FASSBINDER-ORTH, C.A.*; KARASOV, W.H.; University of Wisconsin-Madison; University of Wisconsin-Madison: Are gut immune and digestive functions regulated independently?

There are many rarely explored questions about whether or how regulatory changes of either digestive or immune function of the gut influence each other. To begin addressing these questions, we tested for simultaneous changes in the digestive physiology and mucosal immune function of the guts of White Leghorn cockerel chicks undergoing food restriction and realimentation. Chicks were assigned to one of three groups: control = fed ad libitum 7-17 d of age; restricted = fed restricted d 12-17 (we tested two restriction levels - 54% and 34% ad libitum); refed = fed restricted d 7-13 and then fed ad libitum d 14-17). Refed chicks, following restriction, exhibited one day of hyperphagy and an increase in assimilaion efficiency (P=0.001). Total small intestine mass and duodenal maltase activity differed among the groups in the order refed > control > restricted, as expected (ANOVA, P < 0.05 for both measures). In contrast, there were no significant treatment effects on our measures of gut immune structure and function, including bursa mass, spleen mass, and total IgA content of intestinal flush samples measured with standard ELISA techniques. The data so far indicate that during restriction-realimentation the gut immune function is maintained unchanged in the face of regulatory changes that influence digestive functions. Supported by Hatch grant to UW-Madison 142P894 and NSF IBN-0216709.