Humidity and Monsoon
Humidity is a part of everyday life. When it rains, it will increase the relative humidity because of the evaporation. The air where the rain is falling may not be completely saturated with water vapor. However, the longer it rains, the more the humidity will increase because of the air constantly drawing the water. As all of you know humidity levels play a pivotal role in ammonia production, as higher humidity enhances the bacterial generation of ammonia. High humidity levels prevent faecal and urinary desiccation and provide the optimal setting for bacterial propagation and subsequent ammonia production.
Recommended Ammonia Level
Considering both human and poultry health, guideline exposure levels for ammonia is set to 20-25ppm in many countries. However, in practice, the concentration of ammonia in some broiler houses may easily exceed 30-70 ppm, particularly in monsoon and wintertime. Ideally, NH3 concentration should not exceed 20 ppm over an eight-hour period or 35 ppm over any ten-minute period during the poultry production cycle.
Ammonia and Poultry
Ammonia in a poultry house comes from the birds themselves. Unused nitrogen is excreted as uric acid (80%), ammonia (10%), and urea (5%). When ammonia gas is exposed to moisture, it reacts and forms a basic, corrosive solution called ammonium. This aqueous ammonium solution causes harm to birds. The ammonium corrodes the lining of the chickens’ respiratory tract and paralyzes or even destroys the cilia of the epithelial cells. In such conditions, the mucus on the mucosal surface of the trachea cannot be cleared by the cilia and thus bacteria become trapped. When the bacteria reach the lungs or the air sacs, they cause infections.
Effects of ammonia emission on birds
Ammonia gas has a characteristic pungent odour. At high concentrations it is irritating to mucous membranes of the respiratory tract and the conjunctivae and corneas of the eyes. Damage to the mucous membranes of the respiratory system increases the susceptibility of birds to bacterial respiratory infection, especially E. coli infection. Problems occurring due to high-performance genetics, feed formulation and medication can lead to production of wet manure causing increased ammonia. High levels also have a negative impact broiler performance, feed efficiency, overall liveability, weight gain, feed conversion, condemnation rate at processing and the immune system of the birds.
Ammonia is a strong oxidative stressor that can cause inflammation. Trials have shown that high concentrations of ammonia can alter the normal organ function of birds, impair energy metabolism, and cause mitochondrial damage in the mucosa of the gastrointestinal tract. The result is an economic loss to the grower and integrator.
Scientific ways to reduce ammonia production in poultry
This technique involves reducing the nitrogen intake per bird by reducing the crude protein in the poultry diet. This works on the concept that ammonia is formed by the breakdown of undigested protein and uric acid in the manure. Therefore, a 1% reduction of CP in the poultry diet resulted in 10–22% reduced NH3 emission in poultry houses. One extra benefit of reduced protein will be the reduced requirement for water intake because excess protein requires water as part of the excretion process. If the protein level in the diet decreases consumption of water is also reduced which results in drier litter and consequently less moisture and ammonia in the air.
There are some additives that can be added to the diet to cut off ammonia. The acidification of the diet helps to reduce the ammonia production problem.
The addition of Orthophosphoric acid in the poultry diet helps to improve protein digestion and controls ammonia emission. Orthophosphoric acid takes part in the initiation of protein digestion at early stage of digestion. It contributes to protein digestion by supplying H+ ions which activate pepsinogen, the precursor to proteolytic enzyme pepsin. After activation of the pepsin enzyme, it breaks down the proteins in the feed which helps in digestion. Due to improved protein digestion nitrogen excretion is reduced and finally, it reduces ammonia emission.
Microbial and enzymatic treatment of litter
This process utilizes beneficial microbes and enzymes which can convert uric acid and urea rapidly into ammonia which can then be lost out thereby reducing the ammonia levels before chicks are placed in the poultry house. Commercial microbial products or Yucca schidigera extract as a natural feed additive were reported to significantly lower ammonia levels. Mitigating ammonia by using yucca extract could be achieved by the modification of gut microbiota, enhancement in digestion, and absorption of nutrients, leading to better growth and production performance of poultry.
Addition of urease enzyme inhibitors
Inhibitors are also used in poultry litter to slowly convert uric acid and urea to ammonia by the process of inhibiting enzymes and microbial activities. Phosphorodiamidate was reported to inhibit urease activity and this reduced the conversion of urea into ammonia.
Ensure proper ventilation
Adjust the ventilation rate – if ammonia levels increase, more ventilation is needed. Over time, higher ventilation rates will tend to reduce litter moisture levels, which in turn will reduce the ammonia generation rate, which in turn leads to lower ammonia levels. However, this should only be in accordance with the climate and temperature of the poultry house. Record the relative humidity in your houses each morning. If you see the relative humidity climbing, make larger increases. Bottom line: don’t wait until you have an ammonia problem to try to solve it. After all, “An ounce of prevention is worth a pound of cure.”
Note: References are available on request
by Dr. Sanjay Gapat, Alivira Animal Healths