A review of the renal system and diurnal variations of renal activity in livestock

Abstract

Kidneys are the main organs regulating water-electrolyte homeostasis in the body. They are responsible for maintaining the total volume of water and its distribution in particular water spaces, for electrolyte composition of systemic fluids and also for maintaining acid-base balance. These functions are performed by the plasma filtration process in renal glomeruli and the processes of active absorption and secretion in renal tubules, all adjusted to an 'activity-rest' rhythm. These diurnal changes are influenced by a 24-hour cycle of activity of hormones engaged in the regulation of renal activity. Studies on spontaneous rhythms of renal activity have been carried out mainly on humans and laboratory animals, but few studies have been carried out on livestock animals. Moreover, those results cover only some aspects of renal physiology. This review gives an overview of current knowledge concerning renal function and diurnal variations of some renal activity parameters in livestock, providing greater understanding of general chronobiological processes in mammals. Detailed knowledge of these rhythms is useful for clinical, practical and pharmacological purposes, as well as studies on their physical performance.

Effect of thermal exposure on diurnal rhythms of physiological parameters and feed, water intake in Tharparkar and Karan Fries heifers

“…Na þ and K þ concentrations were within reported reference ranges (Radostits et al 1974). Significant diurnal variations (P 5 0.05) in the plasma levels of Na þ and K þ have been observed in the present study and these are in agreement with the findings of Skotnicka et al (2007). Significant rhythmic fluctuation in blood Na þ and K þ concentrations with opposing patterns were found in our study; similar findings were reported by Yashiki et al (1995) and Table 2.…”

Glomerular filtration rate in cows estimated by a prediction formula

“…Only a few studies have reported glomerular filtration rate (GFR) estimates in cows to date (Skotnicka et al 2007), because the traditional method of urinary clearance measurement requires an intravenous infusion and accurately and repeatedly timed blood and urine collections over a period of several hours. Moreover, the standard tracer inulin has an inherent disadvantage for cows because of extremely low solubility.…”

Diurnal variations of renal activity in goats

“…Studies on chronobiological aspects of physiological functions have been carried out mainly on humans and laboratory animals. A few studies have been carried out on livestock (2)(3)(4).…”

“…They are responsible for maintaining the total volume of water and its distribution in particular water spaces, for electrolyte composition of bodily fluids and especially extracellular fluid, and for maintaining acid-base balance. Moreover, kidneys are responsible for expelling metabolites from the organism, especially for protein metabolism and other unnecessary and harmful substances, and at the same time maintaining the necessary substances in blood (4). Kidneys take part in the synthesis of hormones or their precursors such as renin, renal erythropoietic factor, calcitriol, and prostaglandins (5)(6)(7).…”