HISTOLOGICAL ASPECTS OF THE MEDULLARY BONE CORRELATED TO DIFFERENT STAGES OF THE EGG FORMATION IN HENS
Keywords:
laying fowl, medullary bone, osteoclast, osteoblastAbstract
The experiment was carried out on a batch formed by 10 laying hens, ISA Brown
hybrid, at the first laying cycles, 50 weeks old, hold single in cages and fed with
granulated forage. The hens were watched for 3 weeks in order to establish the
moment of the oviposition and depending on that their slaughtering was set out so
that the different stages of the egg formation could be observed. The hens were
divided into 4 groups – I, II, III, IV- depending on the time elapsed from the last
oviposition. Femur fragments have been drawn from the central zone of the
diaphises and transformed in hematoxiline-eozine and alcian-blue stained
preparations, the trichromic Mallory method and the Dorfmann-Epstein method for
the emphasising of the alkaline phosphatasis. At the hens of the first group the
presence of the medullary bone is shown and is characterised by an intense
ossification process with compact bone structure, with well formed osseus
trabeculae that occupy the medullar cavity. There is also present a rich content of
acid mucopolyssacharide. The hens from the second group (II) have a well formed
medullary bone, with visible osseus trabeculae. From the histological point of view,
the medullary bone of the hens from the third group (III) is rarefied with large
areolae, with collagen fibres that lack osein, having thus a characteristic aspect of
massive decalcification. At the hens from the fourth group (IV) the medullary bone
shows synthesis processes and bone matrix forming, positive, intensive FAL activity,
that proves the presence of active osteoblasts, i.e. bone remodelling processes.
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