The comparative gastrointestinal morphology of Jaculus jaculus (Rodentia) and Paraechinus aethiopicus (Erinaceomorpha)

Abstract

Jaculus jaculus (Lesser Egyptian jerboa) and Paraechinus aethiopicus (Desert hedgehog) are small mammals which thrive in desert conditions and are found, among others, in the Arabian Peninsula. Jaculus jaculus is omnivorous while P. aethiopicus is described as being insectivorous. The study aims to describe the gastrointestinal tract (GIT) morphology of these animals which differ in diet and phylogeny. The GITs of J. jaculus (n = 8) and P. aethiopicus (n = 7) were weighed, photographed, and the length, basal surface areas, and luminal surface areas of each of the anatomically distinct gastrointestinal segments were determined. The internal aspects of each area were examined and photographed while representative histological sections of each area were processed to wax and stained using haematoxylin and eosin. Both species had a simple unilocular stomach which was confirmed as wholly glandular on histology sections. Paraechinus aethiopicus had a relatively simple GIT which lacked a caecum. The caecum of J. jaculus was elongated, terminating in a narrow cecal appendix which contained lymphoid tissue on histological examination. The internal aspect of the proximal colon of J. jaculus revealed distinct V-shaped folds. Stomach content analysis of J. jaculus revealed mostly plant and seed material and some insects, whereas P. aethiopicus samples showed plant material in addition to insects, indicating omnivorous feeding tendencies in areas where insects may be scarce.

Comparative gastrointestinal morphology of Tachyoryctes splendens (Rüppell, 1835) and Heliophobius emini, (Noack, 1894) two species of East African mole‐rats

“…Similar V‐shaped mucosal folds to those observed in T. splendens have been observed in insectivorous rodents Acomys spinosissimus (Southern African spiny mouse) (Boonzaier et al, ) and Jaculus jaculus (Lesser Egyptian jerboa) (Pereira et al, ), but not reported in other African mole‐rat species (Kotzé et al, ). These folds have been postulated to slow down the flow of digesta (Sperber et al, ; Björnhag & Snipes, ) and it is interesting that in T. splendens both a colonic groove and herring‐bone patterned colonic folds were observed.…”

“…The colonic groove of H. emini resembled that of Georychus capensis (Cape mole-rat) in that the groove walls were low ridges and was wide in the proximal colon and narrowed as it progressed to the distal colon (Kotz e et al, 2009). However, the papillae were not as robust as described in the other Bathyergidae, but was more delicate and similar to that observed in H. glaber Similar V-shaped mucosal folds to those observed in T. splendens have been observed in insectivorous rodents Acomys spinosissimus (Southern African spiny mouse) (Boonzaier et al, 2013) and Jaculus jaculus (Lesser Egyptian jerboa) (Pereira et al, 2016), but not reported in other African mole-rat species (Kotz e et al, 2010). These folds have been postulated to slow down the flow of digesta (Sperber et al, 1983;Bj€ ornhag & Snipes, 1999) and it is interesting that in T. splendens both a colonic groove and herring-bone patterned colonic folds were observed.…”

“…This was done to better compare the species quantitatively and provide an accurate representation of the regions of the GIT. These measurements were successfully utilized in studies on African mole‐rats and various rodents (Boonzaier et al, ; Kotzé et al, ; Pereira et al, ; Walters et al, ).…”

Comparative gastrointestinal morphology of seven golden mole species (Mammalia: Chrysochloridae) from South Africa

“…The macroscopic lack of differentiation between the small and large intestine, due to the absence of a cecum, in the present species was previously observed also in the Hottentot golden mole ( A. hottentotus ), as well as the other insectivorous small mammals including the Reddish‐gray musk shrew ( C. cyanea ; Boonzaier et al, ), Tailless tenrec ( Tenrec ecaudatus ; Mitchell, ), and Desert hedgehog ( Paraechinus aethiopicus ; Pereira et al, ). The absence of a cecum, taeniae, haustra, or any form of specialization of the combined small and large intestine is seen in various insectivorous mammals (Stevens & Hume, ).…”

Morphometric analysis of the gastrointestinal tract of four African muroid rodent species (Rhabdomys dilectus, Rhabdomys pumilio, Aethomys chrysophilus, and Lemniscomys rosalia)

“…When present, the stomach content was examined macroscopically using a Leica MZ6 dissecting microscope ( Leica Microsystems, Oberkochen, Germany). Furthermore, a representative stomach content sample was prepared for histological examination by processing to wax, sectioning, and staining with H&E. Fiji by ImageJ software (National Institute of Health) was used to measure the areas of recognizable material (plant, insect and/or seed) and expressed as a percentage of the total recognizable material seen on the section (Pereira et al, ).…”