Handling, confinement and anaesthetic exposure induces changes in the blood and tissue immune characteristics of gilthead sea bream

Abstract

The gilthead sea bream Sparus aurata is a species of great ~nterest 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 handllng 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.

Assessing the population transmission dynamics of tilapia lake virus in farmed tilapia

“…Several studies also indicated that stocking density was inversely proportional to body weight, daily weight gain and length of Nile tilapia fingerlings that were closely associated with fish immunity (Breine, Nguenga, Teugels, & Ollevier, 1996;Gustafson, Ellis, & Bartlett, 2005;Inendino, Grant, Philipp, & Goldberg, 2005;Sanudi, Jere, Mzengereza, & Chirwa, 2015). Confinement stress was evidenced to suppress phagocyte-mediated reactive oxygen species (ROS) production, revealing that co-impact of virus and confinement stress to fish larvae without intact immune system could lead to lower tolerance and mass mortalities in farmed fish (Avtalion, 1981;Cubero & Molinero, 1997;Wise, Schwedler, & Otis, 1993).…”

Tricaine methane-sulfonate (MS-222) application in fish anaesthesia

“…Circulating leucocyte counts are often used to assess the immunological health of fish. Specific changes were found in gilthead seabream anaesthetized with MS‐222 in transport simulation (Cubero and Molinero, 1997), i.e. in the basophilic percentage drop, delay in acidophilic and basophilic response, and lymphoctopenia in thymus and pronephros.…”

Survival and behavioural responses of cool and warm water fish sedated with AQUI-S® 20E (10% eugenol) at high loading densities

“…Live transport can create stressful conditions for fish that may ultimately impact post‐transport survival (Harmon ). Procedures taken during transport to minimize the stress placed on fish include withholding feed 24–48 h prior to transport to minimize ammonia accumulation (Randall & Tsui ; Treasurer ), decreasing temperature prior to transport and maintaining proper temperature throughout transport (Golombieski, Silva, Baldisserotto & da Silva ; Pavlidis, Angellotti, Papandroulakis & Divanach ; Zhang, Goodwin, Pfeiffer & Thomforde ), minimizing physical handling during tank loading and offloading (Cubero & Molinero ; Farrell, Tang, Nomura & Brauner ), minimizing decreases in water quality (Erikson, Sigholt & Seland ), adding salt (Swanson, Mager, Doroshov & Cech ) and selecting proper loading densities (Urbinati, de Abreu, da Silva Camargo & Landinez Parra ; De Abreu, Sanabria‐Ochoa, Goncalves & Urbinati ; Carneiro, Kaiseler, Swarofsky & Baldisserotto ; Pearson, Small, Beecham, Sink, LaBarre & Minchew ).…”