KR101350373B1 - Composition comprising a stem bark extracts of albizzia julibrissin for inhibiting gonadal maturation in fishes - Google Patents

Abstract

The present invention relates to a gonad maturation inhibiting composition of fish comprising the bark extract of Albizzia julibrissin . The bark extract according to the present invention is safe for consumers as well as fish derived from natural plants, and can effectively inhibit the maturation of the gonads of fish, which is useful for mass production or aquaculture of fish.

Description

Gonad maturation inhibitory composition of fish comprising the extract of the silk tree {COMPOSITION COMPRISING A STEM BARK EXTRACTS OF ALBIZZIA JULIBRISSIN FOR INHIBITING GONADAL MATURATION IN FISHES}

The present invention relates to a gonad maturation inhibiting composition comprising a silk tree extract.

The fish farming industry in Korea has increased continuously along with industrial development, and the production of aquaculture has increased 3.5 times from about 26 thousand tons in 2000 to about 90 thousand tons in 2006, accounting for about 40% of the total domestic fishery production. Has grown into an important food industry (Ministry of Maritime Affairs and Fisheries, 2008). In particular, the flounder, which occupies the world's No. 1 aquaculture production, produced about 43 thousand tons in 2006, accounting for about 50% of Korea's total fish production. However, due to quantitative increases, the competitiveness of fish farming has been declining year by year due to deterioration of the breeding environment, disease outbreaks, rising farming costs, and import of cheap live fish from abroad. To this end, the government has focused on the development of four key technologies, such as the development of formulated feed, breeding, vaccine development and improvement of breeding facilities, as a way to enhance aquaculture competitiveness at the national level.

However, the rapid increase in production since 2001 has led to oversupply, which has resulted in a drop in fish prices, an increase in aquaculture costs, and a slowdown in production, which has led to an urgent need to strengthen competitiveness and take measures to solve this problem. In order to strengthen the competitiveness due to oversupply, it suggests the establishment of a production system that can control the supply and demand of farmed flounder to maintain a reasonable price, the production of high-quality flounder, and the development of growth promotion technology to reduce the cost of farming (Ministry of Maritime Affairs & Fisheries, 2006) . Promoting growth in fish farming is an important task for increasing productivity as well as reducing farming costs. Marine fish, including flounder, are generally faster to grow than females, and males tend to be sexually mature before they reach product size, so farming only females improves production and produces a constant size. Many techniques have been developed to raise only females because they can be increased (review in Piferrer, 2001; Hendry et al., 2003).

In the case of flounder, which is the most aquaculture in Korea, females are sexually matured from 2 years of age, and thus the gonads develop. As a result, energy consumption and stamina decrease, and survival rate drops sharply from 2 years. It has been farmed annually to produce flounder less than 1kg. Therefore, the price competitiveness is inevitably worsened because a large number of products of a certain size are shipped.

Since most fish consume about 20% of the energy used for gonad maturation, infertility of females uses the energy used for reproductive activity for metabolism and growth, which can increase female survival and promote growth. There was a suggestion. On this basis, a method of producing infertile triploid fish has been proposed (Qinet al., 1998; Felipe et al., 1999; Davis at al., 2004; Cal et al., 2006). In these studies, infertile triploid females have suppressed gonad development and show higher growth rates of more than 14% after 2 years compared to normal diploid fish (Cal et al., 2006), but their immunological and physiological functions are normal. The mortality rate is higher than that of fish and it is not applied to aquaculture in recent years due to consumer's perception problem (Budi ㆁ o et al., 2006; Gao et al., 2007). In addition, research has been conducted on the production of fish modified with growth hormone genes to promote growth (Maclean and Talwar, 1984; Du et al., 1992; Delvin et al., 1994; Kim et al., 2007; Zang et al., 2007), too, have not been industrialized due to the issue of consumer safety and avoidance of GMOs.

On the other hand, a great deal of research has been conducted on the promotion of gonad maturation, from basic physiological studies to industrial applications. However, the research on gonad inhibition has only basic physiological studies on some fishes, and there is no research on developing a gonad inhibitor or related research to increase productivity by using it in industry.

