title: Artificial formula induces precocious maturation of the small intestine of artificially reared suckling rats.
abstract: BACKGROUND
  The artificially reared rat model was used successfully to study the effect of nutrition during the early postnatal period on growth and development of the neonate. Overgrowth and morphologic changes of the gastrointestinal tract are known consequences of artificial rearing. The major goal of our study was to elucidate whether artificial rearing-enhanced gut development is caused by artificial diet or by gastrostomy and the artificial rearing technique itself.
  
  
  METHODS
  Suckling rats at day 8 of age underwent intragastric cannulation and were machine fed either a cow's milk-based artificial rat's milk substitute or pooled rat's milk for 4 days. Dam-fed littermates served as a control.
  
  
  RESULTS
  Body growth did not differ in the three experimental groups. In rats receiving rat's milk substitute, small intestinal wet weight was approximately 60% greater than in rats fed rat's milk or control rats. Additionally, the entire small intestine was approximately 20% longer in the rat's milk substitute group. Morphologically, rat's milk substitute-fed pups demonstrated significantly greater intestinal villus length and crypt depth compared with rat's milk-fed or control rats. Jejunum and midjejunum of the rat's milk and control groups did not differ in these parameters. Intestinal sucrase activity of rat's milk substitute-fed rats was significantly elevated compared with rat's milk-fed rats or control animals.
  
  
  CONCLUSIONS
  These results indicate that cow's milk-based formula, not gastrostomy or artificial feeding technique, is a principal cause of the small intestine overgrowth and precocious maturation of some intestinal functions observed in artificially reared sucklings.
authors.affiliation: Department of Pediatrics and Steele Memorial Children's Research Center, University of Arizona, Tucson 85724-5073, USA.
authors.forename: B
authors.initials: B
authors.lastname: Dvorak
authors.forename: D L
authors.initials: DL
authors.lastname: McWilliam
authors.forename: C S
authors.initials: CS
authors.lastname: Williams
authors.forename: J A
authors.initials: JA
authors.lastname: Dominguez
authors.forename: N W
authors.initials: NW
authors.lastname: Machen
authors.forename: R S
authors.initials: RS
authors.lastname: McCuskey
authors.forename: A F
authors.initials: AF
authors.lastname: Philipps
mesh_terms: D000818:Animals; D000833:Animals, Suckling / Q000254:growth & development*; D001834:Body Water; D004247:DNA / Q000096:biosynthesis; D004750:Enteral Nutrition; D005260:Female; D005526:Food, Formulated; D005774:Gastrostomy; D007421:Intestine, Small / Q000254:growth & development* / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013393:Sucrase / Q000378:metabolism; D015430:Weight Gain
chemical_list: D004247:DNA; D013393:Sucrase