Safety under the condition for use
The microbial feed additives regulated by Regulation
(EC) No. 1831/2003 and in accordance with the previous
guidelines are subjected to detailed safety assessment with
the intention of ensuring that they are innocuous to target
animals, users, and consumers. Particular attention is
focused on the presence of transmissible antibiotic resistance
markers, and the potential for production of harmful
metabolites. The guidelines do not diVerentiate between
species and strains with long histories of safe use and other
micro-organisms.
3.3.1. Studies on target species
3.3.1.1. Tolerance testing on target species/animal
categories. For each animal category, a target specie tolerance
testing shall be designed to determine a safety margin.
The aim of such trial is to evaluate for the animals the risk
of an accidental overdosing originated during feed production
(e.g., mixing heterogenicity). The trial shall be conducted
at a dosage being at least 10-fold the maximum
recommended dosage proposed by the applicant. In farm
animals, an experimental duration period of one month for
young and fast-growing animals and three month for adults
such as dairy cattle in lactation should be respected. For
breeding animals, the experimental duration period should
be the total length of a reproductive cycle. The tolerance
test requires at least the assessment of clinical signs (i.e.,
morbility and mortality) and zootechnical parameters (i.e.,
weight gain, feed intake, feed conversion ratio, laying rates,
egg mass, and milk production). When safety margin is less
than 10, to demonstrate the safety of the additive, data on
haematology, blood chemistry, and histopathology must be
available.
Studies on the eVects of the microbial additive on the
microXora of the digestive tract are also required when a
claim is made concerning an eVect on the intestinal microXora.