Intestinal hydrolase transcriptional responses during rapid diet adjustment in nestling house sparrows (Passer domesticus)

ANTONIO BRUN; MAGALLANES, MELISA; ROTT, KATHERINE H.; CAVIEDES-VIDAL E; KARASOV, WILLIAM H.

Congreso; Annual Meeting SEB; 2018

We studied nestling house sparrows (Passer domesticus), which undergo a natural switch from insects to starch-containing seed diet during development. Nestlings, 3-day-old, were captured and fed a low-starch/high-protein diet for three days before being switched to a high-starch/lower protein diet (dietary lipid was held constant). Intestinal tissue was then harvested at 12, 18, 24, 48, and 72 hours after the diet switch and analyzed for enzyme activity per gram tissue and for corresponding mRNA relative to reference mRNA. -glucosidase (AG) (i.e., maltasic, sucrasic) activities and mRNA increased between 18 and 24 h after dietary starch level was increased, whereas in the same individuals aminopeptidase-N (APN) activity and mRNA declined by 24 h. In analogous experiments, APN activity and mRNA were induced between 18 and 24 h after dietary protein level was increased. These results are consistent with the idea that dietary induction of intestinal hydrolytic activity by dietary substrate is transcriptionally controlled. Changes in intestinal hydrolase activity are so fast (< 1 d) that nestlings could potentially track daily changes in resource availability with fine-tuned changes in digestive performance. Supported by NSF IOS-1354893.