Changes in intestinal microbiota, immune- and stress-related transcript levels in Senegalese sole (Solea senegalensis) fed plant ingredient diets intercropped with probiotics or immunostimulants

• Published in: Aquaculture
• Main Authors: Batista S., Ozório R.O.A., Kollias S., Dhanasiri A.K., Lokesh J., Kiron V., Valente L.M.P., Fernandes J.M.O.
• Other Authors: CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2016
• Subjects: Nordland; University of Nordland
• Online Access: https://hdl.handle.net/10216/120279; https://doi.org/10.1016/j.aquaculture.2016.03.002

Senegalese sole (Solea senegalensis) is a highly valued flatfish that grows well with diets containing plant ingredients but their effects on immune competence is still a matter of debate. The current study aimed to examine changes in innate immune parameters and gut microbiota in Senegalese sole fed with 35% or 72% of plant ingredients with or without probiotic or yeast supplementation. Overall, fish fed diets with 72% of plant ingredients showed lower transcript levels of key immune- and stress-related genes in distal intestine, rectum and head-kidney than the 35% diets. In particular, hsp90b mRNA levels in distal intestine were down-regulated by 70% and 60% with the use of high content of plant ingredients in the diet containing the multispecies probiotic and autolyzed yeast, respectively. Denaturing gradient gel electrophoresis showed lower similarity values for distal intestine than rectum. Also fish fed high content of plant ingredients displayed lower similarity values, pointing to a difference in the microbial populations between fish fed different plant ingredient contents on the diet. Our data revealed that inclusion of plant ingredients was associated with differences in gene expression and a more diverse microbiota profile but without a significant effect on growth performance. Moreover, probiotic supplementation resulted in up-regulation of hsp90b, gpx, cat and apoa1 transcript levels in distal intestine concomitantly with a growth rate reduction compared to non-supplemented fish. Statement of relevance: There is an increasing trend in the aquaculture industry to replace fishmeal for plant ingredients, as a means of promoting sustainability of the industry. This paper contributes significantly to our limited knowledge of how plant ingredients and supplements affect gut microbiota and immunocompetence. © 2016 Elsevier S. M. G. Batista is supported by FCT — SFRH/BD/76668/2011. This work was also supported by the PROBIOSOLEA Project with the financial support of Quadro de Referência Estratégico Nacional — QREN and Programa Operacional Regional do Norte — ON2 (Ref. no. 13551), supported by the European fund for regional development FEDER. We would like to thank to CIIMAR/ICBAS (UP) and FBA (University of Nordland) for the use of the facilities and equipment and for technical support.