RU2098953C1 - Method for producing fish larvae in closed water supply system - Google Patents

Abstract

FIELD: fishery, in particular, commercial carp production. SUBSTANCE: method involves disinfecting incubators; disintegrating larvae; providing incubation and holding larvae in ozonized water, which is preliminarily cleaned from organo-mineral contaminants, deodorized and saturated with oxygen in reactor. Ozone is supplied at pressure of 1.2-1.6 atm, flow rate of 1.25-50 l/min (depending on type and number of incubators) to reach ozone concentration in air-ozone mixture 8 mg/l. Air-ozone mixture and water contact time is 5 min. Method allows survival rate to reach 92-96%. Water consumption for producing 1 million larvae for incubation and holding period of 2 days is 1.-2.5 cub m. EFFECT: increased efficiency, reduced water consumption and decreased production cost. 1 tbl

Description

 A method of obtaining larvae in a closed water supply system.

 The invention relates to fish farming, and in particular to industrial fish farming, and can be used in hybrid breeding centers for the day of obtaining sterile larvae.

 A known method of obtaining larvae. The disadvantages of this method are the high complexity, the use of scarce and expensive preparations and chemicals, the complete disinfection of the larvae, the high energy consumption for the preparation of water and its significant consumption, and, most importantly, the lack of process integrity, which leads to low yield of the larvae and their survival, are not ensured.

 Closest to the proposed method is a method of obtaining larvae in a closed cycle. The disadvantages of this method is the irrational use of ozone (residual concentration of ozone in water 5 mg / l), which leads to a significant cost overrun of electricity and money.

With such excessive saturation of water with ozone (over 1 hour excess of I00000 mg), it may be released into the environment, which creates a health hazard for the maintenance staff (maximum concentration of ozone in the air is 0.1 mg / m ³ ).

 With such a large excess of ozone in water, it cannot be ruled out that it can get into incubators and containers for keeping the larvae and causing their death. It is known that at a concentration of ozone in water even at a dose of 0.003 mg / L, the death of aquatic organisms was noted (A.N. Nikonorov, 1985), and at a dose of 0.09 0.2 mg / L, inhibition and death of adult carp larvae were noted (A. I. Ivashchenko, I990).

Disinfection of incubators (if they are disinfected) and de-sticking of eggs are carried out in other ways and, apparently, are not effective enough. And as a result of the above noted disadvantages, the survival rate of larvae with this method is only 41.6%
The purpose of the invention is to increase the yield of larvae, their survival and lower operating costs.

 The essence of the method and its distinguishing features are that a holistic process has been developed for obtaining larvae, which ensures disinfection of incubators, de-sticking of eggs, its incubation and aging of larvae. At the same time, a high yield of sterile larvae (96-98%), their high survival rate (94-96%), a decrease in operating costs and safe working conditions for maintenance personnel are noted.

 All of the above technological operations for obtaining larvae are provided with ozonated water, which is disinfected, deodorized, clarified, saturated with oxygen, and purified from organic and mineral contaminants by ozone in the reactor, where the ozone-air mixture is supplied under a pressure of 1.2-1.6 atm, in the amount of 1 , 25 50 l / min (depending on the type of incubators used and their quantity) with an ozone concentration of 8 mg / l in the ozone-air mixture and a contact time of water and the ozone-air mixture of 5 minutes.

 The goal is achieved as follows: water from an art well or an open reservoir is fed into a switchgear and flows by gravity into the reactor, and an ozone-air mixture with an ozone concentration of 8 mg / l is also fed into it through a bubbler. The contact of water and the ozone-air mixture is carried out in countercurrent for 5 minutes.

 Disinfected, decontaminated, deodorized, clarified, purified from organo-mineral contaminants and oxygenated water from the reactor through the heat exchanger enters the ozone decomposition tank (its volume is calculated taking into account the saturation of water with ozone and the time of one revolution of water in the system). From the ozone decomposition tank, water flows by gravity into the incubator (s).

 After filling after 5-15 minutes (this time is enough for their disinfection), fertilized eggs are placed. With the movement of water, it mixes, and after 15-40 minutes (depending on the dose of caviar and stickiness), the caviar is completely de-gelled.

 18-20 hours after laying eggs in the apparatus (s), the incubation of eggs ends, the period of larvae incubation begins. 8-16 hours after hatching of the larvae, the yolk sac resolves, the larvae are active and switch to endogenous nutrition. For 2 days. maintained (incubation is carried out in incubation apparatus) the size of the larvae reaches 7.8 <8.1 im length, 1.7-1.9 mg of weight.

