Fig. 1

Kefir modulates repetitive behaviour and reward-seeking behaviour. Repetitive/anxiety-like behaviour was assessed using the marble burying test (a). Anhedonia and reward-seeking behaviours were investigated using the female urine sniffing test (b, c) and saccharin preference test (d, e). The marble burying test was normally distributed and analysed using a one-way ANOVA, followed by a Dunnett’s post hoc test. The female urine sniffing test and saccharin preference test were non-normally distributed and analysed using the Kruskal-Wallis test, followed by the Mann-Whitney test. Significant differences are depicted as *p < 0.05, **p < 0.01 and ***p <0.001; milk control compared to kefir supplementation, ^$p < 0.05; undisturbed control compared to milk control. All data are expressed ‘as mean ± SEM (n = 11–12). Dots on each graph represent individual animals