Drinking Water: – As Risk Factor for Poultry Health

In the poultry industry, there is the importance of adequate physical, chemical and microbiological quality of water. In poultry farming, agreat number of birds are affected by water quality as water is provided from the same source to many birds. The drinking water plays an important role in the transmission of several bacterial, viral and protozoan diseases that are of economic importance and leads to huge production losses to the poultry industry. Important factors to prevent waterborne diseases in poultry production are the protection of supply sources, disinfection and the quality control of in terms of microbiological, chemical and physical characteristics of the water. Water is an essential nutrient for birds and therefore quality preservation is fundamental for good flock performance. The farmer may prevent many diseases in bird flocks by controlling the quality of the ingested water, this will certainly result in decreased costs and increased the profit of production, which are of primary importance in livestock husbandry practices.

Water as a vehicle of infection for poultry

Water is the most abundant and widely distributed in nature. In the natural state, water is one of the purest compounds known; nevertheless, it is currently difficult to find a freshwater source that has not been altered by humans. Nowadays wastewater from agriculture and urban areas, which might contain high levels of pathogenic microorganisms, are disposed of on the soil or into the aquatic environment. The residues are then carried to the superficial and underground waters by the rain. The use of physical, chemical and microbiological qualities is of fundamental importance in animal production because many animals have access to the same water source and a problem in the water quality would affect a great number of animals. This is particularly relevant in poultry production, where one single water source serves thousands of birds. Therefore, proper control measures should be considered as a priority, in order to prevent the occurrence of diseases that are spread through water, and would certainly result in great economic losses. Although water does not provide ideal conditions for the pathogenic microorganism to multiply, they will generally survive for enough time to allow waterborne transmission. Water is, therefore, an excellent transmission route of agents responsible for human and animal diseases, mainly those in which fecal-oral transmission occurs since contamination of water supplies is still gradually increasing as a result of urban and rural activities.

The scenario is not so different in the rural area, where many factors increase the risk of occurrence of waterborne diseases. Examples of such factors are the inadequate disposal of organic and inorganic residues from agriculture and livestock productions; the lack of concern regarding the quality control of the drinking water given to animals, resulting in the animals drinking very low quality water and finally the general belief that any water sources in the rural area have good quality and can be used as drinking water for both humans and animals, no matter if they have been submitted to adequate water treatment or not. The use of potable water in animal rearing is a preventive approach that is expected from farmers, mainly from poultry farmers, who are unique in many aspects. The intensive methods of rearing poultry have more preventive consciousness regarding diseases. Disease dissemination through water can result in great losses to the producer, besides the hazards of carrying zoonosis pathogens to the herd, which would reflect in a Public Health problem. Diseases that can be transmitted to the birds flock through the drinking water may originate from water contamination by feces and secretions of sick birds, or by the utilization of water already contaminated by pathogenic organisms that originate from other animal species and the man, such as in the case of salmonella and Escherichia coli, respectively. Diseases caused by bacteria, virus, and protozoa are among the most common diseases in the poultry industry in which drinking water plays an important role.

POULTRY DISEASES POTENTIALLY TRANSMITTED BY WATER

Bacterial Diseases

1. Chronic Respiratory Disease (CRD)

Etiologic Agent: Mycoplasma gallisepticum. The disease might be complicated by the presence of Escherichia coli.

Main clinical signs: respiratory distress, weight loss, respiratory rales, decreased egg production, poor flock uniformity and feed conversion, increased carcass condemnation. The etiological agent may contaminate water by the expectorations of the birds and Escherichiacoli may be present by fecal contamination of the drinking water.

• Colibacillosis

Etiological Agent: Escherichia coli.

Main signs: exacerbation of respiratory symptoms, which are complicated by septicemia, occurring after stressing situations. The pathogen may be present due to fecal pollution of the water.

• Avian Cholera

Etiological agent: Pasteurellamultocida.

Main signs: appetite loss, prostration, decreased egg production, cyanotic combs, high mortality, and respiratory signs. The pathogen may be present as a result of the fecal pollution of the water.

• Fowl Typhoid

Etiological agent: Salmonella Gallinarum.

Main signs: prostration, green diarrhea, mortality, and decreased production. The agent may be present in the water as a result of fecal contamination.

Diseases caused by virus

1. Newcastle Disease

Etiological agent: Paramyxovirus.

Main signs: respiratory, neural or digestive signs, decreased egg production, high mortality. The etiological agent may be present in the water due to pollution by feces and discharges from the respiratory tract of infected birds.

• Infectious bronchitis

Etiological agent: Coronavirus.

Main signs: respiratory impairment, decreased egg production. The etiological agent may contaminate water by fecal pollution or by discharges from the respiratory tract of infected birds.

• Marek’s disease

Etiological agent: Herpesvirus.

Main signs: weight loss, paralysis, and mortality. The etiological agent may be present in the water due to epithelial desquamation of infected birds.

Water treatment

Disinfection of water is of primary importance in poultry farming. The aim is to eliminate pathogens that might be in the water, both those originated from contamination of the water source and those incorporated in the way between the water source and the drinkers. A second objective is to leave residual levels of chlorine in the water in order to eliminate pathogens that might be added to it if infected birds have access to water in the drinkers. The use of water with controlled microbiological quality as drinking water for birds is of fundamental importance, considering that:

– Many birds have access to the same water source;

– Birds ingest water daily;

– Water is considered a good transmission vehicle for many pathogens;

– Residues from human and animal activities pollute a great number of water sources.

To assure that the water consumed by birds will not pose risk to the flock health, it should be disinfected.The most recommended disinfecting agent is chlorine, due to its efficiency, cost, practical use and inequity to birds when adequately applied. Water treatment in the rural area may use diverse compounds as chlorine sources, which present different levels of available chlorine, among which two are cited below:

Calcium hypochlorite:White powder that contains 70% of available chlorine

A commercial solution of sodium hypochlorite: clear liquid with 10-12% available chlorine.

In emergency situations, bleach may also be used as chlorine source; it contains available chlorine levels of 2.0%. Adequate chlorine dosage in drinking water for birds is 3 ppm, although birds may tolerate residual chlorine concentrations of more than 10 ppm can be used. Concentrations of 5 ppm are indicated to control biofilm formation. The presence of organic material rapidly inactivates chlorine, therefore, drinkers should be cleaned daily to avoid accumulation of organic material. Water pH should be lower than 8.5, and optimal pH values are from 6.0 to 8.0. Chlorination should be suspended two days before any vaccination with live bacteria and virus via drinking water. Supply of chlorinated water may be resumed 4 hours after vaccination is completed. Residual chlorine concentrations between 2 and 5 ppm have resulted in no performance impairment and have been suggested as the levels to be added to the water supplied to broilers and laying hens. The microbiological quality of water given to broilers improved at 2 ppm of residual chlorine.It should be remembered that chlorine reacts notonly with microorganisms during chlorination, but also with organic and inorganic substances, generating the water chlorine demand. The presence of residual chlorine is thus important since it will be responsible for the elimination of the microorganisms that contaminate, by different routes, the water given to the birds. Residual chlorine should be measured 30 min after the disinfectant comes into contact with the water.

Conclusion

After considering all these points, proper and hygienic drinking water should be provided to the poultry birds. It is of foremost importance from a production and economic point of view.