Background
In order to improve health management in farm animals and reduce the
use of antibiotics, we need to develop new means of prophylaxis. Stressed animals
are likely to have an increased risk of health problems, thus easy and early stress
detection will contribute to a better management of animal health. Patterns of volatile
organic compounds (VOCs) may be specific to a state of stress in young animals. This
could be olfactory products that reflect metabolism, the functionality of the
intestinal immune system and associated microbiota. If a signature stress scent
could be identified, one perspective would be to develop a bio-electronic nose for
identification of relevant VOCs, to be used as a tool for early, non-invasive
screening of stress levels.
Rats have a very sensitive olfactory perception, and can distinguish
between odours, which differ only slightly (e.g. Clarin et al., 2010). They
have been found to discriminate between male and female faeces, even from
different species (fox and horse; Rampin et al., 2006). They may thus be able
to detect potential differences in VOCs between stressed and non-stressed
individuals.
The overall project aims i) to develop an experimental model using
chickens (stressed and non-stressed) and assess the consequences in terms of
behaviour and health , ii) to
develop an animal ‘sensor’, by training rats to recognize the smell of stressed
chicken faeces, iii) analyse the VOCs of interest by
mass spectrometry combined with gas chromatography (GC -MS). The student
project described here will concentrate on the second aim.
Student project
1. To develop an experimental protocol in which rats
show they can distinguish between two odours
2.
To apply
this protocol using odours emitted from faeces from stressed and non-stressed
animals (rats and/or chickens)
The student will have a large degree of freedom to pursue different
methodologies, based on the literature and the student’s own ideas. We can
provide the rats, different experimental arenas (new designs can be built),
faeces samples from different species (rats, chickens) and different individuals
(stressed, non-stressed), as well as single-molecule odorous compounds.
Faeces odour is very complex, containing hundreds of different
molecules. Differences between faeces samples may be subtle as well as
disguised by the natural variation between samples of other molecules not
related to stress levels. It may thus not be possible for the rat to learn how
‘stress faeces’ smells. Depending on the progress of the overall project, GC-MS
analyses may indicate several candidate molecules, which could be tested in
their pure form (or mixed with non-stressed faeces) on the same trained rats to
determine their capacity to elicit the same behavioural response.
When and where?
The project should be carried out in the first half of 2014 –
starting February or March, and will last 5-6 months in total. The student will
work at the INRA campus at Jouy-en-Josas, south of Paris.
The student will receive a monthly payment of 436,05 €.
Contact
INRA, UR
1197 "Neurobiologie de l'Olfaction et Modélisation en Imagerie"
(NOeMI), 78350
Jouy-en-Josas.
References
Clarin T, Sandhu S, Apfelbach R
(2010).Odor detection and odor discrimination in subadult and adult rats for
two enantiomeric odorants supported by c-fos data. Behavioural Brain Research 206: 229–235.
Rampin O, Jérôme N, Briant C, Boué F, Maurin Y (2006).
Are oestrus odours species specific? Behavioural Brain Research 72: 169–172.