What are the prevention and control measures for chicken infectious proventriculitis?

In recent years, an infectious disease characterized mainly by poor growth, emaciation, poor uniformity, proventriculus enlargement like a milky white ball, proventriculus mucosa ulceration and sloughing, and gizzard erosion has caused great losses to the farming industry. This disease is infectious proventriculitis.

1. Pathogen

The pathogen of this disease has not yet been clearly identified. The pathogen of this disease is a coronavirus, and some other viruses are also related to this disease, such as low-fiber diets, fungal toxins, reovirus, tumor-inducing virus, avian reticuloendotheliosis virus, polyomavirus, adenovirus, double-stranded RNA virus, and bacteria, etc. Therefore, this disease is a syndrome caused by one or several infectious pathogenic microorganisms and non-infectious factors; the digestive tract and endocrine organs are the target organs of these pathogenic factors.

2. Epidemiological characteristics

1. Infectious proventriculitis can spread among different breeds of laying hens and broilers. The disease can also be found in the current 817 crossbred broilers. The disease can now be seen in all parts of the country. The incidence rate varies from place to place due to differences in region and feeding management. Generally, the lowest incidence is about 10%, and the mortality rate is as high as about 30%. Some reports say that the disease can be seen in broilers at 21 days of age. In laying hens, the course of the disease is generally about two weeks, and the peak of death from infection with this disease is more than one week.

2. The cause of this disease is complex, and the pathogen may be transmitted vertically. In the same chicken farm and the same batch of chickens, chickens of different breeds were found to develop the disease at the same time. Vertical transmission from breeding chickens is suspected.

3. Predisposing factors

1. Feed-related predisposing factors: unbalanced feed nutrition, low protein, vitamin deficiency, mold, toxins, etc. are all predisposing factors for the occurrence of this disease.

2. Ophthalmia: Ophthalmia is an important predisposing factor for this disease. Clinical findings show that in any chicken farm with proventriculitis, symptoms of the ophthalmia type occur first.

3. Infectious diseases: The pathogens of some infectious diseases are now also predisposing factors for this disease, such as the clinically common fowl pox, intestinal toxicity syndrome, reticuloendotheliosis, chicken anemia agent, Marek's disease, etc.

4. Clinical symptoms

After infection with this disease, the initial symptoms include ruffled feathers, listlessness, drooping wings, tearing, and swollen eyes. In the middle stage, feed intake and water intake decrease sharply, and the chickens also have respiratory symptoms and pass white or green loose droppings. Sick chickens gradually become emaciated, showing a negative growth trend. Chickens that survive have uneven size and body weight, and there is no peak in egg production. The production level of the flock declines, and a small number of sick chickens may develop lameness and eventually die of exhaustion. The course of this disease is generally 8 to 10 days.

5. Necropsy symptoms

1. The proventriculus of sick chickens has characteristic features. On necropsy, the proventriculus is enlarged like a ball, milky white in color, and on careful observation a grayish-white grid-like appearance can be seen.

2. When the proventriculus is cut open, the proventriculus wall can be seen to be thickened and edematous, and serous fluid can flow out with a gentle press. The papillae are swollen and hemorrhagic, and the papillary boundaries are fused with no distinguishable boundaries; the gizzard, thymus, and spleen are severely atrophied; the intestinal tract shows mucosal sloughing and hemorrhagic symptoms.

6. Prevention and control measures

1. Emergency vaccination. The whole flock of chickens should be urgently injected with inactivated oil-emulsion vaccine against chicken proventriculus-type infectious bronchitis, 0.5 ml per chicken, changing the needle after every 10 to 15 chickens. Healthy chickens should be injected first, followed by severely sick chickens, to prevent transmission and spread through the needle.

2. Control measures

① Strengthen management in ordinary times, improve environmental sanitation, maintain appropriate rearing density, and pay attention to ventilation.

② This disease is a novel coronavirus disease, and treatment with antibiotics alone is ineffective. Vaccine injection should be adopted. At 10 to 20 days of age, inject inactivated oil-emulsion vaccine or tissue inactivated vaccine against chicken proventriculus-type infectious bronchitis, 0.3 to 0.5 ml per chicken; inject once more 15 to 20 days before laying, 0.5 ml per chicken, which can effectively prevent this disease.

3. Drug treatment

① For the whole flock of chickens, in the morning give Xianweishukang (mixed with 100 kg water) for drinking, in the afternoon give penicillin (50,000 units per chicken) + Qidu (mixed with 150 kg water), and in the evening mix Jin'an (300 jin of feed per bag) into the feed, for five consecutive days.

② Diyanke (mixed with 100 kg water) for drinking + Xianweiyankang (500 chickens per bag) mixed into the feed. For severe cases, combine with penicillin (50,000 units per chicken) for 5 consecutive days. After adopting the above methods for 5 days, the condition of the flock improved markedly, and the outbreak was brought under control.