Dietary tryptophan supplementation in privately owned mildly anxious dogs

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)

Abstract

Food composition has been reported to influence mood and behaviour in humans and animals and it could help to reduce unwanted behaviour in dogs. Anxiety-related behaviour is associated with the functioning of the central serotonergic system and here it was investigated if dietary supplementation with the serotonin precursor tryptophan (Trp) affects behaviour in privately owned dogs. For 8 weeks, privately owned dogs were fed a control diet (n = 66) or a diet containing 2.6-fold more Trp than the control diet (n = 72), using a randomised double-blinded, placebo-controlled approach. A third diet fortified with Trp, beet pulp, salmon oil, soy lecithin, and green tea extract was studied for its potential in 69 dogs. Owners reported on their dogs’ behaviour in the home-situation by filling out a web-based questionnaire before the onset of dietary treatment and after 4 and 8 weeks of feeding the diets. Thirty-four dogs fed the control diet and 39 dogs fed the Trp diet were subjected to behaviour tests before and after 8 weeks of dietary treatment. The tests included open-field situations and owner-separation procedures and were set up to measure anxiousness. Blood was collected after 8 weeks from dogs in the control (15 dogs) and Trp (15) groups for evaluation of plasma amino acid concentrations. Dietary effects on behaviour were investigated for significance by means of testing interactions between diet and time, using Residual Maximum Likelihood. Intake of the Trp supplemented diet significantly increased plasma Trp concentrations by 37.4% and its ratio with large neutral amino acids by 31.2% compared to the control diet but owners did not report on behavioural changes that could be attributed to a specific dietary treatment. Also, the dogs’ responses in the behavioural tests, including those in saliva cortisol, were unaffected after 8 weeks of consuming the Trp supplemented food. A number of significant changes in both owner-reported assessments and behavioural responses did occur over time, possibly mirroring a placebo-effect and/or influences of a new diet regardless of its specific composition. It is concluded that intake of diets supplemented solely with Trp or in combination with beet pulp, salmon oil, soy lecithin, and green tea extract does not change (anxiety-related) behaviour in privately owned dogs that do not show clear signs of abnormal behaviour. The influence of dietary Trp intake on behaviour of pathological anxious or chronically stressed dogs remains to be established
Original languageEnglish
Pages (from-to)197-205
JournalApplied Animal Behaviour Science
Volume121
Issue number3-4
DOIs
Publication statusPublished - 2009

Fingerprint

Dietary Supplements
Tryptophan
tryptophan
Dogs
Diet
dogs
diet
salmon oil
beet pulp
Beta vulgaris
Lecithins
green tea
Tea
anxiety
phosphatidylcholines
placebos
Anxiety
testing
Fortified Food
Neutral Amino Acids

Keywords

  • separation anxiety
  • saliva cortisol
  • amino-acids
  • food-intake
  • serotonin
  • stress
  • behavior
  • plasma
  • brain
  • responses

Cite this

@article{24789ddc77ba434ba26e68352a772fa1,
title = "Dietary tryptophan supplementation in privately owned mildly anxious dogs",
abstract = "Food composition has been reported to influence mood and behaviour in humans and animals and it could help to reduce unwanted behaviour in dogs. Anxiety-related behaviour is associated with the functioning of the central serotonergic system and here it was investigated if dietary supplementation with the serotonin precursor tryptophan (Trp) affects behaviour in privately owned dogs. For 8 weeks, privately owned dogs were fed a control diet (n = 66) or a diet containing 2.6-fold more Trp than the control diet (n = 72), using a randomised double-blinded, placebo-controlled approach. A third diet fortified with Trp, beet pulp, salmon oil, soy lecithin, and green tea extract was studied for its potential in 69 dogs. Owners reported on their dogs’ behaviour in the home-situation by filling out a web-based questionnaire before the onset of dietary treatment and after 4 and 8 weeks of feeding the diets. Thirty-four dogs fed the control diet and 39 dogs fed the Trp diet were subjected to behaviour tests before and after 8 weeks of dietary treatment. The tests included open-field situations and owner-separation procedures and were set up to measure anxiousness. Blood was collected after 8 weeks from dogs in the control (15 dogs) and Trp (15) groups for evaluation of plasma amino acid concentrations. Dietary effects on behaviour were investigated for significance by means of testing interactions between diet and time, using Residual Maximum Likelihood. Intake of the Trp supplemented diet significantly increased plasma Trp concentrations by 37.4{\%} and its ratio with large neutral amino acids by 31.2{\%} compared to the control diet but owners did not report on behavioural changes that could be attributed to a specific dietary treatment. Also, the dogs’ responses in the behavioural tests, including those in saliva cortisol, were unaffected after 8 weeks of consuming the Trp supplemented food. A number of significant changes in both owner-reported assessments and behavioural responses did occur over time, possibly mirroring a placebo-effect and/or influences of a new diet regardless of its specific composition. It is concluded that intake of diets supplemented solely with Trp or in combination with beet pulp, salmon oil, soy lecithin, and green tea extract does not change (anxiety-related) behaviour in privately owned dogs that do not show clear signs of abnormal behaviour. The influence of dietary Trp intake on behaviour of pathological anxious or chronically stressed dogs remains to be established",
keywords = "separation anxiety, saliva cortisol, amino-acids, food-intake, serotonin, stress, behavior, plasma, brain, responses",
author = "G. Bosch and B. Beerda and A.C. Beynen and {van der Borg}, J.A.M. and {van der Poel}, A.F.B. and W.H. Hendriks",
note = "Online first",
year = "2009",
doi = "10.1016/j.applanim.2009.10.003",
language = "English",
volume = "121",
pages = "197--205",
journal = "Applied Animal Behaviour Science",
issn = "0168-1591",
publisher = "Elsevier",
number = "3-4",

}

Dietary tryptophan supplementation in privately owned mildly anxious dogs. / Bosch, G.; Beerda, B.; Beynen, A.C.; van der Borg, J.A.M.; van der Poel, A.F.B.; Hendriks, W.H.

