Effects of whey protein supplementation on gut microbiota in colitis mouse model

The Ulcerative Colitis (UC) is characterized by chronic relapsing intestinal inflammation. Considering the impact of UC on the quality of life, dietary interventions have been proposed to reduce the associated symptoms. Supplementation with bioactive peptides like whey protein (WP) may reduce symptoms of UC by modulation of gut microbiota and immune system due the production of mucins and metabolites. In this way, the short-wave ultraviolet (UV-C) procedures have been used to improve the digestibility and release of bioactive peptides during WP digestion. In the present study induced UC mice were fed a standard diet plus WP with or without UV-C treatment. We induced UC in mice by a treatment with dextran sulfate sodium (DSS). Male C57BL/6J mice (n = 10 per group) were divided in: H group – healthy mice; C group – DSS mice that did not receive WP; W group – DSS mice fed with WP without UV-C treatment and WU group – DSS mice fed with WP functionalized by UV-C treatment. WP administration started seven days before colitis induction and continued through the seven days of DSS induction. The severity of colitis was daily determined by disease activity index (DAI) and the fecal microbiota was analyzed in the days 0, 7, 12 and 14. In all DSS-induced mice, a reduction in the alpha-diversity was observed across the experimental time. Moreover, all groups display a similar Shannon index through the experiment (p > 0.05). Microbiota composition was affected by the treatment. A decrease in Lachnospiraceae both in W and WU groups (p < 0.05) was observed. However, at study end (day 14) a restore in Lachnospiraceae was observed (p > 0.05). Finally, Oscillospiraceae (associated with H group) and Turicibacter (W group), increased during the experiment. The animals in the WU group showed a reduction in the characteristic symptoms of colitis (diarrhea, weight loss, and presence of blood in the feces), without differing from the H group on day 11 of the protocol (p<0.05). The results indicate that the different WP production could result in a restoration in beneficial taxa and slower symptom progression in colitis mouse model. Although future studies are needed to confirm these beneficial effects. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001. Processo FAPESP: 2017/01189-0.