12.4. Effect of stress on protective barriers

Unit 12 - Stress and immune response
12.4. Effect of stress on protective barriers
Stress in fish causes chemical changes in mucus leads to decrease in its effectiveness against invading pathogens. It also upsets the normal electrolyte balance in fish so in freshwater fish the water is absorbed into the body where as in marine fish the water is dehydrated. In addition Handling stress and chemicals used in disease treatment in fish disrupts the physical barrier which makes easy for the pathogens to invade the fish and cause the disease. Stress also cost the fish its energy and also compromise in osmoregulatory function.
Scales and Skin
Handling stress is the most common stress that causes most damage in the scales and skin of the fish. Cut in skin or remove of scale creates an opening for invasion by pathogenic organisms. The infestations with parasites cause damage to gills, skin, fins, and loss of scales which favors bacteria to enter into fish and cause disease in fish.
Stress also play its role in immune system among physical stress temperature in particular has a major impact on the immunity. Cold temperature can severely decrease the activity of killer cells which intern affect the immune system. quick decrease in temperature leads to decrease in antibody release in the fish.
Prevention of Stress
To prevent the stress in aquaculture system main emphasis should be given to the water quality, followed by good nutrition and sanitation.

Last modified: Thursday, 21 June 2012, 9:23 AM