title: Oral gavage in rats: animal welfare evaluation.
abstract: The effect of chronic daily orogastric gavage with water (5 mL/kg) on behavior and physiology was evaluated in male Sprague-Dawley rats. Treatment groups included: unmanipulated control, restraint control, dry gavage, and gavage, with all rats singly housed (n = 9 or 10  per group). In addition, a group of pair-housed rats (n = 18) was included to determine whether social housing affected response to gavage. Weekly body weights and food consumption were recorded as well as use of a nylon chew toy for enrichment. Feces were collected biweekly at the  end of the light and dark phases for fecal corticoid metabolite determinations. After 28 d of treatment, animals underwent conditioned place preference testing to evaluate sensitivity to motivational properties of the anxiolytic drug chlordiazepoxide (5.6 mg/kg SC). Brain and paired adrenal  gland weights were collected at necropsy. Week 2 total fecal corticosterone levels were elevated in all groups and attributed to a fire alarm accidentally tripped during building renovations. No differences occurred in body weight or food consumption between any groups. All groups used a nylon  chew toy given for enrichment and demonstrated mild preference for the drug-associated chamber. Fecal weights and corticoid metabolite levels were similar between all groups at week 4 and showed normal diurnal variation. No biologically significant variations were noted in brain or paired  adrenal gland to body weight ratios. We conclude that orogastric gavage of aqueous solutions at 5 mL/kg does not negatively affect the welfare of laboratory rats acclimated to handling.
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, Canada. pvturner@uoguelph.ca
authors.forename: Patricia V
authors.initials: PV
authors.lastname: Turner
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Vaughn
authors.forename: Janet
authors.initials: J
authors.lastname: Sunohara-Neilson
authors.forename: Jelena
authors.initials: J
authors.lastname: Ovari
authors.forename: Francesco
authors.initials: F
authors.lastname: Leri
mesh_terms: D000284:Administration, Oral; D000827:Animal Welfare; D000818:Animals; D001835:Body Weight; D016022:Case-Control Studies; D002707:Chlordiazepoxide / Q000494:pharmacology; D003345:Corticosterone / Q000032:analysis; D004435:Eating; D005243:Feces / Q000737:chemistry; D007756:Laboratory Animal Science / Q000379:methods*; D008297:Male; D009042:Motivation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012931:Social Environment; D014867:Water / Q000008:administration & dosage
chemical_list: D014867:Water; D002707:Chlordiazepoxide; D003345:Corticosterone