The objective of the current study was
to investigate whether plasma citrulline or intestinal
fatty acid-binding protein (I-FABP) concentrations
might be used as longitudinal markers for small intestinal
function in piglets after weaning. Plasma citrulline
and I-FABP concentrations were measured longitudinally
in weaned and unweaned piglets, and related to
intestinal absorption values (i.e., plasma mannitol and
d-xylose concentrations in a sugar absorption test).
Within each litter (n = 10), 2 piglets with a close-tolitter-
average BW were selected. At 20.8 ± 0.4 d of age,
the selected piglets per litter were either weaned conventionally
(CW) or remained with the sow (UNW).
One day before, and 0.5, 2, 4, and 7 d after weaning
of the CW piglets, the selected piglets of both groups
were subjected to a sugar absorption test. After a 2-h
fast, piglets were administered an oral dose of 2 mL/
kg of sugar solution, containing 50 mg/kg of mannitol
and 100 mg/kg of d-xylose. One hour after administration,
a blood sample was collected from a jugular vein
for determination of plasma I-FABP, citrulline, mannitol,
and d-xylose concentrations. Plasma I-FABP concentration
showed great variation within treatments,
and no difference was observed in plasma I-FABP concentrations
between the CW and UNW treatments (P
= 0.63). The absorption of d-xylose was not different
between treatments (P = 0.83). Mannitol absorption,
however, was less in the weaned CW piglets compared
with the UNW piglets (P = 0.003), with the nadir on d
4 postweaning. Weaning also reduced plasma citrulline
concentrations in the CW treatment compared with the
UNW treatment (P < 0.001). On d 4 and 7 postweaning, plasma citrulline concentrations of CW piglets were less (P < 0.001 and P = 0.0013) than preweaning values. Furthermore, in the CW treatment, plasma citrulline concentrations correlated with plasma mannitol concentrations at d 4 postweaning (r = 0.89, P = 0.008) and overall (r = 0.76, P = 0.001). Based on these results, plasma citrulline concentration seems to be a possible marker for monitoring intestinal function in pigs after weaning.