Growth rate and hatching date in ostrich chicks reflect humoral but not cell-mediated immune function

Summary, in English

A tradeoff between immune response and life history traits, in particular growth rate, has been documented in various bird species. Ostriches are fast-growing birds and a typical feature of cohorts is that offspring often differ greatly in size. We investigated the relationship between hatching date and growth rate of chicks and both cell-mediated (measured using a phytohaemagglutinin (PHA) injection) and humoral immune responses in ostrich chicks maintained on a research farm. Chicks with higher growth rates had intermediate responses to both diphtheria and tetanus toxoids. By contrast, no relation between growth rates and responses to PHA injection were found. We conclude that chick growth rate variation may be explained beyond a certain threshold by a tradeoff between the humoral response and growth. Both responses to PHA injection and humoral responses in chicks were found to decrease with chick hatching date. Within the context of ostrich farming, these results could partially explain size variations observed in cohorts of chicks, as well as high mortality rates during their first 3 months of age.

• Author: Maud Bonato; Matthew R. Evans; Dennis Hasselquist; Schalk W. P. Cloete; Michael I. Cherry
• Department/s: MEMEG; Molecular Ecology and Evolution Lab
• Publishing year: 2009
• Language: English
• Pages: 183-191
• Publication/Series: Behavioral Ecology and Sociobiology
• Volume: 64
• Issue: 2
• Links: http://dx.doi.org/10.1007/s00265-009-0835-1
• Document type: Journal article
• Publisher: Springer
• Topic: Biological Sciences
• Keywords: Growth rate; Immune response; Stabilising selection; Seasonal effect; Struthio camelus
• Status: Published
• Research group: Molecular Ecology and Evolution Lab
• ISBN/ISSN/Other: ISSN: 1432-0762