Basic Concepts to establish Pharmacological Treatments in Poultry.
Nowadays, poultry companies have become a producer industry on a large scale. The poultry industrialization makes necessary the systematization of all its own aspects of the industry.
Once this reality has been assumed, the designer of every single stage may turn to several experts, in order to get information as accurate as possible.
It is possible to find opposed opinions among experts as their premises start from interdisciplinar criteria.
It is a utopia thinking to eliminate the use of pharmacologic products, as well as selecting products by its price or producer laboratory.
It is necessary to use pharmacological products reasonably based of multidisciplinary knowledge that combines physiology, poultry pathology, pharmacology, toxicology, business economy and public health.
Only if we take into account all these aspects we will be able to establish an accurate therapeutical plan for the modern agriculture.
Due to the diversity of therapeutical and pharmacological plans in aviculture, we will focus on antibiotics treatments for broilers.
Knowledge to Consider:
A) Related to poultry anatomy and physiology
The main poultry anatomic and physiologic characteristics are the following:
1. Anatomic proximity among liver, ovaries, and intestines that permits the transmission of germs among them
2. Presence of nutritive vitelo during the first days that permit the diffusion of salmonella, through excrements.
3. High physiologic temperature, initially used to fight against infections, is also due to a long incubation period of some poultry bacterial infections.
4. Absence of ganglionar lymphatic system. That is the reason why many poultry infections have general character instead of regional.
Some of the characteristics described before, permit to establish early diagnostics in respiratory infections in 30-35 days old birds because the causing microorganism can be isolated in the bone marrow, within 10-15 days before causing clinical symptoms. This discovery is a step forward in poultry therapeutic because it always permits to use specific antibiotics
B) Related to active principles
The poultry industry development does not correspond with the poultry pharmacologic knowledge development. Unfortunately most treatments, specially related aspects with doses and security, are based on empiric data derivated from individual clinical experience.
Extrapolation of data from experimental reports about mammals as well as the use of products under treatment is commonly used.
It is also necessary the poultry clinic collaboration in order to develop clinical and pharmacological assays protocol during the study of pharmacologic and toxicological parameters of each molecule in birds. That makes necessary the incorporation of specific data in poultry.
In the present situation, the clinical veterinary must strive to look for basic information about the molecules that are being used, inhibitory minimum concentrations and activity specter.
The use of different quinolonas, depending if destined to respiratory processes or salmonellas treatment constitutes a practical example.
C) Related to the way in being administered
Most administration channels in poultry industry are drinking water orally, feed orally, subcutaneous perenteral and intramuscular perenteral.
On the contrary, one of the least used is the intravenous perenteral due to its difficulty. The used administration channel can affect the stability of the active principle between the application and the ingestion, and in the final dose of active principle that arrives to the bird.
Orally, through drinking water, acquire big influence the stability of the active principle in water and the variation of drinking water consume due to the ambient temperature can increase up to 6% for every single degree above 20Âº C. The administration of doxiciclina is a practical example of that. To avoid these difficulties, an administration channel through bomb dosidi fiers is being is being introduced although it still presents some difficulties. Finally we must have into account the proliferation of fungus, specially polymer producer yeasts, in presence of excipients which contents lactose.
The administration through the feed is submitted to the influence of feed consume, palatability, mixture homogeneity mixture, medicament stability from the its elaboration to its consume by the birds. These aspects
In the perenteral administration we must have into account the necessity of equipment without infection and the use of sterile solvent.
In the subcutaneous perenteral administration we must consider the possibility that the medicament reaches physically to aerial sacks extensions. It is important to apply it on the upper neck zone.
The perenteral administration is usually been realized in chest musculature and extremities. We must take into account that the medicament can originate local necrosis that affects a future commercialization. When the active principle is nefrotoxic or secreted by kidney must be applied to chest musculature because the special anatomy of the renal system avoids the correct diffusion through the organism.
D) Related to its use
Among all the daily uses in a poultry farm, the illumination program is the most important program as it has much influence in oral medications (drinking water or feed).
The descriptor veterinary must take into account the pharmacological concept of plasmatic average life (time that a pharmacologic concentration is reduced in plasma by 50%). Therefore the prescriber veterinary must know the minimum inhibitory concentration of the chemotherapies that recommend and establish a proper administration guideline depending on the light.
E) Related to the pharmacological specialty
Any pharmacological specialty is composed by active principles, non active principles and excipients.
The non active principles and excipients can influence positively or negatively on the pharmacological characteristics of the active principle, especially in absorption and stability. The medicament manufacturer companies must inform to clinical veterinaries about the characteristics of their preparations may differ to the active principle characteristics.
