Anaesthesia of common carp (Cyprinus carpio L.) with 2-phenoxyethanol: Acute toxicity and effects on biochemical blood profile

Abstract

The aim of the present study was to assess acute toxicity of the 2-phenoxyethanol anaesthetic in carp, and assess changes in their tissues using the biochemical blood profiles. Acute toxicity values of 2-phenoxyethanol in the carp fry determined by the OECD 203 method "Acute toxicity test in fish" were 10minLC50 0.39; 10minLC0.1 0.30; 10minLC99.9 0.50 ml·l-1, 96hLC50 0.17; 96hLC0.1 0.13; and 96hLC99.9 0.26 ml·l-1. A biochemical analysis of blood plasma (VETTEST 8008 analyser, Medisoft Co.) was used to determine changes in the biochemical profile of blood in carp stockfish due to anaesthesia by 2-phenoxyethanol. The analyses were made immediately prior the anaesthesia and after a 10 min and 24 h exposure to the anaesthetic at a concentration of 0.30 ml·l-1. A total of 30 two-year-old carp were examined. A significant increase in blood plasma alanine aminotransferase (ALT) levels from 0.15 μkat·l -1 to 0.35 μkat·-1 (P < 0.05) was found 24 h after anaesthesia. The other indices monitored [cortisol, glucose (GLU), total proteins (TP), triglycerides (TRIG), ammonia (NH3), alkaline phosphatase (ALP), aspartate aminotransferase (AST) and creatine kinase (CK)] showed no significant differences among the groups of fish examined. The results showed that 2-phenoxyethanol at a concentration of 0.30 ml·l-1 is not completely safe for carp fry and two-year old carp. In view of different sensitivities in different age group mentioned above, the authors assume that concentration will be safe for broodstock carp.