The present invention has been made to solve the problems described above, it is an object to provide a composition that can be safely applied to the fish as a natural extract, while having an effective gonad inhibition effect that can effectively suppress the maturation of the gonads of the fish .

In order to achieve the above object, the present invention provides a gonad inhibiting composition comprising a bark extract.

The bark extract according to the present invention can suppress the development and maturation of the germ cells of the fish and thus can be effectively used for mass production or culture of fish.

Figure 1 is a schematic of the extraction process of the bark extract bark according to the present invention.
Figure 2 is a photograph of the larvae ( O.latipes ) used to test the gonad inhibition effect of the bark extract according to the present invention.
Figure 3 is a photograph of the killing device used in the experiment of the present invention.
4 is a photograph of a 1m X 1m X 0.7m goldfish circulation filtration tank used in the experiment of the present invention.
Figure 5 is a photograph of the histological development state of the calf and ovary of 0.9cm in length three months after hatching.
FIG. 6 shows that the silk bark extract according to the present invention is fed with the silk bark extract by adding 10 mg, 20 mg and 40 mg to 1 g of feed, respectively, at 45 and 97 days after breeding. Comparing maturation status, the change in gonadosomatic index (GSI) is shown as a bar (control: untreated silk bark extract).
7 is added to the feed according to the concentration of bark extract according to the present invention (control: untreated, 10 mg / g-feed, 20 mg / g-feed and 40 mg / g-feed) to feed the immature pine Thus, 45 and 97 days after breeding, changes in histological patterns of the gonads of the larvae were shown.
8 is added to the feed according to the concentration of bark extract according to the present invention (control: untreated, 10 mg / g-feed, 20 mg / g-feed and 40 mg / g-feed) to feed the mature pine fish Every 15 days, the scattered amount (average value) of the killifish is examined and graphed.
Figure 9 is added to the feed according to the concentration of bark extract according to the present invention (control: untreated, 10 mg / g-feed and 20 mg / g-feed) to feed the mature goldfish, gonads of female Changes in weight index (Gonadosomatic index, GSI) are shown as a bar.
Figure 10 is a photograph of the tissue state of the goldfish ovary immediately before the start of the breeding experiment according to the present invention (March 16, 2010).
Figure 11 shows the change of ovarian tissue when feeding the goldfish by adding the bark extract according to the present invention to the feed by concentration (control: untreated, 10 mg / g-feed and 20 mg / g-feed) It is shown.
Figure 12 is the liver weight index of females when feeding the goldfish by adding the bark extract according to the present invention to the feed by concentration (control: untreated, 10 mg / g-feed and 20 mg / g-feed) (Hepatosoatic index, HSI) shows the comparison of the bar.
Figure 13 shows the change in ovarian tissue when feeding the goldfish by adding the bark extract according to the present invention to the feed by concentration (control: untreated, 10 mg / g-feed and 20 mg / g-feed) It is shown.
14 is added to the feed of the bark extract according to the present invention by concentration (control: untreated, 10 mg / g-feed, 20 mg / g-feed and 40 mg / g-feed) to feed the immature pine fish As a result, on the 97th day, the degree of obesity of the ferns was compared with a bar.
15 is added to the feed by the concentration of bark extract according to the present invention (control: untreated, 10 mg / g-feed, 20 mg / g-feed and 40 mg / g-feed) to feed the goldfish On the 90th day, the goldfish's obesity degree is compared with a bar.
Figure 16 is added to the feed of the barberry extract according to the present invention by concentration (control: untreated, 10 mg / g-feed, 20 mg / g-feed and 40 mg / g-feed) to feed the larvae Day 127 shows changes in survival rate of females.
FIG. 17 shows the survival rate of females at 90 days after feeding to goldfish by adding the bark extract according to the present invention to the feed by concentration (control: untreated, 10 mg / g-feed and 20 mg / g-feed) It is shown.
Figure 18 shows the change in EROD activity of liver tissue after 60 days of breeding feed to the goldfish feed supplemented with silkworm bark extract according to the present invention 10mg per 20g feed each to goldfish.

