Meeting Abstract

S9.1-4  Tuesday, Jan. 7 09:10  Costs of Income Versus Capital Provisioning of Nutrients for Immune Defenses in Birds KLASING, K. C.; Univ. California, Davis kcklasing@ucdavis.edu

An important life history variable is recognized between species that provision offspring using energy gained concurrently (income breeders) and those that provision offspring using energy stores accumulated at an earlier time (capital breeders). Life history variability in the temporal investment in immunity has received very little attention. Previously we examined levels of innate immune defenses of 35 species of temperate and tropical birds and found evidence for an income-capital investment axis. Some species invested constitutively to maintain relatively high circulating concentrations of protective proteins (income defenders), whereas other species maintained low levels until the time of a challenge and then martialed stored resources to quickly bolster defenses (capital defenders). In general, species with higher adult body weight were more likely to be capital defenders. In order to examine the nutritional demands of a capital defense strategy we measured the amount of nutrients needed for a vigorous response to a bacteria challenge in adult healthy chickens. We found that the amount of nutrients needed to mount a large innate immune response was 88% higher than expected due to a mismatch in the balance of essential amino acids in the leukocytes, protective proteins and hepatic tissue accreted for the innate response relative to the storage tissue (e.g. skeletal muscle) that releases these amino acids. This mismatch was driven primarily by the very high levels of cysteine in the protective and antioxidant proteins and peptides accreted during the protective response.