 Examples of specific performance are presented in the table. The table shows that carp caviar was incubated in Weiss, IVL-2, and Amur apparatuses. Water was treated with ozone in the same reactor, where the concentration of ozone in the ozone-air mixture was 8 mg / l, and the contact time of water and the ozone-air mixture was 5 minutes. However, depending on the incubation apparatus and their quantity, the flow rate of the ozone-air mixture is from 1.25 l / min to 25.

 In the Weiss apparatus, the eggs incubation time was 18 hours, the larvae yield was 98%, and their survival after 2 days. keeping 96%, the average weight of the larvae was 1.9 mg. Caviar disease was not noted by saprolegnia. The water quality in the closed water supply system after 58 hours of operation was good, the oxygen content was 8.2 mg / l.

 Similar results on the yield of larvae and their survival were obtained using the IVL-2 incubator and two Amur incubators. When ozonating water to ensure the IVL-2 incubator, the ozone-air mixture flow rate was 12.5 l / min, and to provide two Amur apparatuses, 25 l / min. The water quality in the systems was also similar. The incubation time was 19 hours.

 In addition, caviar was incubated in Weiss and IVL-2 apparatuses, where water in a closed system was also ozonated in the same reactor at a constant concentration of ozone in the ozone-air mixture of 8 mg / L. and a feed rate of 1.35 L / min into the reactor. However, the contact time of the ozone-air mixture and water was 2 and 7 minutes. As a result of the change in the contact time, significantly worse results were obtained. So, when the ozone-air mixture and water were in contact for 2 minutes, the larvae yield was only 59% and their survival rate was 6l%, incubation lasted 23 hours. Water quality was significantly worse compared to the five-minute contact. Transparency decreased 256 cm to 140, increased, (chemical oxygen consumption) from 4 dr 19 mg / L, and the oxygen content was almost critical 5.2 mg / L. In the water there were a large number of microorganisms, and caviar was affected by saprolegnii fungi. After 2 days. The average weight of the larva was 1.36 mg. The incubation period increased to 23 days.

 With an increase in the contact time in the reactor of water and the ozone-air mixture up to 7 min, the results on the yield of larvae and their survival improved, however, they were significantly worse compared to those when the contact time was 5 min, and the water quality was good. However, a residual amount of ozone in a dose of 1.5 mg / l was noted in water. Apparently, this was a negative factor in the yield of larvae and their survival.

 Similar results were obtained when using the IVL-2 incubator, where the contact time in the reactor of water and the ozone-air mixture was 3 and 8 minutes.

 An example of the practical implementation of the proposed method is the construction and operation of an incubation-larval workshop at the Nesvizhsky state farm of the Minsk region.

Degreasing of carp caviar, its incubation and larvae incubation are carried out in 4 devices (2 IVL-2, 2 Amur). The total volume of water in the closed water supply system is about 7 m ³ , its turnover is 1 time in 3 hours. Ozonation of water is performed in the reactor when the ozone-air mixture is supplied at a pressure of 1.2 1, atm. in an amount of 50 l / min, where the concentration of ozone in the ozone-air mixture is 8 mg / l and the contact time of water and the ozone-air mixture is 5 minutes.

10 minutes after filling the apparatus with ozonated water, fertilized eggs were laid for incubation in the amount of 5.470 million pieces. Caviar was mixed due to the flow of water, and after 40 minutes, all of it became dehydrated. The temperature in the closed water supply system was constant, 25 ^o C. It was maintained automatically by the heat exchanger. The incubation period lasted 19 hours. The yield of larvae was 5.305 million pieces, or 97%.
After hatching, the larvae were kept for 2 days. in the same devices. 10-16 hours after hatching, the yolk sac resolves in the larvae; they actively move and switch to endogenous nutrition. After 2 days. keeping survivability of the larvae amounted to 4.988 million pieces or 94% of the number of hatched. The average length of the larvae was 7.9 mm and the weight was 1.75 mg.

 Saprolegnia was not noted.

 The water quality in a closed system after 62 hours of operation was as follows: transparency 264 cm, COD 6 mg / l, oxygen content 7.9 mg / l, ammonium nitrogen I, and nitrate 3 mg / l. Microorganisms were absent. There was no residual ozone after water exiting the reactor.

Claims (1)

 A method for producing fish larvae in a closed water supply system, including hatching apparatus and a reactor, including placing fertilized eggs for incubation in disinfected incubation apparatus, keeping larvae and water regeneration, characterized in that before using the fertilized eggs in the hatching apparatus in the reactor, the used water is purified from organic and mineral contaminants, neutralize, disinfect and saturate with oxygen by supplying an ozone-air mixture at a pressure of 1.2 1.6 atm, soon at a concentration of 1.25 50 l / min, with an ozone concentration of 8 mg / l in the mixture and a contact time of 5 minutes with water.

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