Renal functions and urea handling in pregnant and lactating Corriedale ewes

Rodriguez, M. N.; Tebot, I.; Bas, Alicia; Nievas, C.; Cirio, A.; Leng, L

doi:10.4141/cjas96-070

Cited by 15 publications

(11 citation statements)

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“…A fall in the filtered load of urea, consecutive to important decreases in renal plasma flow, glomerular filtration rate and plasma urea level, was the main change observed. Changes in the tubular handling of urea (fractional excretion) induced by the LP diet were not found, in coincidence with our previous results concerning the Corriedale breed [23].…”

Section: Discussionsupporting

confidence: 91%

Microbial protein production determined by urinary allantoin and renal urea sparing in normal and low protein fed Corriedale sheep

et al. 2002

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-The aim of the present study was to compare the amount of microbial N entering the duodenum and the efficiency of N utilisation for microbial protein synthesis in normal (NP, 17.4 g N/d) and low protein (LP, 7.5 g N/d) fed Corriedale sheep. Renal functional tests for urea handling studies, and determination of urinary allantoin as an indirect method to estimate the microbial protein production were used. Although the N intake was 57% lower in LP sheep, the microbial N production was not very different between both diets (NP: 3.99 ± 0.01 vs. LP: 3.79 ± 0.02 g/d, P < 0.05). The efficiency of the microbial protein synthesis in the rumen, expressed as grams of microbial N per kg of digestible organic matter apparently digested in the rumen, was not statistically different for both diets. The urinary elimination of urea was reduced by 84% in LP sheep, essentially due to an important decrease in both renal plasma flow (-63%) and glomerular filtration rate (-71%). These haemodynamic changes would also reduce the filtered load and the urinary elimination of allantoin, thereby leading to an underestimation of the amount of microbial protein entering in the duodenum. Since the renal urea spared by the kidneys remains in the blood, it limits the drop of the available urea for ruminal recycling consecutive to a low nitrogen diet. (NP,17,4 g N/j) ou hypoprotéique (LP, 7,5 g N/j). Des tests de fonctionnement rénal pour étudier les transferts d'urée, et le dosage de l'allantoïne pour estimer la production de protéine microbienne ont été utilisés. Malgré une ingestion d'azote réduite de 57% chez les moutons LP, la production d'azote microbien n'a pas été très différente entre les deux régimes (NP: 3,99 ± 0,01 vs. LP: 3,79 ± 0,02 g/j, P < 0,05). L'efficacité de la synthèse protéique microbienne dans le rumen, exprimée en grammes d'azote microbien par kg de matière organique apparemment digérée dans le rumen, n'a pas été statistiquement différente dans les deux régimes. L'élimination urinaire d'urée a été réduite de 84% chez les moutons LP, grâce essentiellement à une importante diminution du débit plasmatique rénal (-63%) et de la filtration glomérulaire (-71%). Ces modifications hémodynamiques réduisant également la charge filtrée et la quantité d'allantoïne éliminée, peuvent être responsables d'une sous estimation de la quantité de protéine microbienne entrant dans le duodénum. L'urée épargnée au niveau rénal restant dans le sang, limite la baisse de l'urée disponible pour le recyclage dans le rumen, observée lors des régimes pauvres en azote.protéine microbienne / allantoïne / urée / mouton

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Section: Discussionsupporting

confidence: 91%

Microbial protein production determined by urinary allantoin and renal urea sparing in normal and low protein fed Corriedale sheep

et al. 2002

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“…These changes may be influenced by the fluid redistribution mentioned earlier, in addition to the urea and creatinine being re-circulated from the blood stream into the digestive tract, as suggested by Igbokwe (1993). As for lactation, it had no effect on serum urea and creatinine concentrations, similarly to the results obtained by Rodriguez et al (1996) working with Corriedale sheep. Furthermore, ElSherif and Assad (2001) observed a sharp decrease in urea and creatinine in lactating ewes after parturition to approach those of the dry animals by the end of the first month.…”

Section: Serum Chemistrysupporting

confidence: 68%

Physiological responses to water restriction in dry and lactating Awassi ewes

et al. 2006

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“…The same authors reported that lactation significantly increased plasma albumin, albumin to globulin ratio and blood creatinine in Barki ewes under semi-arid conditions. No alteration was caused by lactation on serum urea and creatinine levels in Awassi ewes [47] and Corriedal [138]. Working with lactating Comisana subjected to 60% water deprivation, Casamassima et al (2008) [74] reported significant elevations in serum concentration of triglycerides, albumin, total proteins and cholesterol.…”

Section: Lactationmentioning

confidence: 91%

“…Similarly, Olsson et al (1982) [137] reported increases in plasma osmolality and Na + concentration in pregnant goats dehydrated for 30h accompanied by a decrease in glomerular filtration rate, while plasma protein and hematocrit did not change with dehydration. Interestingly, it was observed that pregnant goats [137] and sheep [138] have a lower capacity to concentrate urine in response to dehydration. Authors in both studies suggested that the apparent reason for this observation is a decreased sensitivity to Arginin-Vasopressin (AVP) which in turn, could be partially due to the effects of high prostaglandin concentrations which increase during late gestation.…”

Section: Pregnancymentioning

confidence: 99%