Chicken respiratory diseases are still the most serious diseases that harm the chicken industry at present. At present, for the prevention and treatment of this kind of diseases, many methods are used, such as mixing materials, drinking water, individual administration or injection, and some methods have no effect because drugs cannot reach the respiratory tract; Although some methods can reach the respiratory tract, due to the different distribution of drugs in the body, liver metabolism and kidney excretion, the efficacy is reduced, and it is time-consuming and laborious. Aerosol spray inhalation provides an optimal way to treat poultry respiratory diseases.
1 Characteristics of aerosol spray inhalation administration
1.1 The drug can be absorbed quickly, can directly reach the action site, and its efficacy appears rapidly. Oral administration, most drugs need to diffuse through the gastrointestinal mucosa and be absorbed into the blood circulation, and then distributed to the corresponding parts with the blood flow to play a role. This not only requires a process, but also drugs are easily affected by various enzymes and pH values in the gastrointestinal tract. In addition, the drug is not completely absorbed in the small intestine, which makes the drug effect slow or even reduce. Administration by intramuscular injection is time-consuming and laborious, although it is absorbed quickly, and sometimes it can cause artificial damage to chickens. In addition, the amount of medicine reaching respiratory mucosa through blood is insufficient, which affects the curative effect. Inhalation administration can make the drug directly reach the lung and air sac to play a role, which can avoid the adverse stimulation of the drug to the gastrointestinal tract and avoid the metabolic degradation of the drug by the liver and gastrointestinal tract. In addition, because of the large alveolar area and abundant capillaries, drugs can be absorbed quickly, and the bioavailability of some drugs is close to 1%, while the bioavailability of oral administration is only 2%(1).
1.2 can play a systemic and local therapeutic role of drugs, and the therapeutic effect is strong.
1.2.1 The rate at which drugs enter the blood from alveoli is affected by periodic breathing, that is, lung clearance, and enters alveoli intermittently. Some drugs can penetrate the alveolar barrier and play a systemic role. After some drugs are absorbed, they can only stay in the alveoli, not easily penetrate the alveolar barrier, and only play a local role (2).
1.2.2 There are airbags in the respiratory system of chickens, which are not found in mammals, which can increase lung ventilation and enhance lung gas exchange. At the same time, chicken's lungs don't expand and contract like mammals' lungs, but gas runs through the lungs and enters and exits the airbag with the pipes in the lungs. This structural feature of respiratory system can enlarge the area of drug diffusion and increase the amount of drug absorption. In addition, inhalation administration can directly attach a large number of drugs to the surface of the airbag and completely kill pathogens on the airbag.
1.3 saves time and labor, and the drug inhalation is reliable and uniform, with good therapeutic effect. Inhalation can reduce the labor intensity of mixing materials, drinking water or catching chickens, and reduce the stress reaction of chickens. For chickens that can't eat or drink water, drugs can quickly reach the trachea, bronchi and other parts through breathing, effectively inhibiting or killing pathogenic bacteria and playing a therapeutic role.
2 mechanism of inhalation in the treatment of respiratory diseases
The occurrence of respiratory diseases is mostly caused by pathogenic microorganisms invading the respiratory system, causing inflammation in the respiratory tract, producing a large number of secretions and forming sputum. The inflammation develops further, which makes the respiratory mucosa hyperemia and bleeding, so as to cause the mucosa to fall off, form embolus, block the larynx and trachea, and form a large number of cheese-like substances on the airbag, resulting in symptoms such as mouth opening and neck stretching, head shaking, cough, asthma and tracheal rales. Therefore, antibacterial and antiviral drugs should be selected to kill pathogenic microorganisms and prevent secondary infection. Use expectorant drugs to crack acidic mucopolysaccharide fibers in sputum, so as to reduce sialic acid content in sputum, reduce sputum viscosity and make it easy to cough up, thus relieving cough and relieving symptoms. Combined with bronchodilator, it relaxes bronchial smooth muscle and is beneficial to sputum discharge. Therefore, the general principle of medication should be antibacterial and anti-inflammatory, expectorant and antiasthmatic, and treat both the symptoms and root causes, so as to achieve the purpose of treatment.
