KR102351106B1 - Eel Juvenile Cultivating Method Using Feed Containing Crab Shell - Google Patents

Abstract

The present invention relates to fish, particularly eels, which can improve the growth rate and survival rate by feeding a feed containing shell powder to young eels at the juvenile stage and edible eels at the adult stage. It relates to the training method of
The method of cultivating eel fry feeding the crab shell-containing feed of the present invention increases the growth rate of body length and weight of eels, increases the non-essential amino acid content of the fish body, and strengthens immunity, compared to the aquaculture method feeding general powder feed. It has a high survival rate without the use of a separate antibiotic, excellent feed efficiency, and can increase the economic feasibility of eel farming by simply crushing and recycling the discarded crab shell aquatic by-products. And minerals are added to the powdered feed, so a high-efficiency feed that combines nutrients and minerals can be supplied to eels at low cost.

Description

Eel Juvenile Cultivating Method Using Feed Containing Crab Shell

The present invention relates to fish that can improve the growth rate and survival rate by feeding a feed containing shell powder to young eels in the juvenile (未成魚) stage and edible eels in the adult stage (未成魚), particularly eels It relates to the training method of

Eel is a catadromous fish that grows in freshwater and matures, descends to the sea to spawn and reproduce. Compared to other fish species, it contains abundant protein, fat, minerals, vitamins, etc., and the level of non-essential amino acids is lower than that of mackerel. It is much higher than that, so it is very popular as a nourishing food for the purpose of nourishing and rejuvenating.

As the demand for eels gradually increases due to income increase and health concerns, the proportion of eels in inland water culture is increasing. Although eels are mainly used, the number of eels coming up to the river is decreasing every year due to environmental pollution, habitat destruction, and reckless harvesting.

In addition, the mortality rate during the aquaculture period from eel to edible eel is an important variable in the business viability of eel farming, and various infectious diseases such as bacterial and parasitic diseases occur due to mass-dense aquaculture, making it difficult for eel farmers. This is being aggravated.

To solve this problem, it is necessary to improve the growth rate and survival rate by improving the eel feed and aquaculture method. Currently, the eel feed is about 70% fish meal, 25% alpha starch, and a small amount of additives (vitamins, minerals, etc.) 5 It is distributed in the form of powdered feed mixed by %, and water is added to the powdered feed and fed in the form of a dough. However, conventional powdered feed has a high degree of kneading and elasticity depending on the type and mixing ratio of fish meal and alpha starch. There is a difference, and depending on these differences, not only palatability but also the amount of empty feed is affected. If the amount of empty feed is large, water quality deteriorates as well as productivity and economic efficiency.

In addition, antibiotics are added to feed or added to the water of aquaculture tanks for the purpose of exterminating various pathogenic bacteria, but they are not effective against infectious diseases caused by pathogens such as viruses or some parasites. The side effect of increasing the accumulation of antibiotics in the human body according to the food chain occurs, and the use of antibiotics also acts as a cause of water pollution.

In addition, the profitability of eel breeding is further worsening due to the recent decrease in the harvesting amount of thread eels and a surge in feed costs due to the increase in the price of fishmeal and starch. Development of aquaculture feed for eels is required.

As such, freshwater eels containing fish oil extracted from silkworm pupae, propolis, vegetable dietary sulfur, squid fermented extract extracted by salting and fermenting squid tenderloin, fish oil extracted from shark roe and distilled water. Aquaculture feed (Korean Patent Publication No. 1568467), shark roe, fish meal, water-soluble fish meal, soybean concentrate powder, vitamin mix, and liquid extract for eels mixed with liquid extract (Korean Patent Publication No. 1514457), squid A powdered feed for freshwater eel eel (Korean Patent Publication No. 1568465) is proposed in which soft meat meal, fish roe content extracted from mullet roe, vitamins, krill extract, soy protein, and shark yolk powder are mixed.

