Doctoral Degrees (Botany and Zoology)

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Browsing Doctoral Degrees (Botany and Zoology) by Author "Ackerman, Dirk J. (Dirk Jacobus)"

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    Die ultrastruktuur van sperme van die rooibok Aepyceros melampus (Lichtenstein, 1812) in die Nasionale Krugerwildtuin met spesiale verwysing na die invloed van koperbesoedeling
    (Stellenbosch : Stellenbosch University, 1995-08) Ackerman, Dirk J. (Dirk Jacobus); Reinecke, A. J.; Stellenbosch University. Faculty of Science. Dept. of Botany & Zoology.
    ENGLISH ABSTRACT: Graling in the Kruger National Park. south of Phalaborwa Gate, is contaminated with copper, probably from a nearby copper refinery. Cattle in the neighbourhood have died from copper poisoning while the average copper concentration in the livers of impala in the Krgler National Park, was found to be abnormally high. The possibility exists that the ultrastructure of spermatozoa may serve as an indicator of environmental conditions. To examine this statement further, the purpose of this study includes the following: - To describe the ultrastructure of normal impala sperm as well as their abnormalities. - To quantify the sperm abnormalities of each experimental animal and to relate the abnormalities with the copper concentration in the impala liver, in order to determine whether any correlation exists between these two variables. Impala have been terminated monthly, from 1992.06.09 to 1993.05.15. in the vicinity of Phalaborwa Gate and in the Skukuza area for other research projects. Their sperm were made available for this study. The control group consisted of 20 animals which comprised 14 animals from an area, not contaminated with copper, along the Nwaswitshaka spruit near Skukula and 6 animals originally from the same area but which had been kept in captivity at Skukuza on a diet, not contaminated with copper. The experimental group consisted of 44 animals which comprised 32 animals from copper contaminated grazing along the Tshutshi spruit south of Phalaborwa Gate and 12 animals captured along the Nwaswitshaka spruit which were kept on a copper contaminated diet in captivity at Skukuza. Sperm from the epididymis of each animal were collected and fixed in a temporary laboratory. The sperm were processed at the Electron Microscopy Unit of the Faculty of Veterinary Science of the University of Pretoria and studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The copper concentration in the liver was analyzed and bone marrow collected of each animal in order to determine the condition of the animal. The external morphology of a normal impala sperm was documented by means of SEM and the dimensions of the sperm determined. SEM micrographs of observed sperm abnormalities were taken. Percentages for normal sperm and the percentages of some abnormalities of a control group (Average liver copper concentration - ALCC = 37.9 ppm WB) were calculated. The same percentages were also calculated for an experimental group (ALCC = 104 ppm WB). The control group and the experimental group exhibited 91.6% and 93.6% normal sperm respectively. The difference in percentage sperm abnormalities of the two groups was of the same order. The increased copper in the livers of the experimental group has thus not lead to an increase of the percentage macro-abnormalities observed with SEM. The ultrastructure of normal impala sperm were described and documented with micrographs by means of TEM. The deviations of the normal sperm ultrastructure were also recorded on micrographs. Percentages were calculated for the normal sperm sections, as well as the abnormalities of some sperm sections of a contrl group (ALCC = 33.86 ppm WB). The same percentages were also calculated for an experimental group (ALCC = 122.5 ppm WB). For the control group the average percentage sperm neck sections with vacuoles was : 31.5% and for the experimental group this percentage was : 57.9%. The increased copper concentrations in the livers of the experimental group thus led to an increase of the percentage of sperm necks with vacuoles. There is also reason to believe that the difference of the percentages of sections of the sperm head, in the control and experimental group, should be remarkably greater. A graphic analysis of the TEM-data has also shown that a statistically significant correlation exists between the percentage of sperm with vacuoles in the neck and the copper concentrations in the livers of impalas. The conclusion is that high level copper concentrations exert a detrimental effect on the ultrastructure of the sperm neck. The possibility also exists that copper concentrations in impala liver > 500 ppm WB. will show a correlation with the percentages of some of the other abnormalities observed.