3 commonly used drugs for inhalation and dosage
3.1 antibiotics
3.1.1 long-acting antibacterial agent Alex Gao (1996) reported that every chicken coop (8×25×2.2m3)
15 kilograms of tap water and 5 bottles of long-acting antibacterial agent (produced by Veterinary Medicine Branch of North China Pharmaceutical Factory) were used every time, and they were fully dissolved at 5 o'clock every morning. It improved after 3 days and recovered after 5 days, but it didn't improve after drinking water with Gaolimi first (3).
3.1.2 Streptomycin Wang Xiaohua et al. (1993) reported that 1 g (1 million IU) of streptomycin was diluted to 2ml with physiological saline, sprayed at a rate of 2, U/m3, and the doors and windows were sealed for 3-4min after spraying with 1-3μm droplets to treat chronic respiratory diseases.
3.1.3 neomycin and kanamycin neomycin can be sprayed at 1g/m3 and inhaled for 1.5h； each time; Treatment of chronic respiratory diseases with kanamycin .5ml/m3 spray.
3.1.4 nystatin is sprayed at 5 units /m3 for 3-4min each time, which can treat lung diseases caused by Aspergillus infection.
3.1.5 Quinolones (such as ofloxacin and enrofloxacin) can be sprayed at a dose of .5g/m3 to treat chronic respiratory diseases, and the effect is good.
3.1.6 Luo Yanhong (1996) reported that 6g of sulfathiazole, .3g of furacilin, 1.8g of vanadate and 9, IU of various antibiotics can be used as aerosol per cubic meter to treat respiratory diseases. Li Zailan et al reported (1994) that each chicken was treated with streptomycin 2, units, gentamicin .6-1, IU and hydrocortisone .6ml by aerosol administration.
3.2 expectorant drugs
3.2.1 Acetylcysteine ester is generally made of 3ml of sodium salt solution of 1-2% acetylcysteine, .25 ml of isoproterenol (1∶2 solution) and EDTA as stabilizer.
3.2.2 triethyl iodide Carefully mix 3g of iodine tablets, 16g of potassium iodide and 915 ml of triethyl glycol until they are completely dissolved to prepare triethyl iodide solution, and then add 2ml of lactic acid and 2ml of pure tap water to 1ml of triethyl iodide solution. When used, according to the dosage of 2.8 ml/m3 for chicks aged 15-25 days, 2.7ml/m3 for chicks aged within 35 days and 2.5 ml/m3 for big chicks, the interval of medication is * * * for 12 days. Each spray lasts for 1min, and then the henhouse is closed for 25min.
3.3 antiasthmatic drugs and bronchodilators
3.3.1 dihydroxyphenyl isopropylaminocarboxylic acid This drug can bind to adrenergic β2 receptor in bronchial vascular bed and other parts, and can relax bronchial smooth muscle, reduce pulmonary and systemic circulation resistance and increase cardiac output. Generally, the dosage of 1-1 day-old chicks is 2mg/kg body weight.
3.3.2 Luo Yanhong (1996) reported that aminophylline aerosol (.3g/m3), ephedrine aerosol (.3g/m3) and atropine aerosol (15g/m3) have special anti-bronchitis effects. In order to promote the absorption of respiratory secretions, sodium bicarbonate 11g, ammonium chloride 6g, trypsin 25mg, deoxyribonuclease 25mg or ribonuclease 25mg can be used simultaneously per cubic meter.
4 Precautions for inhalation administration
4.1 Selection of drugs suitable for inhalation administration requires that the drugs used are neither irritating to the respiratory tract of birds, but also soluble in their secretions, otherwise they cannot be absorbed. In order to increase the stability of the drug, antioxidants such as vitamin C and sodium metabisulfite can be added.
