strain of Fujian oysters with white shells and high meat yield, comprising the following steps: a. Initial selection: First, from the population of 1-year-old Fujian oysters, select thin-shelled oysters with white shell color and shell thickness of 0.8-1.5 mm, and high meat yield of more than 20% as the core population, and breed them after self-reproduction; b. Secondary selection: the selected core population in step a is used as the base population, and the thin shell with white shell color, shell thickness of 0.8-1.5 mm, and high meat yield of more than 20% is selected from the population by using the truncated selection method to obtain the preferred population; c. Self-breeding and one-to-one fertilization: the preferred population in step b is used as the breeding population, and the offspring is cultured according to the conventional artificial breeding method of oysters to obtain a new strain F1 with white shell color, thin shell thickness of 0.8-1.5 mm, and high meat yield of more than 20%; d. Evaluation and selection of F1 using white thin shell thickness and meat yield: the selected individuals from F1 are used to select 10% of the individuals in the population by using the truncated selection method, and the individuals with white shell color, thin shell thickness of 0.8-1.5 mm, and meat yield of more than 20% are calculated to obtain the parent oysters to produce F2 generation by using the conventional artificial breeding method of oysters; e. Directional purification of new strain of white thin shell oyster: the selected individuals F1 in step d are used as the parents to produce offspring F2, and 5-10% of the oyster individuals with meat yield of more than 30% are selected as the parents to repeat the steps b, c, and d for several times. Through multiple generations of continuous selection, a new strain of oyster with white shell color, thin shell thickness of 0.8-1.5 mm, and high meat yield of more than 20% is obtained.

[0007] Further, in the above steps, the shell height, shell length, shell width, and shell thickness are measured, the average value of the left and right shell thicknesses is measured by using an electronic vernier caliper, and the meat yield is determined by using the percentage ratio of the weight of the soft body to the total weight of the oyster (including the sum of the shell weight and the soft body weight).

[0008] Further, in steps c, d, and e, the specific method for culturing the offspring according to the conventional artificial breeding method of oysters is as follows: the D-type larvae are cultured at a density of 5-6 individuals / ml, and the density is gradually reduced as the larvae grow, to 2-3 individuals / ml; the water is changed twice a day, and the water is changed by 20%-30% each time, and the water is increased to 80%-100% after the larvae attach; the D-type larvae are fed with chrysophyta, and the daily feeding amount is gradually increased from 10-20 thousand cells / ml at the initial stage to 30-40 thousand cells / ml at the middle stage, and 50-60 thousand cells / ml at the later stage; the larvae are fed with platymonas sp. after the shell tip is added, and the daily feeding amount is 10-20 thousand cells / ml; the larvae are fed with microalga nannochloropsis sp. during the cultivation period, the water temperature is 25-28°C, and the cultivation from D-type larvae to creeping larvae takes 16-18 days; the larvae are collected by attaching to the base when the larvae grow to a shell length of 320-350 um, and 60-80% of the larvae have eye spots; the base is a comb shell, and the amount of the base is 5000 pieces / m 3, the average amount of seedling per piece is 15-20, that is, the seedling requirement is reached, the oyster seed grows to about 1-2mm in shell length, and each selected line is marked and moved to the sea area for cultivation; during the cultivation of the larvae, the density of the larvae of each group of selected lines is kept the same, the feeding amount and water exchange rate are consistent, and the cultivation conditions are the same; the cultivation containers and instruments of each group of selected lines are used separately to avoid mixing.

[0009] In the above step e, the shell thickness and meat yield rate evaluation is carried out by establishing full half-cell families through nested design, and the genetic forces of the shell color white, shell thickness 0.8-1.5mm, and meat yield rate higher than 20% of Fujian oyster shell thickness, shell height, shell length, shell width, total weight, shell weight, and meat weight parameters are evaluated by two-factor system grouping variance and covariance analysis.

[0010] Compared with the prior art, the advantages and beneficial effects of the present application are: According to the stable genetic characteristics of the white shell thickness of Fujian oyster, the genetic mechanism of the shell type and the shell thickness is utilized, and through the technical means of primary screening, secondary selection, optimal group self-reproduction, and directional purification, the synergistic selection of quantitative traits and economic traits is realized, and through the technical means of shell thickness, shell depth index, and meat yield rate evaluation analysis, the new strain of Fujian oyster with shell thickness of 0.8-1.5mm, shell color white, shell depth of more than 2cm, and meat yield rate of more than 20% can be obtained, which provides the possibility for the cultivation of new varieties.

