Rumen Ciliate Protozoa of the Sable Antelope Hippotragus Niger

Abstract

Of the 11 ciliate protozoa present in the rumen of the sable antelope. two are holotrichs and nine entodiniomorphs. One new species Diplodinium (Eudiplodinium) sablei is described. The seven antelopes investigated gave an average total number of protozoa per cm3 rumen fluid of 1,79 ± 0,39 x 10 5 , a relatively low figure typical of grazing wild ungulates. S. Afr. J. Zool. 14: 37-42 (1979) Van die 11 siliaat-protozoa teenwoordig in die rumen van die swartwitpens was twee holotriche en nege entodiniomorphe vorme. Een nuwe spesies Diplodinium (Eudiplodinium) sable; word beskryf. Die sewe swartwitpense wat ondersoek is, het gemiddeld 1,79 ± 0,39 x 10 5 protozoa per cm 3 rumenvloeistof gehad, 'n relatief lae syfer tipies van weiende wildsbokke. The sable antelope belongs to the subfamily Hippotragin and the southern subspecies Hippotragus niger nig Harris, 1838 occurs south of the Zambesi River in Rhodesia, northern Botswana and south western Mocam-bique. The Rhodes Matopos National Park, some 43200 ha in size, lies 48 km southwest of Bulawayo and consists of large broken granite hills with gorges, surrounded by woodland interspersed with grassland and savanna woodland of variable tree density. It is a habitat ideally suited for a grazer such as the sable antelope. Several sable antelopes were culled from this park in Rhodesia during February 1977. The study was undertaken because no information existed about the population composition and identities of the rumen protozoa of this antelope. Material and Methods Soon after an animal was killed the digestive tract was removed and an incision of approximately 25 cm was made in the rumen wall. A sample of the contents was thoroughly mixed and filtered through cheese cloth. The rumen fluid was preserved in a 1:1 ratio with 10% (v/v) formalin. Total numbers of protozoa were counted as described by van Hoven (1974). The organelles were found to be readily visible and recognizable in unstained preparations. A microscope with interference contrast colouring was used. When necessary for the study of skeletal plates, staining with chlorzinc iodine was used. Slides were made by mixing a drop of filtered rumen fluid with a drop of glycerine and smearing it over the slide. After placing a cover-slip over the mixture the edges were sealed with Depex mounting medium. Glycerine-mounted preparations were used in determining the species composition of the total protozoan community in the rumen. Measurements were made with a calibrated ocular micrometer and drawings were done with the aid of a drawing tube. Terminology used in descriptions follows the system of Lubinsky (1958). The formalin-fIxed samples were also prepared for scanning electron microscopy. When it became apparent that the protozoans were covered by excess debris the samples were cleaned by hand. It was observed that some 0; the protozoans sedimented faster than the debris, thus the