109.3 Saturday, Jan. 7 Effect of food restriction and realimentation on growth, immune response, and body composition in Zebra finches NAN TIE, D.E.*; KILLPACK, T.L.; KARASOV, W.H.; Univ. Wisconsin, Madison email@example.com
Short term food restriction of nestling altricial birds can retard growth and development. Compensatory growth (CG), a period of accelerated growth after restriction, allows nestlings to compensate for a period of reduced growth. There is mixed evidence regarding the occurrence of CG in altricial birds and if CG leads to trade-offs in allocation to tissue development or immune function. We hypothesized that food restricted zebra finch nestlings would display compensatory mass gain, no difference in structural growth, increased tissue water content (an index of functional immaturity), decreased lipid content, and reduced immune function compared to nestlings fed ad libitum. Control broods were fed ad libitum until 33 days of age. Experimental broods were fed ad libitum until 6 days of age, food restricted to 70% ad libitum for 3 days, followed by a return to ad libitum feeding until 33 days of age. Body mass, structural growth, and food intake were taken daily until 33 days of age. All broods were tested for innate immune response to lipopolysaccharide and adaptive immune response to keyhole limpet hemocyanin (KLH). Average body mass of experimental broods was 25% lower than controls after the 3-day restriction. Body mass did not differ between treatments 2 days after realimentation, demonstrating compensatory mass gain in experimental broods. Structural growth and KLH response showed no significant difference between treatments. Adaptive immune response was 80% lower than adult response, indicating that fledglings at age 33 still have undeveloped humoral immune function and treatment differences may not be detectable. Analyses of innate immune response and body composition will be reported. Support USDA-Hatch.