Parotid saliva of sheep. 1. Effects of level of intake and type of roughage

1982 ◽  
Vol 33 (3) ◽  
pp. 573 ◽  
Author(s):  
PT Doyle ◽  
JK Egan ◽  
AJ Thalen
Keyword(s):  
Secretion Rate ◽  
Parotid Saliva ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Sulfate Sulfur ◽  
Consumption Values ◽  
Parotid Duct ◽  
The Right

In three experiments, quantitative collections of saliva were made from the right parotid duct of six Merino wethers. Experiment 1 assessed the repeatability of the collection techniques and found little difference in salivary parameters measured at intervals over a 6-week period. When chopped lucerne was given at three levels (experiment 2) the secretion rate of parotid saliva (g 19.5h-1) increased (P < 0.01) with increasing lucerne consumption as did the concentrations and amounts of total and urea nitrogen in saliva (P < 0.05 to P< 0.01). Only minor changes in the secretion of total and reducible sulfur occurred. Plasma urea nitrogen (P < 0.05) and blood sulfate sulfur (P < 0.01) concentrations increased with increasing lucerne consumption. Values are given to indicate the variability between sheep in volume and composition of parotid saliva secretions. In experiment 3 the sheep were offered four different roughage diets. The secretion rate of saliva (g 19.5h-1) increased (P < 0.01) when more fibrous roughages were given. The type of roughage also affected (P < 0.01) the concentrations and amounts of total and urea nitrogen in saliva, but there was little effect upon the secretion of total or reducible sulfur. Plasma urea nitrogen and blood sulfate sulfur concentrations were different (P < 0.01) on the various roughage diets. The results are compared with the findings of previous research, and estimates of the amounts of nitrogen and sulfur recycled to the rumen in saliva are made.

The Origin and Fate of Salivary Urea and Ammonia in Man

1977 ◽  
Vol 52 (1) ◽  
pp. 9-17 ◽  
Author(s):  
J. Kopstein ◽  
O. M. Wrong
Keyword(s):  
Plasma Concentration ◽  
Nitrogen Concentration ◽  
Urea Concentration ◽  
Ionic Diffusion ◽  
Parotid Saliva ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Parotid Duct ◽  
Hydrolysis Of ◽  
Hydrolysis Of Urea

1. Saliva obtained from the parotid duct of normal and uraemic subjects had an average urea concentration of 86% of the plasma concentration whereas in mixed saliva obtained from the mouth the urea concentration was only 31% of the plasma concentration. Ammonia concentrations were low or unmeasurable in parotid saliva but varied between 0·6 and 26 mmol/kg in oral saliva, showing a positive correlation with the plasma urea concentration. 2. The urea in samples of mixed oral saliva incubated at 37°C disappeared by 290 min. Ammonia steadily increased during incubation; within the first 100 min, the increase could be largely accounted for by bacterial hydrolysis of urea, but later non-urea sources became relatively more important. 3. These findings suggest that the ammonia in mixed oral saliva is derived by bacterial hydrolysis of urea within the mouth. However, the concentration of ammonia plus urea nitrogen in oral saliva was only 76% of the urea nitrogen concentration of parotid saliva, which suggests that some ammonia is lost from the mouth by buccal absorption or by volatilization. 4. To assess the role of non-ionic diffusion of ammonia through the buccal mucosa, we studied the effect of pH on the disappearance of ammonia from buffered solutions retained in the mouth. Ammonia concentrations fell more rapidly at pH 9 than at pH 7, as also did those of hydrazine, a non-volatile analogue of ammonia which is known to be absorbed through other mucosae by non-ionic diffusion. These findings suggest that salivary ammonia is reabsorbed passively through the oral mucosa in the un-ionized phase.

scholarly journals PSVII-6 Effects of heat stress on proteolysis in dairy cattle skeletal muscle

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 168-168
Author(s):  
Melissa S Roths ◽  
Megan A Abeyta ◽  
Tori Rudolph ◽  
Brittany Wilson ◽  
Matthew B Hudson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Heat Stress ◽  
Dairy Cattle ◽  
Electric Heating ◽  
Economic Loss ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
E3 Ligases ◽  
Acclimation Period ◽  
Milk Urea

