Meeting Abstract

31.1  Monday, Jan. 5  Understanding the role of lysozyme in birds: physiological interactions between experimental immune enhancement and challenge. MATSON, K.D.*; HORROCKS, N.P.C.; VERSTEEGH, M.A.; TIELEMAN, B.I.; University of Groningen; University of Groningen; University of Groningen; University of Groningen k.d.matson@rug.nl

In pigeons, we examined the interactions between experimental immune enhancement and challenge. Immune enhancement took the form of a six day course of oral lysozyme supplementation (180 mg/bird/day); a non-specific immune challenge was presented as a single injection of lipopolysaccaride (LPS, 2.5 mg/kg) on day six. Lysozyme is a naturally-occurring antibacterial protein in birds; it functions by hydrolyzing cell-wall peptidoglycan, making Gram-positive bacteria particularly susceptible to its effects. In contrast, LPS is a building block of Gram-negative bacterial cell membranes and is a classic endotoxin. In all birds, a range of immunological indices and physiological parameters were measured twice: before and after LPS challenge. These measures included body temperature, metabolic rate, blood glucose and ketone levels, plasma haptoglobin concentration, and bacteria-killing abilities. We compared the pre-challenge baseline levels of these measures in lysozyme and control birds. We also compared the LPS-induced within-individual changes in these measures in all birds. Since lysozyme can bind with LPS and is thought to have anti-inflammatory properties, we hypothesized that supplementing birds with lysozyme would mitigate the energetically-expensive inflammatory effects of an LPS challenge. We also hypothesized that baseline comparisons, reflecting the effects of lysozyme alone, would show greater impacts on immunological indices than on other physiological parameters (e.g. metabolic rate). Initial analyses suggest larger than expected effects of lysozyme treatment. With some measures, it appears as if the effects of LPS in lysozyme birds are the result of both slightly depressed baseline levels and greater response levels compared to control birds.