Die ultrastruktuur van sperme van die rooibok Aepyceros melampus (Lichtenstein, 1812) in die Nasionale Krugerwildtuin met spesiale verwysing na die invloed van koperbesoedeling

[摘要] 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 KrglerNational Park, was found to be abnormally high.The possibility exists that the ultrastructure of spermatozoa may serve as an indicator ofenvironmental conditions. To examine this statement further, the purpose of this studyincludes 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 theabnormalities with the copper concentration in the impala liver, in order to determinewhether any correlation exists between these two variables.Impala have been terminated monthly, from 1992.06.09 to 1993.05.15. in the vicinity ofPhalaborwa 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 comprised14 animals from an area, notcontaminated 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 44animals which comprised 32 animals from copper contaminated grazing along the Tshutshi spruit south of Phalaborwa Gate and 12 animals captured along the Nwaswitshaka spruitwhich were kept on a copper contaminated diet in captivity at Skukuza.Sperm from the epididymis of each animal were collected and fixed in a temporarylaboratory. The sperm were processed at the Electron Microscopy Unit of the Faculty ofVeterinary Science of the University of Pretoria and studied by means of scanning electronmicroscopy (SEM) and transmission electron microscopy (TEM).The copper concentration in the liver was analyzed and bone marrow collected of each animalin order to determine the condition of the animal.The external morphology of a normal impala sperm was documented by means of SEM andthe dimensions of the sperm determined. SEM micrographs of observed sperm abnormalitieswere 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 samepercentages 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 spermrespectively. The difference in percentage sperm abnormalities of the two groups was of thesame order. The increased copper in the livers of the experimental group has thus not leadto an increase of the percentage macro-abnormalities observed with SEM.The ultrastructure of normal impala sperm were described and documented with micrographsby means of TEM. The deviations of the normal sperm ultrastructure were also recorded onmicrographs. Percentages were calculated for the normal sperm sections, as well as theabnormalities of some sperm sections of a contrl group (ALCC = 33.86 ppm WB). Thesame 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 copperconcentrations in the livers of the experimental group thus led to an increase of the percentageof 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 beremarkably greater.A graphic analysis of the TEM-data has also shown that a statistically significant correlationexists between the percentage of sperm with vacuoles in the neck and the copperconcentrations in the livers of impalas. The conclusion is that high level copperconcentrations 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 showa correlation with the percentages of some of the other abnormalities observed.

[发布机构] Stellenbosch University