Linking environmental stressors and cancer-related proxies in sentinel coastal birds (Eurasian oystercatchers) in Northern Norway

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1. Purpose
The main objective of this project is to understand the physiological mechanisms connecting anthropogenic pollution (organo-halogenated compounds and mercury) to oncogenic processes in a non-model avian species: the Eurasian oystercatcher (Haematopus ostralegus).
Birds are animal models of strong interest to study the coevolution of life-history traits and cancer resistance, notably via their putative ability to escape the transformation of benign to malignant tumour cells (cancer resistance). In particular, previous descriptive data have highlighted a positive dynamic of telomeres (the protective end of linear chromosomes) with age in oystercatchers, suggesting that they evolved non-telomere related anti-cancer mechanisms. Yet, precise descriptive data on telomere dynamics, telomerase activity (an enzyme able to lengthen telomeres in old cells) and cancer-related proxies have never been collected simultaneously in a same cohort of individuals.

2. Distress
Individuals will be caught on their nest and handled within 15-20 minutes before the birds are released. During capture, body mass and size will be recorded, and a blood sample will be taken from the brachial vein (we will sample a maximum of 1 ml of whole blood which corresponds to much less than 1% of the total body mass). One feather will be cut from the wing coverts (outermost wing coverts) using scissors. In addition, we will sample a skin sample (5 mm2) from the patagium using a biopsy punch.

3. Expected benefits
This pilot project is designed to assess the suitability of this avian model species for larger sampling at a later point, should the preliminary data obtained in the lab be conclusive regarding the mechanisms regulating the length of telomeres.


4. Number of animals and species
For this pilot project, we plan on catching 20 adult oystercatchers during egg incubation (only one individual per pair).

5. How to adhere to 3R
Replacement is not relevant as our working hypothesis relies on the specific physiology of the species. Reduction is done by limiting the sampling to 20 individuals to test their suitability (assessed by biomarkers later analyzed in the lab) for a later larger project (providing funding).
Refinement is done by sampling the minimum amount of blood required and by replacing their eggs by dummy eggs during the capture to avoid breakage during capture.