Effects of Temperature and Body Weight on Endogenous Nitrogen Excretion in the Bluegill Sunfish (Lepomis macrochirus)

1969 ◽  
Vol 26 (7) ◽  
pp. 1813-1821 ◽  
Author(s):  
Jan Savitz
Keyword(s):  
Body Weight ◽  
Lepomis Macrochirus ◽  
Nitrogen Excretion ◽  
Bluegill Sunfish ◽  
Effects Of Temperature ◽  
Excretion Rates ◽  
Very High

The effects of temperature and body weight on endogenous nitrogen excretion (ENE) rate were examined for fish acclimated at 7.2, 15.6, 23.9, and 29.4–32.2 C. Nitrogen excretion rates were very high at the highest temperature and decreased with a decrease in acclimated temperature from 29.4–32.2 C to 15.6 C. Nitrogen excretion rates were equal at 15.6 and 7.2 C. From these data, an estimate of maintenance protein for a population of bluegidl sunfish (Lepomis macrochirus) was calculated on a seasonal and yearly basis.

Nitrogen Excretion and Protein Consumption of the Bluegill Sunfish (Lepomis macrochirus)

1971 ◽  
Vol 28 (3) ◽  
pp. 449-451 ◽  
Author(s):  
J. Savitz
Keyword(s):  
Mathematical Description ◽  
Lepomis Macrochirus ◽  
Specific Dynamic Action ◽  
Nitrogen Excretion ◽  
Bluegill Sunfish ◽  
Protein Consumption ◽  
Dynamic Action ◽  
Excretion Rates

Nitrogen excretion rates increase with an increase in protein consumption levels. A mathematical description of this relation was formulated from the data. Estimates of the effect of specific dynamic action on nitrogen excretion were also calculated.

Effects of temperature and genotype on sex determination and sexual size dimorphism of bluegill sunfish Lepomis macrochirus

Aquaculture ◽  
2014 ◽  
Vol 420-421 ◽  
pp. S64-S71 ◽  
Author(s):  
Han-Ping Wang ◽  
Ze-Xia Gao ◽  
Dean Rapp ◽  
Paul O'Bryant ◽  
Hong Yao ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sexual Size Dimorphism ◽  
Lepomis Macrochirus ◽  
Bluegill Sunfish ◽  
Size Dimorphism ◽  
Effects Of Temperature

Regeneration of nitrogen and phosphorus by bluegill and gizzard shad: effect of feeding history

1995 ◽  
Vol 52 (11) ◽  
pp. 2327-2338 ◽  
Author(s):  
Martha E. Mather ◽  
Michael J. Vanni ◽  
Thomas E. Wissing ◽  
Scott A. Davis ◽  
Maynard H. Schaus
Keyword(s):  
Excretion Rate ◽  
Lepomis Macrochirus ◽  
N:P Ratio ◽  
Nitrogen Excretion ◽  
Gizzard Shad ◽  
Small Fish ◽  
Nitrogen And Phosphorus ◽  
Nutrient Excretion ◽  
N:P Ratios ◽  
Excretion Rates

We combined laboratory and field studies to experimentally assess how the effects of feeding regime and time since feeding influence nitrogen (N), phosphorus (P), and the N:P ratio excreted by two common freshwater fish, bluegill (Lepomis macrochirus) and gizzard shad (Dorosoma cepedianum). In addition, for adult gizzard shad, we modelled excretion rates as a function of the nutrient content of ingested sediment detritus. For both bluegill and gizzard shad, feeding significantly increased nutrient excretion rates and altered excreted N:P ratios. For both species, excretion rates were highest immediately after feeding and declined thereafter. Because the phosphorus excretion rate decreased more rapidly after feeding than did the nitrogen excretion rate, the excreted N:P ratio increased with time since feeding. Young-of-year gizzard shad excreted more nitrogen than adults, resulting in a higher excreted N:P ratio for these small fish. For P, predictions from our model agreed well with our experiments with gizzard shad; for N, the agreement was not as strong yet was still reasonable. In summary, N:P ratios excreted by these fish differed across species, size, and time since feeding. Variation in these factors may explain discrepancies among studies that examine both trophic interactions and nutrient budgets.

scholarly journals Renal haemodynamic and tubular actions of urotensin II in the rat

2008 ◽  
Vol 198 (3) ◽  
pp. 617-624 ◽  
Author(s):  
Alaa E S Abdel-Razik ◽  
Ellen J Forty ◽  
Richard J Balment ◽  
Nick Ashton
Keyword(s):  
Body Weight ◽  
Renal Medulla ◽  
Fractional Excretion ◽  
Haemodynamic Effects ◽  
Urotensin Ii ◽  
Sprague Dawley ◽  
Minimal Impact ◽  
Sprague Dawley Rats ◽  
Fractional Excretion Of Sodium ◽  
Excretion Rates

Urotensin II (UTS) is a potent vasoactive peptide that was originally identified in teleost fish. Mammalian orthologues of UTS and its receptor (UTSR) have been described in several species, including humans and rats. We have shown previously that bolus injections of UTS caused a decrease in urine flow and sodium excretion rates in parallel with marked reductions in renal blood flow (RBF) and glomerular filtration rate (GFR). The aim of this study was to determine the effect of UTS infusion at a dose that has minimal impact upon renal haemodynamics in order to identify a potential direct tubular action of UTS. Infusion of rat UTS (rUTS) at 0.6 pmol/min per 100 g body weight in male Sprague–Dawley rats, which had no effect on RBF and caused a 30% reduction in GFR, resulted in a significant increase in the fractional excretion of sodium (vehicle 2.3±0.6 versus rUTS 0.6 pmol 4.5±0.6%, P<0.05) and potassium. At the higher dose of 6 pmol/min per 100 g body weight, haemodynamic effects dominated the response. rUTS induced a marked reduction in RBF and GFR (vehicle 1.03±0.06 versus rUTS 6 pmol 0.31±0.05 ml/min per 100 g body weight, P<0.05) resulting in an anti-diuresis and anti-natriuresis, but no change in fractional excretion of sodium or potassium. Uts2d and Uts2r mRNA expression were greater in the renal medulla compared with the cortex. Together, these data support an inhibitory action of Uts2d on renal tubule sodium and potassium reabsorption in the rat, in addition to its previously described renal haemodynamic effects.

Stresses in a Metal Tube Under Both High Radial Temperature Variation and Internal Pressure

1954 ◽  
Vol 21 (2) ◽  
pp. 101-108
Author(s):  
Chieh-Chien Chang ◽  
Wen-Hwa Chu
Keyword(s):  
Stress Distribution ◽  
Temperature Variation ◽  
Modulus Of Elasticity ◽  
Coefficient Of Thermal Expansion ◽  
Metal Tube ◽  
Radial Temperature ◽  
Variation Of Parameters ◽  
Effects Of Temperature ◽  
Fundamental Equations ◽  
Very High

Abstract The paper treats the stress distribution in a metal tube which is subject to a very high radial temperature variation and pressure. The radial temperature distribution across the tube wall and the variations of the modulus of elasticity and the coefficient of thermal expansion are obtained from experimental data, and all these effects of temperature are taken into account in the calculations. The fundamental equations in the case of plane strain and plane stress can be formulated as the nonhomogeneous Whittaker differential equations. The corresponding solutions are obtained by the method of variation of parameters and in terms of Kummer series. An example is shown, and the stress distribution across the wall is given. For comparison, the stress distribution of the case of constant modulus of elasticity and coefficient of expansion is included.

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