[0011] The new strain of Fujian oyster cultivated by the present application has a shell thickness of 0.5-1.0mm less than that of ordinary Fujian oyster, a meat yield rate higher than 20%, a meat yield rate higher than that of ordinary Fujian oyster by more than 30%, and has the advantages of stable heredity, high commodity value, and the like, and has a huge prospect for popularization and cultivation. DETAILED DESCRIPTION

[0012] The present application is further explained and described below through specific embodiments.

[0013] Example 1: 20000 wild Fujian oysters in coastal waters of Fujian are selected.

[0014] a, primary screening: first, from the 1-year-old population of wild and cultivated Fujian oysters, the groups with shell color white, shell thickness of 0.8-1.5mm, shell shape cup type, oyster cup depth of more than 2cm, and meat yield rate higher than 20% are selected as the core population for self-reproduction and cultivation; b, secondary selection: take the core group with shell thickness of 0.8-1.5 mm, shell color white, shell shape cup type, oyster cup depth more than 2 cm, and meat yield higher than 20% as the basic group, and use the truncated selection method to select 10% of the group with shell thickness of 0.8-1.5 mm, shell color white, shell shape cup type, oyster cup depth more than 2 cm, fast growth rate, and meat yield higher than 20% as the preferred group; c, self-breeding and one-to-one fertilization: take the preferred group in step b as the breeding group, and use the conventional artificial breeding method of oysters to breed the offspring, to obtain a new strain F1 with shell color white, shell thickness of 0.8-1.5 mm, shell shape cup type, oyster cup depth more than 2 cm, and high meat yield; d, evaluation and selection of F1 using shell thickness, shell depth index and shell convexity index: from the F1 selected, 2000 individuals are selected from 10% of the group using the truncated selection method, and the shell thickness, shell height (SH), shell length (HL), and shell width (SW) are measured, the shell depth index is determined using the SW / (SH+SL+SW) x 100 ratio percentage, and the meat yield is determined using the ratio percentage of the weight of the oyster soft body to the total weight of the oyster (including the sum of the shell weight and the soft body weight), and the individuals with shell depth index above 20% and meat yield above 20% are selected as parent oysters to breed F2 generation.

[0015] e, directional purification of new strain of thin-shelled high-meat-yield Fujian oysters: take the white thin-shelled Fujian oyster new strain F1 with shell depth more than 2 cm in steps c and d as the parent, and use the inbred strain F2 of the selected group with shell color white, shell thickness of 0.8-1.5 mm, and shell shape depth more than 2 cm in step d as the material, and select 5-10% of the Fujian oysters with fullness degree above 30% as the parent, and then breed the offspring and more than 50 sibling lines, and repeat steps b, c, and d several times, to obtain a new strain of Fujian oysters with shell color white, shell thickness of 0.8-1.5 mm, oyster shell depth more than 2 cm, and high meat yield.

[0016] Example 2:

[0017] The white thin-shelled Fujian oyster new strain with shell thickness of 0.8-1.5 mm obtained in Example 1 is normally bred, and after 10 months, part of it is measured for various indicators and compared with the ordinary Fujian oyster variety at 10 months of age, and part of it is normally bred.

[0018] 1. Shell thickness: 50 randomly selected 10-month-old shell thickness 0.8-1.5mm, cup-shaped Fujian oyster new strain obtained by seed production of example 1, 50 randomly selected ordinary 10-month-old Fujian oyster varieties were measured and recorded. According to the results, the average shell thickness of the white thin shell Fujian oyster new strain of example 1 was more than 20% less than that of ordinary Fujian oyster, and the shell weight was more than 30% less.

[0019] 2. Meat yield: as above, the oyster soft body was taken out. According to the results, the average weight of the soft body of the white thin shell Fujian oyster new strain of example 1 was 20-30% higher than that of ordinary Fujian oyster.

[0020] Example 1 cultivated white shell thickness 0.8-1.5mm Fujian oyster new strain oyster cup depth increased by more than 15% compared with ordinary Fujian oyster, and the meat yield also increased by more than 30%.

