The Alltech Feeding Times Issue 36 - Winter 2021 Winter 2021 - Page 15

How is ammonia gas formed ?
Nitrogen is a component of poultry diets , via either protein or other sources . Some of this nitrogen can be used by the bird and is incorporated into tissues or eggs , but most of it is excreted in the urine or feces in the forms of uric acid ( around 80 %), ammonia ( around 10 %) and urea ( around 5 %). Once the uric acid and urea are excreted , they are converted into ammonia through microbial and enzymatic breakdown via the bacteria and enzymes found in manure . After this process , ammonia is readily released into the air as a gas that can be detected by both birds and farmworkers .
Factors that influence how ammonia is formed and released into the poultry house environment :
• Litter type
• Bird activity
• Stocking density
• Manure handling
• Frequency of manure removal
• Ventilation rate
Factors that influence how manure bacteria and enzymes break down nitrogen to form ammonia :
20 – 30 ppm for 16 – 28 days . Studies of turkeys have found that , among birds dealing with an E . coli challenge , those that were exposed to ammonia levels between 10 – 40 ppm had more bacteria in their lungs than the birds that were not exposed to ammonia . In layers , it has been suggested that early exposure to ammonia could have a lasting effect and might impact how pullets perform later as laying hens . Additionally , chronic exposure to high ammonia concentrations may impair egg production for layers .
At a microscopic level , researchers have found that exposure to ammonia can trigger changes within the animal . In poultry , high-level exposure to ammonia for 20 days decreased the intestinal surface area ( possibly impacting nutrient absorption ), decreased the bird ’ s resistance to oxidative stress , altered the intestinal tract ’ s ability to break down nutrients and impacted immune organs . Exposure to high concentrations of ammonia for even a short period of time may impact birds just as much as exposure to medium concentrations of ammonia for longer periods .
How to reduce ammonia levels in poultry houses
There are several strategies for decreasing ammonia in the barn . These strategies can be used individually or in combination and can help encourage good barn air quality and better poultry performance potential . These strategies include ventilation and management of both the barn and the poultry litter / manure .
• Nitrogen content
• Temperature • Moisture / humidity
• pH
What impact can ammonia have on the bird ?
The results of poultry research studying how ammonia levels can impact production are varied . Some groups suggest that 25 ppm should be the maximum , whereas other groups suggest that exposing birds to 20 ppm for long periods of time could lead to issues like a debilitated immune system and respiratory tract damage . Other research suggests that , when poultry can choose between environments featuring different levels of ammonia , they choose environments with ammonia levels under 11 ppm .
Ammonia is toxic to animals . High levels of ammonia may lead to observable changes , such as difficulty breathing , irritation of the trachea ( the breathing tube ), air sac inflammation , inflammation of the mucus membranes of the eye or a combination of these symptoms . Many other , less obvious changes can take place upon exposure to lower levels of ammonia . Studies have found that exposure to 20 – 25 ppm throughout production can result in increased susceptibility to secondary challenges ( viral or bacterial ), decreased feed efficiency and tissue damage . These changes have been noted in broilers exposed to ammonia levels between
Ventilation acts as an in-barn air quality control , removing ammonia from the barn and bringing in clean air . This method does not , however , reduce or inhibit the formation of ammonia . Nevertheless , maintaining , appropriate ventilation during all seasons will help reduce the gaseous ammonia levels in the barn and keep the litter dry .
Good barn management can help to diminish the formation of ammonia gas . Proper barn management includes ensuring that the litter or manure is not wet . Several ways to keep litter from getting wet are to fix leaky drinkers and sprinkler systems ; choose the appropriate litter ; maintain a suitable barn relative humidity for the age of the bird ; reduce the potential for condensation ; and properly heat and ventilate the barn .
Strategies for managing the litter and manure can be separated into two main management actions : Managing the bird diet : The formation of ammonia in the manure and its subsequent release as a gas can be traced back to increased nitrogen levels in the manure . Fecal nitrogen levels can increase if the bird does not properly break down and absorb the protein in the feed . This can happen if the bird ’ s diet features too much complex