Effect of dietary supplementation of Spirulina (Arthrospira platensis) on bacterial diversity in the caecum of rabbits

The composition and the activity of the caecal microbiota have a strong influence on health in growing rabbits, but only about 24 to 40 % of the microbial species of the microbiota can be cultured in vitro. The experiment established with rabbits (Pannon White) from rabbit-farm of Kaposvar University. Young rabbits were weaned at 35th day of life. Spirulina - a type of blue-green algae, rich in protein, vitamins, minerals, and carotenoids, contains nutrients - has been used as human food supplement for over 20 years, but its use has started as an animal feed supplement in the last few years. Recent studies shown, that Spirulina has several biological activities, such as immunomodulation, antioxidant, anticancer, antimicrobial and probiotic effects. The objective of this study was to evaluate the effect of supplementation of the growing rabbits’ diet by Spirulina (treated group) on the bacterial diversity of the rabbits’ caecum with the aid of bacterial ribosome coding DNA based quantitative PCR (QPCR) reactions at the Molecular Biology Laboratory, University of Kaposvár. After the preparation of caecal samples (bacterial DNA extraction) the quantity of bacteria (belonging to phylum Firmicutes and Bacteroidetes) were determined by QPCR reactions. MxPro 3000P QPCR apparatus (Agilent Technologies) was used for the bacterial target sequence amplification applying primers and SYBR Green in the experimental assembly. Specificity of PCR reactions were checked by melting point anaysis. All investigated bacterial group showed slight changes, occurred both in the control and the treated groups. The amount of Bacteroidetes and Clostridium group representing Firmicutes phylum displayed a slight increase. Because of non-significant changes in portion of the caecum, we can conclude, that Spirulina has no significant effect on the monitored bacterial community.