Effect of microalgae on intestinal inflammation triggered by soybean meal and bacterial infection in zebrafish

PLoS One. 2017 Nov 8;12(11):e0187696. doi: 10.1371/journal.pone.0187696. eCollection 2017.

Abstract

Soybean meal has been used in many commercial diets for farm fish; despite this component inducing intestinal inflammation. On the other hand, microalgae have increasingly been used as dietary supplements in fish feed. Nevertheless, the vast quantity of microalgae species means that many remain under- or unstudied, thus limiting wide scale commercial application. In this work, we evaluated the effects to zebrafish (Danio rerio) of including Tetraselmis sp (Ts); Phaeodactylum tricornutum (Pt); Chlorella sp (Ch); Nannochloropsis oculata (No); or Nannochloropsis gaditana (Ng) as additives in a soybean meal-based diet on intestinal inflammation and survival after Edwardsiella tarda infection. In larvae fed a soybean meal diet supplemented with Ts, Pt, Ch, or Ng, the quantity of neutrophils present in the intestine drastically decreased as compared to larvae fed only the soybean meal diet. Likewise, Ts or Ch supplements in soybean meal or fishmeal increased zebrafish survival by more than 20% after being challenged. In the case of Ts, the observed effect correlated with an increased number of neutrophils present at the infection site. These results suggest that the inclusion of Ts or Ch in fish diets could allow the use of SBM and at the same time improve performance against pathogen.

MeSH terms

  • Animal Feed / adverse effects*
  • Animal Feed / analysis
  • Animals
  • Bacterial Infections / immunology
  • Bacterial Infections / microbiology
  • Bacterial Infections / prevention & control*
  • Bacterial Infections / veterinary
  • Dietary Supplements / adverse effects
  • Edwardsiella tarda / growth & development
  • Edwardsiella tarda / pathogenicity
  • Fish Diseases / etiology
  • Fish Diseases / immunology
  • Fish Diseases / microbiology
  • Fish Diseases / prevention & control*
  • Glycine max / adverse effects*
  • Glycine max / immunology
  • Inflammation
  • Intestines / immunology*
  • Intestines / microbiology
  • Microalgae / chemistry*
  • Microalgae / immunology
  • Neutrophils / immunology
  • Zebrafish / immunology
  • Zebrafish / microbiology

Grants and funding

This work was supported by Fondo Nacional de Desarrollo Cientifico y Tecnologico [grant number 1171199] to CGF, http://www.conicyt.cl/fondecyt/sobre-fondecyt/que-es-fondecyt/; Direccion de Investigacion UNAB [grant number DI-1229-16/R] to CGF, http://investigacion.unab.cl/investigacion/oportunidades-de-financiamiento/; Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias [grant number 15110027] to CGF, http://www.incar.cl/; Fundación para la Innovación Agraria [grant number PYT 2016-0339] to NE, http://www.fia.cl/.