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Determinants and short-term physiological consequences of PHA immune response in lesser kestrel nestlings

Airam Rodríguez1, Juli Broggi, Miguel Alcaide

  • 1Department of Evolutionary Ecology, Estación Biológica de Doñana (CSIC), Seville, Spain; Department of Research, Phillip Island Nature Parks, Cowes, Victoria, Australia.

Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology
|May 9, 2014
PubMed

Insights

Phytohaemagglutinin (PHA) immune challenge in lesser kestrel nestlings did not cause severe short-term energetic costs. However, the immune response was condition-dependent, showing rapid carotenoid mobilization and triglyceride decrease.

Area of Science:

  • Avian ecology
  • Immunology
  • Physiology

Background:

  • Individual immune responses are influenced by genetic, physiological, and environmental factors.
  • The Phytohaemagglutinin (PHA) test is a common method to assess immune function by eliciting innate and acquired immunity.
  • Understanding immune response determinants is crucial for conservation and understanding ecological interactions.

Purpose of the Study:

  • To investigate the determinants and short-term consequences of PHA-induced immune response in lesser kestrel (Falco naumanni) nestlings.
  • To analyze the impact of PHA challenge on various physiological, metabolic, genotypic, and biometric variables.
  • To determine if MHC heterozygosity or resting metabolic rate influences PHA response.

Main Methods:

  • Repeated measures analysis of blood parameters (carotenoids, triglycerides, cholesterol, uric acid, etc.), resting metabolic rate, MHC class II B heterozygosity, and body mass.
  • Administered PHA challenge to lesser kestrel nestlings under semi-captivity with a homogeneous diet.
  • Measured physiological and biometric variables before and after PHA challenge (<12 hours).

Main Results:

  • PHA challenge did not significantly affect most physiological parameters within 12 hours, except for a decrease in triglycerides and an increase in carotenoids.
  • Uric acid levels correlated with the PHA-induced immune response (skin swelling).
  • Changes in body mass, cholesterol, total antioxidant capacity, and triglycerides were positively correlated with PHA response, indicating condition-dependency.

Conclusions:

  • PHA response in lesser kestrel nestlings under optimal conditions does not incur severe short-term energetic costs.
  • The immune response is condition-dependent, involving rapid carotenoid mobilization and triglyceride reduction.
  • MHC heterozygosity and resting metabolic rate were not found to be related to PHA response in this study.

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