The above inventions provide an effect of improving the growth rate and survival rate of eel farming by using propolis, dietary sulfur, etc. useful for strengthening the immunity of eels such as eels, squid, shark roe, mullet roe, squid, krill, etc. useful for the growth of eels However, these materials are formulated for freshly hatched eels of eels and are not satisfactory in economic terms because they are expensive compared to fish meal, alpha starch, and additives (vitamins, minerals, etc.) There are disadvantages.

Accordingly, Korea Patent Publication No. 1302299 contains fish meal (40-50%), krill meal, wheat flour, fermented soybean meal, fish oil, soybean oil, squid liver powder, corn gluten, and additives (seupinuinje) for breeding after eel fry. EP feed for eels has been proposed, which reduces the fish meal content compared to conventional powdered feed and does not use alpha starch. It can be improved, and the feeding lubricating agent (TMG, DMPT, IMP, GMP, MSG) promotes the eel's feed intake and improves the digestibility, so it provides an effect that can be applied immediately without an adaptation period when switching to EP feed.

However, since fish meal or alpha starch substitute materials contained in feed for breeding after frying eels are not cheap compared to these, the economic benefit is not great. There is a disadvantage in that eels are always exposed to pathogenic bacteria and viral diseases due to a lack of ingredients that increase immunity against various infectious diseases.

The present invention is to solve the above problem, and it is a method of cultivating eels that can improve the growth rate and survival rate while reducing costs compared to the conventional aquaculture method of feeding powdered feed until the young eels (juveniles) become adults. is to provide

In order to solve the above problems, the present invention administers the microorganisms of the genus Bacillus to a circulation filtration system at a concentration of 1 to 5 mg/kg/day based on the number of breeding in the breeding tank, and the breeding water is fed at a rate of 10 to 15 rotations/day circulating; stocking eels weighing 4-7 g in a circulating filtration system at 25-32 ° C. to which the microorganisms are administered; Feeding powder feed to the stocked eels for 2 to 4 days; Contains crab shell powder consisting of 5 to 12% by weight of crab shell powder, 60 to 70% by weight of fish meal, 20 to 25% by weight of alpha starch, 1 to 5% by weight of vitamins and minerals, and 1 to 5% by weight of maltodextrin preparing a powdered feed; and feeding the powdered feed containing the crab shell powder in an amount of 2 to 5% by weight/day of the total weight of the fish body throughout the young eel growth stage and the edible eel growth stage after feeding the powdered feed; containing, crab shells Provided is a method for breeding eel fry using a feed containing feed.

In this case, the circulation filtration system includes a breeding tank for accommodating eels, a filtration tank for receiving breeding water contained in the breeding tank to remove foreign substances from the breeding water, a pump for circulating and transporting breeding water from the filtration tank to the breeding tank, breeding It is preferable to include a heater for maintaining a constant temperature of the water and a level switch for maintaining a constant water level in the filtration tank.

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In addition, the crab shell powder is preferably a powder obtained by grinding at least one crustacean shell selected from the group consisting of red snow crab, snow crab, blue crab, shrimp and crayfish into 40 to 200 mesh.

The method of cultivating eel fry feeding the crab shell-containing feed of the present invention increases the growth rate of body length and weight of eels, increases the non-essential amino acid content of the fish body, and strengthens immunity, compared to the aquaculture method feeding general powder feed. Even without the use of antibiotics, the survival rate is high, the feed efficiency is excellent, and the aquaculture by-products of crab shells that are discarded are simply crushed and recycled, so the economic feasibility of eel farming can be improved.

In addition, various organic and mineral components as well as chitin and chitosan contained in crab shells are added to powdered feed, so a high-efficiency feed that combines nutrients and minerals can be supplied to eels at low cost.

