BIOCHEMICAL ASPECTS OF BOTH THE CORTICAL BONE AND THE MEDULLARY BONE IN HENS AT DIFFERENT STAGES OF THE EGG FORMATION

Abstract

10 hybrid ISA Brown hens, 50 weeks old, hold single in cages and fed with combined
granulated forage, were monitored for a period of 3 weeks. They were divided into 4
groups depending on the stages of the egg formation. When 53 weeks old, the hens
were sacrificed and the bones of the inferior members (femur, tibiotarsus) were
prevailed and thereafter prepared to determine the content of dry matter, crude ash
and minerals (calcium, phosphorous, magnesium) both for samples of the whole
bone and for the samples of the cortical and medullary bone. There were no
significant differences in the content of dry matter of the cortical and medullary bone
samples of the femur, tibia among the individuals (p>0.05) . The content in crude
ash of the femur falls significantly (p = 0.042) in the hens slaughtered 10 to 12 hours
after oviposition. In the cortical bone from the femur the values of calcium,
magnesium and phosphorous were not modified irrespective of the egg position in
the oviduct. In the medullary bone from the femur the content in calcium and
phosphorous was correlated with the egg formation stage; as for magnesium there
were no significant differences during the egg formation irrespective of the stage.
As for the cortical bone of the tibia of the hens from the 4 groups there are no
significant differences (p>0.05) regarding the content in calcium, magnesium and
phosphorous. In the medullary bone the content in calcium, magnesium and
phosphorous was modified significantly depending on the position of the egg in the
oviduct, and on the egg formation stage respectively.