4.2 to control the droplet size, the smaller the droplet, the deeper it enters the lung, but the worse the retention rate in the lung, most of it is easy to be excreted from the breath, which affects the efficacy. When the fog drops are large, most of them fall on the mucosal surface of respiratory tract, fail to enter the lungs, and are absorbed slowly. According to the comprehensive research results, the appropriate droplet size is .5-5μl for entering the lung and 1-3μl for entering the upper respiratory tract.
4.3 mastering the hygroscopicity of drugs to make particles reach the deep part of the lung, drugs with slow hygroscopicity should be selected. Because the hygroscopic drug particles can gradually increase in diameter when they pass through the respiratory tract with high humidity, which affects the drug reaching the alveoli, thus affecting the curative effect.
4.4 master the dosage of inhalation administration of the same drug, and the dosage of inhalation administration may not be the same as that of other dosage forms, so it cannot be applied at will. For drugs that can be absorbed by lungs and air bags, the effective dose should be determined by measuring the absorbed blood concentration. Drugs with low safety factor must be tested for toxicity to ensure safety.
4.5 Choose an ideal propellant, such as aerosol for inhalation administration. The ideal propellant condition is that the vapor pressure should be greater than atmospheric pressure at room temperature; Non-toxic, no allergic reaction and irritation; Non-explosive and non-flammable; Colorless, odorless, tasteless, stable in nature, does not react with drugs, containers, etc., and is cheap and easy to obtain. Commonly used are chlorofluorocarbons and compressed gases, such as inert gases such as CO2 or N2.
4.6 Inhalation therapy is best carried out at night or in the dark, so as to reduce the operation noise, so as to avoid panic and stress reaction affecting the productivity of chickens. After spraying, the poultry house should be sealed for 3-6min. In addition, pay attention to the operator's personal protection, so as to avoid some drugs from damaging the human body.
how to idealize aerosol administration
1. the purpose of aerosol inhalation administration:
broiler chickens are administered by mixing materials, drinking water, individual drips, intramuscular injection or subcutaneous injection. Due to the unique physiological structure of poultry, the above administration route can not achieve the best treatment effect for respiratory diseases of broilers. At present, aerosol administration as a route of administration has been gradually recognized by the industry, but there are still many problems in specific operation. Therefore, according to the clinical practice of aerosol administration, we systematically summarized the aerosol equipment, equipment operation, drug combination and other links, hoping to provide useful technical reference and guidance for on-site veterinarians. The purpose of aerosol administration is to relieve the respiratory symptoms of broilers, promote sick chickens to eat drinking water, win time and effect for the administration of other therapeutic drugs, and achieve treatment or help broilers to achieve normal slaughter.
2. Aerosol spray drug delivery equipment and operation method:
1. Aerosol spray drug delivery equipment:
The equipment must be able to solve the three major problems of droplet size, noise and spray speed. The equipment we provide is a spray equipment that combines imported fans with domestic high-pressure hoses and watering cans. The power of the fan is 1. kW, and the voltage is 22V V.
2. Operation of aerosol administration:
1. Adjustment of aerosol particles: < P > The appropriate diameter of aerosol particles is 1-2 microns. First, put clean water in the watering can, start the equipment, lift the watering can horizontally, stretch out your arm two meters away from the watering can, and see 1-2 small water droplets sticking to the hair of your arm in the light, which shows that the size of the water droplets is appropriate.
2) power supply inspection:
according to the power consumption of spraying equipment and other henhouse appliances, measure the load of transmission line in henhouse to prevent the line from catching fire due to excessive current.
3) Number of aerosol spray drug delivery equipment:
Each aerosol spray drug delivery equipment can be used by 5, chickens, and the aerosol spray drug delivery takes about 3 minutes. If there are too many chickens, we should consider adding more spray equipment.
4) Dust suppression in the henhouse:
When the relative humidity in the henhouse is low and the dust is heavy, the henhouse should be humidified (sprayed to the top of the henhouse) with a nozzle for disinfection before spraying, subject to the clear visibility of the henhouse.