The inventors of the present invention have been searching for and studying a natural material that effectively inhibits gonad maturation of fish without causing adverse effects on the body of fish and consumers' body, while the bark extract of the present invention effectively controls the gonad maturation system of fish. It was confirmed to show activity (see Experimental Examples 1 to 3).

Accordingly, the present invention provides a gonad maturation inhibiting composition of fish comprising the bark extract.

Hereinafter, the present invention will be described in more detail.

The 'Prune bark extract' of the present invention is obtained by treating the bark bark with an extraction solvent. As the extraction solvent, a solvent selected from lower alcohols such as water, ethanol and methanol, or a mixed solvent thereof can be used. The active ingredient of the bark tree bark can be extracted at room temperature or warmed under the conditions that are not destroyed or minimized, and the extraction method is, for example, cold extraction, ultrasonic extraction, reflux cooling extraction, hot water extraction, supercritical extraction, and the like. Can be extracted using. The extract also includes an extract obtained by an extraction treatment, a diluent or concentrate of the extract, a dried product obtained by drying the extract, or these modifiers or purified products. According to the embodiment of the present invention, the bark of the silk tree can be used by purchasing a commercially available haphwanpi. The purchased Hwanhwanpi may be dried and then made into a powder to extract the bark extract according to the present invention. More specifically, water was added to the powdered silk tree bark sample and extracted several times at about 60 to 80 ° C. for about 3 to 5 hours. The extract was loaded on Diaion HP 20 to attach the active ingredient, followed by 60% methanol and then fractionated with 80% methanol, which was then dried and powdered to obtain a silk tree bark extract according to the present invention (see FIG. 1). .

The gonad inhibiting composition of the fish of the present invention refers to a composition having an effect of inhibiting the development of the gonad of fish, specifically, in addition to inhibiting the maturation of oocytes in the early stages of maturation of immature female fish, For fish, this includes inhibiting the oocytes from forming egg yolks and, in the case of fish after maturation, reducing egg production. In the present invention, the degree of maturation of the gonads was evaluated by histological examination of the gonads and by measuring the gonadosomatic index (GSI).

As described above, the female fish matures and the gonad develops, and the survival rate decreases rapidly after a certain time due to the energy consumption and stamina of the gonad, so the flounder is usually only grown for 1 to 1.5 years. Since only fish are produced, there is a problem that only a certain size of goods are shipped in bulk. In order to solve the above problems, the present invention provides a bark bark extract having the effect of inhibiting the maturation of the gonads to increase the survival rate of female fish as well as preventing excessive energy from being consumed in the gonad development.

In order to explore whether the silkworm bark extract exhibits the inhibitory effect of the gonad development as described above, the extract according to the present invention was mixed with the feed while feeding the fish and goldfish for a certain period of time. After breeding for a period of time, randomly collected killifish or goldfish were examined to determine the gonad development status, the change of the spawning sheep and the liver tissue of female fish. In addition, the experiment was performed on each of immature fish, mature fish, mature fish in order to determine the gonad development inhibitory effect of the bark extract of the present invention at each stage of the development of fish (Experimental Examples 1 to 3) Reference)

As a result of the experiment, the bark extract according to the present invention has little toxicity to fish (see Experiment 6), and effectively inhibits gonad maturation of fish without adversely affecting the growth of fish (see Experiment 4). Found that More specifically, immature fish delayed the development and maturation of germ cells, decreased maturity in mature fish, and suppressed oocytes in the ovary in mature fish. Therefore, the bark extract of the present invention is useful for suppressing gonad maturation of fish and thus can be used for efficient farming of fish.

The silk tree bark extract of the present invention may be provided in the form of adsorbed or mixed with the feed so that the fish can be ingested with the feed or the like, or may constitute a feed composition of the fish. At this time, the feed composition comprising the extract of the bark may be prepared in a formulation that is commercially available as a feed of fish in general. In the case of the feed composition, the amount of the bark extract according to the present invention in the feed may be 1 to 5% by weight of the total feed weight. However, the present invention is not limited thereto, and the dietary amount of the feed composition may vary depending on the weight, health condition, size, etc. of the fish, and can be easily determined by those skilled in the art.

