EFFECT OF EXPERIMENTAL TRYPANOSOMA EVANSIINFECTION ON HAEMATOLOGICAL PARAMETERS AND SEMEN CHARACTERISTICS OF YANKASA RAMS
EFFECT OF EXPERIMENTAL TRYPANOSOMA EVANSIINFECTION ON HAEMATOLOGICAL PARAMETERS AND SEMEN CHARACTERISTICS OF YANKASA RAMS
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Date
2015-11
Authors
ABIDEMIOGUNDELE, FRANCIS
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Abstract
This study was designed to evaluate the effect of experimental Trypanosoma evansi
infection on haematological and reproductive parameters of Yankasa rams. Twelve rams
allotted to two groups were used; Group A (Infected, n=7) and group B (Control, n=5).
Each animal in the infected group was inoculated via the jugular vein with 1mL of blood
from the donor rats containg 1 X 106 trypanosomes. The infected rams were allowed to
run the course of the disease for fourteen weeks. Experimental rams were monitored for
clinical manifestations of the disease. Temperature and body weight changes were
observed and recorded daily and weekly respectively. Scrotal circumferences were also
monitored. Haematological parameters (PCV, RBC, WBC and differential leucocyte
counts) and total protein were determined weekly. Similarly, semen volume, gross
motility, live - dead sperm ratio, sperm morphological abnormalities and concentration as
well as reaction time of infected and control rams were evaluated on a weekly basis. The
testes and epididymides in each group were harvested for gross and histological
examination. The data obtained were analysed using Student‟s t-test on Graph Pad Prism
version 5.0., P ˂ 0.05 was considered significant. Infected rams had a pre-patent period
of 5.3±0.29 days and the parasitaemia was intermittent. Pale mucous membrane, rough
hair coat, loss of weight, dullness, edema of the face and lower jaw, corneal opacity,
lacrimation were the clinical signs observed. There was progressive decrease in mean
PCV and RBC count from first week post infection (28.9 ± 0.51%)(9.05 ± 0.26 x106
cells/mm3)and culminating in anaemia in infected animals (21.2 ± 1.99%) and (5.42 ±
0.49 x106 cells/mm3). There was a transient decrease in total plasma protein reaching its
least mean value of 5.1± 0.20 g/dl at 8 weeks post infection. There wassignificant
(p˂0.05)increases in leucocyte countin the infected post infection as compared to the
control rams.There were no significant (P˂0.05) differences in the differential leucocyte
counts in the infected group compared to the control. The results showed non sign
weeks post infection)and sperm concentration was significantly lowerfrom (2.87 ± 0.29
x106 cells/mm3) at pre-infection to (1.01 ± 0.17 x106 cells/mm3) at 14 weeks post
infection. Reaction time showed significant (p˂0.05) increase from pre infection
value(26.7 ± 4.54 to 94.7 ± 7.54 secs) 13 weeks post infection. Furthermore, the gross
motility for infected rams was significantly (p˂0.05) lower. There was a drastic surge in
sperm morphological abnormalities from pre-infection (20.86 ± 0.52%) to (90.75 ±
2.73%) at 13 weeks post infection. Following post mortem examination no pathologies
were observed grossly on the testes and epididymides but histologically, the testes
showed extensive fibrosis and thickening of the seminiferous tubules with necrotized
spermatogonic cells. Seminiferous tubules were devoid of spermatids. The epididymis
revealed extensive fibroplasia and necrosis of epididymal cells with depleted epididymal
sperm reserves. Conclusively,Trypanosoma evansi infection produced deleteriouseffects
onhaematological values and testicular functions thus affecting reproductive performance
of Yankasa rams.
Description
DEPARTMENT OF VETERINARY PARASITOLOGY AND ENTOMOLOGY,
FACULTY OF VETERINARY MEDICINE
AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
Keywords
EFFECT,, EXPERIMENTAL TRYPANOSOMA,, EVANSIINFECTION,, HAEMATOLOGICAL PARAMETERS,, SEMEN CHARACTERISTICS,, YANKASA RAMS,