5) Indoor environment control:
Increase the indoor temperature before humidifying and dusting in the house, so that the indoor temperature can meet the requirements of age temperature after dusting. Stop the fan when aerosol spray is administered (close the window in summer).
6) Dispensing
Dilute the medicine (see III. Prescription of Medicine) into liquid medicine, and use 3-4L liquid medicine for every 1 chickens, and it is appropriate that it will fog in the henhouse after spraying.
7) Spraying time:
Spray in the early morning in summer, and in other seasons, after turning off the lights at night, wait until the chickens are quiet. For severe chickens, spray again in the early morning of the next day after spraying at night, with an interval of 6-8 hours.
8) Spraying:
The watering pot is lifted horizontally to make the aerosol drop from a height more than one meter away from the chicken back, and each drop point is 2 meters away from the watering pot (the droplet at this position is most suitable). Turn on the light to observe that the house is full of aerosol, and the visibility is 5-1 meters, indicating that the dosage of the medicine reaches the standard. Wait 3-6 minutes before opening doors, windows or fans. Note: Anyone who is allergic to sprayed drugs is prohibited from being on the scene. Operators should wear goggles and masks to avoid damage to human body caused by certain drugs.
Third, the mechanism of aerosol spray in the treatment of respiratory diseases:
The occurrence of respiratory diseases is mostly caused by pathogenic microorganisms invading the respiratory system, causing inflammation in the respiratory tract, producing a large number of secretions and forming sputum. The inflammation develops further, which makes the respiratory mucosa hyperemia and bleeding, so as to cause the mucosa to fall off, form embolism, block the larynx and trachea, and form a large number of cheese-like substances on the airbag, resulting in symptoms such as mouth opening and neck stretching, head shaking, cough, asthma, and tracheal rales. Therefore, antibacterial and antiviral drugs should be selected to kill pathogenic microorganisms and prevent secondary infection. Use expectorant drugs to crack acidic mucopolysaccharide fibers in sputum, so as to reduce sialic acid content in sputum, reduce sputum viscosity and make it easy to cough up, thus relieving cough and relieving symptoms. Combined with bronchodilator, it relaxes bronchial smooth muscle and is beneficial to sputum discharge. Therefore, the general principle of aerosol administration should be antibacterial and anti-inflammatory, expectorant and antiasthmatic, and treat both the symptoms and root causes, so as to achieve the purpose of treatment.
1. Selection of state (chicken flock): When respiratory symptoms are more than 2% in a large flock, the effect of aerosol administration in the whole flock can be better, and when it is less than 2%, aerosol administration can be selected locally. Aerosol administration is not recommended for the whole group
Second, the choice of drugs: mainly based on the location of the respiratory tract {the composition of the respiratory system }
the prescription of aerosol administration
A, the infection of the upper respiratory tract (above the glottis)
* The mucus is a little below the larynx, and the voice is clear but purring
* There is mucus in the nasal cavity. Shaking head
* mucus in the upper trachea
* Laryngeal bleeding
Prescription: Hepatobiliary Oral Liquid+Erythromycin Thiocyanate (tylosin)
Dosage: 8-1, ml/5, chickens each time, and the dosage of antibiotics is L/3-1/2 of the oral dosage
Dilution method: 1. (Can't be added at the same time)
* Mucus is in the throat, and the purring sound is dull
Prescription: Gan 'an oral liquid+doxycycline!
dosage of medicine: 6-8ml/5 chickens each time, and the dosage of antibiotics is 1/3-1/2 of the oral dosage.
Dilution methods: 1. Calculate the amount of water needed for aerosol administration. 2. The temperature of water is not suitable for hot water (destroying the medicinal properties). 3. Add one medicine to dissolve the medicine, then add the second medicine and stir. (can't be added at the same time)
B. Lower respiratory tract infection:
* There is mucus and annular bleeding in the bronchus, which can be scraped off with scissors (note: the blood of viral diseases is in the meat, so it can't be scraped off.