Chemical and behavioural characterization of the rabbit mammary pheromone.

Mammals owe part of their evolutionary success to the harmonious exchanges of information, energy and immunity between females and their offspring. This functional reciprocity is vital for the survival and normal development of infants, and for the inclusive fitness of parents. It is best seen in the intense exchanges taking place around the mother's offering of, and the infant's quest for, milk. All mammalian females have evolved behavioural and sensory methods of stimulating and guiding their inexperienced newborns to their mammae, whereas newborns have coevolved means to respond to them efficiently. Among these cues, maternal odours have repeatedly been shown to be involved, but the chem…

The mammary pheromone of the rabbit: from where does it come?

Newborn rabbits, Oryctolagus cuniculus, are directed to their mother's nipples by specialized odour cues. Previous investigations have suggested that these cues are released from the doe's abdominal surface from structures located around the nipple. We tested pups with samples of various cutaneous tissues or fluids collected from lactating females to determine the location of the source of the odour cues. After finding that the nipples from lactating does were more attractive than those of virgin females, we conducted three experiments using skin samples collected at increasing distance from the nipples, dermal and mammary tissues taken below the nipples, and milk collected at different lev…

Perceptual interactions between fruity and woody notes of wine

The quantitative olfactory interactions in three binary mixtures of wine aroma compounds were studied. For the first two mixtures, whisky lactone (woody note) was mixed separately with two esters (fruity note), ethyl butyrate and isoamyl acetate. For the third mixture, guaiacol (woody note) was mixed with ethyl butyrate (fruity note). Perceived odour intensity of 24 stimuli (four supra-threshold concentration levels of two compounds and the respective 16 mixtures) were evaluated in five replications, by a trained panel of 13 subjects. The results showed that for the three binary mixtures studied, quantitative perceptual interactions were non-level independent, non-symmetrical, and reached t…

A variety of common odour cues and (at least) one pheromone shaping the behaviour of young rabbits: a brief survey

Many Common Odour Cues and (at Least) One Pheromone Shaping the Behaviour of Young Rabbits

Critical evaluation of two commonly used techniques for the treatment of data from extract dilution sniffing analysis

The data from the extract dilution sniffing analysis of beer samples have been treated by two methods of analysis to give either «charm» or «FD» values. The results obtained from these two methods were compared and demonstrated that the rank order of intensity of the odor-active regions was different for most panelists when the data were presented as charm rather than FD values. Points of uncertainty observed while using this method such as between- and within-individual reproducibility and gaps in the coincident response five also been discussed

From 160 to 20 to 1 odorant: steps in a chemo-ethological strategy to identify a mammalian pheromone

This paper presents the strategy used to fractionate a complex odorant mixture into 20 candidate compounds, to finally single out a compound which activity explains the activity of the whole mixture. The joint chemical-behavioral approach will be outlined, and followed by a description of the experiments permitting to enter the isolated key-compound into the category of biologically-active compounds termed "pheromone".

Evaluation of the representativeness of the odor of beer extracts prior to analysis by GC eluate sniffing

The importance of obtaining and proving that the odor of an extract is representative of the odor of the original product from which it was obtained, before analysis by GC-FID, GC-MS, or GC sniff, is discussed. The sensory methods, such as triangle tests, matching tests, and quantitative analysis, used to determine the representativeness of the odor of an extract are described. Beer extracts obtained by three methods were used to illustrate the interest of the sensory tests. A method using a mixture of XAD resins was proved by sensory analysis to give some extracts with sensory characteristics representative of the particular beers from which they were obtained

The responsiveness of young rabbits to the mammary pheromone : a predictor of survival ?

