Elsevier

The Journal of Nutrition

Volume 145, Issue 2, February 2015, Pages 358-364
The Journal of Nutrition

Dietary Linoleic and α-Linolenic Acids Affect Anxiety-Related Responses and Exploratory Activity in Growing Pigs1, 2, 3

https://doi.org/10.3945/jn.114.199448Get rights and content
Under an Elsevier user license
open archive

ABSTRACT

Background: Growing evidence suggests that the dietary ratio of linoleic acid (LA) to α-linolenic acid (ALA), the precursors of arachidonic acid (AA) and docosahexaenoic acid (DHA), respectively, may affect behavior in mammals.

Objective: This study aimed at evaluating the impact of dietary LA and ALA intake on behaviors of growing pigs, a pertinent model for human nutrition.

Methods: At 7 wk of age, 32 pigs were allocated to 4 dietary treatments varying in daily intake of LA (1.3 and 2.6 g · kg body weight−0.75 · d−1 for low- and high-LA groups, respectively) and ALA (0.15 and 1.5 g · kg body weight−0.75 · d−1 for low- and high-ALA groups, respectively) for 4 wk. Between days 12 and 18, general behavior in the home pen was observed and pigs were subjected to an open field and novel object test. At 11 wk of age, brain fatty acid composition was analyzed.

Results: Compared with high LA intake, low LA intake increased the time spent on exploration, particularly nosing in the home pen (P < 0.05) and the open field (P < 0.05), and tended to reduce the time spent lying with eyes open in the home pen (P = 0.09). Time spent lying with eyes open also tended to be affected by the interaction between LA and ALA (P = 0.08). A high-LA/high-ALA intake (ratio of 2; P < 0.05) and a low-LA/high-ALA intake (ratio of 1; P = 0.06) decreased the latency to approach the novel object compared with a low-LA/low-ALA intake (ratio of 9). DHA in the frontal cortex was positively correlated with exploratory behaviors in the home pen (rs = 0.56, P < 0.01), whereas AA was negatively correlated with time spent lying with eyes closed (rs = –0.48, P < 0.01).

Conclusions: Low LA intake and a low dietary LA:ALA ratio increased exploration and decreased anxiety-related behaviors in pigs. It is suggested that changes in brain DHA and AA induced by dietary LA and ALA intake mediate these behavioral changes.

KEY WORDS

polyunsaturated fatty acids
omega-6
docosahexaenoic acid
novelty
pigs

Abbreviations

AA
arachidonic acid
ALA
α-linolenic acid
DPA
docosapentaenoic acid
LA
linoleic acid
LC-PUFA
long-chain PUFA

Cited by (0)

1

Supported by the Dutch Ministry of Agriculture, Nature, and Food Quality.

2

Author disclosures: C Clouard, WJJ Gerrits, I van Kerkhof, W Smink, and JE Bolhuis, no conflicts of interest.

3

ec1, ec2, ec3, ec4 are available from the ‘Online Supporting Material’ link in the online posting of the article and fromthe same link in the online table of contents at http://jn.nutrition.org.