Updated: Nov 15, 2019
This week, we will be discussing about the Stress and Gout and their effect of poultry. Enjoy and Learn.
The health of your birds can depend on how much stress your birds are exposed to during their everyday life. Stress acts on the hypothalamus resulting in the release of corticotrophin releasing factor (CRF). CRF stimulates the anterior pituitary gland to release adrenocorticotrophin hormone (ACTH), which acts on the adrenal gland medulla to release epinephrine, norepinephrine and adrenorphines. These compounds have an effect on energy metabolism (an increase in lipolysis, glycogenolysis, and insulin production, and a decrease in gluconeogenesis and glucose utilization), and blood flow (an increase in blood flow to skeletal muscles, heart muscles, brain, skin and gastrointestinal tract as a result of increased heart rate and contraction and increased blood volume). Energy that could have been used in the production of more meat and eggs in these birds ends up being used to respond to stress.
Causes of stress: A husbandry system can be stressful if it exerts abnormal or extreme demands on the bird. Stresses can be mental, physical or a combination of both.
Family poultry are subjected to mental stress (pain, fear, anxiety) during a variety of common activities including:
Being chased by predators
Running away from vehicles
Tying and wing restraint,
Bundling in crates
Being on vehicle roof tops for transportation
Not having adequate food or water
The mental stress associated with these activities may be caused by visual, auditory, social, and/or physical factors.
Birds are subjected to physical stress (environmental: heat, cold, wind, strokes, wounds, etc.) through injuries and by actions such as:
Being caught by the legs and tied in groups
Holding upside down
Loading and unloading
During transport (vehicle movements, windy conditions, change of environment)
Mixed stressors can come from living conditions such as:
Environmental changes (fluctuations in temperature, lighting schedules or intensity, rains, flooding),
Changes in the social order in a flock (new entrants from the market or gifts)
They can also be caused by disease, such as, parasitism (ecto-, haemo-, and endoparasitism, inapparent infections, and exposure to poisons (household insecticides and herbicides, poisonous plants and poisonous animals)
Consequences of stress:
Immunosuppression: All stimuli that provoke stress will cause immunosuppression.
Indigenous poultry are particularly susceptible to stress and this may be reflected in their poor responses to vaccination (Newcastle disease, infectious bursal disease). This has been demonstrated by comparing the responses of commercial birds and indigenous chickens and ducks.
Immunosuppressed birds succumb more easily to both infectious conditions (viral diseases and bacterial diseases) and non-infectious conditions (such as worm infestations) than non-immunosuppressed birds. Some of these birds become carriers of various diseases for other healthy birds around them.
To be optimal, any disease control and prevention measures should consider the stressors in family poultry. The raising, transportation, marketing, and movement of birds to and from various sites need to be done in a way that minimizes stress for the birds.
Uric acid is produced in the liver and is the product of nitrogen metabolism in birds. Consequently, birds can develop gout secondary to an accumulation of urates. Gout is not a disease entity but a clinical sign of severe renal dysfunction that causes hyperuricemia and accumulation of urates in tissues of birds. There are two forms of gout which are the visceral gout and articular gout. In this article we will be discussing about the Visceral gout.
Clinical signs and lesions: The urate deposits appear as white chalky coating. Within the viscera they are observed microscopically as blue or pink amorphous material or as feathery crystals or basophilic spherical masses in tissues.
Cause, transmission, and epidemiology: The condition is due to a failure of urinary excretion, which can be as a result of:
Obstruction of ureters
Dehydration – most common cause
Renal damage – kidney necrosis
Vitamin A deficiency
Secondary to urolithiasis
Treatment with sodium bicarbonate
Diagnosis: This form is characterized by precipitation of urates in the kidneys, and serous surfaces of the liver, heart, mesenteries, air sacs or peritoneum. In severe cases surfaces of muscles and synovial sheaths of tendons and joints are affected. Precipitation of urates can occur within the liver, spleen and other organs.
Treatment: Correcting the cause of the renal damage will prevent other birds from developing gout.
Prevention: Visceral gout is prevented by feeding a correctly balanced diet and providing adequate water for chickens.
Recovery: Individual affected birds will not recover, but once the cause of the condition is corrected, there will not be an increased residual risk to new birds on the premises.
Source: Handbook of Poultry Diseases Important in Africa