[0021] The above examples are only to illustrate the technical concept and characteristics of the present application, and cannot limit the protection scope of the present application. Any equivalent transformation or modification made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A method for breeding a new line of white thin-shelled, high-meat-yield Fujian oyster, characterized in that, The breeding method comprises the following steps: a. Primary screening: first, from the population of 1-year-old oysters in Fujian, oysters with white shell color, shell thickness of 0.8-1.5 mm, and meat yield higher than 20% are selected as the core population for self-breeding and growing; b. Secondary optimization: the selected core population in step a is used as the basic population, and the top 10% of the population with white shell color, shell thickness of 0.8-1.5 mm, and meat yield higher than 20% is selected as the optimized population by using the truncated selection method; c. Self-breeding of the optimized population and one-to-one fertilization: the optimized population in step b is used as the breeding population, and the offspring is bred according to the conventional artificial breeding method of oysters to obtain new strain F1 with white shell color, shell thickness of 0.8-1.5 mm, and meat yield higher than 20%; d. Evaluation and selection of F1 using white shell thickness and meat yield: from the selected F1, the top 10% of the population is selected by using the truncated selection method, and the individuals with white shell color, shell thickness of 0.8-1.5 mm, and meat yield higher than 20% are calculated as the parent oysters for conventional artificial breeding of oysters to produce F2; e. Directional purification of new strain of white shell oysters in Fujian: the selected individuals F1 in step d are used as the parents for self-breeding to produce offspring F2, and the top 5-10% of the oysters with meat yield higher than 30% are selected as the parents for self-breeding and sibling family breeding, and steps b, c, and d are repeated for several times, so that the new strain of oysters in Fujian with white shell color, shell thickness of 0.8-1.5 mm, and meat yield higher than 20% can be obtained through multi-generation continuous selection.

2. The breeding method according to claim 1, wherein In the above steps, the shell height, shell length, shell width, and shell thickness are measured, the average value of the left and right shell thicknesses at the middle position is measured by using an electronic vernier caliper, and the meat yield is determined by using the ratio of the weight of the soft body to the total weight of the oyster (including the sum of the shell weight and the soft body weight).

3. The breeding method according to claim 1, wherein The specific method for cultivating the offspring in steps c, d and e is as follows: the D-type larvae are cultivated at a density of 5-6 larvae per milliliter, and the density is gradually reduced as the larvae grow, until the density of the creeping larvae is reduced to 2-3 larvae per milliliter; the water is changed twice a day, and each time 20%-30% of the water is changed, and after the larvae attach, the water is changed to 80%-100%; the D-type larvae are fed with golden algae, and the daily feeding amount is gradually increased from 10-20 thousand cells per milliliter at the beginning to 30-40 thousand cells per milliliter at the middle stage, and 50-60 thousand cells per milliliter at the later stage, and the flat algae is added after the larvae develop to the late shell top stage, and the daily feeding amount is 10-20 thousand cells per milliliter; the Nannochloropsis oculata can be appropriately fed during the cultivation of the larvae, the water temperature during the cultivation of the larvae is 25-28°C, and it takes 16-18 days to cultivate the D-type larvae to the creeping larvae; when the larvae grow to a shell length of 320-350 um, and 60-80% of the larvae have eye spots, the larvae are collected by placing the attachment base; the attachment base is a comb shell, and the amount of the attachment base placed is 5,000 pieces per square meter 3 , and the average amount of the larvae collected from each piece is 15-20, i.e., the requirement for collecting the larvae is met, the oyster larvae grow to a shell length of 1-2 mm, the selected lines are marked, and are moved to the sea area for cultivation; during the cultivation of the larvae, the density of the larvae of each group of selected lines is kept the same, the feeding amount and the water change rate are consistent, and the cultivation conditions are the same; the cultivation containers and tools of each group of selected lines are used separately to avoid mixing.

4. The breeding method according to claim 1, wherein In step e, the shell thickness and meat yield evaluation are performed by establishing full and half sibling families through nested design, and the genetic force of the shell color, shell thickness, shell height, shell length, shell width, total weight, shell weight, and meat weight of the oysters with white shell color, shell thickness of 0.8-1.5 mm, and meat yield higher than 20% is evaluated by using two-factor system grouping variance and covariance analysis.