Mesobiliverdin IXα-enriched microalgal feed supplement promotes beneficial gut microbiota in rabbits

Studies were conducted to determine if an antibiotic-free diet supplemented with mesobiliverdin IXα-enriched microalgae extract promotes beneficial gut microbiota in 4- to 6-wk-old New Zealand White rabbits. Mesobiliverdin IXα is a cytoprotective haem-derived bilin with anti-inflammatory and antioxidant properties. Rabbits given supplemented feed had body weight gains, lower serum cytokine IL-6 levels and similar blood chemistry profiles compared to rabbits provided control non-supplemented feed. Microbiota 16s genomic analyses of caecotropes revealed that supplemented feed elicited caecal microbiota relative abundance increases of genera Family_XIII_AD3011 and Papillibacter, Bacteriodes vulgatus and families Lachnospiraceae, Akkermansiaceae and Bacteriodaceae and lower abundance of genera Anaeroplasma, Monoglobus, Tyzerella, Eubacterium ventriosum group and Eubacterium rumenatium group compared to non-supplemented feed. The caecal microbiota profile of rabbits fed supplemented feed resembles that described for rabbits treated with the anti-inflammatory anthocyanin procyanidin B2 and the analgesic meloxicam and shows less resemblance to the previously reported profiles of rabbits provided feed supplemented with antibiotics.