Strong Immunity as a Must for Healthy Birds

21 июл 2014г.

– Mr. Dzhavadov, what veterinary preparations are used by poultry factories in Russia today?

– Speaking on the preparations of immunobiological sphere which includes vaccines, it should be noted that they account for over dozen at the moment, especially those that are in use in egg production and parental stock breeding. 

And number of these medicines will grow from year to year while every year brings new deceases to prevent which it is necessary to develop vaccines.


– What new deceases of birds have appeared in the world lately? What are the risks that Russian poultry farmers will face them?

– New infectious deceases are appearing constantly. It is associated with new variant strains, new Gumboro disease virus, new adenovirus infections affecting liver. At the moment the birds in Russia do not suffer from the above infections, however one cannot exclude that soon our poultry farmers will face the above infections. Poultry and eggs are supplied to Russia from the foreign countries as well and many infections are transmitted in a transovarial way, i.e. through eggs.


– Do you consider numerous emerging infections a serious problem of the industry?

– A very serious one. Today many vaccines are implemented already and physicians have forgotten about the principle of interval between vaccinations which is unacceptable. We keep poultry, especially meat one, for a limited time – breeding period in contemporary farms makes 32-35 days: this time is enough for a broiler to gain slaughter weight of 1.5 kg and it can be forwarded to processing. As a result, we have to vaccinate a bird up to 7 times, and immunology laws requires that period between vaccines should be 2 weeks ideally and 5 days as a minimum, with the last vaccination done not later than two weeks before the slaughter to ensure the bird’s immunity formation. This interval is very complicated to observe.

In egg farming breeding period is much longer which requires more vaccinations.


– So, would you name vaccination a cure-all solution?

– Speaking on virus infections, most of them can really be defeated by vaccination. However, in the most cases birds die in the result of bacterial infection. And in such cases one can’t avoid using antimicrobials the most popular of which are antibiotics.


– Many poultry farmers all over the world are trying to minimize using of antibiotics today. Is there any reasonable cause for that?

– Antibiotics played a very important role in medical treatment of both humans and animals since penicillin invention, but incorrect application of these preparations results in emergence of antibiotic-resistant microorganisms.

It all began when stock farmers started to use antibiotics as growth-promoting agents. It’s a wrong way while antibiotics affect intestinal microflora impeding strong immunity formation and normal food digesting.

Besides, antibiotics are not fully disposed from the body and remain in the products of animal origin. If laying hens are given antibiotics within the productive period eggs containing antibiotics will be delivered directly to the consumer’s table. Consumption of these products can have an adverse effect on human health.


– Other words, antibiotics are harmful even in small amounts?

– I think that small amounts of antibiotics are even more harmful while in this case we train pathogenic bacteria to resist antibiotics and, as a result, larger doses of these preparations do have any effect on pathogenic microflora. Consumption of products of animal origin containing antibiotics residuals leads to the loss of efficiency of antibacterial preparations in human’s organism.


– Is there any alternative to antibiotics?

– There are several ways to avoid antibiotics application. Some bacterial deceases like pateurellosis, mycoplasmosis, salmonelloses, provoked by certain salmonellas can be defeated by vaccines that are less harmful than antibiotics.

For certain types of salmonellosis and colibacillosis there is no vaccine, however, as alternatives to antibiotics one may use probiotics (containing lactobacteria, for example), prebiotics (organic acids) that displace pathogenic flora from intestinal tract.

Besides, there is a substitution therapy, so called traps for microbes which block bacteria in certain areas and excrete them from the body. Alltech Company, for example, has developed mannan-oligosaccharide-based Bio-Mos and Actigen preparations that force growth and productivity, improve functioning of gastroenteric tract and immune system. Introduced into the intestinal tract, these preparations inhibit its colonization by the pathogenic flora blocking fimbria of Type I which prevents bacteria attaching to the digestive tract mucous membrane.

Furthermore, some infections can be cured by bacteriophages, or viruses that defeat bacteria, instead of antibiotics.

But the best method is not to cure decease but to ensure conditions that will help the immune system defeat the bacteria. Incorrect vaccination and implementation of antibacterial preparations lead to immunodepressive state of the organism which may result in development of secondary infections, low effectiveness of vaccinations and immunity weakness.


– What countries are leading in vaccine development today?

–  In terms of veterinary vaccines, the leaders are the Netherlands, France, the USA. However, Russian enterprises and research organizations can also develop effective vaccines as well as produce them on the basis of ready developments, foreign ones among them.

Our Institute, for instance, is developing and producing vaccines that struggle not only viruses and bacterial infections but also parasitic deceases, given that very few scientists are able to develop anti-parasite vaccine.


– Would you, please, tell us about bird vaccination by spraying? What are the advantages of this method?

– The main advantage of airborne method, or spraying, is its ease in application: there is no need to give an injection to every bird. This method is very cost-effective. Besides, airborne vaccination is the most effective method of respiratory diseases, including infectious bronchitis, metapneumovirus, etc.

There are several types of airborne vaccination: microdrop spraying and macrovesicular  spraying. The choice should be made basing on the infection that is struggled against. Minor drops get into lower respiratory tract: bronchi and lungs; larger ones – into upper tract: nasal passages, trachea or worse.

The point is that deep penetration of certain infection’s virus, even if it is a vaccine, is very dangerous and can give rise to various complications.

Choice of vaccination method between macrovesicular and microdrop spraying depends not only on the infection type against which preventive measures are taken but also on overall epidemical situation at the farm. For example, if a factory had cases of respiratory micoplasmosis, a bird should not be vaccinated by microdrop spraying because preparations entering lower respiratory tract may give rise to various complications.

However, spraying can’t fully eliminate traditional vaccination methods. Thus, inactivated vaccines can be introduced only by hypodermic or intramuscular injection. Living vaccines can be implemented through injections, spraying, aerosol dispersing, with drinking and even feeding.


– Can feed additives replace vaccines to any extent?

– As per today it is impossible to form strong immunity with the help of feed additives that is why additives, immune stimulants, preparations improving immune system are effective only if accompanied by vaccination.


– Would you, please, tell us few words about innovations in vaccination sphere?

– Vaccines are upgraded constantly. The scientists have already mastered to make not only live engineered and inactivated vaccines, but also immune complexes. I would especially emphasize recombination vaccines, i.e. the vaccines produced by integration of one virus genome particle into another virus genome structure with the help of genetic engineering. Such complexes form rather a strong immunity and do not cause much harm to the organism.


– Nowadays we see growing number of ecofarms that have refused veterinary preparations completely. Do you consider this way of work feasible for our country?

– What concerns minor farms that serve premium niche, full elimination of veterinary preparations is possible but it is very complicated to grow a bird without vaccination that is why finished product will cost very high. But one of the specific features of Russian poultry industry is dominancy of large factories that can’t eliminate vaccination yet. However, one can avoid using antibiotics, if implement appropriate therapeutic and preventive measures and high quality biopharmaceuticals.


– What vaccines and vaccination method do you consider the most perspective ones?

– Among vaccination methods one of the most perspective ones is a method of embryo vaccination when preparation is introduced before the birth of a bird. In this case chickens are produced with protection.

Speaking on innovative technologies in general, I would say that future belongs to complex engineered vaccines. Some experts foresee a coming invention of a preparation that will unite all the vaccines though I do not believe that it will appear at the market in the nearest future.


Guest: Edward Dzhavadov, the Head of Russian Research and Development Veterinary Institute of Poultry Farming
Interviewer: Elena Maksimova



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