1 to 7 are graphs showing experimental results on the weight, body length, survival rate, weight gain, feed efficiency, instantaneous growth rate, and protein efficiency in feed of eels for each feeding period of a feed containing 10% by weight of crab shell.
8 to 14 are graphs showing experimental results on the weight, body length, survival rate, weight gain, feed efficiency, instantaneous growth rate, and protein efficiency in feed of eels by crab shell content.
15 to 21 are powder feed, feed containing 10% by weight of crab skin, chitin and chitosan feed, and comparative experimental results for eel weight, body length, survival rate, weight gain, feed efficiency, instantaneous growth rate, and protein efficiency in feed is a graph showing
22 is a graph showing the mortality rate of eels for each period of supply of a feed containing 10 wt% of crab shells.
23 is a graph showing the mortality rate of eels by crab shell content.
24 is a graph showing a comparison experiment with mortality rates of eels supplied with powdered feed, 10% by weight of crab shell feed, chitin and chitosan feed.

Eels can be classified into eel (white porcelain), black eel (black eel), young eel (chiman), and edible eel (only adult) depending on the growth stage. We provide a method for cultivating eels that improves the growth rate and survival rate of eels while reducing feed costs by adding crab shell powder, a by-product of aquaculture, to the feed fed during the eel growth stage.

Crab is one of the aquatic invertebrates, and there are various types of it depending on the habitat. Crab is a representative food using crab. Soy sauce crab is fermented in soy sauce. It is cooked in a variety of cooking methods.

However, the edible parts of the crab are the flesh or intestines, and the crab shells (back shells and leg shells) excluding them are hard and are discarded as waste without ingestion. Most of them are disposed of in landfills and other methods.

Crab shells are rich in chitin and chitosan, which have the effect of strengthening the immunity of fish, fatty acids such as EPA (eicosapentaenoic acid), amino acids represented by light protein, and minerals such as calcium, which can increase the growth rate of eels. However, since the organic matter content is low, most of them adversely affect body growth when fed as feed for general fish.

Accordingly, the crab shell by-products can be converted into chitin and chitosan and fed as feed for fish, but for this purpose, the crab shells have to undergo alkali treatment, hydrolysis, etc., which does not satisfy economic feasibility.

However, eels have high activity of chitinase that can break down chitin and collagenase that can break down hard proteins, so they have the ability to digest and decompose crab shells. Therefore, in the present invention, crab shell powder is fed in the eel growth stage and edible eel growth stage, when the eel's chitinase and collagenase activity reaches a level that can sufficiently digest the crab shell.

For the breeding of eels, feed is fed to the breeding tank in which the eels are housed, and the breeding water from the breeding tank is transferred to a filtration tank, and foreign substances are filtered and removed. And, the circulation filtration system includes a heater for maintaining a constant water temperature and a level switch for maintaining a constant water level in the filtration tank, and the breeding water in the breeding tank may be transferred to the filtration tank by a fall. This system has the advantage of reducing the failure of the pump due to foreign substances because the pump transports the breeding water from which foreign substances have been removed.

Since the eel accommodated in the circulation filtration system is a young eel stage, the water temperature of the breeding water is maintained at 25 ℃ or more, preferably 28 ℃ or more, and the higher the breeding water temperature, the faster the growth, but in consideration of the cost of maintaining the temperature. It is appropriate to keep the temperature below 32°C, preferably below 30°C.

Since the circulation filtration system reuses breeding water, the amount of supplementation for breeding water is small, and since the heated water is continuously purified and used, it has the advantage of requiring less energy to maintain the water temperature. Feed that is easily dissolved in breeding water and the feed released in breeding water deteriorates the water quality as it circulates through the system.

In order to solve this problem, a high-efficiency water purification device must be installed in the filtration tank, but installation costs are high, so a method for purifying water quality at a low cost is required. ( Bacillus sp.) It is preferable to add microorganisms.

The microorganisms of the genus Bacillus produce enzymes, decompose waste, and inhibit the growth of pathogenic bacteria to improve the water quality of breeding water and remove odors, while growing in the intestines of eels, improving the feed efficiency of eels, and improving the immune system and overall stress It also helps to increase the growth rate and survival rate of eels by improving resistance.

During the breeding period, the microorganisms of the genus Bacillus are administered at a concentration of 1-5 mg/kg daily based on the breeding water contained in the breeding tank, the breeding water is circulated at a rate of 10-15 rotations/day, and the dissolved oxygen is maintained at 6-9 ppm. It is preferable and the breeding water is supplemented by the amount lost during filtration and the amount naturally evaporated, but an appropriate amount may be changed depending on the water quality.

