Feeding mice aged and fresh blackberries powder supplements result in shifts in the gastrointestinal microflora

•Blackberries have an important role in the small intestine for retaining gut health.•Non-culture based technique was utilized to examine shifts in gut bacteria of mice.•PCR-based DGGE and sequencing were performed to identify bacteria.•Blackberries supplements changed gastrointestinal microflora in mice.•Blackberries increased probiotic bacteria and decreased pathogenic bacteria.

Blackberries contain anthocyanins and phenolic acids derived from anthocyanin fragments that have an important role in the small intestine for retaining gut health. It has been hypothesized that supplementing diets with blackberries may improve gut health through a prebiotic mechanism. Unfortunately identification of gut bacteria is difficult since only 20% of bacterial species can be cultured using current techniques. Therefore, a non-culture based technique was utilized to examine shifts in gut bacteria of mice fed one of five diet treatments: (1) control, (2) aged blackberries supplemented at 5% (w/w), (3) aged blackberries supplemented at 10% (w/w), (4) fresh blackberries supplemented at 5% (w/w), and (5) fresh blackberries supplemented at 10% (w/w). Mice feces were initially collected before supplementing blackberries as a control (0 week) and were collected every 2 weeks for up to 10 weeks. Polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-based DGGE) was performed and further identification of bacteria was conducted by excising and sequencing target bands. Banding patterns were more consistent over time in those groups that had a diet supplemented with 10% aged or fresh blackberries compared to the 2 groups fed a diet supplemented with 5% of fresh or aged blackberries. From the sequencing data, Lactobacillus johnsonii was present in all groups after 2 weeks of sampling. The Aerococcus spp. and Actinomycetes were increased in blackberries treatments as well as Enterobacter spp., Klebsiella pneumonia and Erwinia spp. were present in aged blackberry treatment. These data indicate that supplementing a diet with aged or fresh blackberries causes shifts in the gastrointestinal microflora.