Effects of a multi-strain Bacillus probiotic on the intestinal microbiome, haemato-immunology, and growth performance of Nile tilapia

• Published in: Veterinary research communications Vol. 48; no. 4; pp. 2357 - 2368
• Main Authors: Ferrarezi, José Victor Safadi, Owatari, Marco Shizuo, Martins, Mateus Aranha, de Souza Sá, Lúvia, Dutra, Scheila Anelise Pereira, de Oliveira, Hugo Mendes, Soligo, Thiago, Martins, Maurício Laterça, Mouriño, José Luiz Pedreira
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-08-2024; Springer Nature B.V
• Subjects: Bacillus; Biomedical and Life Sciences; Feed additives; Immunology; Intestine; Juveniles; Life Sciences; Metagenomics; Microbiomes; Mucus; Oreochromis niloticus; Probiotics; Species richness; Tilapia; Veterinary Medicine/Veterinary Science; Zoology; Metagenomics; α-diversity; Haematology; Immunology; Microbiology; Aeromonas
• ISSN: 0165-7380; 1573-7446; 1573-7446
• DOI: 10.1007/s11259-024-10412-1

The study evaluated dietary supplementation with a feed additive composed of multi-strain
Bacillus
for Nile tilapia
Oreochromis niloticus
. In vitro and in vivo assays employing culture-based microbiological methods and metagenomics were performed. Additionally, the study assessed the haemato-immunology, intestinal microbiome, and growth performance of the animals. For this, 30 juvenile Nile tilapia were used in the in vitro assay and 180 (60 + 120) in the in vivo assays. In the in vitro assay, we found evidence of adhesion of the probiotic bacteria to the intestinal mucus of fish, corroborated in the 15-day in vivo assay, in which the count of
B. licheniformis
was significantly higher in fish fed with probiotic when compared to fish of the control group. Furthermore, in the 50-day in vivo trial, a metagenomic analysis provided evidence for the modulation of the intestine microbiome of Nile tilapia by dietary supplementation of the probiotic. In addition, there was an increase in species richness, higher abundance of potentially probiotic autochthonous species and a lower abundance of
Aeromonas
sp. when the animals were fed the supplemented diet. Finally, no significant differences were observed in growth performance and haemato-immunological analyses, suggesting no harm to fish health when the product was supplemented for 15 and 50 days. The in vitro results indicate that the multi-strain probiotics were able to adhere to the intestinal mucus of Nile tilapia. Additionally, a modulation of the intestinal microbiome was evidenced in the in vivo assay.