Food anticipatory behaviour as an indicator of stress response and recovery in Atlantic salmon post-smolt after exposure to acute temperature fluctuation

• Published in: Physiology & behavior Vol. 105; no. 2; pp. 350 - 356
• Main Authors: Folkedal, Ole, Stien, Lars H, Torgersen, Thomas, Oppedal, Frode, Olsen, Rolf Erik, Fosseidengen, Jan Erik, Braithwaite, Victoria A, Kristiansen, Tore S
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 18.01.2012; Elsevier
• Subjects: acute exposure; Animals; Aquaculture; Behavioral psychophysiology; Behaviour; Biological and medical sciences; Conditioning, Classical - physiology; cortisol; excretion; Feeding Behavior - physiology; fish; Fundamental and applied biological sciences. Psychology; Hydrocortisone - secretion; Image analysis; Light; Marine; Motivation; Motivation - physiology; oxygen; Oxygen Consumption; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Salmo salar; Salmo salar - physiology; Stress; stress response; Stress, Physiological - physiology; Temperature; Time Factors; Welfare; Image analysis; Temperature; Behaviour; Motivation; Welfare; Salmo salar; Stress; Aquaculture; Acute; Anticipation; Exposure; Recovery; Indicator; Vertebrata; Pisces; Behavior
• ISSN: 0031-9384; 1873-507X
• DOI: 10.1016/j.physbeh.2011.08.008

Abstract In this study we evaluated Pavlovian conditioned food anticipatory behaviour as a potential indicator for stress in groups of Atlantic salmon, and compared this with the physiological stress responses of cortisol excretion into water and hyper-consumption of oxygen. We hypothesised that environmental stress would result in reduced feeding motivation. To assess this, we measured the strength of anticipatory behaviour during a period of flashing light that signalled arrival of food. Further, we expected that fish given a reduced food ration would be less sensitive to environmental stress than fish fed full ration. The fish responded to an acute temperature fluctuation with hyper-consumption of oxygen that decreased in line with the temperature, and elevated cortisol excretion up to 1 h after the stressor. These physiological responses did not differ significantly between the food ration groups. The anticipatory behaviour was significantly reduced after the stressor and returned to control levels after 1 to 2 h in the reduced ration group, but not until after 3 to 4 h in the full ration group. Our results show that acute stress can be measured in terms of changes to feeding motivation, and that it is a more sensitive indicator of stress that influences the fish over a longer time period than measures of change in cortisol excretion.