Meeting Abstract

100.5  Wednesday, Jan. 7  Phenotypic plasticity of intestinal dissacharidase activity is fully reversible in young House sparrows KOHL, K.*; BRZEK, P.; CAVIEDES-VIDAL, E.; KARASOV, W.H.; University of Wisconsin, Madison; University of Wisconsin, Madison; Universidad Nacional de San Luis-CONICET, Argentina; University of Wisconsin, Madison pbrzek2@wisc.edu

Environmental variation during development can produce significant variation among individuals phenotypes (phenotypic plasticity). This variation includes also digestive morphology and physiology. We showed previously in House sparrow (Passer domesticus) nestlings that the presence of starch in diet between days 3 and 12 posthatch significantly increased maltase activity. However, it remained unclear whether this modulation is irreversible or reversible reflecting, respectively, a developmental plasticity or a phenotypic flexibility. To answer this, nestlings were raised from 3 days of age until 30 days on diets with either 0% starch or 25% starch (+starch), with some individuals experiencing a switch in their assigned diet at 12 days of age. Thus, there were four treatment groups: 1) fed 0 starch diet throughout, 2) fed + starch diet throughout, 3) initially fed 0 starch diet then switched to +starch, and 4) initially fed +starch diet then switched to 0 starch. Birds in both groups fed on +starch diet on days 12-30 showed ca. 50% higher summed activity of disaccharidases (maltase and sucrase) than those fed on diet 0 starch. Digestive enzyme activities in 30-day-old birds were not influenced by the diet prior to day 12. Therefore, observed plasticity in activity of intestinal dissacharidases is completely reversible, revealing a phenotypic flexibility. Supported by NSF IOS-0615678 to W.H.K.