National audience; L’objectif de cette expérience était d’étudier le lien existant entre le poids et la réponse/non réponse des lapereaux à la phéromone mammaire, et leur ingestion de lait, leur survie et leur croissance. Pour cela, 293 nouveau-nés de 30 portées on été individuellement testés pour leur réactivité à la phéromone mammaire et leur ingestion de lait au lendemain de leur naissance (J1), et suivis pour leur mortalité et leur croissance jusqu’à J21. Environ 90% des lapereaux ont répondu à la phéromone à J1. Les lapereaux non réactifs à la phéromone ingéraient moins de lait et présentaient un taux de mortalité plus élevé que les lapereaux qui y répondaient (P<0,05). Cet impact est …

Influence of culture conditions on production of flavour compounds by 29 ligninolytic Basidiomycetes

The odorous volatile metabolites produced by 29 ligninolytic Basidiomycete strains (identified by gas chromatography coupled to mass spectroscopy — GC-MS) and the flavour quality of their cultures were investigated on 6 different liquid media tested with and without agitation. 113 compounds were identified, the most numerous being alcohols (2-methyl 1-propanol, 2-methyl 1-butanol, 3 methyl 1-butanol, 2 phenyl ethanol, 3,4, dimethoxy phenyl methanol, 4 vinyl phenol), aldehydes (3, 4 dimethoxybenzaldehyde) and ketones (4-hydroxy 3-methyl 2-phenyl 2-cyclopentene 1-one). One third of these compounds possessed an aromatic skeleton. The influences of medium composition and agitation conditions on…

Impact of ethanol on the perception of wine odorant mixtures

International audience; Several studies have focused on perceptual interactions in binary odor mixtures, but few on more complex mixtures. The aroma of wine is an example of a complex odor mixture. Our aim was to assess the impact of ethanol on the perception of mixtures of Woody (whiskey lactone) and Fruity (isoamyl acetate) odorants commonly found, physico-chemically and perceptually, in wine. Physico-chemically, reduced whiskey lactone volatility was observed in hydro-alcoholic solutions. Perceptually, a synergy effect by the Woody on the Fruity odor was observed in aqueous solutions, which disappeared with the addition of ethanol. Conversely, the Woody odor was masked in both aqueous an…

GC sniffing analysis : olfactive intensity measurement by two methods

The intensity perceived by sniffing after GC elution of six volatile compounds was measured by ten judges using two pieces of apparatus: a PC mouse which is moved on a 60-cm length scale and a rheostat apparatus which measures the finger span. The choice of the components mixed was influenced by purity, elution time, presence in food and known Steven's slopes. The histograms obtained by summing the responses (determined by measuring the areas under the peaks) of ten people show no significant differences between the two pieces of apparatus. Histograms realised in parallel by Charm analysis with three other judges showed great differences between subjects. However, the mean of the three Char…

Odour cues and pheromones in the mediation of rabbit female-offspring relations

Communication odorante et phéromonale à finalité alimentaire entre la lapine et les lapereaux.

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Detection of powerful odorants in heated milk by use of extract dilution sniffing analysis

SummaryThe odour impact compounds of raw, pasteurized and UHT bovine milk were investigated using vacuum extraction and extract dilution sniffing analysis using CharmAnalysis™. Fifteen odour peaks with Charm values between 10 and 3443 were detected. Of these peaks, twelve were identified as hexanal, ethyl butanoate, 2-heptanone, heptanal, dimethyl sulphone, l-octen-3-ol, ethyl hexanoate, 2-nonanone, nonanal, benzothiazole, 2-undecanone, indole and one as a mixture of 2-tridecanone and δ-decalactone. Dimethyl sulphone, indole and one unknown compound (retention index 1154) were the only ones detected as odour impact compounds in all three types of milk. Ethyl butanoate and ethyl hexanoate we…

Powerful odorants in bovine, ovine, caprine and water buffalo milk determined by means of gas chromatography-olfactometry

SummaryThe main compounds responsible for the aroma of bovine, ovine, caprine and water buffalo freshly secreted milk have been identified by means of a gas chromatography–olfactometry technique. Of the fourteen odour-active volatile compounds detected, eight were present in all milks studied. Ethylbutanoate and ethylhexanoate (fruit-like aroma), among the neutral odorants, were the major contributors to the odour of bovine, ovine and caprine milk. The aroma of water buffalo milk was less dependent on ethylhexanoate and was also due to l-octen-3-ol (aroma of raw mushrooms), nonanal (freshly cut grass), indole (stable, animals) and an unidentified constituent, characterized by a retention in…

Newborn rabbit responsiveness to the mammary pheromone is concentration-dependent.