Feeding starts when the weight of the young eels is 4~7 g, stocking the young eels in the circulation filtration system, feeding the powdered feed for 2~4 days, and then removing the crab shells with 40~200 mesh. Finely ground powder is mixed with powdered feed to prepare crab shell powder to contain 5 to 12% by weight of the feed, and then feed.

The crab shell powder can be used not only with crab shells but also with crustacean shells, for example, red snow crab, snow crab, blue crab, shrimp, crayfish, etc. shell parts can be used, and one or two of them can be used. A mixture of the above can also be used.

If the content of crab shell powder is less than 5% by weight, the body length and weight can have an effect proportional to the content of the crab shell powder, but it is difficult to expect improvement in survival rate due to the insignificant strengthening of immunity against pathogenic microorganisms. It is undesirable because it cannot be absorbed by the eel because it exceeds the eel's chitin, chitosan, and light protein decomposition ability, but rather deteriorates the water quality.

It is appropriate to feed feed once a day, and feed at 2-5 wt%/day of the total weight of the eels housed in the breeding tank.

The powder feed currently uses most of the feed used as dough feed for eels, and thus the prepared crab shell-containing feed is about 5 to 12 wt% of crab shell powder, 60 to 70 wt% of fish meal, and 20 to 25 wt% of alpha starch. %, and 1 to 5% by weight of additives of vitamins and minerals.

The crab shell-containing feed is fed by kneading it in water. In order to prevent the dough from easily dissolving in water, 1 to 5% by weight of maltodextrin may be added, and since maltodextrin has viscosity in contact with water, use crab shell-containing feed. It prevents the deterioration of water quality caused by feed containing crab shells by making them agglomerate.

However, since the supply of maltodextrin tends to decrease the growth and survival rate of the eels, it is desirable to use the minimum amount within the range where the water quality is normally managed.

The crab shell-containing feed of the present invention is effective in increasing the body length and weight of eels compared to general powdered feed, and increases the survival rate by strengthening immunity, and increases the content of non-essential amino acids contained in the eel. Compared to the conventional powdered feed, the feed efficiency is excellent, and since the discarded crab shells are simply crushed and recycled, the economic feasibility of eel farming can be improved.

In addition, various organic and mineral components as well as chitin and chitosan contained in crab shells are added to the powdered feed, so there is an advantage in that it is possible to supply eels with a high-efficiency feed that combines nutrients and minerals at low cost.

Hereinafter, the present invention will be described in more detail based on the following examples.

However, the following examples are only for illustrating the present invention, and the present invention is not limited by the following examples, and can be substituted and changed to other equivalent examples without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in the art to which the present invention pertains.

<Example>

1. Breeding eel fry

1) Water tank installation

Two 600 liter filtration tanks and three 250 liter breeding tanks are set as a set, and a water pump, a level switch, and a heating electric heater (1 kW) are installed here, and the breeding tank is located higher than the filtration tank The breeding water filtered in the filtration tank was installed in the filtration tank and transferred to the breeding tank by the water pump, and then circulated back to the filtering tank by a natural fall (circulation filtration system).

In addition, using an electric heater, the water temperature of breeding water was maintained at 28.6~31.2 ℃ and dissolved oxygen was maintained between 6.5~8.7 ppm, and the water purification bacteria (MIC ^{TM) of the genus Bacillus was added to the circulation filtration system.} , Inve) was added every day to stabilize the water quality, and the number of breeding was managed so that 12 rotations per day could be made.

2) standing

For eels, 16.4±2.37 cm in length and 5.5±1.21 g in weight were selected and used in a circulation filtration farm. Three breeding tanks and a control tank using the circular filtration farm were used as it is. were received one by one.

From 3 days before the start of the experiment, powdered feed with a protein content of 49% by weight (dough feed for eel surplus, Woosung feed, Korea) was kneaded and fed to adapt to the breeding feed. was used.

