Meeting Abstract

77.2  Friday, Jan. 7  Allocation of endogenous and dietary protein in the reconstitution of the gastrointestinal tract in migratory blackcaps, Sylvia attricapilla, at stopover sites MUNOZ-GARCIA, Agusti*; AAMIDOR, Sarah; MCCUE, Marshall; MCWILLIAMS, Scott; PINSHOW, Berry; Ben Gurion University; Ben Gurion University; St. Mary’s University; University of Rhode Island; Ben Gurion University agustimg@gmail.com

During migratory flight, the mass of the gastrointestinal tract (GIT) of small birds decreases by as much as 40% compared with that of non-migrating birds. At stopover sites, birds need 2-3 days to rebuild their GIT so they can restore body mass and fat reserves to continue migration. The source of protein used to rebuild the GIT may come from food ingested, from endogenous protein reallocated from other organs, or both; however, the relative contribution of these sources to rebuild the GIT is unknown. We simulated in-flight fasting and re-feeding in two groups of blackcap warblers (Sylvia attricapilla), a migratory passerine, with a diet containing either 3% or 20% protein. During refeeding, birds received a dose of ¹⁵N-L-leucine to determine whether blackcaps use endogenous or dietary protein to rebuild the GIT during refueling at a stopover site. We predicted that the proportion of reallocated protein from pectoral muscle to GIT will be higher in the group fed with low protein content. The concentration of ¹⁵N in pectoral muscle was similar for both groups, but ¹⁵N in the intestine was higher in the 3% group. Because the intestine masses were higher in the 20% protein group we concluded that blackcaps on the low protein diet allocated greater amounts of protein from muscle to intestine that those fed high protein diets.