In: Applied Animal Behaviour Science, Vol. 121, No. 3-4, 2009, p. 197-205.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Dietary tryptophan supplementation in privately owned mildly anxious dogs

AU - Bosch, G.

AU - Beerda, B.

AU - Beynen, A.C.

AU - van der Borg, J.A.M.

AU - van der Poel, A.F.B.

AU - Hendriks, W.H.

N1 - Online first

PY - 2009

Y1 - 2009

N2 - Food composition has been reported to influence mood and behaviour in humans and animals and it could help to reduce unwanted behaviour in dogs. Anxiety-related behaviour is associated with the functioning of the central serotonergic system and here it was investigated if dietary supplementation with the serotonin precursor tryptophan (Trp) affects behaviour in privately owned dogs. For 8 weeks, privately owned dogs were fed a control diet (n = 66) or a diet containing 2.6-fold more Trp than the control diet (n = 72), using a randomised double-blinded, placebo-controlled approach. A third diet fortified with Trp, beet pulp, salmon oil, soy lecithin, and green tea extract was studied for its potential in 69 dogs. Owners reported on their dogs’ behaviour in the home-situation by filling out a web-based questionnaire before the onset of dietary treatment and after 4 and 8 weeks of feeding the diets. Thirty-four dogs fed the control diet and 39 dogs fed the Trp diet were subjected to behaviour tests before and after 8 weeks of dietary treatment. The tests included open-field situations and owner-separation procedures and were set up to measure anxiousness. Blood was collected after 8 weeks from dogs in the control (15 dogs) and Trp (15) groups for evaluation of plasma amino acid concentrations. Dietary effects on behaviour were investigated for significance by means of testing interactions between diet and time, using Residual Maximum Likelihood. Intake of the Trp supplemented diet significantly increased plasma Trp concentrations by 37.4% and its ratio with large neutral amino acids by 31.2% compared to the control diet but owners did not report on behavioural changes that could be attributed to a specific dietary treatment. Also, the dogs’ responses in the behavioural tests, including those in saliva cortisol, were unaffected after 8 weeks of consuming the Trp supplemented food. A number of significant changes in both owner-reported assessments and behavioural responses did occur over time, possibly mirroring a placebo-effect and/or influences of a new diet regardless of its specific composition. It is concluded that intake of diets supplemented solely with Trp or in combination with beet pulp, salmon oil, soy lecithin, and green tea extract does not change (anxiety-related) behaviour in privately owned dogs that do not show clear signs of abnormal behaviour. The influence of dietary Trp intake on behaviour of pathological anxious or chronically stressed dogs remains to be established

AB - Food composition has been reported to influence mood and behaviour in humans and animals and it could help to reduce unwanted behaviour in dogs. Anxiety-related behaviour is associated with the functioning of the central serotonergic system and here it was investigated if dietary supplementation with the serotonin precursor tryptophan (Trp) affects behaviour in privately owned dogs. For 8 weeks, privately owned dogs were fed a control diet (n = 66) or a diet containing 2.6-fold more Trp than the control diet (n = 72), using a randomised double-blinded, placebo-controlled approach. A third diet fortified with Trp, beet pulp, salmon oil, soy lecithin, and green tea extract was studied for its potential in 69 dogs. Owners reported on their dogs’ behaviour in the home-situation by filling out a web-based questionnaire before the onset of dietary treatment and after 4 and 8 weeks of feeding the diets. Thirty-four dogs fed the control diet and 39 dogs fed the Trp diet were subjected to behaviour tests before and after 8 weeks of dietary treatment. The tests included open-field situations and owner-separation procedures and were set up to measure anxiousness. Blood was collected after 8 weeks from dogs in the control (15 dogs) and Trp (15) groups for evaluation of plasma amino acid concentrations. Dietary effects on behaviour were investigated for significance by means of testing interactions between diet and time, using Residual Maximum Likelihood. Intake of the Trp supplemented diet significantly increased plasma Trp concentrations by 37.4% and its ratio with large neutral amino acids by 31.2% compared to the control diet but owners did not report on behavioural changes that could be attributed to a specific dietary treatment. Also, the dogs’ responses in the behavioural tests, including those in saliva cortisol, were unaffected after 8 weeks of consuming the Trp supplemented food. A number of significant changes in both owner-reported assessments and behavioural responses did occur over time, possibly mirroring a placebo-effect and/or influences of a new diet regardless of its specific composition. It is concluded that intake of diets supplemented solely with Trp or in combination with beet pulp, salmon oil, soy lecithin, and green tea extract does not change (anxiety-related) behaviour in privately owned dogs that do not show clear signs of abnormal behaviour. The influence of dietary Trp intake on behaviour of pathological anxious or chronically stressed dogs remains to be established

KW - separation anxiety

KW - saliva cortisol

KW - amino-acids

KW - food-intake

KW - serotonin

KW - stress

KW - behavior

KW - plasma

KW - brain

KW - responses

U2 - 10.1016/j.applanim.2009.10.003

DO - 10.1016/j.applanim.2009.10.003

M3 - Article

VL - 121

SP - 197

EP - 205

JO - Applied Animal Behaviour Science

JF - Applied Animal Behaviour Science

SN - 0168-1591

IS - 3-4

ER -