Phosphate Absorption at Different Intestinal Sites in the Developing Lamb

Abstract

SUMMARYNet phosphate absorption was studied at different sites of the intestine in milk-fed lambs of different age (1 week, 3-4 weeks, 10-13 weeks) and also in lambs fed a solid diet (age: 10-13 weeks). Disappearance of phosphate from ligated intestinal segments filled or perfused with an electrolyte solution containing 1.2 mmol/l phosphate was employed as measure for phosphate absorption. In all groups of animals the mid-jejunum absorbed phosphate with the greatest velocity. In the 1-week-old lambs the proximal colon descendens was almost as efficient, though phosphate absorption at this site was minimal in the other groups of animals. With the exception of the distal jejunum, phosphate absorption appeared to decrease with age. Between animals of the same age fed either a liquid milk diet or a solid diet phosphate absorption did not differ significantly. Phosphate absorption from the mid-jejunum was inhibited by galactose and glucose in the 1-week-old lambs. The significance of these findings in relation to control of phosphate absorption in the developing lamb is discussed.

Effect of dietary phosphorus on intestinal phosphorus absorption in growing Holstein steers

“…Scharrer (1985) observed the same phosphate absorption efficiency from the descending colon as the upper and mid-jejunum in young lambs.…”

“…The strong relationship between dietary P and manure P content in most species (Erickson et al, 1999;Knowlton and Herbein, 2002;Wu et al, 2003) makes dietary nutrient management a useful approach to reduce the environmental impact of livestock farms, but also makes it important to have detailed knowledge of the fate of dietary P and its utilization in the digestive tract. In ruminants, absorption of P is modulated by endocrine and nutritional factors such as mineral content of the diet, P content of the diet, and the forms of P in the diet (Field et al, 1983;Scharrer, 1985;Care, 1994).…”

II. Quantitative aspects of phosphorus absorptionin ruminants

“…In adult sheep fed balanced phosphorus diets, phosphorus is mainly absorbed in the proximal jejunum. In phosphorus-depleted sheep, the distal colon and even the caecum can absorb phosphorus very efficiently [25]. Consequently, the diversity and potentiality of phosphorus absorption could explain the adjustment capacities of ruminants for phosphorus absorption which is also the case for monogastrics.…”

“…The main intestinal absorption sites are in the duodenum [20] and jejunum [21][22][23]. The absorption of phosphorus from the large intestine is controversial: it is either inexistent [22] or very low [21,23,24] or substantial [25]. In adult sheep fed balanced phosphorus diets, phosphorus is mainly absorbed in the proximal jejunum.…”

Physiologie de l'absorption intestinale du phosphore chez l'animal

“…Chez les ovins, comme chez les monogastriques, l'absorption intestinale de phosphore augmente au cours des premiers mois après la naissance (Scharrer, 1985) puis diminue avec l'âge (Braithwaite, 1975). Comme chez ceux-ci également, le pourcentage de P absorbé au niveau de l'intestin grêle augmente lorsque la teneur de la ration en P diminue (Care et al, 1980), augmentation résultant d'un transfert accru des ions phosphates au niveau de la bordure en brosse (Shirazy-Beechey etal, 1991).…”