Do Digestive Bacteria Suffer from Oxidative Stress: A Study on Ruminal Bacteria

Author(s): Muhammad Kaleem, Yves Farizon, Géraldine Pascal, Tiphaine Blanchard, Laurent Cauquil, Sylvie Combes, Denys Durand, Francis Enjalbert, Djamila Ali Haimoud-Lekhal, Annabelle Meynadier

Background: Heating oils and oilseeds results in oxidized fatty acids with potential antimicrobial properties that could affect digestive microbiota, and therefore health.

Objectives: The objectives of this study were to explore the effect of lipid oxidation products on digestive bacteria using rumen content culture.

Methods: A long-term in vitro study was conducted to check the effects of one hydroperoxide, 13OOH cis-9,trans-11-C18:2 (13HPOD), and two aldehydes, hexanal and trans-2,trans-4-decadienal (T2T4D), on rumen bacteria and superoxide dismutase (SOD) activity. Rumen fluid was incubated with one of the three oxidation products for 54 h or 102 h. Controls without oxidation products were also incubated.

Results: The bacterial community was highly affected by T2T4D, in particular the Bacteroidetes/Firmicutes ratio and the relative abundance of the Bacteroidales S24-7 group family, leading to an alteration of fermentation responsible for a higher final pH than those in control cultures, and a diminution of SOD activity. Other oxidative products did not affect SOD activity, as well as hexanal did not modify the bacterial community compared to that of the control.

Conclusion: The modification of the ruminal bacterial community by T2T4D represents a potential risk for the health of its host. Oxidative stress needs to be investigated in digestive ecosystems.