The present invention provides improved chlortetracycline-containing
animal feed compositions and processes and apparatuses for their
preparation. In certain embodiments, raw fermentation broth comprising
chlortetracycline is divided into two portions. The first portion is
mixed with a compound that complexes chlortetracycline. The second
portion is acidified and the solids are removed. The acidified liquid is
treated with a complexing agent to produced a chlortetracycline complex.
The first and second portions thus treated are then mixed and the mixture
is passed on to a filter press or other means for separation of the
solids to produce a wet cake comprising complexed chlortetracycline. In
alternative embodiments, the second portion may be acidified and filtered
and admixed with the first portion prior to the complexing step. The
resulting mixture is passed on to a filter press or other means for
separation of the solids. In still further embodiments, the complexing
steps are replaced with neutralizing or basification steps to yield the
free base form of chlortetracycline. The wet filter cake comprising
chlortetracycline and fermentation solids is dried and sized to produce a
dried semi-finished product in the form of a powder, meal, granules,
pellets, tablets, etc. The semi-finished product may be standardized to
produce an animal feed supplement having a desired potency. In a further
aspect, the present invention relates to a method of combating microbial
infection and promoting growth in animals comprising orally administering
to said animals an effective amount of an animal composition according to
the present invention.