Department of Physics, Chemistry and Biology Master Thesis




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Department of Physics, Chemistry and Biology

Master Thesis

Taste preference thresholds of black-and-white ruffed lemurs (Varecia variegata) for nine substances tasting sweet to humans

Sandra Nicklasson

LiTH-IFM- Ex--15/3007--SE

Supervisor: Matthias Laska, Linköping University

Examiner: Mats Amundin, Linköping University

Department of Physics, Chemistry and Biology

Linköpings universitet

SE-581 83 Linköping, Sweden





Institutionen för fysik, kemi och biologi

Department of Physics, Chemistry and Biology

Avdelningen för biologi

Instutitionen för fysik och mätteknik




Rapporttyp

Report category


Examensarbete

D-uppsats



Språk/Language

Engelska/English


Titel/Title:

Taste preference thresholds of black-and-white ruffed lemurs (Varecia variegata) for nine substances tasting sweet to humans


Författare/Author:

Sandra Nicklasson



Sammanfattning/Abstract:
Comparative studies of taste perception are an important tool to study the mechanisms underlying the evolution of the sense of taste, as the taste perception of a species is thought to be linked to its feeding ecology. The different species within the primate order display a high diversity in dietary specializations, with the black-and-white ruffed lemur (Varecia variegata variegata) being one of the most frugivorous primates. The aim of the study was to determine taste preference thresholds of black-and-white ruffed lemurs to stevioside, rebaudioside A, glycine, L-alanine, L-proline, saccharin, sorbitol, polycose and galactose. All of these substances have been described as sweet-tasting to humans. A two-bottle preference test of short duration was used, with tap water as the alternative simulus. Taste preference thresholds were found to be 0.1-0.2 mM for stevioside, 0.05-0.15 mM for rebaudioside A, 15-20 mM for glycine, 2 mM for L-alanine, 10-20 mM for L-proline, 30-110 for sorbitol, 30-40 mM for polycose, 70-90 mM for galactose and saccharin was instead rejected at 1 mM by one individual. L-alanine, stevioside and saccharin were either rejected at some concentrations or were neither preferred nor rejected at any concentration. These three substances have a bitter side taste to humans, and it is possible that the lemurs in this study are particularly sensitive to bitter taste. In general, the black-and-white ruffed lemurs were found to prefer the taste of the majority of the tested substances over water.

ISBN

LITH-IFM-A-EX15/3007—SE

__________________________________________________

ISRN

__________________________________________________

Serietitel och serienummer ISSN

Title of series, numbering


Handledare/Supervisor Matthias Laska
Ort/Location: Linköping

Nyckelord/Keyword:

Amino acids, black-and-white ruffed lemurs, galactose, primates, starch, sweeteners, taste



Datum/Date
2015-05-18

URL för elektronisk version

     

Content


1. Abstract 1

2. Introduction 1

3. Material & methods 4

3.1 Animals and housing 4

3.2 Chemicals 5

3.3 Experimental setup 5

3.4 Data analysis 7

4. Results 7

4.1 Stevioside 7

4.2 Rebaudioside A 8

4.3 Glycine 9

4.4 L-alanine 9

4.5 L-proline 10

4.6 Polycose 11

4.7 D-sorbitol 11

4.8 Saccharin 12

4.9 Galactose 12

5. Discussion 13

5.1 The taste preference threshold for galactose, polycose and three amino acids 13

5.2 The taste preference threshold for sorbitol, stevioside, rebaudioside A and taste rejection threshold for saccharin 17

5.3 General individual differences 19

5.4 Rejected and non-preferred substances 20

5.5 Conclusion 21

5.6 Societal and ethical considerations 21

6. Acknowledgements 22

7. References 22

1. Abstract

Comparative studies of taste perception are an important tool to study the mechanisms underlying the evolution of the sense of taste, as the taste perception of a species is thought to be linked to its feeding ecology. The different species within the primate order display a high diversity in dietary specializations, with the black-and-white ruffed lemur (Varecia variegata variegata) being one of the most frugivorous primates. The aim of the study was to determine taste preference thresholds of black-and-white ruffed lemurs for nine substances tasting sweet to humans; stevioside, rebaudioside A, glycine, L-alanine, L-proline, saccharin, sorbitol, polycose and galactose. A two-bottle preference test of short duration was used, with tap water as the alternative simulus. Taste preference thresholds were found to be 0.1-0.2 mM for stevioside, 0.05-0.15 mM for rebaudioside A, 15-20 mM for glycine, 2 mM for L-alanine, 10-20 mM for L-proline, 30-110 for sorbitol, 30-40 mM for polycose, 70-90 mM for galactose. One individual rejected saccharin at 1 mM, and no taste preference could be observed for this substance for any individual. L-alanine, stevioside and saccharin were either rejected at some concentrations or were neither preferred nor rejected at any concentration. These three substances have a bitter side taste to humans, and it is possible that the lemurs in this study are particularly sensitive to bitter taste. In general, the black-and-white ruffed lemurs preferred the taste of the majority of the tested substances over water.


Keywords: amino acids, black-and-white ruffed lemurs, galactose, primates, starch, sweeteners, taste

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