Enhanced transport of calcein into rainbow trout, Oncorhynchus mykiss, larvae using cavitation level ultrasound

Enhanced diffusion of calcein into rainbow trout, Oncorhynchus mykiss, larv ae was examined using cavitation level ultrasound for the purpose of mass-m arking. Three variables, consisting of two voltage amplitudes (90 and 120 m V), two calcein concentrations (600 and 900 mg/l) and two duration of treat ments (5 and 15 min) were examined. Thirty-day-old yolk sac fry (n = 640) w ere treated with calcein and/or ultrasound. Overall mean diffusion of calce in ranged from 3.8 to 36.2 ng/fish. The highest absorption level was observ ed with highest amplitude applied for 15 min in 900 mg/l of calcein solutio n. Significantly higher diffusion resulted with 120 mV when compared agains t 90 mV (P < 0,05). A high level of background autofluorescence (7.8 ng/fis h) was also measured. Results from these experiments demonstrate: that a se veral-fold increase in the rate of diffusion of calcein into fish can be ac hieved when treated with cavitation level, low frequency ultrasound (40 kHz and 90 or 120 mV). The technique has potential for use in delivery of comp ounds for marking fish as well as for delivery of therapeutants such as vac cines and antibiotics. <(c)> 2001 Elsevier Science B.V. All rights reserved .