Requirements for the assessment of microbial feed
additives
3.1. Identity, characterisation, and conditions of use, methods
of control
This section relates the identity of the additive (proposed
proprietary name, type of additive according to its main
function, qualitative and quantitative composition, qualitative
and quantitative composition of any impurities, physical
state of each form of the product and manufacturing
process); characterisation of the active agent(s) (nomenclature,
biological origin, genetic modiWcation, compliance
with release Directive for genetically modiWed micro-organisms
(GMOs), toxin production and virulence factors, antibiotic
production and antibiotic resistance, other relevant
properties); characterisation of the additive: physico-chemical
and technological properties (stability of the additive,
other physico-chemical or biological properties, incompatibilities
with other feed ingredients); conditions of use of the
additive (technological and zootechnical additives, safety
data sheet); control methods (general methods and description
of the qualitative and quantitative methods for routine
control of the active agent in premixtures and feedingstuVs).
3.2. EYcacy
Studies on eYcacy of probiotics strains must be performed
in target species/animal categories. The claims for
microbial products are: improved performance and feed
conversion for the target species; reduced morbidity or
mortality which improves the welfare of the target species;
beneWts for the consumer through improved product quality
and beneWts for the wider environment. According to
the current guidelines, the demonstration of these eVects
should be based on a minimum of three trials demonstrating
a statistically signiWcance (P< 0.05) on the speciWc
A. Anadón et al. / Regulatory Toxicology and Pharmacology 45 (2006) 91–95 93
animal categories, where an eVect is claimed. The three statistically
signiWcant studies preferably should be done in at
least two diVerent locations. Current categories comprise,
as examples, piglets (suckling, weaned), pigs for fattening,
sows (for reproduction, and to have beneWt in piglets),
poultry [chickens for fattening and reared for laying hens,
turkeys (for fattening, for breeding purposes, and reared for
breeding)], calves (for fattening, for rearing), cattle for fattening,
dairy cows (milk production, for reproduction),
lambs (for rearing, for fattening), dairy sheep (milk production),
ewes for reproduction, kids (for rearing, for fattening),
dairy goats, goats for reproduction, rabbits for
fattening, and breeding does. The trials should be compliant
with the criteria established by a recognised and externally
audited, quality assurance scheme. The trial protocol
should be carefully drawn up by the Study Director with
regard to general descriptive data as follows including any
subsequent amendments documented: for herds, location
and size, feeding and rearing conditions; for aquatic species,
size and number of tanks or pens at the farm and water
quality. For all trials, the conditions including animals (species—aquatic
species intended for human consumption
should be identiWed by their colloquial name followed in
parenthesis by their Latin binomial-, breed, age, sex, initial
weight, identiWcation procedure, physiological stage, and
general health), diet—description of manufacture and
quantitative composition in terms of ingredients used, relevant
nutrients—analysed values—and energy, concentration
of the micro-organism in the feedingstuVs, date, and
exact duration of testing, the timing and prevalence of any
undesirable consequences of treatment in individuals or
groups shall be described in details to allow a proper scientiWc
assessment. All additives studied under farm conditions
must have good scientiWc evidence of safety for the
user, consumer, animal, and environment. With respect to
the eYcacy of multi-component additives (comprised of
two or more strains of micro-organisms), the evidence of
eYcacy should be demonstrated for the complete additive
at the lowest dose level claimed.
3.3. 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., mixin