Angers, 20 February 2017: Thanks to a new protocol, the Center for Functional and Evolutionary Ecology (CEFE) team, from the Paul-Valéry University in Montpellier, tested Nor-Mite® efficacy, a plant-extract based repellent. This product, added in the hens feed, contributes to manage the growth of populations of red mites in livestock.

Nor-Mite, a natural-compound repellent

Nor-Mite® is a natural mineral feed formulated with cloves (Eugenia caryophyllus) and lemongrass (Cymbopogon nardus) extracts. Once integrated into feed, Nor-Mite repellent components are spread by the animal (via its droppings) and repel the red mites from their source of food. Repelled from the chickens’ blood – their only source of food – the red mite cannot reproduce at the usual rhythm and thus see its population decrease drastically. According to trials conducted in 2013 by Nor-Feed, this reduction reaches or even exceeds 80%. Red mites are a real issue in laying hens, causing losses estimated at 130 million € per year in Europe (Georges et al., 2009, Sparagano et al., 2009)

Understanding the mode of action

To better understand the mechanisms of action of Nor-Mite, Nor-Feed partnered with the CEFE to answer two questions:

  1. Does ingestion of Nor-Mite alter the volatile organic compounds (odor-forming) emitted by hens?
  2. Do the odors emitted by chickens after ingestion of Nor-Mite have a repelling effect on red mites?

To answer these questions, two experiments were carried out by the CEFE, using advanced techniques.

Experiment 1: Analysis of the odor of chickens before and after ingestion of Nor-Mite

The odor of chickens is:

  • first captured using the headspace method, prior to Nor-Mite ingestion
  • then characterized by gas chromatography and mass spectrometry
  • and finally compared to the hens odor after the product ingestion.

The headspace capture technique allows to select exclusively the volatile compounds which form the odors, by avoiding non-volatile compounds which are extracted at the same time with the more commonly used solvent techniques. The gas chromatography technique widely used in the industry to detect and quantify several compounds, consists in first separating the volatile compounds in a system containing a carrier gas and directing them – one after the other – towards a detector (spectrometer). The compounds resulting from this separation are, in a second step, ionized in the spectrometer and identified by comparison with a database. Results: The molecules present in Nor-Mite are found in the odors emitted by the hens who have ingested the product.

Experiment 2: red mite response to hen odor

The second experience was made through choice tests using an olfactometer. It consists of characterizing the red mite response vis-a-vis:

  • The crude odor of hens who ingested or not Nor-Mite
  • The odor of eugenol, one of the main active molecules present in Nor-Mite

During these experiments, the red mite response to the Nor-Mite volatile molecules was measured with an olfactometer. This tool allows to observe and register the comportment of an arthropod (insect, mite…) vis-a-vis attractive or repulsive compounds.
Results: Among the 50 red mites, 39 (or 78%) of them chose the odor of chickens that had not ingested Nor-Mite.
This same experiment concluded on the eugenol repellent effect: among the 40 red mites, no one of them chose the odor of eugenol. 36 went to the negative control compartment and the 4 others did not leave the starting point. This test confirms that Nor-Mite plays its role of repellent through the odors released by the hen and that eugenol is involved in this repellent activity. Additional tests will help us identify other molecules involved in the repelling activity of Nor-Mite and their possible synergistic effect with eugenol. Nor-Feed is investigating the effect of Nor-Mite and its main active ingredients on other arthropods and insects.

Response of the Poultry Red Mite Dermanyssus gallinae to changing VOCs emitted by its host Gallus gallus domesticus fed with additive repellents, Marine El Adouzi et al., Centre of Functional and Evolutionary Ecology & University Paul-Valéry (Montpellier).
EURAAC, 8th symposium of the EURopean Association of ACariologists, 2016

About CEFE (Center for Functional and Evolutionary Ecology)

The CEFE is currently the largest French research center in Ecology. It performs independent, fundamental scientific research on the dynamics of biodiversity, planetary environmental change, and sustainable development.

About Nor-Feed

Since 2003, Nor-Feed ( develops, produces and markets natural plant extracts for animal health and nutrition.

The company focuses its efforts on a concise portfolio to propose efficient, standardized and documented products, in a logic of sustainable development.

Nor-Feed supports its clients in the technical, marketing and regulatory fields.



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