Abstract Heat stress (HS) occurs when internal body temperatures are elevated above a thermoneutral zone in response to extreme environmental temperatures. In the U.S. dairy industry, HS results in economic loss due to decreased feed intake, milk quality, and milk yield. Previous work has demonstrated increased plasma urea nitrogen in heat stressed dairy cattle which is thought to originate from increased skeletal muscle proteolysis, however this has not been empirically established. The objective of this investigation was to determine the extent to which HS promotes proteolysis in skeletal muscle of dairy cattle. We hypothesized HS would increase activation of the calpain and proteasome systems in skeletal muscle. To test this hypothesis, following a 3-d acclimation period in individual box stalls, all lactating dairy cows were held under thermoneutral (TN) conditions for 4-d for collection of baseline measures and then exposed to TN or HS conditions for 7-d followed by a biopsy of semitendinosus (n=8/group). To induce HS, cattle were fitted with electric heating blankets, which they wore for the duration of the heating period. This approach increased rectal temperature 1.1°C (P&lt; 0.05), respiratory rate by 33 bpm (P&lt; 0.05), plasma urea nitrogen by 19% (P=0.08) and milk urea nitrogen by 26% (P&lt; 0.05), and decreased dry matter intake by 32% (P&lt; 0.05) and milk production by 26% (P&lt; 0.05) confirming HS. Contrary to our expectations, we discovered that calpain I and II abundance and activation, and calpain activity were similar between groups. Likewise, protein expression of E3 ligases, MafBx and Murf1, were similar between groups as was total ubiquitinated proteins and proteasome activity. Collectively, and counter to our hypothesis, these results suggest skeletal muscle proteolysis is not increased following 7-d of HS. These data question the presumed dogma that increased blood urea nitrogen is due to elevated proteolysis in skeletal muscle.

Time-response relationship of ractopamine feeding on growth performance, plasma urea nitrogen concentration, and carcass traits of finishing pigs1

2013 ◽  
Vol 91 (2) ◽  
pp. 811-818 ◽  
Author(s):  
V. V. Almeida ◽  
A. J. C. Nuñez ◽  
A. P. Schinckel ◽  
C. Andrade ◽  
J. C. C. Balieiro ◽  
...  
Keyword(s):  
Growth Performance ◽  
Nitrogen Concentration ◽  
Carcass Traits ◽  
Time Response ◽  
Response Relationship ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Relationship Of

The relationship of plasma urea nitrogen with growth traits and age at first estrus in gilts1,2

2013 ◽  
Vol 91 (7) ◽  
pp. 3137-3142 ◽  
Author(s):  
C. A. Lents ◽  
L. A. Rempel ◽  
J. Klindt ◽  
T. Wise ◽  
D. Nonneman ◽  
...  
Keyword(s):  
Growth Traits ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Relationship Of ◽  
The Relationship

1377 Interactive effects of supplemental Zn sulfate and ractopamine hydrochloride on growth performance, carcass traits, and plasma urea nitrogen in feedlot heifers

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 666-666
Author(s):  
C. L. Van Bibber-Krueger ◽  
J. M. Gonzalez ◽  
R. G. Amachawadi ◽  
H. M. Scott ◽  
J. S. Drouillard
Keyword(s):  
Growth Performance ◽  
Carcass Traits ◽  
Interactive Effects ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Ractopamine Hydrochloride

Metabolism of 15N-Labelled Urea in the Functioning and Defunctioned Human Colon

1990 ◽  
Vol 79 (3) ◽  
pp. 253-258 ◽  
Author(s):  
B. J. Moran ◽  
A. A. Jackson
Keyword(s):  
Human Colon ◽  
Urea Hydrolysis ◽  
Bacterial Activity ◽  
The Body ◽  
Urea Molecule ◽  
Urea Nitrogen ◽  
Nitrogen Pool ◽  
End Colostomy ◽  
15N Urea ◽  
The Right

1. The luminal metabolism of urea was studied using double-labelled urea ([15N2]urea) which was placed in the lumen of the colon through a colostomy. The recovery of label was measured as [15N2]urea or [14N,15N]urea in urine and as 15N in stool. 2. Five patients with a loop colostomy allowed a comparison of the right functioning colon with the left defunctioned colon in the same individual. Five subjects with a left end-colostomy enabled a comparison of the right with the left functioning colon. 3. A significantly greater proportion of labelled urea was recovered as [15N2]urea in the urine when the dose was placed in the left defunctioned colon (29%) compared with either the left or the right functioning colon (9 and 4%, respectively). This is interpreted as being a result of a decrease in the bacterial activity and concomitant urea hydrolysis in the defunctioned colon. 4. On average more than half of the label was retained in the body, regardless of whether the urea was placed in the functioning or the defunctioned colon, on the left or on the right. 5. The data confirm that the colon is permeable to the intact urea molecule. Intraluminal urea is readily hydrolysed in the functioning colon. A large proportion of the nitrogen released by urea hydrolysis may be retained within the metabolic nitrogen pool of the host. There are significant differences in the handling of urea nitrogen in the defunctioned colon relative to the functioning colon.

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