Non-Lethal Biomarkers Response in Fish Caged in a Rice Field During a Bifenthrin Application.

BACCHETTA C., CAZENAVE J., MORA C., ROSSI A.

Montevideo

Congreso; Setac Latin America 15th Biennial Meeting; 2023

There is a growing need to develop and improve non-lethal biomonitoring of fish, capable of providing information regarding stress response. Moreover, native fish inhabiting rice fields are exposed to multiple stressors like the exposure to current-used pesticides, extreme temperatures, and hypoxic conditions. The aim of the present study was to assess metabolic and immunological biomarkers in plasma and skin mucous of Piaractus mesopotamicus caged in a rice field during a bifenthrin (BF) application. Fish from a local farm (n =32; 44.6 ± 10.1 g; 14.2 ± 1.0 cm total length) were randomly divided into a control group and a bifenthrin-exposed group. Each was placed in different irrigation canals next to a paddy field (San Javier, Santa Fe, Argentina). These sites had separate water supplies but were under similar environmental conditions. Two cages (n = 8 fish/cage) per site were placed separately at each irrigation canal. BF application (Seizer ®; 100 cm3/ha) was carried out with coastal spraying equipment. Fish were removed 72 h afterwards for blood and mucous biochemical analyses. Glucose (Glu), triglycerides (Tg), total proteins (TP), and albumin (Alb) concentration were measured as metabolic biomarkers in plasma, together with alkaline phosphatase (AP) and lysozyme (Lys) activities as immunological endpoints in this sample. Mucous was investigated for TP concentration and for protease (P), AP, and Lys activities. The insecticide application caused changes in plasma metabolic and immunological profiles: AP activity and Glu, TP, and Alb concentration increased while Tg level and Lys activity decreased. Furthermore, in skin mucous, BF exposure significantly increased AP and P activities. These results evidenced the current use of BF in rice fields might alter the metabolic and immunological status of fish inhabiting rice fields. Our results also show that blood and skin mucous are very promising matrices for the development of non-lethal biomarkers to assess fish health in a stressed environment.