A. G. Koshchaev, A. S. Kozubov, A. V. Elisyutikova, S. V. Fedorovich
Kuban State Agrarian University, Krasnodar, Russia
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Volume 26 No. 8
Date of paper submission: 06.02.2026, date of review: 15.04.2026, date of acceptance: 23.05.2026
Published: 08/31/2026
Abstract. The purpose of the study is to evaluate the effect of synbiotic feed additives based on Bacillus subtilis B-945, inulin and lactulose in doses of 3, 5 and 7 % of the feed weight on the microbiome of the distal intestine of juvenile sterlet. Methods. The study was carried out on sterlet fingerlings (n = 200 in the group) in a recirculating aquaculture system (RAS) (21 °C, 90 days). Metagenomic analysis of combined chyme samples was performed by V3–V4 sequencing of the 16S rRNA gene on Illumina MiSeq (SILVA 138 database), processing was performed in QIIME 2 and RStudio. Scientific novelty. The effect of this synbiotic on the taxonomic structure and diversity of the intestinal microbiome of juvenile sterlet was studied for the first time. Results. It was found that a dosage of 5 % forms the richest microbial community, while 7 % causes dysbiotic changes. Compared with the control (Shannon index 5.31; Observed OTUs 498), a 3 % dose moderately increased alpha diversity (Shannon index 5,37; OTUs 565), increasing the proportion of Firmicutes to 52,0 % and reducing Fusobacteria to 13,8 %. The maximum alpha diversity was observed at 5 % (Shannon index 5,65; OTUs 572), the minimum at 7 % (Shannon index 5.25; OTUs 441), where PCoA analysis revealed isolated clustering. At a dose of 7 %, the proportion of Firmicutes increased to 63,1 %, Fusobacteria decreased to 7,5 %. At the level of genera, Clostridium sensu stricto 1 increased from 7,2 % to 21,1 %, Paeniclostridium – from 11,2 % to 32,5 %, Fusobacterium decreased from 86,7 % to 58,0 %. The genus Escherichia-Shigella was completely eliminated at 5 % and 7 %.
Keywords: sterlet, synbiotic, feed additive, microbiome, alpha diversity, beta diversity, 16S rRNA, Bacillus subtilis B-945, inulin, lactulose
For citation: Koshchaev A. G., Kozubov A. S., Elisyutikova A. V., Fedorovich S. V. Microbiome of the distal intestine of juvenile sterlet fed with a synbiotic feed additive. Agrarian Bulletin of the Urals. 2026; 26 (08): 1491‒1501. https://doi.org/10.32417/1997-4868-2026-26-08-1491-1501. (In Russ.)
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