An n-3 fatty acid deficient diet affects mouse spatial learning in the Barnes circular maze

Abstract

Deficiency in n-3 fatty acids has been accomplished through the use of an artificial rearing method in which ICR mouse pups were hand fed a deficient diet starting from the 2nd day of life. There was a 51% loss of total brain DHA in mice with an n-3 fatty acid-deficient diet relative to those with a diet sufficient in n-3 fatty acids. n-3 fatty acid adequate and deficient mice did not differ in terms of locomotor activity in the open field test or in anxiety-related behavior in the elevated plus maze. The n-3 fatty acid-deficient mice demonstrated impaired learning in the reference-memory version of the Barnes circular maze as they spent more time and made more errors in search of an escape tunnel. No difference in performance between all dietary groups in the cued and working memory version of the Barnes maze was observed. This indicated that motivational, motor and sensory factors did not contribute to the reference memory impairment.

Figure 1

Fig. 1A. Latency to find the escape tunnel in the Barnes maze reference memory test. Values are given as means + SEM (n-3 Adq, n=9; n-3 Def, n=12; Dam, n=12). Repeated measures ANOVA revealed a significant effect of Diet (F(2,256)=46.58, p<0.0001) and Days (F(15,128)=11.83, p<0.0001). There was no significant Diet X Days interaction (F(30,256)=1.40, p>0.05). Post-hoc comparisons using Tukey's test supported that the n-3 Def group was different from the n-3 Adq and Dam-reared groups (p<0.05). Fig. 1B. Errors made in the Barnes maze reference memory test. Values are given as means + SEM (n-3 Adq, n=9; n-3 Def, n=12; Dam, n=12). Repeated measures ANOVA revealed a significant effect of Diet (F(2,256)=37.27, p<0.0001), Days (F(15,128)=11.13, p<0.0001) and a Diet X Days interaction (F(30,256)=1.74, p<0.05). Post-hoc comparisons using Tukey's test supported that the n-3 Def group was different from the n-3 Adq and Dam-reared groups (p<0.05).

Figure 1

Fig. 1A. Latency to find the escape tunnel in the Barnes maze reference memory test. Values are given as means + SEM (n-3 Adq, n=9; n-3 Def, n=12; Dam, n=12). Repeated measures ANOVA revealed a significant effect of Diet (F(2,256)=46.58, p<0.0001) and Days (F(15,128)=11.83, p<0.0001). There was no significant Diet X Days interaction (F(30,256)=1.40, p>0.05). Post-hoc comparisons using Tukey's test supported that the n-3 Def group was different from the n-3 Adq and Dam-reared groups (p<0.05). Fig. 1B. Errors made in the Barnes maze reference memory test. Values are given as means + SEM (n-3 Adq, n=9; n-3 Def, n=12; Dam, n=12). Repeated measures ANOVA revealed a significant effect of Diet (F(2,256)=37.27, p<0.0001), Days (F(15,128)=11.13, p<0.0001) and a Diet X Days interaction (F(30,256)=1.74, p<0.05). Post-hoc comparisons using Tukey's test supported that the n-3 Def group was different from the n-3 Adq and Dam-reared groups (p<0.05).

Figure 2

Fig. 2A. Escape latency (average across all training days) in the working memory version of the Barnes maze. Values are given as means + SEM, where individual values are expressed as a percentage of the average trial 1value. Repeated measures ANOVA revealed a significant effect of Trial (F(3,20)=6.90, p<0.01). There was neither a significant effect of Diet (F(2,40)=1.42, p>0.05) nor a significant Diet x Trial interaction (F(6,40)=0.33, p>0.05). Fig. 2B. Error rates (average across all training days) in the working memory version of the Barnes maze. Values are given as means + SEM, where individual values are expressed as a percentage of the average trial 1value. Repeated measures ANOVA revealed a significant effect of Trial (F(3,20)=8.33, p<0.001). There was neither a significant effect of Diet (F(2,40)=2.169, p>0.05) nor a significant Diet x Trial interaction (F(6,40)=0.62, p>0.05).

Figure 2

Fig. 2A. Escape latency (average across all training days) in the working memory version of the Barnes maze. Values are given as means + SEM, where individual values are expressed as a percentage of the average trial 1value. Repeated measures ANOVA revealed a significant effect of Trial (F(3,20)=6.90, p<0.01). There was neither a significant effect of Diet (F(2,40)=1.42, p>0.05) nor a significant Diet x Trial interaction (F(6,40)=0.33, p>0.05). Fig. 2B. Error rates (average across all training days) in the working memory version of the Barnes maze. Values are given as means + SEM, where individual values are expressed as a percentage of the average trial 1value. Repeated measures ANOVA revealed a significant effect of Trial (F(3,20)=8.33, p<0.001). There was neither a significant effect of Diet (F(2,40)=2.169, p>0.05) nor a significant Diet x Trial interaction (F(6,40)=0.62, p>0.05).