Sensory stimulation modulates feeding response and enteroendocrine function in gilthead seabream ( Sparus aurata )

Optimal feed intake relates to sensory properties of feed, and it is key to maintain the animal’s motivation to eat during unfavorable circumstances. We tested whether attractive chemosensory cues could improve stress-induced anorexia. Two experiments were conducted initially in gilthead seabream (Sparus aurata) fed either a control diet or the same diet supplemented with a palatability enhancer (PE). The experiments were conducted in summer (average T = 23 °C) and winter (T = 16 °C). There were no differences in feed intake during the summer period, but the PE diet had a 48% higher consumption during a winter storm (p = 0.064). To test the effect of PE in feed intake during stressful conditions, two other experiments were conducted (spring: 19 °C and autumn: 14 °C), including a stress period. Stress resulted in a reduction in feed intake (29.5% or 61.0% depending on temperature), which was alleviated (lower reduction: 4.4% or 38.0%) in fish fed the PE supplemented diet. The expression of several entero- and neuroendocrine genes was assessed, which revealed increased and decreased ghrelin- and cholecystokinin-expression in the stomach of animals fed the PE diet, respectively. Findings indicate that enhancing the attractive qualities of feeds through olfactory and gustatory stimulation can be a valuable strategy for addressing stress-induced anorexia in fish aquaculture.