D. Glaser

Gustatory responses of pigs to various natural and artificial compounds known to be sweet in man

Abstract The gustatory preferences in pigs towards 33 compounds known to be sweet in humans were evaluated through a specific two-choice preference method. All the 14 carbohydrates tested are preferred over water, sucrose being the most effective. Sucrose and fructose response intensities are identical in pigs and humans but lactose, maltose, d -glucose and d -galactose are two times less efficient in pigs. The molar order of effectiveness is sucrose > d -fructose > maltose=lactose > d -glucose > d -galactose, roughly similar to humans. As in humans, d -glucose, l -glucose and methyl α- d -glucopyranoside display equal potency, while methyl β- d -glucopyranoside is ineffective. The 7 polyols tested are attractive; xylitol is the preferred one, being as effective as sucrose. Out of 12 intense sweeteners tested, 7 are ineffective (aspartame, cyclamate, monellin, NHDC, P-4000, perillartine, thaumatin), and 5 are attractive (acesulfame-K, saccharin, alitame, dulcin, sucralose), but with a much weaker efficiency (acesulfame, 18×less; saccharin, 65×less) than with humans.

The taste responses in primates to the proteins thaumatin and monellin and their phylogenetic implications

Electrophysiological and behavioural methods have been applied to 34 species of the primates and, for comparison, to the Madagascan hedgehog to determine their responses to the proteins thaumatin and monellin. These substances elicit an intensely sweet taste sensation in man. All Catarrhina prefer monellin to water. The responses of the Prosimii as well as those of the South American primates to monellin are different, some species show a reaction, other species are not sensitive. In the case of thaumatin neither the Prosimii--including Tupaia and Tarsius--nor the South American primates show any response to this protein. Only the Cercopithecidae, the Hylobatidae and the Pongidae respond to this protein like man and prefer this substance to water. This physiological aspect of taste constitutes a clear dichotomy within the order Primates. This capability to taste thaumatin probably developed as long as 38 million years ago.

Differential behavioral responses to taste stimuli in non-human primates

Gustatory stimuli are known to elicit differential orofacial motor reactions in man. This phenomenon is named gustofacial reflex and has been shown to be elicitable in perinatal neonate human infants. Sweet and bitter stimuli (0·4 m sucrose and 0·0007 m quinine hydrochloride aqueous solutions, respectively) were presented to 12 different species of non-human primates. Some of the animals tested were several weeks of age, others were adolescents or adults. Both types of taste solutions, even in small amounts, were found to serve as potent stimuli to trigger characteristic and differential orofacial and other behavioral responses. Videotaped behavior reactions were presented in a double-blind manner to naive evaluators, who easily classified the behavior patterns along a pleasant-unpleasant continuum and were able to identify the stimuli. Analysis of the videotaped reactions made it possible to present the findings in a semi-quantitative manner. These findings are compared with taste-triggered behavior both in man and in non-primate mammals.

Rate of metabolism in the smallest simian primate, the pygmy marmoset (Cebuella pygmaea)

Rate of metabolism was measured with six adult pygmy marmosets (Cebuella pygmaea) at regulated ambient temperatures ranging between 20°C and 35°C. A novel combined nest box and metabolic chamber was designed to allow nighttime measurements on immobile animals in their home cage without disturbance. The basal rate of metabolism (BMR) was 98 ml O2 h−1, representing 74% of the value expected from the equation of McNab [Quarterly Review of Biology 63:25–54, 1988] relative to body mass. The thermoneutral zone was approximately 27–34°C. Below the lower critical temperature (27–28°C), thermal conductance (12.9 ml O2 h−1 °C−1) was close to the predicted value. Body temperature ranged between 34.9°C and 35.5°C at night. When two animals rested together overnight in the nest box, the lower critical temperature was slightly lowered, and individual energy expenditure at 20–21°C was reduced by about 34%. The basal rate of metabolism of C. pygmaea is much lower than reported in an earlier study based on daytime measurements but agrees with values reported from a more recent study conducted at night with a classical metabolic chamber. In order to compare the BMR of C. pygmaea with that of other primates, 23 species were included in a comparative study taking into account both phylogeny and body mass (independent contrasts approach). The scaling exponent of BMR to body mass obtained was indistinguishable from that published for eutherian mammals in general. Cebuella and Callithrix exhibit the lowest basal rates known for simians. This trait may possibly be linked to the natural diet, which includes a large proportion of gums that are difficult to digest, but additional metabolic studies on primates are needed for further examination of its adaptive significance. Am. J. Primatol. 41:229–245, 1997.

