title: Effect of fasting in the digestive system: histological study of the small intestine in house sparrows.
abstract: In birds and mammals the metabolic response to fasting has been studied and can be characterized by three consecutive phases reflecting metabolic and physiological adjustments. An effective way to minimize energy expenditure during food scarcity is to decrease the mass of the organs. As the digestive system is metabolically expensive to maintain, the small intestine and the liver are the most affected organs. We evaluated the effects of phase III starvation on the mass of the different organs and histological parameters on house sparrows, a small non-migrant bird. In a short period of time (34 h) we observed a larger reduction in the digestive organ mass when compared to the mass of the body and non-alimentary tissues. Furthermore, the intestinal mass was proportionally more reduced than its length and nominal surface area. A reduction on the intestinal mucosal layer also resulted in a shortening of villus (length and thickness) and crypt depth. Moreover, the morphology of the enterocytes changed from cylindrical to cubical, suggesting that the surface exposed to the lumen was conserved. This may indicate an adaptive response to the moment of refeeding. The nominal surface area/body mass remained constant in both groups and several histological parameters were reduced, suggesting that starving induces the atrophy of the small intestine. However, the goblet cells were conserved after fasting indicating a protective tendency.
authors.affiliation: Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), CCT-San Luis, CONICET, San Luis, Argentina.
authors.forename: Samanta Celeste
authors.initials: SC
authors.lastname: Funes
authors.affiliation: Área de Morfología, Departamento de Bioquímica y Ciencias Biológicas, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina.
authors.forename: Verónica Palmira
authors.initials: VP
authors.lastname: Filippa
authors.affiliation: Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), CCT-San Luis, CONICET, San Luis, Argentina; Área de Biología, Departamento de Bioquímica y Ciencias Biológicas, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina.
authors.forename: Fabricio Damián
authors.initials: FD
authors.lastname: Cid
authors.affiliation: Área de Morfología, Departamento de Bioquímica y Ciencias Biológicas, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina.
authors.forename: Fabián
authors.initials: F
authors.lastname: Mohamed
authors.affiliation: Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), CCT-San Luis, CONICET, San Luis, Argentina; Área de Biología, Departamento de Bioquímica y Ciencias Biológicas, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina.
authors.forename: Enrique
authors.initials: E
authors.lastname: Caviedes-Vidal
authors.affiliation: Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), CCT-San Luis, CONICET, San Luis, Argentina; Área de Biología, Departamento de Bioquímica y Ciencias Biológicas, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina. Electronic address: jg.chediack@gmail.com.
authors.forename: Juan Gabriel
authors.initials: JG
authors.lastname: Chediack
mesh_terms: D000818:Animals; D005215:Fasting / Q000502:physiology*; D007421:Intestine, Small / Q000473:pathology*; D009929:Organ Size; D046370:Sparrows / Q000502:physiology*
keywords: Gastrointestinal tract; Histological parameters; Non-migrant birds; Starvation