RU2463591C1 - Method of chicken embryo selection - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: method of chicken embryo selection involves visual estimation of eggs, calculation of pre-incubation weight and index form with the embryos to be additionally estimated by embryonic growth rate during incubation by determining an embryo diameter after 18-19 h of incubation and a yolk sac vasculature diameter after 63-64 h of incubation; it is followed by selecting the embryos with the yolk sac vasculature diameter is min. 2 cm and a difference of the yolk sac vasculature diameter and the embryo diameter falling within the range of 1.0-1.5 cm.

EFFECT: method enables higher volume of the produced extra-embryonic fluid, increased virus titre, and may be used in manufacturing of vaccines for farm animals.

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Description

The invention relates to the biological industry, in particular to the production of vaccines for farm animals.

Chicken embryos have been widely used in the biological industry since the late 30s of the XX century. Their use made it possible to expand the range of viruses cultured in laboratory conditions, since they have several advantages over laboratory animals. The shell and the shell shell reliably protect against bacterial infection of the external environment, the insufficient development of the immune system provides high sensitivity to viruses, chicken embryos are an easily accessible object that does not require care and feeding.

At the same time, the following requirements are imposed on chicken embryos used to obtain virus-containing material: embryos must be obtained from farms that are safe for infectious diseases, the shell must be unpigmented clean (cannot be washed), the age of the embryo must correspond to the chosen infection method (Belousova P .V., Trotsenko NI, Preobrazhenskaya EA, Workshop on Veterinary Virology. - M.: KolosS, 2006, - 248 p.).

A known method for assessing the development of chicken embryoshell eggs in the first day of incubation, proposed by Professor Orlov MV (Orlov M.V. Biological control in incubation. - Moscow: Rosselkhozizdat, 1966, - 164 p.). The author evaluated chicken embryos by the time of blastodisc appearance by ovoscopy in the first hours after the start of incubation. At the same time, it was noted that the embryos in which the blastodisk is visible earlier and further developed more intensively. The percentage of hatching and hatchability from such eggs was 38.5% higher.

However, this method did not find wide practical application, since it requires frequent removal of eggs from the incubator in the first hours of incubation, and does not take into account the fact that the process of division of the embryonic leaves begins immediately after fertilization, that is, even in the chicken oviduct. By the time of laying the eggs in the incubator, there are large variations in the degree of development of the embryo, since it is not known how many eggs were in the chicken oviduct (Rolnik V.V. Biology of bird embryonic development. - Leningrad: Nauka, 1968, - 425 pp.).

The proposed method for the selection of chicken embryos is based on the task of obtaining the maximum amount of extraembryonic (allantoic and amniotic) liquid for vaccine production.

The problem is achieved by the method of selection of chicken embryos, including a visual assessment of eggs, taking into account the mass and shape index before laying in the incubation, characterized in that the embryos are additionally evaluated by the intensity of embryonic development at 18-19 and 63-64 hours of incubation, and the diameter difference between the chicken embryo the embryo should be in the range of 1.0-1.5 cm, and the diameter of the vascular field of the yolk sac should be at least 2 cm.

Technical result - the proposed method allows to increase the volume of extraembryonic fluid and increase the titer of the virus.

An example of a specific implementation.

The studies were performed on chickens of the breed white leggorn of the maternal line, maternal form SP 9 of the cross SP 789 in the VNITIP EPH.

For the experiment, 300 eggs were selected by random sampling. Evaluation of hatching eggs was carried out according to the methodological recommendations of VNITIP (Guidance on biological control when incubating eggs of poultry. Methodical recommendations / L.F. Dyadichkina, N.S. Pozdnyakova, O.V. Glavatskikh, etc. - Sergiev Posad, 2010, 84 from.).

The embryo development intensity was taken into account at 18-19 and 63-64 hours of incubation by measuring the diameter of the blastodisc and the vascular field of the yolk sac using a caliper with an accuracy of 0.1 mm without opening the shell. Based on the data obtained, the difference for each embryo was calculated.

By biometric analysis of the data according to the generally accepted technique (Merkuryeva E.K., Shangin-Berezovsky G.N. Genetics with the basics of biometrics. - Moscow: Kolos, 1983, - 400 p.) The experimental embryos were divided into 3 groups according to development intensity (tab. .one).

Table 1 Indicators of the qualitative development of chicken embryos Indicators Development intensity groups intense medium low Egg weight, g 64.8 ± 0.54 64.3 ± 0.77 62.4 ± 0.76 Index of the form,% 74.4 ± 0.38 75 ± 0.5 73.8 ± 0.57 Blastodisk diameter at 18-19 hours of incubation, cm 0.77 ± 0.03 0.80 ± 0.02 0.81 ± 0.03 The diameter of the vascular field of the yolk sac at 63-64 hours of incubation, cm 2.24 ± 0.02 1.94 ± 0.01 1.62 ± 0.03 The difference in diameter of the embryo of the chicken embryo, cm 1.47 ± 0.02 1.14 ± 0.01 0.81 ± 0.02

As can be seen from table 1, the intensively developing embryos had a large diameter of the vascular field of the yolk sac at 63-64 hours of incubation, as well as a larger difference in the diameters of the embryo of the chicken embryo.

After 7 days of incubation, 30 embryos were selected from each group and sent to the laboratory for infection with the Newcastle disease virus (VLB). Infection was carried out by introducing the virus into chicken embryos in an allantoic fluid. After infection, the embryos were placed in a thermostat to accumulate the virus. On the 9th day after the start of incubation, extraembryonic fluid was collected separately according to the embryonic development intensity groups (Table 2).

table 2 Total volumes of extraembryonic fluid by groups of intensity of embryonic development Indicator Development intensity groups Intense Medium Low Volume of extraembryonic fluid, ml 323 316 285

As can be seen from table 2, the total volume of extraembryonic fluid was greater in the group with intensive embryonic development.

In extraembryonic fluid, the amount of Newcastle disease virus was determined by its titer (the amount of virus contained in a unit volume of material). Virus titer was determined by 50% infectious effect according to the groups of embryonic development intensity (Table 3).

Table 3 Extra-embryonic fluid VLB titer according to embryonic development intensity groups Indicator Development intensity groups Intense Medium Low Virus titer, lg EID 50 / ml 9.3 8.7 8.6

As can be seen from table 3, the titer of the virus is higher in intensively developing embryos.

The test results showed the advantage of the method for selecting chicken embryos for the needs of the biological industry according to the intensity of embryonic development. The use of intensively developing embryos allows to increase the volume of extraembryonic fluid obtained by 2% compared with embryos with medium development and by 12% compared to low-developing ones, as well as to increase the titer of the virus.

Claims (1)

A method for selecting chicken embryos, including visual assessment of eggs, taking into account the mass and shape index before laying in the incubation, characterized in that the embryos are additionally evaluated by the intensity of embryonic development during the incubation period by determining the embryo diameter at 18-19 hours of incubation and determining at 63-64 hour of incubation of the diameter of the vascular field of the yolk sac, then embryos are selected for which the diameter of the vascular field of the yolk sac is at least 2 cm, and the difference between the diameters of the vascular field and the embryo is range 1.0-1.5 cm.