Type-1 Diabetes Mellitus (T1D) onset and development is closely linked with imbalance of gut microbiome, while supplementation with probiotics may result in positive alterations in gut microbiome composition. In the present study, the effect of a dietary intervention including free or immobilized cells of the presumptive probiotic Pediococcus acidilactici ORE5 on Corinthian currants, a food with beneficial impact in the condition of diabetes, was investigated. Male Wistar rats were studied which were divided into 4 groups: healthy animals, which received the free (H_FP) or the immobilized cells (H_IPC), and diabetic animals, which received the free (D_FP) or the immobilized cells (D_IPC), for 4 weeks (109 cfu/day, in all groups). At the end of the dietary intervention, D_IPC group exerted lower concentration of the inflammatory cytokine IL-1b compared to D_FP. Consumption of immobilized on Corinthian currants P. acidilactici ORE5 cells by diabetic animals led to increased loads of fecal lactobacilli and lower levels of Enterobacteriaceae, coliforms, and E. coli, while Actinobacteria phylum, Akkermansia, and Bifidobacterium genera abundances were increased, and fecal lactic acid was elevated. Overall, the results of the present research demonstrated that functional ingredients can ameliorate gut dysbiosis present in T1D and could be used to design dietary patterns aiming at T1D management. However, well-designed clinical trials are necessary, in order to confirm the beneficial effects in humans.