Yeast-fermented spirulina as a functional feed additive: Impacts on growth efficiency and gut microbial diversity in native Indonesian ducks

The effects of supplementing with fermented spirulina ( Arthrospira platensis ) on the small intestine microbiota of native Indonesian Magelang ducks were examined in this study. The primary objective of this study was to evaluate the effects of different levels of yeast-fermented Spirulina supplementation on the small intestinal microbiota of Indonesian Magelang ducks, while growth performance was assessed as a supporting parameter. The ducks were supplemented with 5%, 10%, or 15% fermented spirulina, with a control group receiving no supplementation. The microbiome was described using 16S rRNA gene sequencing. The microbiome analysis revealed that supplementation significantly altered the microbial community, particularly increasing the population of Cetobacterium somerae , a beneficial bacterium known for its antiviral properties. • Research Focus : The study investigates the effects of fermented Spirulina supplementation on the small intestine microbiota of Magelang ducks using 16S rRNA gene sequencing. • Experimental Setup : 200 one-day-old Magelang ducks were divided into four groups and fed different concentrations of fermented Spirulina (5%, 10%, and 15%), with a control group receiving no Spirulina supplementation. • Microbial Diversity : The supplementation of fermented Spirulina led to significant changes in microbial diversity, with the 5% supplementation group showing the highest microbial richness, particularly dominated by Ligilactobacillus araffinosus. • Growth Performance : Ducks supplemented with 15% Spirulina exhibited the best feed conversion ratio (FCR = 2.67), indicating improved feed efficiency, while 5-10% supplementation promoted beneficial shifts in gut microbiota. • Microbial Shifts : Spirulina supplementation at different levels resulted in shifts in gut microbial composition, enhancing probiotic bacteria like Ligilactobacillus while reducing pathogenic species like Shigella sonnei and Fusobacterium mortiferum. • Intestinal Health : Spirulina supplementation, particularly at 5–10%, maintained optimal intestinal health, with no significant changes in intestinal length or pH, suggesting a balanced gut ecosystem. • Conclusion : Fermented Spirulina shows strong potential as a natural, sustainable feed additive that improves gut health and productivity in Magelang ducks, with 5-10% supplementation yielding the most beneficial results.