The effect of the intensity of odour signals has rarely been investigated in the regulation of odour-guided behaviour in young mammals. This series of experiments used the mammary pheromone (MP) of the female rabbit to assess the influence of stimulus concentration on neonatal pup responsiveness. The MP is a single compound isolated from rabbit milk that releases in pups the typical head searching and oral seizing behaviour. The pups (n = 621) were exposed to graded concentrations of the MP in bioassays varying in stimulus delivery conditions. Experiment 1 demonstrated that in aqueous dilutions the MP efficiently elicits behavioural responses only within a limited range of concentrations (f…

Volatile compounds produced by the ligninolytic fungus Phlebia radiata Fr. (Basidiomycetes) and influence of the strain specificity on the odorous profile

Abstract The odorous volatile compounds produced by 3 strains (out of 25 strains tested) of Phlebia radiata Fr. were investigated on six synthetic media and identified by GC-MS analysis. One of the 3 strains was odourless. Aromatic primary alcohols and a sesquiterpenic alcohol, α-bisabolol, were the most abundant metabolites for both of the other strains, which exhibited similar flavours and a similar gas chromatographic profile.

The reactivity of neonatal rabbits to the mammary pheromone as a probe for viability

International audience; Newborn rabbits depend on a daily nursing interaction with the mother to gain milk and to survive. During this interaction, they localise and seize the nipples displaying a typical behaviour triggered by maternal odour cues. The mammary pheromone constitutes such a signal in domestic rabbits: it elicits sucking-related movements in more than 90% of the pups. However, some newborns remain unresponsive to the presentation of the pheromone, even pups apparently healthy and highly motivated to suck. The main goal of the present study was therefore to explore the link between the unresponsiveness of rabbit pups to the mammary pheromone and their growth and survival in bre…

A single key-odorant accounts for the pheromonal effect of rabbit milk : Further test of the mammary pheromone's activity against a wide sample of volatiles from milk.

In the rabbit, lactating females emit a volatile compound in milk, the mammary pheromone (MP), that triggers rooting for the nipple and its grasping in pups. Previous studies have shown that the MP seems to act selectively, in terms both of intensity and quality. Here, we aimed to add new evidence to these properties of the MP. Newborn rabbits (n=825) were submitted to an oral activation test allowing to measure their searching/grasping responses towards different stimuli. In Experiment 1 we assessed whether pups respond to the MP in an intensity-dependent manner. In Experiment 2 we assessed the activity of 20 volatiles previously identified in rabbit milk, other than the MP, which were nev…

Evaluation of olfactory intensity : comparative study of two methods

Two experimental procedures recommended for the evaluation of the psychophysical characteristics of odorous compounds, olfactory matching with the 1-butanol scale and cross-modality matching with the finger span are compared. The intensity of ethyl butyrate and guaiacol solutions presented at four different concentration levels was evaluated by a panel of sixteen subjects over five repetitions using the two methods. Each stimulus was delivered to the subject from a Teflon bag through a nose-shaped glass sniffing port. The discrimination ability, repeatability, panel homogeneity and within-subject variability of the methods were assessed. Results indicate that with both methods, subjects wer…

Volatile compounds in strawberry jam : influence of cooking on volatiles

Volatile constituents of strawberry jam were identified and their olfactive impact estimated by HRGC effluent sniffing. Amounts of volatiles in jam were only slightly affected by addition of sugar, but were closely related to design of the cooker and to the pressure used. Losses by evaporation during cooking were studied. Different types of behaviour were observed for the specific aromatic components. Cooker design largely influenced flavor losses at low pressures. Condensation of vapors during cooking and incorporation of the condensate in pectin solutions could result in a more flavorfull product.