Concentrations within the plasma from our study are
not even 50% of the least muscle tolerance concentration
for any time points. At this time no published
tetracycline residue studies are available; therefore, the
true tissue concentrations of tetracycline in vivo are unknown.
However, based on oxytetracycline tissue concentrations
in pigs and ruminants, the concentrations
of tetracycline will likely be a maximum of 6 to 7 times
the plasma concentrations in the kidney (Mercer et al.,
1978). The lung, which is often the target of tetracycline
treatment, only reaches or slightly exceeds the
concentration in the plasma. Other tissues such as fat
reach less than one-half of peak plasma concentrations
(Mercer et al., 1978; Craigmill, 2003).