DAO 31:89-94 (1997)  -  doi:10.3354/dao031089

The gilthead sea bream Sparus aurata is a species of great interest for aquaculture, and in the last few years its culture has increased in the Mediterranean. This study was carried out to elucidate the mechanisms underlying the immunological response of fish after handling and confinement, procedures commonly associated with fish transport, as well as to determine the putative protective role of an anaesthetic (tricaine methanosulphonate) during confinement. Handling produces changes not only in circulating blood cells but also in the immunological cell populations of the thymus, spleen and pronephros. A stronger response in immunological cells was obtained when handling was followed by confinement. Circulating white blood cells returned to normal approximately 48 h after the onset of stress, whereas immunological tissue cells recovered later. The presence of an anaesthetic partially prevented the circulatory response, suggesting that the immunological response was less and supporting therefore the belief that the anaesthetic plays a protective role. However, it worsened the effect of handling plus confinement on haematopoietic organs, indicating that examining immunological cells in circulation only can lead to a false conclusion. Our results suggest that fish are not completely recovered until at least 144 h (6 d) after handling and transport, when cellular recovery in immunological organs occurs.

Handling · Confinement · Gilthead sea bream · Anaesthetic (tricaine methanosulphonate) · Thymus · Spleen · Pronephros