Serum total and bone alkaline phosphatase levels and their correlation with serum minerals over the lifespan of sheep. Acta Veterinaria Hungarica

This study aimed to assess serum total alkaline phosphatase (ALP) and its
bone isoform (BALP) levels during the ageing and in different physiologic states
of sheep, in order to expand the knowledge about the variation of these biomarkers
over the sheep lifespan. Ninety female sheep were divided into nine
groups of various ages and physiological states (dry, lactation and pregnancy). Serum
ALP, BALP and mineral levels were determined by commercial immunoassay,
molecular absorbance spectrophotometry and chemical luminescence for
BALP determination. Serum ALP and BALP decreased as sheep aged, and no statistically
significant differences were obtained between ewes in different physiologic
states. The continuous decline of serum BALP concentration along the sheep
lifespan, namely in mature and old sheep, is a sign of decreasing bone turnover
associated with ageing. Serum calcium concentrations increased slightly until 2
years of age and then showed a tenuous but statistically significant decrease in
mature sheep, while serum phosphorus maintained an uninterrupted decrease as
sheep matured. The knowledge of serum values of bone biomarkers throughout
the sheep lifespan may be useful in preclinical orthopaedic research studies and
for animal science studies using sheep.