A stereological comparison of villous and microvillous surfaces in small intestines of frugivorous and entomophagous bats: species, inter-individual and craniocaudal differences
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Date
1997Author
Makanya, AN
Maina, JN
Mayhew, TM
Tschanz, SA
Burri, PH
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
The extents of functional surfaces (villi, microvilli) have
been estimated at different longitudinal sites, and in the
entire small intestine, for three species of bats belonging to
two feeding groups: insect- and fruit-eaters. In all species,
surface areas and other structural quantities tended to be
greatest at more cranial sites and to decline caudally. The
entomophagous bat (Miniopterus inflatus) had a mean body
mass (coefficient of variation) of 8.9 g (5 %) and a mean
intestinal length of 20 cm (6 %). The surface area of the
basic intestinal tube (primary mucosa) was 9.1cm2 (10%)
but this was amplified to 48cm2 (13 %) by villi and to
0.13m2 (20 %) by microvilli. The total number of microvilli
per intestine was 4´1011 (20 %). The average microvillus
had a diameter of 89 nm (10 %), a length of 1.1 mm (22%)
and a membrane surface area of 0.32 mm2 (31 %). In two
species of fruit bats (Epomophorus wahlbergi and
Lisonycteris angolensis), body masses were greater and
intestines longer, the values being 76.0 g (18 %) and 76.9 g
(4 %), and 73 cm (16 %) and 72 cm (7 %), respectively.
Surface areas were also greater, amounting to 76cm2
(26 %) and 45cm2 (8 %) for the primary mucosa, 547cm2
(29 %) and 314cm2 (16 %) for villi and 2.7m2 (23 %) and
1.5m2 (18 %) for microvilli. An increase in the number of
microvilli, 33´1011 (19 %) and 15´1011 (24 %) per intestine,
contributed to the more extensive surface area but there
were concomitant changes in the dimensions of microvilli.
Mean diameters were 94 nm (8 %) and 111 nm (4 %), and
mean lengths were 2.8 mm (12 %) and 2.9 mm (10 %),
respectively. Thus, an increase in the surface area of the
average microvillus to 0.83 mm2 (12 %) and 1.02 mm2 (11%)
also contributed to the greater total surface area of
microvilli. The lifestyle-related differences in total
microvillous surface areas persisted when structural
quantities were normalised for the differences in body
masses. The values for total microvillous surface area were
148cm2 g-1 (20 %) in the entomophagous bat, 355cm2 g-1
(20 %) in E. wahlbergi and 192cm2 g-1 (17 %) in L.
angolensis. This was true despite the fact that the insecteater
possessed a greater length of intestine per unit of
body mass: 22mmg-1 (8 %) versus 9–10mmg-1 (9–10%)
for the fruit-eaters.
URI
http://jeb.biologists.org/content/200/18/2415.full.pdf+htmlhttp://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/50020
Citation
The Journal of Experimental Biology 200, 2415–2423 (1997)Publisher
Institute of Anatomy, University of Berne, Bühlstrasse 26, CH-3000, Berne 9, Switzerland, Department of Veterinary Anatomy, University of Nairobi Department of Human Anatomy and Cell Biology, University of Nottingham, Nottingham NG7 2UH, UK
Subject
BatsEntomophagous
Frugivorous
Intestine
Villi
Microvilli
Craniocaudal variations
Miniopterus inflatus
Epomophorus wahlbergi
Lisonycteris angolensis