THE DETERMINATION OF DIFFERENT FEED CONSTITUENTS
USING THE MICROSCOPIC METHOD
Igor
Ujčič-Vrhovnik, Breda Jakovac-Strajn
University of Ljubljana, Veterinary Faculty, Institute
for Hygiene and Pathology of Animal Nutrition,
Gerbičeva 60, 1000 Ljubljana, Slovenia
igor.ujcic@vf.uni lj.si
Determining
the proper quality and safety of animal feed requires constant
surveillance and examination. Because of that, along with an organoleptic examination, microbiological,
microscopic, chemical and other analyses need to be carried out. To
perform the microscopic examination, which is the only official method to
determine constituents of animal origin in feed (European Community,
2003), instruments such as mills, mixers, and
strainers as well as a stereomicroscope and a light microscope with
polarization, fluorescent light and phase contrast are needed. The aim of
the microscopic examination is to identify constituents on the basis of
their morphological and histological characteristics, to estimate the
quantity and the proportion of the constituents in the feed mixture and
to detect pollution of the feed. A microscopic feed examination is also
adequate and applicable for detection of botanical impurities, like
poison plants and their toxic seeds. There is an EU
Directive (European Community, 2002) concerning undesirable substances in
animal feed, containing a list of undesirable chemical and botanical
impurities. Among the botanical impurities mentioned in the Directive,
there are also: Datura stramonium,
Ricinus communis,
Claviceps purpurea,
Crotalaria spp.,
Prunus armeniaca, containing
alkaloids and glycosides. Undesirable substances of plant origin that are
not mentioned in the legislation, but are spread with raw material for
animal feed could also be detected with this method. One example are seeds of the plant Ambrosia artemisiifolia, whose
pollen is a strong allergen for humans.
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