Can digestive biomarkers detect early effects of bifenthrin exposure in native fish?

The digestive health of fish is directly related to their ability to process food and therefore, to their welfare and growth performance. However, the digestive tract of fish is also one of the main routes of entry for pesticides, which could ultimately affect metabolism. The aim of this study was to assess the responses of digestive biomarkers in two native and commercially important fish species confined in cages in a rice field during a bifenthrin (BF) application. Two cages per species were placed at each experimental site: the control site and the site where BF was sprayed (Seizer®; 100 cm³ ha^-1). At 72 h after application, morphological and biochemical biomarkers, the intestinal accumulation of BF and digestive enzyme activities in different tissues were evaluated in Hoplosternum littorale and Piaractus mesopotamicus. Short-term in situ exposure caused increased plasma glucose levels and intestinal accumulation of BF in both fish species, without changes in condition factor or hepatosomatic index. Lower lipase and amylase activities were observed in the intestinal tissue of P. mesopotamicus while H. littorale showed no enzymatic changes. Digestive biomarker enzymes could be used as early warning tools to reflect the health status of sensitive fish in rice-fish cocultures predicting economic implications for producers.