swim back home
Stress and Reaction to Injury
swim back home |
Stress and Reaction to Injury |
IV. Stress and Reaction to Injury
A. Stress
Any factor which causes a fish to depart from a state of optimal balance of
organ function is stressor (poor water quality, crowding, temperature change,
etc.)
The stress response includes:
1. Resistance - catecholamine
release (effects in seconds, minutes).
Fish attempts to regain "original" level of homeostasis.
2. Adaptation — Cortisol release (effects in hours, weeks, months).
Fish attempts to develop
a "new" level of homeostasis under the influence of a chronic stressor.
3. Exhaustion — Fish exhausts its reserve of energy, hormone precursors
which were needed to maintain the "new" level of homeostasis (example
— spawned — out Pacific Salmon)
When stress occurs fish become extremely susceptible to infectious diseases.
B. Inflammatory Process
Fish - production of heat is not a component of inflammatory process as in mammals. Note: the water temperature affects the rate of the inflammatory process and rate of antibody production.
The acute inflammatory process includes capillary dilatation, exudation of fibrinogen and immunoglobulins and then migration of phagocytes, lymphocytes and thrombocytes into the area.
Liquefactive, coagulative, and fat necrosis can result.
The types of exudate formed can include suppurative, catarrhal, fibrinous, serous ("abscesses" rarely found)
If the fish survives, the lesions can resolve by healing, or can have sequelae, such as granuloma formations, fibrosis.
 |
|
|
|
|
|
|
|
|
 |
 |
|
||||||
 |
 |
 |
 |
 |
 |
 |
|
|