In addition, the composition comprising the bark extract of the present invention may be used for the purpose of maintaining long-term survival of fish. As described above, the development of the gonads tends to reduce the survival rate of female fish. Since the bark extract of the present invention inhibits the development of the reproductive system, female fish delays the deterioration of stamina due to spawning and the like, and consequently prolongs the survival of the female.

Hereinafter, the present invention will be described in detail with reference to the following Examples and Experimental Examples. However, the following examples and experimental examples are illustrative of the present invention, and the content of the present invention is not limited by the following examples and experimental examples.

Preparation Example 1 Preparation of Silk Tree Bark Extract

As for the bark of Albizzia julibrissin ., The bark of the bark (Synthesis bark) from Wonkwangdang was used as a medicinal herb. The authenticity of the herb was confirmed by the Oriental Medical University. The samples were dried to form a powder, and then 10 l of water was added to the powder (3.0 kg), and extracted three times at 65 ° C. for 4 hours. Water extracts for medicinal herbs containing functional substances were loaded on a column filled with Diaion HP 20, the active ingredients were attached to the column, 60% methanol was poured out, and the active ingredient was extracted and separated with 80% methanol ( See FIG. 1). The separated crude extracts were concentrated and dried and then refrigerated until subjected to experiments on gonad maturation inhibition. In the following experiment, the gonad maturation inhibitory effect was examined using the bark extract prepared as described above.

<Test fish and breeding of fish>

1. Experimental fish

The general mechanism of gonad maturation and degeneration of fish is the same for both freshwater and marine fish, and has a characteristic period of spawning periods throughout the year. The fish used in this study was purchased from Oryzias latipes , developed by Carolina TM Science & Math, USA from the Institute of Chemical Safety and Safety, so that the maturity and spawning during the year is raised when the water temperature is 28 ℃ and photoperiod 15L9D.

Goldfish were also used at the Southern Institute of National Fisheries Research and Development for experiments on gonad maturation of more than two years.

2. Breeding of Fish

Songsari was equipped with a glass tank of 45cmL × 36cmH × 30cmW as shown in Figure 3 and accommodated 10 to 50 by the type of experiment, all tanks were kept constant at 25 ℃. The photoperiod was adjusted to 15L9D, and the feed was fed twice a day to Tetra feed to 10% of body weight. Drug extracts selected to search for gonad inhibitors were adsorbed to feed in a certain amount and used in experiments.

Goldfish purchased on March 2 at the National Institute of Fisheries Science, Southern Internal Water Research Institute, has an average weight of 35.03 ± 2.35g and a body length of 12.94 ± 0.49cm. Three experiments were set up by receiving 30 males and females randomly in a circulating 0.7 Ton water tank. The experimental group was a 10mg / g-feed experimental group to which 10mg of silkworm bark extract of Preparation Example 1 was added per 1g of feed, a 20mg / g-feed experimental group to which 20mg of silkworm bark extract of Preparation Example 1 was added to 1g of feed, and feed A 40 mg / g-feed experiment was added to 40 g of the silkworm bark extract of Preparation Example 1 per g, and the control extract was not added to the silkworm bark extract of Preparation Example 1.

Experimental Example 1 Inhibition of Gonad Development of Immature Fishes

In the immature state, the bark extract of Preparation Example 1 was added to the feed, and the experiment was carried out using immature larvae 3 months after hatching to investigate the effects on germ cell formation and development. . As shown in FIG. 5, the size of the calendula and the state of development of the gonad at the start of the experiment were 1.0 ± 0.3 cm in average length. In histological examination of the gonads, most of the gonads could not be cut, so the GSI could not be measured. In addition, the gonads of the immature pine larvae were hardly distinguished from each other in appearance, and after fixing the whole pine larvae for 24 hours in a Bouin's solution, the sections were successively sectioned to a thickness of 5 to 6 μm by a paraffin sectioning method. Tissue specimens were double stained with hematoxylin and eosin to examine the development of the tissues. As a result, the oocytes of the gonads had oocytes of early maturation, which consist mostly of the oocytes of the periphery. 10 mg / g-feed experiment, 20 mg / g-feed experiment and 40 mg / g-feed experiment with 10 mg, 20 mg and 40 mg of the bark extract of Preparation Example 1 per 1 g of feed, respectively Separated, the breeding was 120 days while feeding twice a day to be 10% of the body weight of the experiment. On the 45th and 97th day after breeding, a part of the larvae were raised and histologically examined for GSI and gonad. The investigation results are shown in FIGS. 6 and 7. In addition, the time at which spawning began to occur and the average amount of scattering are as shown in Table 1 below.

