Weight Gains of Overnourished and Undernourished Preweanling Rats

Maturation of Jejunum and Ileum in Rats

“…2), where water transport was against the relatively small osmotic gradient. Body water content (8) and extracellular volume appear to be greater in suckling than in older rats. Because extracellular volume expansion induces distension of the intercellular spaces in the intestinal epithelium and secretion of water into the lumen (9), it may be assumed that the expected relative state of extracellular volume expansion in suckling rather than in older rats induced water flow into the lumen of the segments of the suckling rats.…”

The Effect of Limited, Moderate and Lengthy Daily Separation from the Mother during the Early Postnatal Period of the Rat on Concurrent and Subsequent Growth, and on Concurrent Oxygen Consumption at, as well as below, Thermal Neutrality

“…These incidental observations were terminated at 6 weeks of age. By that time, the rats had displayed several traits that characterize starvation and subsequent rehabilitation, including: low oxygen consumption during starvation with increased oxygen consumption early in rehabilitation [15]; a delay in the opening oftheeyes [20]; failure to show compensatory growth [6,8,11,16,20]; a greater reduction in growth by males than by females [6,20]. They had also displayed two previously unreported differences, viz.…”

The Rationale for Culling of Rodent Litters

“…tional to the litter size (Widdowson and McCance, 1960;Heggeness et al, 1961;Kumaresan et al, 1967;Priestnall, 1974;Galler and Turkewitz, 1975;Buhrdel et al, 1978;Kreckmann et al, 1994). For example, we have found that for rats commonly referred to as Charles River CD rats (cesarean-derived, an offshoot of Sprague-Dawley rats) used in our laboratories (maternal body weight in the range 300-400 g), the average pup weight at weaning for a 5-member unculled litter is 68 g, compared with only 40 g for an unculled litter size of 18 (Table 1).…”