3) Feed preparation

Finely grind the skin of red snow crab and filter it through a 100-mesh sieve to prepare crab shell powder, and then, as an experimental feed, a control without crab shell (powder feed 100%); 2% by weight of a feed containing 2% by weight of crab shell powder and 8% by weight of maltodextrin in 90% by weight of powdered feed; 5% by weight of a feed containing 5% by weight of crab shell powder and 5% by weight of maltodextrin in 90% by weight of powdered feed; and 10 wt% of a feed containing 10 wt% of crab shell powder in 90 wt% of a powdered feed; was prepared as a basic feed.

In addition, the crab shell contains about 15% by weight of chitin and 12.75% by weight of chitosan, and chitin containing 1.5% by weight of chitin and 8.5% by weight of maltodextrin corresponding to 10% by weight of crab shell powder in 90% by weight of powdered feed A feed; and a chitosan feed containing 1.275 wt% of chitosan corresponding to 10 wt% of crab shell powder and 8.725 wt% of maltodextrin in 90 wt% of powdered feed; was prepared.

4) Breeding experiment

The experiment was started from the 4th day after stocking, and all experiments were carried out while feeding once a day for 8 weeks, and after supplying powdered feed, crab shells 10 for 8 weeks, 4 weeks, 2 weeks and 1 week Experiments for each feeding period in which feed containing weight % is supplied; Experiments by crab shell content in which feeds containing 2 wt%, 5 wt% and 10 wt% of crab shell content were supplied for 8 weeks; A comparative experiment in which a feed containing 10% by weight of crab shell and a feed containing chitin and chitosan were supplied for 8 weeks; was carried out separately.

The tank was cleaned every morning, and water quality was measured before cleaning the tank. Feeding was carried out in the morning after cleaning the tank. The amount of feed was 3% by weight/day of the total weight of all eels housed in the tank.

2. Measurement and Pathogenic Bacterial Attack Test

1) Measurement of growth rate and survival rate

In the breeding process, the first and last measurements were performed twice to minimize the stress of the individuals, and before the breeding experiment and after 8 weeks of the breeding experiment, the height and weight were measured up to 0.1 cm and 0.1 g for each individual. and the average value was arranged in units of 10 animals.

Every morning, while cleaning the tank, the carcasses were collected, and the survival rate was calculated based on the accumulated mortality.

The onw-way ANOVA test was performed using the average value of all experimental sections, and the significant difference between the experimental sections was performed under the significance level of 95% using Duncan (1952)'s multiple test to compare the experimental sections. was calculated based on

* Weight gain (%)=(final weight-initial weight)/initial weight×100

* Specific growth rate (%/day)=(loge final weight-loge initial weight)/days

* Feed efficiency (%)=wet weight gain(g)/dry feed intake(g)×100

* Protein efficiency ratio = wet weight gain/protein intake

* Survival (%) = No. of fish at end of exp./No. of fish at initial×100

2) Attack test by pathogenic bacteria

The pathogenic microorganisms used in the experiment were Streptococcus sp. (JNU-01 strain) bacteria that develop at 20°C or higher, and microorganisms that cause death due to symptoms such as sclerosing ulcer and protrusion were used.

The pathogenic microorganism was cultured in a 200 ml flask from 4 weeks before the end of the eel experiment, and 1 ml was injected at a concentration ^{of 10 8} ~ 10 ^{9 cells/ml on the third day of fasting after the end of the experiment.} kept as is.

Confirmation of carcasses was terminated 48 hours after injection, and no more carcasses were identified after that.

3. Experimental results

1) Growth rate and survival rate

1-1) Growth rate and survival rate of control group

The eel fry of the control group used eels raised in the breeding tank of the farm, and the weight grew from 5.5±1.21 g/individual at first to 20.5±1.38 g/individual after 8 weeks (FIG. 1), and the length was 16.4±2.37 cm. It grew to 24.6±0.52 cm in (FIG. 2).

