Systemic responses to different enteral feeding schedules in rats

The purpose of this study was to describe selected temporal systemic responses to different enteral feeding schedules using an animal model, as one prerequisite for determining optimal delivery times for human enteral feedings. The effect of feeding schedules and time of day were examined relative to body weight and plasma glucose, insulin, glucagon, and corticosterone levels. Adult male Sprague-Dawley rats (N = 80) were used in a 4 x 4 randomized block design. Rats started the feeding schedules on Day 11 post-gastrostomy tube placement. The following feeding schedules, often used by humans, were tested: 24-hour enteral; 24-hour oral; 12-hour (rest time) enteral; and 12-hour (rest time) oral. Plasma was collected on Day 20. Despite very different feeding schedules, there were no statistical differences in weight gain, or plasma glucose and glucagon levels. Levels of insulin and corticosterone were significantly influenced by time of day and/or feeding group. Temporal pattern disruption was greatest in the rest-time fed enteral group. Both route and timing of enteral delivery modified metabolic hormone patterns.