As a result, 45 days after breeding, GSI showed high value before and after 4 in control and 10 mg / g-feed, whereas GSI was around 1 in 20 mg / g-feed and 40 mg / g-feed. Low values were observed. Histological examination also showed mature oocytes and mature oocytes in the control and 10 mg / g-feed groups, but in the 20 mg / g-feed and 40 mg / g-feed groups, It consisted of. However, at the 97th day, the GSI was increased around 6 even in the 20 mg / g-feed experiment and mature oocytes were contained in the female ovary. However, the 40 mg / g-feed group was still composed of the most popular oocytes. In the 40 mg / g-feed group, by the 127th day of breeding, they were in the same maturity as the control group. The start of spawning in each experimental group was found to be 46 days, 87 days, and 107 days in the 10 mg / g-feed, 20 mg / g-feed and 40 mg / g-feed groups, respectively. From this, it can be seen that the development and maturation of germ cells are delayed as the amount of the bark extract of Preparation Example 1 increases.

Changes in Mean Daily Scattering Amounts During Emergence and Period of Initial Laying Individuals According to Saponin Contents in Feeding Immature Young Ferns Feeding Saponins Control 10 mg / g-feed 20 mg / g-feed 40mg / g-feed Rearing days 46 46 87 107 No. of spawning eggs / day / individual 14.5 20.0 13.2 6.2

Experimental Example 2 Inhibition of Gonad Maturation in Mature Fishes

In order to investigate the maturation control effect of the bark extract of Preparation Example 1 on the mature female scorpion, the change of laying hens was examined in the scorpion with the average weight of 0.44g and the body length of 3.62cm, which the gonads are continuously spawning. Observed. The fern was equipped with a glass tank of 45 cmL × 36 cmH × 30 cmW and housed 10 females and 5 males in one tank, and all tanks were kept constant at 25 ° C. The photoperiod was adjusted to 15L9D, and the feed was fed twice a day to Tetra feed to 10% of body weight. In order to investigate the gonad inhibitory effect, the bark extract of Preparation Example 1 was adsorbed to the feed in a constant amount for each experimental group and used in the experiment. The spawning amount was examined every day, and the average value was calculated from the amount of one-day spawning for 15 consecutive days. The results are shown in Fig.

As a result, there was no difference in daily egg production between 9.8 ± 1.5 and 8.9 ± 0.5 in the control and 10 mg / g-feed groups. However, in the 20 mg / g-feed and 40 mg / g-feed experiments, the daily spawning doses were 4.7 ± 1.1 and 1.2 ± 0.3, respectively, and the overall spawning volume was decreased. From these results, it can be seen that when the silk tree bark extract of Preparation Example 1 is added in an amount of 20 mg or more per feed, it has an inhibitory effect on the gonads of fish.

