GROSS AND HISTOLOGICAL STUDIES ON SOME LYMPHOID ORGANS OF THE GRASSCUTTER (Thyronomysswinderianus)
GROSS AND HISTOLOGICAL STUDIES ON SOME LYMPHOID ORGANS OF THE GRASSCUTTER (Thyronomysswinderianus)
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Date
2014-06
Authors
KORZERZER, Rachel Mngu-suur
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Abstract
The present study analyses the gross and histological features of some lymphoid organs in the
grasscutter. Twelve, apparently, healthy grasscutters,between the ages of three and seven months
were obtained from Benue State and used for this study. The animals were transported in cages
to the Department of Veterinary Anatomy, Ahmadu Bello University, Zaria where they were
rested for 14 days before been sacrificed using chloroform inhalation anaesthesia. After
dissection, the thymus, mesenteric lymph node and spleen were exposed, separated from
surrounding tissue and photographed for gross assessment. Tissue samples were routinely
prepared for histology using H & E as general histological stain and Rhodamine B-aniline
methylene blue as special stain. Grossly, the thymus was bilateral on either side of the thoracic
midline. Mean ± SEM values for thymic weights were 1.23 ± 0.048g, 0.53 ± 0.019g and 0.30 ±
0.042g at three, five and seven months of age, respectively. Histologically, the thymus showed
loss of lymphoid cells as the grasscutters advanced in age.The spleen was dark red in colour,
ovoid in shape and the size increased with age, having maximum value at seven months of age in
both males and females. Mean ± SEM values for splenic weights were 0.67 ± 0.09g, 1.65 ± 0.35g
and 2.31 ± 0.06g at three, five and seven months of age, respectively. The percentage ratio of
splenic weight to body weight was 0.1%. The mesenteric lymph nodes were constantly bean
shaped and appeared as opaque white masses which resembled fat, but were distinguished from
fat by their consistent shape. The mesenteric lymph node weights were 0.056 ± 0.005g, 0.143 ±
0.034g and 0.1600 ± 0.023g at three, five and seven months of age, respectively.In conclusion,
this study revealed that while the general morphologies of the thymus, spleen and mesenteric
lymph nodes in the grasscutter are similar to that in other mammals, the relative amount of white
to red pulp in the spleen showed some specie-specific characteristics, the thymus also showed a
constant decrease in weight and size with advancing age, and at seven months there was no
Hassal’s corpuscle and cortex-medulla distinction.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE
STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTSFOR THE
AWARD OF THE DEGREE OF MASTER OF SCIENCE IN VETERINARY
ANATOMY
Keywords
GROSS,, HISTOLOGICAL ,, LYMPHOID,, ORGANS,, GRASSCUTTER.