Simple SummaryThe aim of this study was to increase the sustainability of piglets farming by including valorised local cereal industry by-products as value-added feed material. In addition, dried sugar beet pulp, as local, high-energy, and nutritionally dense feed material for piglet feeding, was tested. The influence of the by-products on piglets’ blood parameters, faecal microbial and physico-chemical characteristics, and growth performance was evaluated. The control group was fed without by-product addition. A 41-day experiment was conducted using 300 (21-day-old) Large White/Norwegian Landrace piglets. Results showed that an extrusion and fermentation combination is a suitable strategy for wheat bran valorisation, as pre-treated wheat bran showed desirable antimicrobial and antifungal properties. Both treatments reduced the total enterobacteria and increased the lactic acid bacteria (LAB) count in piglets’ faeces. The consistency of the piglets’ faeces was within a physiological range throughout the whole experiment. It was established that the LAB count in piglets’ faeces is associated with specific volatile compounds’ formation (butanoic acid; butanoic acid, 3-methyl-; butyric acid (2-methyl-); pentanoic acid). Finally, the significantly higher body weight gain of the treatment groups could be associated with desirable changes in micro-organism populations in the piglets’ faeces, and the tested local feed material could be suggested for piglets’ nutrition.In this study, a 41-day experiment was conducted using 300 (21-day-old) Large White/Norwegian Landrace piglets (100 piglets in each group). Three dietary treatments were compared: (i) a basal diet (C-I), (ii) a basal diet with the addition of extruded–fermented wheat bran (Wex130/screwspeed25Lpa) (TG-II), and (iii) a basal diet with the addition of dried sugar beet pulp (TG-III). Analyses of piglets’ blood parameters, faecal microbial and physico-chemical characteristics, and piglets’ growth performance were performed. It was found that the extrusion and fermentation combination led to an additional functional value of Wex130/screwspeed25Lpa, which showed desirable antimicrobial and antifungal properties in vitro (inhibited 5 out of 10 tested pathogenic strains and 3 out of 11 tested fungi). Both treatments reduced total enterobacteria and increased lactic acid bacteria counts in piglets’ faeces. The consistency of the piglets’ faeces (in all three groups) was within a physiological range throughout the whole experiment. Strong positive correlations were found between the LAB count in piglets’ faeces and butanoic acid; butanoic acid, 3-methyl-; butyric acid (2-methyl-); pentanoic acid. The treatment groups obtained a significantly higher body weight gain and average daily gain. Finally, substituting the piglets’ diet with Wex130/screwspeed25Lpa and sugar beet pulp led to favourable changes in micro-organism populations in the piglets’ faeces as well as better growth performance.