Experimental Example 3 Gonad Maturation Inhibition of Mature Fish

  The average GSI of goldfish at the start of March 16 breeding experiment was 8.52 ± 0.56% (see Fig. 9), and histological features of the ovary were almost the same as those of the oocyte-forming oocytes from the surrounding popular oocytes as shown in Fig. 10. It was composed of oocytes of various maturity levels, including mature oocytes. After one month (April 16), the GSI of the control group was 11.36 ± 1.49%, which was not significant but slightly increased, but there was little change in the GSI in the 10 mg / g-feed and 20 mg / g-feed groups. As shown in FIG. 12, even in the histological aspect, the control group was composed almost entirely of oocytes, but in the 10 mg / g-feed and 20 mg / g-feed experiments, the oocytes were more mature than a month ago. The incidence of oocytes increased, but the frequency of oocytes in yolk formation was higher than that of the control. Two months later (May 17), the control GSI was 12.40 ± 1.71%, which was not significant, but slightly elevated, with ovary and mature eggs with scattered traces and mature oocytes for subsequent spawning. Most of them had ovaries composed of blast cells. However, GSI levels were significantly lower in the 10 mg / g-feed and 20 mg / g-feed groups (3.28 ± 1.12% and 5.24 ± 0.80%). Most of them consisted of oocytes of the most popular. Three months later, on June 16, the control group had a GSI of 7.81 ± 1.21%, which was not significantly lower than last month, but histological examination of the ovary consisted of mature oocytes and mature oocytes. The gonads were maintaining maturity. However, in the 10 mg / g-feed and 20 mg / g-feed groups, the GSI was 3.18 ± 0.83% and 3.19 ± 0.67%, which was significantly lower than the control group. In the experimental group, oocytes of the most popular and meiosis cells were composed. In the 20mg / g-feed experiment, some oocytes that remained unscattered were sometimes seen, but most of them were composed of oocytes of meiosis electricity. It was in a state of rest.

Experimental Example 4 Effect on Fish Growth

Investigation of changes in body weight, body weight and obesity from the test specimens to clarify whether addition of silkworm bark extract of Preparation Example 1 to the feed to feed inhibit the growth of the gonads and inhibit the growth. It was. The degree of obesity for a fish is shown in Figure 14, the degree of obesity for goldfish is shown in Figure 15.

Changes in obesity in each experimental section were observed in Immature female larvae for 97 days with 10 mg, 20 mg and 40 mg of bark extract of Preparation Example 1 per gram of feed. The g-feed experimental group showed significantly higher change in obesity in each experimental group than the other experimental groups. This result is because the gonad development was lower in the 20mg / g-feed and 40mg / g-feed groups than in the control and 10mg / g-feed groups.

  In the case of goldfish, as shown in Figure 15, the change in obesity degree of the experimental section of the female according to the concentration of the silkworm bark extract of Preparation Example 1 is added per feed, but the silkworm bark extract was added as compared to the control The experimental group fed the feed showed a slightly higher value.

Experimental Example 5 Effect on Survival Rate

While feeding the feed supplemented with silkworm bark extract of Preparation Example 1, the larvae were bred for 97 days and goldfish for 90 days, and the survival rate of the larvae according to the concentration of the silkworm bark extract of Preparation Example 1 was changed in FIG. The survival rate of the goldfish is shown in FIG. 17. All of the larvae survived over 95% and the goldfish showed 100% survival rate during the experiment, indicating that there was no harmful effect by the extract of bark of Preparation Example 1.

Experimental Example 6 Stability of Fish Fractions

    In order to determine whether the extracted fractions were added to the feed and were safe when fed to fish, the toxic effects of EROD (ethoxyresorufin O-de-ethylase) were measured and liver toxicity was investigated. Addison et al. (1994) was used to obtain microsomes from the samples of liver of a fern, and EROD was measured by Addison and Payne (1986). EROD activity was measured at 544 nm excitation and 590 nm emission with a fluorescence plate reader, repeated three times for each sample, and the average value was used. As a result, as shown in Figure 18, there was no significant difference in the activity of the EROD in each experimental section, there seems to be no hepatotoxicity by the bark extract prepared according to the present invention.

As discussed above, the bark extract of the present invention can be seen that the gonads of fish inhibit the differentiation and maturation. In addition, it is safe for fish in the diet and no significant change in the liver weight index or liver tissue pattern due to the diet of the extract according to the present invention, it can be seen that it is also suitable for the diet of fish. Therefore, the bark extract according to the present invention, which exhibits the effect of inhibiting gonad development of fish, can be applied to the field of fish farming for reducing the spawning amount of fish and maintaining the survival period.

references

Addison, R.F., Payne, J.F., 1986. Assessment of hepatic mixed function oxidase induction in winter flounder (Pseudopleuronectes americanus) as a marine petroleum pollution monitoring technique, with an Appendix describing practical field measurements of MFO activity. Canadian Technical Report of Fisheries and Aquatic Science 1505.

