The effect of Spirulina (Arthrospira platensis) as a microbial diatory feed supplement for juvenile of Nile Tilapia (Oreochromis niloticus)

Tilapia is the second most farmed fish in tropical and sub-tropical countries worldwide. This study investigated the effect of replacing fish meal by Spirulina platensis (groups fed with 5%, 10% and 15% Spirulina) on the growth of Nile tilapia O. niloticus juveniles. Intestinal microbiota of tilapia has been studied by MiSeq Illumina sequencing. No significant differences (P > 0.05) were observed for the protein, carbohydrate and lipids of fish fed with control food and different concentrations of spirulina. However, the Margalef species richness of the intestinal bacteria of tilapia fed with spirulina was significantly higher (P < 0.05) compared to the control samples. Evenness was significantly higher (P < 0.05) for tilapia fed with food substituted with the highest concentration of spirulina. Also, few potentially probiotic genera, like Bacillus and Actinomycetes were detected in the gut of the experimented Tilapia. On the other hand, the highest percent of potentially pathogenic genera was recorded for the genera Pseudomonas and Corynebacterium. In most cases, the highest abundances of potentially pathogenic species were found in control samples. As manipulation of the feed was shown to improve Tilapia microbiota, which could lead to further improvements in aquaculture production.