ABSTRACT
Sesame oil cake, (Gingelly oil cake-GOC) was fermented with Bacillus subtilis and Saccharomyces cerevisiae by pilot scale solid state fermentation to ameliorate antinutritional factors and to improve its nutritional quality. Five experimental diets were prepared with 0%, 5%, and 7.5% levels of raw and fermented GOC. A 56-day feeding trial was conducted on juveniles (2.87±0.12 g) of Penaeus vannamei. The best growth (weight gain 416.97 ± 12.14%), digestive enzyme profiles (protease), nutrient utilization and immune parameters were observed in shrimp fed with fermented GOC at 5 and 7.5% levels compared to control and unfermented GOC fed shrimp. Total genomic DNA was extracted from shrimp gut samples, and the bacterial 16S rRNA (V3–V4 region) was amplified for microbiome analysis. Libraries were prepared using the Nextera XT Index Kit and sequenced on the Illumina NovaSeq platform. Sequencing data were processed using the QIIME2 pipeline for bioinformatic analysis. The linear discriminant analysis (LDA) effect size (LEfSe) method was employed to identify differentially abundant bacterial taxa between the treatment groups.
The Venn diagram shows that feeding shrimp with 5% GOC results in the highest number of unique ASVs followed by fermented GOC and the lowest in shrimp fed with 7.5% GOC. Shrimp fed with fermented GOC exhibited higher levels of known probiotic bacterial genus, Bifidobacterium, Bacteroides, Prevotella, Parabacteroides and Geminobacterium that primarily aid in digesting complex plant fibers and produce short-chain fatty acids (SCFAs) like acetate, propionate and butyrate, and support gut health. They also help regulate the immune system, modulate inflammation by inducing anti-inflammatory responses, and protect against pathogens. Improved gut microbiome from fermented GOC enhanced digestion, nutrient utilization, immunity, and growth in shrimp.
Keywords: Penaeus vannamei, Intestinal microbiota, Solid State fermentation, Sesame oil cake, immunity