The survival rate was 79.5±3.91%, and the survival rate was low (FIG. 3) because they were early individuals, and the weight gain was 296.1±20.07% (FIG. 4), feed efficiency 19.6±2.07% (FIG. 5), instantaneous growth rate (SGR) 0.018± 0.0007%/day (FIG. 6), the protein efficiency in the feed was investigated as 0.401±0.0408% (FIG. 7).

1-2) Growth rate and survival rate by supply period of feed containing 10 wt% crab shells

Weight growth did not show a significant difference from the control group when powdered feed was fed for 7 weeks and 10 wt% feed was fed in the last week, but 28.7-29.4 It was measured in g/individual and showed a significant difference with the control (P<0.05) (FIG. 1).

The length was 25.2±0.62 cm when supplied for 1 week, and there was no significant difference from the control group, but when it was supplied for 2, 4, or 8 weeks, it was 27.1-27.4 cm, which was significantly larger than that of the control group (P<0.05) (P<0.05) ( Fig. 2).

Survival rate, weight gain, feed efficiency, instantaneous growth rate and protein efficiency in feed also showed similar results to changes in body weight and body length. There was a significant difference, and specifically, in the experimental group of 2, 4, and 8 weeks of feeding, the survival rate was 87.1 to 89.0% (FIG. 3), the increased weight was 450 to 475% (FIG. 4), and the feed efficiency was 35.3 to 37.9% (FIG. 5), instantaneous growth rate 0.025~0.026%/day (FIG. 6), and protein efficiency in feed 0.739~0.825% (FIG. 7), which was significantly higher than that of the control group (P<0.05).

1-3) Growth rate and survival rate according to crab shell content

Body weight growth increased from the 5 wt% feed experimental group, and was significantly highest in the 10 wt%-containing feed experimental group, 28.7±2.03 g/individual (P<0.05) ( FIG. 8 ).

In body length, the body weight showed a tendency to increase as the crab shell content increased, but in the 2 wt% experimental group, there was no significant difference from the control group, and 5 wt% and 10 wt% increased steadily for 8 weeks in the 10 wt% feed. It grew to 27.1±0.58 cm during the period (P<0.05) ( FIG. 9 ).

There was no significant difference in the survival rate between the control group and the experimental group containing 2% by weight, but there was a significant difference in the feed containing 5% by weight or more, and it was found to be 88.6±3.76% in the experimental group containing 10% by weight (P<0.05) (Fig. 10).

Weight gain, feed efficiency, instantaneous growth rate, and protein efficiency in the feed all tended to increase as the crab shell content increased, and 2 wt% and 2 wt% of the control were low without significant difference, and were significant in the feed containing 5 wt% or more. In the experimental group containing 10% by weight, increased weight 463.4±45.88% (FIG. 11), feed efficiency (%) 36.4±4.60% (FIG. 12), instantaneous growth rate 0.026±0.0019 %/day (FIG. 13), feed My protein efficiency was 0.825±0.1037 (Fig. 14) (P<0.05).

1-4) Growth rate and survival rate according to the content of crab shell, chitin, and chitosan

Weight growth was significantly lower in the control group and the chitin-containing feed, and the feed containing 10 wt% of crab shell showed a significantly higher final weight, resulting in 28.7±1.38 g (P<0.05) (FIG. 15).

In body length, the feed containing 10% by weight of crab shell showed the same trend as the weight growth, and was significantly higher than the control and chitin-containing feed at 27.1±0.38 cm (P<0.05) (FIG. 16).

The survival rate was the highest 88.6±3.82% in the feed containing 10 wt% crab shells (P<0.05), followed by 79.5% in the control group. % significantly showed the lowest survival rate (FIG. 17).

Weight gain, feed efficiency, and instantaneous growth rate also show similar trends, with the most significantly high 463.4±36.45.89 % (increased weight, FIG. 18) and 36.4±4.60 % (feed efficiency, FIG. 19) and 0.026±0.0017%/day (instant growth rate, FIG. 20) (P<0.05).

