Evaluation of the Sedative Effect of Limonene to Reduce Stress During Transportation of Gilthead Seabream (Sparus aurata)

Abstract

Common aquaculture practices such as fish transport can induce stress. With interest in animal welfare increasing among consumers as well as for the industry, the main objective of this study was to evaluate the sedative action of limonene to reduce stress during fish transportation in an important commercial species such as Sparus aurata. After the optimal dose of limonene was determined through measurements of the reduction in respiratory rate, fish transported for 6 h with the sedative showed higher water oxygen levels together with a more homeostatic state, judged by lower changes in osmolality or stress parameters (plasma cortisol and glucose and gene expression of stress biomarkers in the head kidney), than fish transported without limonene. Limonene-treated fish also presented a reduced metabolism, which may suggest a more relaxed state. However, the sedative benefits of limonene were partly masked by the negative effects of its solvent (ethanol); therefore, finding an alternative could enhance the potential of limonene as a sedative for fish transport. The findings of this research could help reduce fish stress derived from aquaculture practices, benefiting both fish and the industry.