engleski

"Mmeat spots" in eggs of commercial layer hens : a sporadic finding or a sign of infection

"Meat spots" or "inclusions" are amorphous material found in the oviduct and in the albumen or chalaza of commercial eggs (Helbacka and Swanson, 1958 ; Bayer et al., I974 ; Solomon, 1999). Since the eggs with such "inclusions" are usually of a lower quality economic losses with this defect being great and reports on "meat spots" in literature are scarce, the initial purpose of this study was to find out the cause of a prolonged occurrence of eggs with meat spots in a big ISA Brown commercial layerfarm. Ten ISA Brown layer hens were sacrificed under chloroform anesthesia, necropsied and the oviduct was taken for histopathological analysis. Hematoxylineosin (HE) was used for staining. These very samples of the oviduct as well as a spleen sample were taken for transmissive electron microscopy (TEM) analysis. A sample of 90 eggs was macroscopically examined on presence of the "inclusion" which were then classified according to their size and the location in the albumen as well as to the correlation of their color with the color and the e shell quality. The "meat spots" were taken for histopathological analysis and stained with hematoxylin-eosin (HE), using Van Gieson method, Mallory with Crosmann modifications, Berlin blue with Weckleinfalkenberg modifications, Kongo red and Von Kossa. The same samples were taken for TEM analysis The fresh parts of the liver spleen, oviduct, ovary and the whole eggs were bacteriologically tested for aerobes. Necropsy did not reveal notable differences between the hens and the bacteriological examination did not confirm the presence of pathogen bacteria Microscopic finding of the degenerated and/or desquamated epithelium as well as the lymphocytic hyperplasia of various degree in muscular layer of the oviductal wall was positively correlated with the finding of the greatest number and of the largest size of "meat spots" in eggs. Histopathological analysis showed the lobular conformation of the meat spot" probably of muscular and connective tissue origin. Virus particles were determined using TEM anal sis. Li ht microscopic finding in the oviduct and in the "meat spots" confirmed the possible correlation between the histopathological changes in the oviduct and meat spots formation. As the TEM analysis confirmed the presence of virus particles in the "meat spot", and this finding was not mentioned in the literature until now, the procedure of virus isolation is in progress.

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