Comparison between the intestinal microbiome of healthy fish and fish experimentally infected with Streptococcus agalactiae

Author(s)

Silva, Bruna Rafaela dos Santos ^[1] ; Derami, Mariana Silveira ^[1] ; Paixao, Douglas Alvaredo ^[2] ; Persinoti, Gabriela Felix ^[2] ; Dias da Silveira, Wanderley ^[1] ; Maluta, Renato Pariz ^[1]

Affiliation

^[1] Univ Estadual Campinas, Inst Biol, Dept Genet Evolucao Microbiol & Imunol, R Monteiro Lobato 255, BR-13083862 Campinas, SP - Brazil

^[2] Ctr Nacl Pesquisa Energia & Mat, Lab Nacl Biorrenovaveis LNBR, R Giuseppe Maximo Scolfaro 10000, BR-13083970 Campinas, SP - Brazil

• Document type: Journal article
• Source: AQUACULTURE RESEARCH; v. 51, n. 8, p. 3412-3420, AUG 2020.
• Web of Science Citations: 1

Abstract

Nile tilapia (Oreochromis niloticus) farming is an economic activity that is soaring in the whole world. Septicemia due to Streptococcus agalactiae is the main disease impacting fish farming. The aim of this study was to compare the gut microbiome of healthy animals and animals experimentally infected with S. agalactiae strain 21171A. The microbiome was established with 16S ribosomal DNA next-generation sequencing (NGS). One hundred Nile tilapias, with an average weight of 35 g, were distributed into two groups. Fifty fish from the challenged group were orally inoculated with 100 mu l of a bacterial solution containing 1.98 x 10(3) CFU/ml of S. agalactiae strain 21171A, while 50 controls were orally inoculated with sterile saline. After the experiment, 24 fish from the challenged group and 27 fish from the control group were analysed. For both groups, bacteria attached to the mucosa (M) and present in faeces (F) were analysed. The mean of the number of taxa identified in the infected group (M + F) (45.87 +/- 30.13) was lower than in the control (M + F) (67.70 +/- 21.10) (p < .01). Nineteen bacterial taxa were more abundant in faecal samples from the infected group when compared with the control group (p < .01). Thirty-nine taxa were associated with mucosa samples from the challenged group when compared to the control samples (p < .01). No OTU was associated with healthy samples. The results demonstrate that the infection with S. agalactiae reduces the variability of the gut microbiota. Moreover, some bacteria proliferate during the infection. (AU)

• FAPESP's process: 16/17421-7 - Comparison between the microbiomes of the respiratory tract of healthy chickens and chickens diagnosed with colibacillosis
• Grantee: Renato Pariz Maluta
• Support type: Research Grants - Young Investigators Grants
• FAPESP's process: 17/22288-7 - Comparison between the gut microbiome of healthy fish and fish experimentally infected with Streptococcus agalactiae
• Grantee: Bruna Rafaela dos Santos Silva
• Support type: Scholarships in Brazil - Master