Addison, R.F., Willis, D.E., Zinck, M.E., 1994. Liver microsomal monooxygenase induction in winter flounder (Pseudopleuronectes americanus) from a gradient of sediment PAH concentrations at Sydney Harbour, NSW. Marine Environmental Research 37, 283 ??. 296.

Arai, K., 2001. Genetic Improvement of Aquaculture Finfish Species by Chromosome Manipulation Techniques in Japan. Aquaculture 197, 205-228.

Biswas, A., Kundu, S., Roy, S., De, J., Pramanik, M., Ray, A.K., 2006. Thyroid Hormone Profile during Annual Reproductive Cycle of Diploid and Triploid Catfish, Heteropneustes Fossilis (Bloch). General and Comparative Endocrinology 147, 126-132.

Budi ㆁ o, B., Cal, R.M., Piazzon, M.C., Lamas, J., 2006.The Activity of several Components of the Innate Immune System in Diploid and Triploid Turbot. Comparative Biochemistry and Physiology-Part A: Molecular & Integrative Physiology 145, 108-113.

Cal, RM, Vidal, S., G ㆃ mez, C., ㅑ lvarez-Bl ㅱ zquez, B., Mart ㅽ nez, P., Piferrer, F., 2006.Growth and Gonadal Development in Diploid and Triploid Turbot (Scophthalmus Maximus). Aquaculture 251, 99-108.

Davis, K. B., Ludwig, G. M., 2004. Hormonal Effects on Sex Differentiation and Growth in Sunshine Bass Morone chrysops ㅧ Morone Saxatilis. Aquaculture 231, 587-596.

Delvin, R. H., T. Y. Yesaki, C. A. Blagl and E.M. Donaldson. 1994. Extraordinary salmon growth. Nature. 371: 209-210.

Du, S.J., Z. Gong, G.L. Fletcher, M.A. Shears, M.J. King, D.R. Idler and C.L. Hew. 1992. Growth enhancement in transgenic Atlantic salmon by the use of an "all fish" chimeric growth hormone gene construct. Bio / technology, 10: 176-181.

Felip, A., Zanuy, S., Carrillo, M., Piferrer, F., 1999. Growth and Gonadal Development in Triploid Sea Bass (Dicentrarchus Labrax L.) during the First Two Years of Age. Aquaculture 173, 389-399.

Flynn, S.R., Benfey, T.J., 2007. Effects of Dietary Estradiol-17β in Juvenile Shortnose Sturgeon, Acipenser Brevirostrum, Lesueur. Aquaculture 270, 405-412.

Gao, Z., Wang, W., Abbas, K., Zhou, X., Yang, Y., Diana, JS, Wang, H., Wang, H., Li, Y., Sun, Y., 2007 Haematological Characterization of Loach Misgurnus Anguillicaudatus: Comparison among Diploid, Triploid and Tetraploid Specimens. Comparative Biochemistry and Physiology-Part A: Molecular & Integrative Physiology 147, 1001-1008.

Gomelsky, B., 2003. Chromosome Set Manipulation and Sex Control in Common Carp: A Review. Aquatic Living Resources 16, 408-415.

Hendry, C.I., Martin-Robichaud, D.J., Benfey, T.J., 2003. Hormonal Sex Reversal of Atlantic Halibut (Hippoglossus Hippoglossus L.). Aquaculture 219, 769-781.

Hong, W., Zhang, Q., 2003. Review of Captive Bred Species and Fry Production of Marine Fish in China. Aquaculture 227, 305-318.

Hyndman, C.A., Kieffer, J.D., Benfey, T.J., 2003. Physiology and Survival of Triploid Brook Trout Following Exhaustive Exercise in Warm Water. Aquaculture 221, 629-643.

Jung, J. H., Shim, W. J., Addison, R. F., Han, C. H., 2006. Protein and gene expression of VTG in response to 4-nonylphenol in rockfish (Sebastes schlegeli). Comparative Biochemistry and Physiology Part C 143, 162 ?? 170.

Kim, M., Lim, H., Ahn, SJ, Jeong, Y., Kim, CG, Lee, HH, 2007.Enhanced Expression of EGFP Gene in CHSE-214 Cells by an ARS Element from Mud Loach (Misgurnus Mizolepis) . Plasmid 58, 228-239.

