Cross-taxa similarities in affect-induced changes of vocal behavior and voice in arboreal monkeys.

International audienceMeasuring the affective state of an individual across species with comparable non-invasive methods is a current challenge in animal communication research. This study aims to explore to which extent affect intensity is conveyed in the vocal behaviours of three nonhuman primate species (Campbell's monkeys, De Brazza's monkeys, red-capped mangabeys), which vary in body size, ecological niche and social system. Similarly in the three species, we experimentally induced a change in captive social groups' affect by locking all group members together in their outside enclosure. The two experimental conditions which varied in affect intensity consisted in imposing a pre-reunion 90 mn-separation by splitting up the respective group into two subgroups (High affect condition) or not (Low affect condition). We measured call rates as well as voice features at the time of reunion in both conditions. The three studied species reacted in a very similar way. Across species, call rates changed significantly between the behaviourally defined states. Furthermore, contact call duration and, to some extent, voice pitch increased. Our results suggest, for the first time in arboreal Old World monkeys, that affect intensity is conveyed reliably in vocal behaviour and specific acoustic characteristics of voice, irrespective of body size and ecological niche differences between species. Cross-taxa similarities in acoustic cues of affect intensity point to phylogenetic constraints and inheritance from a common ancestor, whereas variations in vocal behaviour and affect intensity-related acoustic cues between species may be an adaptation to specific social requirements and depend on social systems. Our findings as well as a comparison with published works on acoustic communication in other vertebrate groups support the hypothesis that affect intensity in human voice originates from precursors already found deep inside the vertebrate phylogeny

Youngsters do not pay attention to conversational rules: is this so for nonhuman primates?

The potentiality to find precursors of human language in nonhuman primates is questioned because of differences related to the genetic determinism of human and nonhuman primate acoustic structures. Limiting the debate to production and acoustic plasticity might have led to underestimating parallels between human and nonhuman primates. Adult-young differences concerning vocal usage have been reported in various primate species. A key feature of language is the ability to converse, respecting turn-taking rules. Turn-taking structures some nonhuman primates' adult vocal exchanges, but the development and the cognitive relevancy of this rule have never been investigated in monkeys. Our observations of Campbell's monkeys' spontaneous vocal utterances revealed that juveniles broke the turn-taking rule more often than did experienced adults. Only adults displayed different levels of interest when hearing playbacks of vocal exchanges respecting or not the turn-taking rule. This study strengthens parallels between human conversations and nonhuman primate vocal exchanges

Physical properties of yogurt fortified with various commercial whey protein concentrates

The effects of whey protein concentrates on physical and rheological properties of yogurt were studied. Five commercial whey protein concentrates (340 g kg−1 protein nominal) were used to fortify milk to 45 g protein kg−1. Fermentation was performed with two different starters (ropy and non-ropy). Resulting yogurts were compared with a control yogurt enriched with skim milk powder. The water-holding capacity of the yogurt fortified with skim milk powder was 500 g kg−1 and ranged from 600 to 638 g kg−1 when fortified with whey protein concentrates. Significant rheological differences have been noticed between the yogurts fortified with different whey protein concentrates, independent of the starter used. Three whey protein concentrates generated yogurts with a behavior similar to the control. The two others produced yogurt with lower firmness (15 g compared with 17 g), lower Brookfield viscosity (6 Pa s compared with 9 Pa s), lower yield stress (2 Pa compared with 4 Pa), lower complex viscosity (13 Pa s compared with 26 Pa s), and lower apparent viscosity (0.4 Pa s compared with 1 Pa s) than the control, respectively. The yogurts with the lowest firmness and viscosity were produced with concentrates which contained the highest amount of non-protein nitrogen fraction (160 g kg−1 versus 126 g kg−1 of the total nitrogen), and the highest amount of denaturation of the whey protein (262 versus 200 g kg−1 of the total nitrogen)

A genome scan for milk production traits in dairy goats reveals two new mutations in <i>Dgat1</i> reducing milk fat content

