Nitrogen excretion of mudskipper fish Periophthalmus cantonensis and Boleophthalmus pectinirostris in water and on land

Morii, Hideaki; Nishikata, K; Tamura, Osamu

doi:10.1016/0300-9629(78)90229-3

Cited by 51 publications

(20 citation statements)

References 11 publications

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“…Homer Smith (1929) first reported that the major site of nitrogen excretion in freshwater fish was across the gills (Smith 1929), but the contribution of other routes may become greater in seawater fish (e.g., Read 1968;Morii et al 1978;Sayer and Davenport 1987b;for review see Wood 1993). In the intertidal blenny, only about 50% of nitrogen was excreted by the head region (gills), while the remaining half was excreted by the "back end" (skin, kidneys, and/or gut) of the fish (Sayer and Davenport 1987b).…”

Section: Introductionmentioning

confidence: 98%

Ammonia and urea excretion in the tidepool sculpin (Oligocottus maculosus): sites of excretion, effects of reduced salinity and mechanisms of urea transport

Wright

Pärt

Wood

1995

Fish Physiol Biochem

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Tidepool sculpins live in a variable environment where water temperature, salinity, gas tensions, and pH can change considerably with the daily tide cycle. Tidepool sculpins are primarily ammoniotelic, with 8-17% of nitrogen wastes excreted as urea. The majority of net ammonia (J(net) amm; 85%) and urea (J(net) urea; 74%) excretion occurred across the gill, with the remainder excreted across the skin, the kidney, and/or gut. Acute (2h) exposure to 50% seawater significantly increased J(net) urea (2.8-fold), but reduced J(net) amm (3.5-fold). In fish exposed to 50% seawater for 1 week, J(net) urea returned to control values, but J(net) amm remained slightly depressed. Unidirectional urea influx (J(in) urea) and efflux (J(out) urea) were measured using(14)C-urea to determine if urea was excreted across the gills by simple diffusion or by a carrier-mediated mechanism. J(in) urea increased in a linear manner with increasing urea water levels (0-11 mmol N l(-1)), while J(out) urea was independent of external urea concentrations. As well, J(net) urea and J(out inurea) were not significantly different from one another, indicating the absence of "back transport". Urea analogs and transport inhibitors added to the water did not have any consistent effect on unidirectional urea flux. These results demonstrate that ammonia and urea excretion rates and sites of excretion in tidepool sculpins are very similar to those found in other marine and freshwater teleosts. Urea and ammonia may play a role in osmoregulation as excretion rates and tissue levels were influenced by changes in water salinity. Finally, we found no evidence for a specific urea carrier; branchial urea excretion is likely dependent on simple diffusion.

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Section: Introductionmentioning

confidence: 98%

Ammonia and urea excretion in the tidepool sculpin (Oligocottus maculosus): sites of excretion, effects of reduced salinity and mechanisms of urea transport

Wright

Pärt

Wood

1995

Fish Physiol Biochem

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“…Wood et al, 1995a;Wood et al, 1995b;Wright et al, 1995b;McDonald et al, 2002;Bucking et al, 2010;Smith et al, 2012), although the contribution of these alternative routes may become greater (~40%) in marine fish (e.g. Read, 1968;Morii et al, 1978;Sayer and Davenport, 1987; for a review, see Wood 1993). The majority of studies examining piscine nitrogen metabolism, including many cited above, have been conducted on fasting fish; however, digestion has large implications for nitrogen metabolism.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen metabolism of the intestine during digestion in a teleost fish, the plainfin midshipman (Porichthys notatus)

