Bharat Sadarao, Kemin Industries South Asia Pvt. Ltd.
Water is the most essential nutrient for all the living beings including poultry. Water is involved in many aspects of poultry metabolism including body temperature control, food digestion and absorption, nutrients transport, and waste products elimination from the body.
Therefore, providing clean and safe drinking water every day is the key of success for better farm health and economic returns to the producer. Although the importance of providing enough water or adequate access to water is well accepted, the importance of water quality on poultry performance is often overlooked. With rise in global population by 9.3 billion in 2050, demand for meat also increases with population growth. As estimated, poultry will account 37% of global meat supply to become world’s largest meat sector by 2022. The increasing consumption of animal products leads to higher pressure on global resources such as land, energy and water. For this, maintaining quality in drinking water for poultry is an important nutritional aspect as birds consume water at twice the level of feed.
Water quality is evaluated based on the factors such as physical (odor and taste) and chemical properties, toxic compounds, macro and micro mineral concentrations, and microbial contamination. Surplus concentrations of these may affect acceptability or palatability of drinking water, and the digestive and physiological functions of birds.
1.PHYSICAL CHARACTERISTICS OF WATER
Temperature, color, taste, odor, etc., are some of the physical characteristics of water which are determined by senses of touch, sight, smell and taste.
- COLOR, TASTE & ODOR
It is known that natural drinking water should be clear, tasteless, odorless and colorless. The most common undesirable characteristics of water depending on the contaminants are: reddish-brown color indicates presence of iron and blue color indicates excess copper. Hydrogen sulfide combined with iron to form black water (iron sulfide) implicates the presence of sulfate-reducing bacteria. Rotten egg odor is an indication of hydrogen sulfide in water. Presence of different salts in water also affects the taste of water. For example, presence of ferrous and manganese sulfates in water relates to the bitter or metallic taste. As a general observation, no health-based guidelines value is proposed for taste and odor.
The most comfortable temperature at which mature birds consume water should be between 50°F to 60°F (10°C to 15°C), but some studies observed that water at temperature of about 77°F (25°C) reduce mortality in chicks and poults. Chicken’s water intake increases by 6-7% for each degree above 21°C. Consumption of water reduces when the temperature is over 86°F (30°C) and birds refuse to drink water if temperature is over 111°F (44°C).
Turbidity in water mainly results from the presence of particulate matter such as silt, clay, algae or organic materials in water. Water with turbidity of less than 5 ppm is usually acceptable. Turbid water is unpalatable and indicates surface contamination, which may clog the water delivery system.
2.CHEMICAL CHARACTERISTICS OF WATER
Drinking water from different sources carries variety of chemicals. These individual chemicals or in combination with other chemicals may affect the performance of poultry.
Water pH at more than maximum acceptable levels for both high and low pH can negatively impact performance (Table – 1). An acidic pH can be responsible for improper digestion, equipment corrosion, impairing the effect of water vaccination or medication, and unpalatable in taste. Whereas, an alkaline pH is also unacceptable since it clogs the watering systems due to high level of mineral content mainly calcium and magnesium, which ultimately results in digestive upsets, diarrhea, poor feed conversion and reduced water/feed intake.
- TOTAL DISSOLVED SOLIDS (TDS)
Calcium, magnesium and sodium salts are the primary cationic components that contribute to TDS. Due to a measure of all dissolved inorganic and organic substances in water, total dissolved solids serve as a very poor predictor of animal health. Table - 2 provides guidelines for the suitability of poultry water with different concentrations of TDS.
Hardness should not be confused with salinity. Hardness is the total concentration of calcium and magnesium in water, whereas salinity includes other dissolved solids. The free calcium and magnesium react with soap to form an insoluble curd-like material. Hard water typically associates with deposit buildups and scale formation in water system components. This may ultimately reduce the effectiveness of water-administered medications, disinfectants and interferes with the cleaning agents. Water hardness has been classified as shown in Table – 3.
- NITROGEN COMPOUNDS
Among the nitrogen compounds, mainly nitrates and nitrites are the major contaminants that results from the biological decay of chemical fertilizers or animal wastes. Nitrate itself is not toxic. After ingestion, nitrate is converted to toxic form of nitrite in the intestinal tract by microorganisms, which interferes with the blood’s ability to absorb oxygen. Chronic nitrate toxicity causes poor growth, decreased feed consumption and poor coordination. Nitrate- nitrogen levels in the drinking water was observed to be as low as 3 to 5 mg/lit depress in broiler growth rate. Table - 4 can be used as a guide for nitrate and nitrite in water.
- NATURALLY OCCURRING CHEMICALS
A wide variety of naturally occurring chemicals are commonly found in drinking water (Table – 5). Sulfate in higher concentration along with magnesium or sodium form epsom salt and is responsible for wet litter condition in poultry due to laxative effect of combine minerals. An off flavor and reduced water consumption was observed in case of higher concentration of manganese. High levels of combinations of sulfate, magnesium or calcium indicated the formation of scale in the watering system.
Similarly, excessive levels of sodium have a “diuretic effect” and chlorides have a "detrimental effect on metabolism". The effects of sodium (Na) and chlorine (Cl) are difficult to separate, since neither exists in its pure state in nature and the elements usually occur together in water. Also, high concentrations of sodium or chloride, together with high levels of sulfate may increase water consumption and litter moisture. This can have an adverse effect on air quality in the poultry house and is responsible for poor performance. An increase in the salinity of water by adding NaCl results in defective egg shells and decreased hatchability of fertile eggs.
High levels of copper can give a bitter taste to the water which might cause oral lesions, gizzard erosions and liver damage. Iron in presence of oxygen gets converted from ferrous to ferric hydroxide, commonly referred as rusty water, which is essential for bacteria for cellular function and results in biofilm buildup.
3. BACTERIOLOGICAL/MICROBIOLOGICAL CHARACTERISTICS OF WATER
Ideally, bacteria should not be present in drinking water; their presence often indicates contamination by organic materials and can result in poor performance. Water is normally tested for total bacterial level as well as coliform bacteria level. The presence of coliform bacteria is generally associated with fecal contamination of drinking water, due to runoff to surface or ground waters supplies. Barton observed that, both top and bottom of farms suffer equally from microbial contamination such as E. coli and Pseudomonas. Table–6 presents the desirable levels of various microorganisms and the maximum acceptable levels that exists in poultry drinking water.
4.OTHER CONTAMINANTS IN WATER
Contaminants that are difficult to detect in water are pesticides, herbicides, industrial residues, petroleum products and heavy metals such as lead or cadmium. Costly testing procedures are required to test these contaminants in water.
To conclude, there were number of studies on water quality standards in past, but very limited scientific research work has been done and published in journals. It means, water quality standards for poultry are poorly researched and not regulated. In 1974, National Academy of Sciences subcommittee has taken a precious decision for summarizing the standards for livestock and poultry, but many of these standards are derived from those set for humans and other species. Now, the time has come to work accordingly to develop a precise tolerance profile for poultry drinking water quality.
Therefore, more attention should be focused on understanding what type of contaminants are present and addressing those that are known to cause poor performance can help producers to improve their bottom line. So, it should be the regular practice, and not a one-time event as water quality changes over the time. In addition, interaction between physio-chemical and microbiological parameters in presence of water complicate the management.
Finally, it is necessary to educate the producers and farm workers about the hazardous effects of polluted water on poultry production and human consumers health.