The quantity of milk and milk fat and proteins are particularly important traits in dairy livestock. However, little is known about the regions of the genome that influence these traits in goats. We conducted a genome wide association study in French goats and identified 109 regions associated with dairy traits. For a major region on chromosome 14 closely associated with fat content, the Diacylglycerol O-Acyltransferase 1 (DGAT1) gene turned out to be a functional and positional candidate gene. The caprine reference sequence of this gene was completed and 29 polymorphisms were found in the gene sequence, including two novel exonic mutations: R251L and R396W, leading to substitutions in the protein sequence. The R251L mutation was found in the Saanen breed at a frequency of 3.5% and the R396W mutation both in the Saanen and Alpine breeds at a frequencies of 13% and 7% respectively. The R396W mutation explained 46% of the genetic variance of the trait, and the R251L mutation 6%. Both mutations were associated with a notable decrease in milk fat content. Their causality was then demonstrated by a functional test. These results provide new knowledge on the genetic basis of milk synthesis and will help improve the management of the French dairy goat breeding program

Etude des relations entre les caracteristiques physicochimiques des laits de chevre et leur aptitude a la coagulation de la presure

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Tenseness relaxed by vocalizing, illustrated by horses (Equus caballus) whinnying

International audienceAnimal calls are commonly considered indicators of a sudden change in their arousal state. However, reports evidencing associated internal physiological changes are rare. By homology with human "emotional" vocal productions (e.g., laughter and crying), we predicted that animal vocal productions may result in relaxing tenseness or excitement. In this study, 15 stallions equipped with a heart rate monitor were presented a mare at some distance so as to prevent contact, thereby increasing the males' arousal. Stallions' heart rates increased just before whinnying but returned to baseline rates while vocalizing. We found that sudden changes of a caller's arousal state could be associated with vocalizing, and this opens new lines for noninvasive research concerning the self-regulation of emotional via vocal production in humans and animals. (PsycINFO Database Recor

Stallion’s voice: an indicator of fertility and a basis for female choice?

International audienceVocalisations of mammals, carrying information on caller’s familiarity, identity, age or size, play a key role in coordinating sexual partners. Some studies showed that females select partners based on vocal attributes. However, we still fail to understand why such capacities evolved and which consequences these choices can have on reproduction. Wild mares actively choose the family group into which they are going to migrate, spotting at a distance the potential stallion partners. Whinnies are vocalizations allowing long-distance communication and we thus investigated if and how they could guide the choice of females. At first, the voices of 15 reproductive stallions were recorded in three national Stud farms while they were held at a distance from a mare. Acoustic analysis then showed that there was a correlation between frequency parameters and the reproductive success of the caller, stallions with a higher-pitched voice presented more successful gestations. Interestingly, acoustic parameters appeared to be more reliable predictors of fertility than seminal and hormonal features. Secondly, 40 adult mares were individually exposed to the simultaneous loud-speaker playback of pairs of whinnies (high-and low-pitched). Mares showed a very clear preference of orientation towards low-pitched voices. These results open lines of basic and applied research on the relationship between vocal characteristics and reproduction in mammals

La voix de l’étalon : un indicateur de fertilité et une base de choix pour les femelles ?

National audienceCertaines vocalisations des mammifères, porteuses d'informations sur la familiarité, l'identité, l'âge ou la taille de l'émetteur, jouent un rôle dans la coordination des partenaires sexuels. Quelques études ont montré que les femelles prennent en compte les qualités vocales des mâles dans leurs choix de partenaires. Cependant, nous comprenons encore mal pourquoi de telles aptitudes ont évolué et quelles conséquences ces choix peuvent avoir sur la reproduction. Dans la nature, les juments choisissent activement le groupe familial dans lequel elles vont s'insérer, repérant à distance les étalons partenaires potentiels. Les hennissements sont des vocalisations permettant cette communication à distance et nous avons donc cherché à savoir si et comment ils pouvaient guider le choix des femelles. Dans un premier temps, les voix de 15 étalons reproducteurs ont été enregistrées dans trois Haras nationaux alors qu'ils étaient tenus en main à distance d'une jument. Des analyses acoustiques ont alors montré qu'il y avait une corrélation entre des paramètres de fréquence et le succès reproducteur de l'émetteur, les étalons avec la voix plus grave présentaient davantage de gestations réussies. De façon intéressante, les paramètres vocaux se sont révélés plus fiables dans la prédiction de la fertilité que les analyses séminales et hormonales. Dans un second temps, 40 juments adultes ont été individuellement confrontées à la diffusion simultanée par haut-parleurs de paires de hennissements (graves et aigus). Les juments ont montré une nette préférence d'orientation vers les voix graves. Ces résultats ouvrent des lignes de recherches fondamentales et appliquées sur le lien entre caractéristiques vocales et reproduction chez les mammifères