On the other hand, the protein efficiency in the feed was significantly highest at 0.825±0.1041 in the feed containing crab shell powder (P<0.05), and the lowest in the feed containing chitin at 0.263±0.0563 (P<0.05) (P<0.05) ( Fig. 21).

2) Eel attack experiment

2-1) Mortality rate according to the supply period of crab shells

After feeding the eel fry containing 10% by weight of crab skin for 8, 4, 2, and 1 week, the mortality rate was investigated by injecting 1 ㎖ of pathogenic microorganisms of the genus Streptococcus at a concentration of ^{10 8} to 10 ^{9 cells/ml.}

The mortality rates according to the supply for 4 and 8 weeks were 16.7±5.82% and 16.7±5.72%, showing the significantly lowest mortality rates, and as the supply period decreased, the mortality rate increased, which was significantly higher in the control group with 0% crab shell content. It was investigated as 96.7±5.77% (P<0.05) ( FIG. 22 ).

2-2) Mortality rate by crab shell content

After feeding and culturing eel fry according to the crab shell content for 8 weeks, the mortality rate was investigated by injecting 1 ㎖ of pathogenic microorganisms of the genus Streptococcus at a concentration of ^{10 8} ~ 10 ^{9 cells/ml.}

In the feed containing 10% by weight of crab shell, it showed the significantly lowest mortality rate of 16.7±5.72%, the next highest at 2% and 5% by weight, and 96.7±5.77%, which was significantly higher in the control group ( P<0.05) ( FIG. 23 ).

2-3) Mortality rate due to feeding with crab shells, chitin and chitosan

After supplying eel fry with 10 wt% of crab shell feed, chitin and chitosan feed for 8 weeks, 1 ㎖ of pathogenic microorganisms of the genus Streptococcus at a concentration of ^{10 8} ~ 10 ^{9 cells/ml were injected to investigate mortality.}

In the feed containing 10 wt% of crab shell, the chitin feed and the chitosan feed showed a significantly low mortality rate of 16.7 to 30.0%, and the significantly highest 96.7±5.77% in the control group (P<0.05) (FIG. 24) .

As described above, the method for nurturing eel fry feeding the crab shell-containing feed of the present invention has higher feed efficiency compared to the aquaculture method feeding general powder feed, and thus the growth rate and survival rate of eels are increased. It is expected that eels can be farmed at low cost by recycling.

Claims (7)

administering the microorganisms of the genus Bacillus to the circulation filtration system at a concentration of 1 to 5 mg/kg/day based on the number of breeding in the breeding tank and circulating the breeding water at a rate of 10 to 15 rotations/day;
stocking eels weighing 4-7 g in a circulating filtration system at 25-32 ° C. to which the microorganisms are administered;
Feeding powder feed to the stocked eels for 2 to 4 days;
Contains crab shell powder consisting of 5 to 12% by weight of crab shell powder, 60 to 70% by weight of fish meal, 20 to 25% by weight of alpha starch, 1 to 5% by weight of vitamins and minerals, and 1 to 5% by weight of maltodextrin preparing a powdered feed; and
After feeding the powdered feed, feeding the powdered feed containing the crab shell powder in an amount of 2 to 5% by weight/day of the total weight of the fish body throughout the young eel growth stage and the edible eel growth stage; containing, containing crab shells A method of breeding eel fry using feed. The method according to claim 1,
The circulation filtration system includes a breeding tank accommodating eels, a filtration tank that receives breeding water contained in the breeding tank to remove foreign substances from the breeding water, a pump that circulates and transports breeding water in the filtration tank to the breeding tank, and breeding water A method of raising eel fry using a crab shell-containing feed, characterized in that it comprises a heater for maintaining a constant temperature and a level switch for maintaining a constant water level in the filtration tank. delete delete delete delete The method according to claim 1,
The crab shell powder is a powder obtained by grinding at least one crustacean shell selected from the group consisting of red snow crab, snow crab, blue crab, shrimp and crayfish into a 40-200 mesh, eel fry using a crab shell-containing feed positive method.

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