Gustatory responses of non-human primates to dipeptide derivatives or analogues, sweet in man

Abstract Dipeptide derivatives or analogues, sweet in man, can be divided into three classes according to their gustatory responses in primates: (i) dipeptides which are sweet to all primates (prosimians, New World simians and Old World simians), such as alitame or l -aspartyl- d -alanine propyl ester (class I); (ii) dipeptides which are sweet to prosimians and Old World simians, but not to New World simians, such as l -aspartyl-(R)-α-methylphenethylamine or l -aspartyl- l -(O-tert-butyl)serine methyl ester (class II); and, (iii) compounds which are sweet only to Old World simians, but not to prosimians and New World simians, such as aspartame (class III). Analysis of these results by means of the multipoint attachment (MPA) theory of sweetness reception (Nofre & Tinti, 1996) leads to the conclusion that the seven basic recognition sites of the sweetness receptor, as inferred from the MPA theory, are (i) in prosimians: Asp-1 or Glu-1, Lys-2, Asp-3 or Glu-3, Thr-4, Ala-5 or Ser-5, Thr-6, Thr-7; (ii) in New World simians: Asp-1 or Glu-1, Lys-2, Asp-3 or Glu-3, Thr-4, Ala-5 or Ser-5, Ala-6 or Ser-6, Thr-7; and, (iii) in Old World simians: Asp-1 or Glu-1, Lys-2, Asp-3 or Glu-3, Thr-4, Thr-5, Thr-6, Thr-7.

Specialization and phyletic trends of sweetness reception in animals

During the last decades, the comparison in various animal species of their gustatory responses to compounds eliciting a sweet taste in humans has extended our knowledge of the great biodiversity of the taste responses and evidenced some specialization and/or phyletic trends within species. Our interest was focused on responses to natural sugars, polyols, and naturally occurring sweeteners, but also on various artificial sweetening compounds, including the very powerful guanidine sweeteners. New results obtained with kangarooswhich originated about 130 MYAhave shown that their sweetness receptor is not designed to taste any of the artificial sweeteners tested. Therefore, the ability to taste complicated artificial sweeteners must have evolved later in higher developed mammals, about 100 million years ago.

The banded karyotype of Saguinus midas tamarin Link, 1795 (Callitrichidae, primates)

The karyotype of Saguinus midas tamarin (2n = 46) is presented. By G-banding all individual chromosome pairs are easily identifiable.

Verhaltens- und elektrophysiologische Experimente über den Geschmackssinn bei Saguinus midas tamarin (Callitrichidae)

The activity in the gustatory nerve from the anterior part of the tongue, the chorda tympani proper nerve, has been recorded during stimulation of the tongue of a New World monkey, Saguinus midas tama

Vergleichende Untersuchungen über den Geschmackssinn der Primaten

The threshold values of taste for the four qualities sweet, salty, bitter and sour were ascertained with a two-tube continuous intake procedure in Tupaia glis, Loris tardigradus, Nycticebus c

Geschmacksschwellenwerte von verschiedenen Zuckerarten bei Callithricidae (Platyrrhina)

to ‘Taste thresholds for common sugars in Callithricidae (Platyrrhina) ’. In Cebuellapygmaea and Leontocebus tamarin (Callithricidae, Platyrrhin