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

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.

EFFECT OF EXPERIMENTAL TRYPANOSOMA EVANSIINFECTION ON HAEMATOLOGICAL PARAMETERS AND SEMEN CHARACTERISTICS OF YANKASA RAMS