Bucking

LeMoine

Craig

et al. 2013

Journal of Experimental Biology

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SUMMARYDigestion affects nitrogen metabolism in fish, as both exogenous and endogenous proteins and amino acids are catabolized, liberating ammonia in the process. Here we present a model of local detoxification of ammonia by the intestinal tissue of the plainfin midshipman (Porichthys notatus) during digestion, resulting in an increase in urea excretion of gastrointestinal origin. Corroborating evidence indicated whole-animal ammonia and urea excretion increased following feeding, and ammonia levels within the lumen of the midshipman intestine increased to high levels (1.8±0.4μmolNg −1). We propose that this ammonia entered the enterocytes and was detoxified to urea via the ornithine-urea cycle (O-UC) enzymes, as evidenced by a 1.5-to 2.9-fold postprandial increase in glutamine synthetase activity (0.14±0.05 and 0.28±0.02μmolmin ). Furthermore, digestion increased urea production by isolated gastrointestinal tissue 1.7-fold, supporting our hypothesis that intestinal tissue synthesizes urea in response to feeding. We further propose that the intestinal urea may have been excreted into the intestinal lumen via an apical urea transporter as visualized using immunohistochemistry. A portion of the urea was then excreted to the environment along with the feces, resulting in the observed increase in urea excretion, while another portion may have been used by intestinal ureolytic bacteria. Overall, we propose that P. notatus produces urea within the enterocytes via a functional O-UC, which is then excreted into the intestinal lumen. Our model of intestinal nitrogen metabolism does not appear to be universal as we were unable to activate the O-UC in the intestine of fed rainbow trout. However, literature values suggest that multiple fish species could follow this model.

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“…Gordon et al (1969Gordon et al ( , 1970Gordon et al ( , 1978 presented a different picture reporting excretion of only about 40% of ammonia-N and 60% urea-N in 3 species of amphibious marine fishes Periophthal-//IUS sobrinus, Sicyasis sanquineus and Periophthalmus cantonensis. However, Morii et al (1978) reported 91 % excretion of ammonia-N by one of these species, P. cantonensis under identical conditions. Inspite of this controversy in some marine fishes, the freshwater fishes show a definite correlation between their ammonia-N excretion and their ability to convert ammonia to urea (table 4).…”

Section: Discussionmentioning

confidence: 99%

“…In rainbow trout, Salmo qairdneri only about 3% of the total N was excreted in the urine and over 60% of the total N excreted was in the form of ammonia (Fromm 1963). Besides the gills, extra-renal excretion of N by the skin has been reported in two mudskipper fishes, P. cantonensis and B. pectinirostris (Morii et al 1978) and an air-breathing marine fish Blennius pholis (Davenport and Sayer 1986). The smooth scaleless mucoid skin of H. fossilis might have also served as an efficient excretory surface for extra-renal excretion of N along with the gills.…”

Section: Vl W Vlmentioning

confidence: 99%

Diurnal variation in renal and extra-renal excretion of ammonia-N and urea-N in a freshwater air-breathing teleost,Heteropneustes fossilis (Bloch)

Saha

Chakravorty

Ratha

1988

Proc. Indian Acad. Sci. (Anim. Sci.)

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Diurnal pattern of excretion of ammonia-N and urea-N through the renal and extra-renal sources were studied in a freshwater air-breathing teleost, H eteropneustes fossilis in its aquatic medium. Arnrnonia-N was the major nitrogen excretory product, however, the rate of excretion of urea-N was comparatively higher than other freshwater teleosts, Almost all arnmonia-N (> 99%) and about 75% of urea-N were excreted through the extra-renal sources. The excretion rate of urea-N was about 10 times higher than arnmonia-N through the renal and arnmonia-N was 7-8 times higher than urea-N through extra-renal sources. Existence of a functional ornithine-urea cycle reported in Heteropneustes fossilis has been suggested to be the reason for this increased rate of urea excretion.Nitrogen excretion (total amrnonia-N + urea-N) during .the night was significantly higher than the day. A higher rate of nitrogen metabolism at night has been suggested for Heteropneustes fossilis which has been reported to be nocturnal in habit.

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Nitrogen excretion of mudskipper fish Periophthalmus cantonensis and Boleophthalmus pectinirostris in water and on land

Cited by 51 publications

References 11 publications

Ammonia and urea excretion in the tidepool sculpin (Oligocottus maculosus): sites of excretion, effects of reduced salinity and mechanisms of urea transport

Ammonia and urea excretion in the tidepool sculpin (Oligocottus maculosus): sites of excretion, effects of reduced salinity and mechanisms of urea transport

Nitrogen metabolism of the intestine during digestion in a teleost fish, the plainfin midshipman (Porichthys notatus)

Diurnal variation in renal and extra-renal excretion of ammonia-N and urea-N in a freshwater air-breathing teleost,Heteropneustes fossilis (Bloch)

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