The Effects of Acute Stress on Rainbow Trout (Oncorhynchus mykiss)


Abstract: The physiological effects of acute stressors (transport, handling, netting and confinement) on rainbow trout in an aquaculture system were investigated. Serum cortisol level, serum glucose and lysozyme activity were determined in rainbow trout stressed by acute stressors, and compared with those of unstressed (control) fish. Serum cortisol, glucose levels and lysozyme activity were significantly higher(P<0.05) in stressed rainbow trout. Cortisol levels in the unstressed fish (average 31.50 µg/dL) were lower than those in stressed fish (average 45.16 µg/dL). In stressed fish, serum glucose levels were an average at 58.53 mg/dL while in unstressed fish were 26.23 mg/dL. Lysozyme activity was typically elevated in rainbow trout upon acute stress (minimum 140- maximum 900 unit/ml). These physiological parameters indicated that rainbow trout are sensitive to disruption by acute stressors in an aquaculture system.

Keywords: Rainbow trout (Oncorhynchus mykiss), acute stress, serum, cortisol, glucose, lysozyme activity

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