102 RELATION BETWEEN FAECAL WATER AND FAT IN PRETERM INFANTS

Abstract

Complete 24 or 72hour stool collections were performed during metabolic balances on 39 occasions in 9 preterm infants with birthweight and gestation (M±2SD) of 1081 ± 173g&28.4±2.1 weeks, between 9-90 days (33±29d). All infants were growing well and receiving food only by the oral route. Five infants were fed expressed breast milk (EBM) and 4 with a preterm formula (P.F.). Milk intake was 182±18 ml/kg/d. The weight of the wet stool (w.s.) pooled for each balance and the weight after freeze drying were recorded. The difference between freeze-dried and w.s. weight was defined as the water content of stool and expressed as % of the weight of w.s. Fat analyses were performed on the same samples using a gravimetric method and the fat content was expressed also as % of weight. The correlation between % of fat and % of water in the stool was very close considering feeds together (r=-0.95 p< 0.001) or individually (EBMr=-0.96 p< 0.001, P.F.r=-0.89 p< 0.001). By using the regression equation of the line y=79.2-0.87x, the % of stool fat (y) can be calculated simply from a knowledge of the % water of the stool (x) to an accuracy of ± 4% (2SEM) without time consuming and expensive analyses of fat.