Bioaccumulation of trimethoprim, sulfamethoxazole and N-acetyl-sulfamethoxazole in Artemia nauplii and residual kinetics in seabass larvae after repeated oral dosing of medicated nauplii
M. Touraki et al., Bioaccumulation of trimethoprim, sulfamethoxazole and N-acetyl-sulfamethoxazole in Artemia nauplii and residual kinetics in seabass larvae after repeated oral dosing of medicated nauplii, AQUACULTURE, 175(1-2), 1999, pp. 15-30
The pharmacokinetics of trimethoprim (TMP), sulfamethoxazole (SMX) and its
metabolite N-acetyl-sulfamethoxazole (N-acetyl-SMX), were studied in Artemi
a nauplii as a function of the duration and temperature of their storage, f
ollowing their enrichment with the therapeutics using the bioencapsulation
technique. A marked decrease in the therapeutic content of the nauplii was
observed upon storage at 18 degrees C and 25 degrees C and it was concluded
that medicated nauplii should either be administered fresh to fish larvae
or after storage for 8 h at 5 degrees C, at the most. Under the latter cond
itions, satisfactory levels of TMP and SMX were achieved, high survival rat
es and dry weight contents of the nauplii were preserved and minimal leakag
e of the therapeutics to the environment was secured. Treatment of seabass
larvae with one, three, six or ten doses of medicated Artemia nauplii, show
ed that maximum levels of the therapeutics are achieved in fish larvae when
10 doses are used. Following the treatment scheme of oral administration o
f 10 doses of medicated Artemia nauplii to fish larvae, the residual kineti
cs of TMP, SMX and N-acetyl-sulfamethoxazole were studied in seabass larvae
. TMP and SMX showed different kinetic characteristics. A steady state of S
MX concentration is considered to be achieved in fish body tissue during th
e 5-day medication period. TMP, SMX as well as the metabolite N-acetyl-sulf
amethoxazole, were detectable in small amounts in fish body tissue even 100
h-post treatment. These data suggest that oral medication of fish larvae t
hrough the use of Artemia nauplii as a carrier of therapeutics, appears to
be a quite promising approach to be used as an alternative method of treatm
ent, which could minimize some of the problems arising from the methods cur
rently in use. (C) 1999 Elsevier Science B.V. All rights reserved.