Abstract
The present study reports aspects of GI tract physiology in the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate, Raja eglanteria. Plasma and stomach fluid osmolality and solute values were comparable between species, and stomach pH was low in all species (2.2 to 3.4) suggesting these elasmobranchs may maintain a consistently low stomach pH. Intestinal osmolality, pH and ion values were comparable between species, however, some differences in ion values were observed. In particular Ca2+ (19.67 ± 3.65 mM) and Mg2+ (43.99 ± 5.11 mM) were high in L. erinacea and Mg2+ was high (130.0 ± 39.8 mM) in C. palgiosum which may be an indication of drinking. Furthermore, intestinal fluid HCO3- values were low (8.19 ± 2.42 and 8.63 ± 1.48 mM) in both skates but very high in C. plagiosum (73.3 ± 16.3 mM) suggesting ingested seawater may be processed by species-specific mechanisms. Urea values from the intestine to the colon dropped precipitously in all species, with the greatest decrease seen in C. plagiosum (426.0 ± 8.1 to 0 mM). This led to the examination of the molecular expression of both a urea transporter and a Rhesus like ammonia transporter in the intestine, rectal gland and kidney in L. erinacea. Both these transporters were expressed in all tissues; however, expression levels of the Rhesus like ammonia transporter were orders of magnitude higher than the urea transporter in the same tissue. Intestinal flux rates of solutes in L. erinacea were, for the most part, in an inward direction with the notable exception of urea. Colon flux rates of solutes in L. erinacea were all in an outward direction, although absolute rates were considerably lower than the intestine, suggestive of a much tighter epithelia. Results are discussed in the context of the potential role of the GI tract in salt and water, and nitrogen, homeostasis in elasmobranchs.
| Original language | English |
|---|---|
| Pages (from-to) | 493-502 |
| Number of pages | 10 |
| Journal | Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology |
| Volume | 155 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 1 2010 |
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Keywords
- Ammonia
- Elasmobranch
- Intestine
- Little skate
- Osmoregulation
- Urea
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Physiology
Cite this
Gastro-intestinal handling of water and solutes in three species of elasmobranch fish, the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate Raja eglanteria. / Anderson, W. Gary; Dasiewicz, Patricia J.; Liban, Suadi; Ryan, Calen; Taylor, Josi R.; Grosell, Martin; Weihrauch, Dirk.
In: Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology, Vol. 155, No. 4, 01.04.2010, p. 493-502.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Gastro-intestinal handling of water and solutes in three species of elasmobranch fish, the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate Raja eglanteria
AU - Anderson, W. Gary
AU - Dasiewicz, Patricia J.
AU - Liban, Suadi
AU - Ryan, Calen
AU - Taylor, Josi R.
AU - Grosell, Martin
AU - Weihrauch, Dirk
PY - 2010/4/1
Y1 - 2010/4/1
N2 - The present study reports aspects of GI tract physiology in the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate, Raja eglanteria. Plasma and stomach fluid osmolality and solute values were comparable between species, and stomach pH was low in all species (2.2 to 3.4) suggesting these elasmobranchs may maintain a consistently low stomach pH. Intestinal osmolality, pH and ion values were comparable between species, however, some differences in ion values were observed. In particular Ca2+ (19.67 ± 3.65 mM) and Mg2+ (43.99 ± 5.11 mM) were high in L. erinacea and Mg2+ was high (130.0 ± 39.8 mM) in C. palgiosum which may be an indication of drinking. Furthermore, intestinal fluid HCO3- values were low (8.19 ± 2.42 and 8.63 ± 1.48 mM) in both skates but very high in C. plagiosum (73.3 ± 16.3 mM) suggesting ingested seawater may be processed by species-specific mechanisms. Urea values from the intestine to the colon dropped precipitously in all species, with the greatest decrease seen in C. plagiosum (426.0 ± 8.1 to 0 mM). This led to the examination of the molecular expression of both a urea transporter and a Rhesus like ammonia transporter in the intestine, rectal gland and kidney in L. erinacea. Both these transporters were expressed in all tissues; however, expression levels of the Rhesus like ammonia transporter were orders of magnitude higher than the urea transporter in the same tissue. Intestinal flux rates of solutes in L. erinacea were, for the most part, in an inward direction with the notable exception of urea. Colon flux rates of solutes in L. erinacea were all in an outward direction, although absolute rates were considerably lower than the intestine, suggestive of a much tighter epithelia. Results are discussed in the context of the potential role of the GI tract in salt and water, and nitrogen, homeostasis in elasmobranchs.
AB - The present study reports aspects of GI tract physiology in the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate, Raja eglanteria. Plasma and stomach fluid osmolality and solute values were comparable between species, and stomach pH was low in all species (2.2 to 3.4) suggesting these elasmobranchs may maintain a consistently low stomach pH. Intestinal osmolality, pH and ion values were comparable between species, however, some differences in ion values were observed. In particular Ca2+ (19.67 ± 3.65 mM) and Mg2+ (43.99 ± 5.11 mM) were high in L. erinacea and Mg2+ was high (130.0 ± 39.8 mM) in C. palgiosum which may be an indication of drinking. Furthermore, intestinal fluid HCO3- values were low (8.19 ± 2.42 and 8.63 ± 1.48 mM) in both skates but very high in C. plagiosum (73.3 ± 16.3 mM) suggesting ingested seawater may be processed by species-specific mechanisms. Urea values from the intestine to the colon dropped precipitously in all species, with the greatest decrease seen in C. plagiosum (426.0 ± 8.1 to 0 mM). This led to the examination of the molecular expression of both a urea transporter and a Rhesus like ammonia transporter in the intestine, rectal gland and kidney in L. erinacea. Both these transporters were expressed in all tissues; however, expression levels of the Rhesus like ammonia transporter were orders of magnitude higher than the urea transporter in the same tissue. Intestinal flux rates of solutes in L. erinacea were, for the most part, in an inward direction with the notable exception of urea. Colon flux rates of solutes in L. erinacea were all in an outward direction, although absolute rates were considerably lower than the intestine, suggestive of a much tighter epithelia. Results are discussed in the context of the potential role of the GI tract in salt and water, and nitrogen, homeostasis in elasmobranchs.
KW - Ammonia
KW - Elasmobranch
KW - Intestine
KW - Little skate
KW - Osmoregulation
KW - Urea
UR - http://www.scopus.com/inward/record.url?scp=77249145842&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77249145842&partnerID=8YFLogxK
U2 - 10.1016/j.cbpa.2009.09.020
DO - 10.1016/j.cbpa.2009.09.020
M3 - Article
C2 - 19782760
AN - SCOPUS:77249145842
VL - 155
SP - 493
EP - 502
JO - Comparative Biochemistry & Physiology; A: Comparative Physiology
JF - Comparative Biochemistry & Physiology; A: Comparative Physiology
SN - 1095-6433
IS - 4
ER -