Maternal separation and gastrointestinal transit time in neonate rats

Abstract

Gastrointestinal transit times (GItts) were compared in separate litters of 10- and 15-day-old Sprague Dawley rats using barium sulphate. By tracking the leading front of the bolus on radiographs, the gastrocaecal transit times in pups were estimated. To measure the total GItt, the duration from orogastric gavage until an observable defecation of barium sulphate was recorded. The gastrocaecal times for 10-day-old pups maintained with their dam (n = 5) ranged from 4-5 h and those removed from the dam ranged from 2.5-5 h. For 15-day-old pups with their dam (n = 6) and without dam (n = 5), gastrocaecal times ranged from 4-6 h and 3.5-5 h, respectively. Ten-day-old pups that remained with the dam had a GItt of 13.8 ± 0.9 h and those kept in the absence of the dam had a time of 9.3 ± 0.7 h. This decrease (P < 0.05) in GItt in the absence of the dam was age-dependent in 10-day-old pups, and was not observed (P > 0.05) in 15-day-old pups. The results provide a basis, for the design of future studies involving neonate rat metabolism, to include maternal presence.

Ingested soluble CD14 from milk is transferred intact into the blood of newborn rats

“…Sprague-Dawley rat pups aged 10 d old were used as a model of pre-weaning infants as at this age the animals only ingest their mothers’ milk. In total, 26 pups (derived from three litters of 13 pups each) weighing between 11 g and 26 g were fasted for 2 h at 37°C to partially empty the stomach and accommodate for the gavage protein solution ( 34 ). Pups were gavage fed 25 μg in 250 μL of PBS of either [ 14 C]sCD14, [ 14 C]BSA, [ 125 I]sCD14 or [ 125 I]BSA using our previous technique ( 34 ).…”