ABSTRACT
The gastrointestinal response in rats nourished by continuous intragastric infusion of a variety of defined formula diets was compared with animals consuming the same diets orally. Two groups of rats were fed isocaloric amounts of DFD (73 kcal/day); group 1: sham-operated, orally-fed; group 2: operated, intragastrically-fed. Diets included; Vivonex (V), Flexical (F), Vital, Vivonex high nitrogen, and a control casein rat liquid formula diet (C). After 2 wk rats were killed and the liver, pancreas, and small bowel removed. The bowel was divided into eight equal segments. Mucosal weight, DNA, and protein concentration per cm segment were measured Pancreatic amylase activity (units/g), and liver weight and lipid content were measured. Weight gain was comparable in all oral-fed groups, but was decreased in all gastric-fed animals compared to the oral-fed group. Nitrogen retention was not influenced by route of feeding but was significantly lower for Vivonex and Flexical animals (p less than 0.01) in both oral-fed and gastric-fed groups. There was significant accumulation of lipid in the liver of both oral-fed and gastric-fed animals sustained on Vivonex and Vivonex high nitrogen (p less than 0.01). Most proximal intestinal segment weight and mucosal weight, protein and DNA were decreased compared to the control diet in both oral-fed and gastric-fed animals. These studies demonstrate that while the gastrointestinal response to isocaloric defined formula diets was significantly influenced by the specific diet, fewer responses were modified by feeding defined formula diets orally versus gastrically.
Subject(s)
Digestive System Physiological Phenomena , Enteral Nutrition/standards , Food, Formulated/standards , Animals , Body Weight , Food, Formulated/analysis , Intestinal Mucosa/metabolism , Intubation, Gastrointestinal , Male , Nitrogen/metabolism , Organ Size , Pancreas/metabolism , Rats , Rats, Inbred StrainsABSTRACT
The gastrointestinal response to oral alimentation of low residue commercial defined formula diets or a rat liquid formula was studied. Male Sprague-Dawley rats (220-250 g) were fed isocaloric amounts (73 kcal/day) of Vivonex (V), Vivonex HN (VHN), Flexical (F), Vital (Vit), or a control Casein diet 116EC (C). Nitrogen (N) retention was calculated from N intake minus N excretion/day. After 2 weeks, rats were killed and the liver, pancreas, and small bowel removed and weighed. Pancreatic amylase activity (U g) and liver lipid were measured. The bowel was divided into eight equal segments, and mucosal weight, DNA, and protein concentration per centimeter were measured. Despite isocaloric feeding, body weight gain was lower in V and VHN groups, and higher in F and Vit groups compared to the C. Amylase specific activity was increased in V, VHN, and F groups, while the liver lipid was increased in the V and VHN groups when compared to C animals. The most proximal intestinal segment weight, mucosal weight, protein and DNA of V, VHN, and Vit groups were less than C animals, while distal segments were similar. F animals showed greater intestinal mass than C rats. These studies indicate statistically significant differences in gastrointestinal response as a result of nutrient variation of defined formula diets.
Subject(s)
Digestive System Physiological Phenomena , Food, Formulated , Amylases/blood , Animals , Body Weight , Food, Formulated/analysis , Intestine, Small/analysis , Lipids/analysis , Liver/analysis , Male , Nitrogen/pharmacology , Organ Size , Pancreas/analysis , Rats , Rats, Inbred Strains , Stomach/anatomy & histologySubject(s)
Glucose/metabolism , Oligosaccharides/metabolism , Parenteral Nutrition , Adult , Blood Glucose/metabolism , Carbohydrates/urine , Dose-Response Relationship, Drug , Fatty Acids, Nonesterified/blood , Humans , Injections, Subcutaneous , Insulin/administration & dosage , Insulin/blood , Male , Oligosaccharides/administration & dosage , Parenteral Nutrition/adverse effects , Structure-Activity Relationship , Time FactorsABSTRACT
Little is known about the specific effects of defined formula diets (DFD) on mucosal growth of the small intestine, pancreas, or liver. In the present study male Sprague Dawley rats weighing 220 to 250 g were fed isocaloric amounts of DFD (61 kcal/day) by continuous intragastric infusion. The diets fed were Vivonex, Vivonex-HN, Flexical, and Ensure. Oral chow-fed rats with intragastric water infusions served as reference. All groups gained weight: chow 50.50 g, Vivonex 21.17 g (P < 0.005), Vivonex-HN 25.40 g (P < 0.005), Flexical 30.5 g (P < 0.01), Ensure 39.29 g (NS). After 2 weeks rats were killed, the small bowel excised, rinsed, and divided into eight equal segments. Mucosal weight, DNA, and protein concentration per centimeter segment were measured. The pancreas was also removed, homogenized, and amylase activity assayed (units/g). Livers were excised, weighed, lipid content measured, and liver histology was examined by light microscopy. Mucosal weight, DNA, and protein concentrations per segment were decreased significantly in most bowel segments of DFD fed rats. Amylase activity per gram pancreas was significantly reduced in rats fed Vivonex, Flexical, and Ensure, Serum amylase activity was also lowered in animals on DFD. There was significant accumulation of lipid in the liver of Vivonex and Flexical animals (P < 0.01). Liver histology confirmed the striking increase in fat in the Vivonex and Flexical groups. These effects may result from differences in DFD absorption, mucosal metabolism, stimulation of enteric hormone release, and/or bile and pancreatic secretions.
