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Feather Pecking Linked to Serotonin Receptor

by 5m Editor
30 June 2010, at 10:24am

NETHERLANDS - Feather pecking in laying hens is associated with serotonin receptor HTR2C, according to a researchers from Animal Breeding and Genomics Centre (ABGC) at Wageningen University.

An article on single nucleotide polymorphisms (SNPs) associated with feather pecking and laying hens was recently published in the journal Behavior Genetics by Filippo Biscarini and colleagues from ABGC.

They found an association between the gene for the serotonin receptor HTR2C and feather damage, which was significant across a population of nine pure-bred selection lines. Furthermore, there was a clear difference in allele frequency of this mutation between brown layers (0.35) and white layers (0.84). This opens up new avenues for further research on this topic.

An association study between SNP markers and feather condition score on the back, rump and belly of laying hens was performed. Feather condition score is a measure of feather damage, which has been shown to be closely related to feather pecking behaviour in hens housed in groups.

A population of 662 hens was genotyped for 1536 SNPs, of which 1022 could be used for the association study. The analysis was conducted across on nine different lines of White Leghorn and Rhode Island Red origin. Across lines, linkage disequilibrium is conserved at shorter distances than within lines; therefore, SNPs significantly associated with feather condition score across lines are expected to be closer to the functional mutations.

The SNPs that had a significant across-line effect, but did not show significant SNP-by-line interaction, were identified to test consistent association across lines.

Both the direct effect of the individual's genotype on its plumage condition and the associative effect of the genotype of the cage mates on the individual's plumage condition were analysed. The direct genetic effect can be considered as the susceptibility to be pecked at, whereas the associative genetic effect can be interpreted as the propensity to perform feather pecking.

Finally, 11 significant associations between SNPs and behavioural traits were detected in the direct model, and 81 in the associative model. A role of the gene for the serotonin receptor 2C (HTR2C) on chromosome 4 was found.

This supports existing evidence of prominent involvement of the serotonergic system in the modulation of this behavioural disorder in laying hens. The genes for IL9, IL4, CCL4 and NFKB were found to be associated to plumage condition, indicating relationships between the immune system and behaviour.

Reference

Biscarini F., H. Bovenhuis, J. van der Poel, T.B. Rodenburg, A.P. Jungerius and J.A.M. van Arendonk. 2010. Across-Line SNP Association Study for Direct and Associative Effects on Feather Damage in Laying Hens. Behavior Genetics (online ahead of publication). DOI: 10.1007/s10519-010-9370-0.

Further Reading

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