Effect of Partial Deprivation of Parotid Saliva on Physiological responses of steers Fed Three Levels of Dietary Sodium

SUMMARYMature sheep fitted with rumen and duodenal cannulae were fed pelleted diets made from hay that had been either coarsely or finely ground. The diets were supplemented with phosphorus and the effects on salivary phosphorus secretion, net intestinal phosphorus absorption and the route of excretion were examined. Changing the particle size of the diet had no effect on overall phosphorus balance but did affect the route of excretion with urine levels being higher and faecal levels lower in periods when the more finely ground diet was fed. This increase in urine excretion was not due to differences in phosphorus intake nor could it be attributed to increased net phosphorus absorption from the intestine. Salivary phosphorus secretion was, however, lower when the more finely ground diet was fed and it would appear that this change in the balance between that absorbed relative to its secretion back into the gut was the major factor contributing to the increased phosphorus excretion in the urine. The significance of these findings in relation to the high levels of phosphorus normally found in the urine of sheep fed concentrate diets compared to those fed roughage diets is discussed.

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The Effects of Feeding Pelleted Diets Made From Either Coarsely or Finely Ground Hay on Phosphorus Balance and on the Partition of Phosphorus Excretion Between Urine and Faeces in the Sheep

Scott¹,

Buchan²

1988

“…Factors that affect the level of phosphorus secretion in the saliva are not as well defined as those which affect flow though measurements of salivary phosphorus secretion in animals fed a variety of diets, do seem to suggest that differences in daily secretion rates between diets are largely related to differences in salivary flow rate (Bailey & Balch, 1961;Hawkins, Autrey & Huff, 1965;Lawlor et al 1966).…”

Section: Discussionmentioning

confidence: 99%

The Effects of Feeding Either Hay or Grass Diets on Salivary Phosphorus Secretion, Net Intestinal Phosphorus Absorption and on the Partition of Phosphorus Excretion Between Urine and Faeces in the Sheep

Scott¹,

Buchan²

1987

SUMMARYMature sheep fitted with ruminal and duodenal cannulas were fed either a pelleted hay or a pelleted grass diet with or without supplementary phosphorus. Salivary phosphorus secretion, net intestinal phosphorus absorption and the route of phosphorus excretion were determined. The route of excretion was markedly affected by diet with urinary excretion being much higher and faecal excretion lower when the grass diet was fed. These effects were not due to differences in phosphorus intake or to differences in net intestinal phosphorus absorption. Salivary phosphorus secretion was, however, lower when the grass diet was fed. The significance of these changes in relation to the control of phosphorus balance in ruminants is discussed.

“…Factors affecting the amount of phosphorus secreted in the saliva are less well defined. Phosphorus concentration in the saliva is known to be dependent on plasma concentration (Denton, 1956;Scott & Beastall, 1978;Mands-Almendros, Ross & Care, 1982) though on a daily basis the amount secreted appears to be largely determined by salivary flow rate (Bailey & Balch, 1961;Hawkins, Autrey & Huff, 1965;Lawlor et al 1966) and as such one would expect a higher rate of phosphorus secretion in sheep fed roughage diets compared to those fed concentrate diets (Sato et al 1976).…”

Section: Discussionmentioning

confidence: 99%

The Effects of Feeding Either Roughage or Concentrate Diets on Salivary Phosphorus Secretion, Net Intestinal Phosphorus Absorption and Urinary Phosphorus Excretion in the Sheep

Scott¹,

Buchan²

1985

SUMMARYMature sheep fitted with rumen and duodenal cannulae were fed either a hay or a concentrate diet and the effects on salivary phosphorus secretion, net intestinal phosphorous absorption and pathway for phosphorous excretion were examined. Route of excretion was markedly affected by diet with urine phosphorus levels being much higher and faecal levels lower when the concentrate diet was fed. This difference was not due to differences in phosphorus intake nor could it be related to differences in either plasma phosphorus levels or net intestinal phosphorus absorption. Salivary phosphorus secretion and renal tubular reabsorptive efficiency for phosphorus were, however, both lower when the concentrate diet was fed. The significance of these effects ofdiet in relation to the control ofphosphorus balance in ruminants is discussed.