Influence of dietary calcium and phosphorus supply on epithelial phosphate transport in preruminant goats.

P homeostasis affected by high or low Ca and/or P supply in preruminant goats was characterized by balance studies in vivo. The main excretion pathway was the renal P(i) excretion whose extent was modulated by variations in dietary P and/or Ca supply. Faecal P excretion remained low irrespective of dietary regimen.

Ontogenesis of epithelial phosphate transport systems in goats.

The rapid development of precocial goats in the first weeks after birth requires an adequate adaptation of phosphate transport systems to maintain the P homeostasis at each developmental stage. Here we examined the age-related development of Na+-Pi transport systems in small intestines, kidneys, and parotid glands of goats. Kinetic parameters were determined by brush-border membrane vesicle uptake studies, and relative expression of NaPi type II mRNA and protein was recorded by molecular biological methods.