In this point we want to introduce the subject matter of the medicament associations that constitute most compositions in veterinarian pharmacological specialties. The clinical practice requires the use of specialties composed of pharmacological specialties but they must be documented enough.
Having into account the etiology, knowing the activity specters and the implications caused by associations or non active principles, the clinical veterinary can decide if the use of preparation or the simultaneous use of mono drugs are advisable or not. Our experience is positive when using together two synergic chemotherapies combined to a molecule with symptomatic effect. However they must fulfill 2 conditions: the synergism must be proved and the symptomatic must not favor infection diffusion (corticoids).
The action specters advise to classify in therapeutical groups:
1. Chemotherapies of wide specter: betalactamics, fluorquinolons, sulfamids and tetracycline.
2. Chemotherapies facing G negatives: aminoglicosids, first generation quinolons.
3. Chemotherapies facing G positives: macrolids
Among the mentioned groups, it is known the synergism between quinolons with betalactamics and aminoglicosids; eritromicina with sulfamids and aminoglicosids, sulfamids with doxiciclina.
Regarding the symptomatic products is advisable the use of pirazol derivatives( antipirina and fenilbutazona) and indolic derivatives ( indometacina) although the last one presents some hepatic toxicity.
F) Related to productive necessities
It is very common to treat only in case of being indispensable, but we must take into account that in this situation the growth of the birds is being affected so the illness has already damaged the poultry industry even if the mortality rate is not very high.
We advise to realize a therapeutical action when the mortality is over 0.1% daily during two consecutive days. That is why we need to dispose in advance of microbiological analysis as we mentioned in former chapters.
G) Related to the Public Health
Finally, to establish a pharmacological treatment, the clinical veterinary must consider the knowledge related to the incidence of the medicament wastes on public health.
The three referential international legislations in force in EU, North American FDA and Japan define waste as any active principle or derivated metabolite contained in feed, of animal origin, destined to human consume, and especially in muscle, liver, kidney, fat and eggs.
In these legislations, the additive waste has been omitted (preservatives, antioxidants and probiotics) as before its incorporation to the additive positive list, its main toxicological characteristics have been studied.
For each active principle and feed, they have been fixed maximum quantities (LMR) that they cannot be exceeded. With this, the manufacture laboratories are obliged to fix for each specialty a retirement period derivated of the pharmacologic characteristics of the active principle and the influence the excipient and the non active principles used have on them.
The clinical veterinary must establish his treatments taking into account these retirement periods.
This new situation despite of enhancing the quality of feed we consume, presents some difficulties:
â¢ There are some difficulties to establish a slaughter calendar for birds as it depends more on the slaughterhouse than the farm necessities.
â¢ Either the production process increases its price and the market price or the corporation benefits have to be reduced.
â¢ The selection criteria is being deformed as so far they could have been based on only one therapeutic criteria.
3. ROAD TO THE TERAPEUTICAL PREVENTION, ANALYSIS AND NUTRITION
From the criteria mentioned previously it comes out the necessity of changing the mentality and opt clearly for the establishment of pharmacological treatments that we can qualify as preventives. Clinics must collaborate with laboratory analysts and nutritionists.
The genetic development in poultry and the growth of tricotecenos presence in cereals, produce an important gap the real vitaminic necessities and the necessity tables especially in group vitaminic B and vitamin C. In our opinion, an important part of the current poultry pathology is related to that lack of vitamins: immune deficiencies, marek and gumboro among others.
Thus, it is necessary the collaboration with the nutritionist in order to dispose of food rich in vitamins or incorporate vitamin shocks to the therapeutic programs.
Another factor to take into account is the information obtained from the systematic analysis that, a part from the preventive information, they provide some important statistics, which are useful to get high valued epidemiological and antibiotic sensibilities map to decide treatments.
4. TERAPHEUTICAL PLANS AND ITS VALORATION
In the previous sections we have studied the different pieces that constitute the basic elements of the therapeutic plans in poultry farming.
We can organize them following the next steps:
1. We must formulate balanced food rich in vitamins of group B and vitamin C.
2. We must incorporate to the food, mycotoxin absorbent products that permit to keep the intestinal mucous in good condition.
3. We must execute systematic analysis in some days of birdsÂ´ life.. For example, in broilers we must execute serologic analysis at 1 day old, bacteriologic and antibiograma at 16 days old and serologic again at the end of its life.
4. Apply macrolidos with aminoglicosidos during the first three days, and repeat it at 10days old.
5. Apply a treatment within 24-26 days, if the mortality increases over0,1% according to the results of the analysis on day 16.
6. Apply symptomatic if necessary further day 30 with or without antibiotic according to the seriousness of the process and taking into account the waste.
7. Finally we must value systematically the efficiency index of each breeding (IE=250-340) in order to demonstrate that we have chosen the right criteria.