Kishi, K., Kitagawa, E., Onikura, N., Nakamura, A., Iwahashi, H., 2006. Expression Analysis of Sex-Specific and 17β-Estradiol-Responsive Genes in the Japanese Medaka, Oryzias Latipes, using Oligonucleotide Microarrays. Genomics 88, 241-251.

Ling, E.N., Cotter, D., 2003. Statistical Power in Comparative Aquaculture Studies. Aquaculture 224, 159-168.

Luckenbach, J.A., Godwin, J., Daniels, H.V., Borski, R.J., 2003. Gonadal Differentiation and Effects of Temperature on Sex Determination in Southern Flounder (Paralichthys Lethostigma). Aquaculture, 216, 315-327.

Maclean, N. and S. Talwar. 1984. Injection of cloned genes into rainbow trout eggs. J. Embryol. Exp. Morphol. 82: 187.

Nam, Y.K., Kim, D.S., 2004. Ploidy Status of Progeny from the Crosses between Tetraploid Males and Diploid Females in Mud Loach (Misgurnus Mizolepis). Aquaculture 236, 575-582.

Nam, Y.K., Park, I., Kim, D.S., 2004. Triploid Hybridization of Fast-Growing Transgenic Mud Loach Misgurnus Mizolepis Male to Cyprinid Loach Misgurnus Anguillicaudatus Female: The First Performance Study on Growth and Reproduction of Transgenic Polyploid Hybrid Fish. Aquaculture 231, 559-572.

Peruzzi, S., Varsamos, S., Chatain, B., Fauvel, C., Menu, B., Falgui ㅸ re, J., S ㅹ v ㅸ re, A., Flik, G., 2005. Haematological and Physiological Characteristics of Diploid and Triploid Sea Bass, Dicentrarchus Labrax L. Aquaculture 244, 359-367.

Piferrer, F., 2001. Endocrine Sex Control Strategies for the Feminization of Teleost Fish. Aquaculture 197, 229-281.

Qin, J.G., Fast, A.W., Ako, H., 1998. Growout Performance of Diploid and Triploid Chinese Catfish Clarias Fuscus. Aquaculture 166, 247-258.

Simpson, M.G., Walker, P., Helm, A., Leah, R., 2002. Histopathological Observations on Liver, Kidney and Gonad of Plaice (Pleuronectes Platessa) Taken from the Mersey Estuary. Marine Environmental Research, 54, 543-546.

Svobodov ㅱ, Z., Flajshans, M., Kol ㅱ rov ㅱ, J., Modr ㅱ, H., Svoboda, M., Vajcov ㅱ, V., 2001. Leukocyte Profiles of Diploid and Triploid Tench, Tinca Tinca L. Aquaculture 198, 159-168.

Withler, R.E., Clarke, W.C., Blackburn, J., Baker, I., 1998. Effect of Triploidy on Growth and Survival of Pre-Smolt and Post-Smolt Coho Salmon (Oncorhynchus Kisutch). Aquaculture 168, 413-422.

Zang, X., Liu, B., Liu, S., Sun, P., Zhang, X., Zhang, X., 2007. Transformation and Expression of Paralichthys Olivaceus Growth Hormone cDNA in Synechocystis Sp. PCC6803. Aquaculture 266, 63-69.

Claims (9)

Composition for inhibiting gonad development of fish comprising the bark extract as an active ingredient. The composition of claim 1, wherein the bark extract is obtained by extracting with methanol. The composition of claim 1, wherein the composition delays maturation of the germ cells of the fish.  The composition of claim 1, wherein the composition inhibits germ cells of fish from forming egg yolk. The composition of claim 1, wherein the composition maintains blood steroid hormone concentrations lower than fish that are not dietary. The composition of claim 1, wherein the composition extends the survival of the fish. The composition of claim 1, wherein the composition is a feed composition of a fish. 8. The composition of claim 7, wherein the silk tree bark extract comprises 0.01 to 10% by weight relative to the total feed composition. The composition for inhibiting gonad development of fish according to any one of claims 1 to 8, wherein the composition is a feed composition for fish.

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