The Effects of Nisin-Producing Lactococcus lactis Strain Used as Probiotic on Gilthead Sea Bream (Sparus aurata) Growth, Gut Microbiota, and Transcriptional Response

Frontiers in Marine Science

Alberto Giardini¹  Genciana Terova²  Federico Moroni²  Simona Rimoldi²  M. Carla Piazzon³  Jaume Pérez-Sánchez⁴  Josep Calduch-Giner⁴  Fernando Naya-Català⁴  Inés Martínez⁵  Fabio Brambilla⁶ 

[1] Centro Sperimentale del Latte S.r.l., Zelo Buon Persico, Italy;Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy;Fish Pathology, Institute of Aquaculture Torre de la Sal (IATS-CSIC), Castellón, Spain;Nutrigenomics and Fish Growth Endocrinology, Institute of Aquaculture Torre de la Sal (IATS-CSIC), Castellón, Spain;Sacco S.r.l., Cadorago, Italy;VRM S.r.l. Naturalleva, Cologna Veneta, Italy;

关键词: aquaculture;    gilthead sea bream;    probiotic;    Lactococcus lactis;    gut microbiota;    transcriptomic;   

DOI  :  10.3389/fmars.2021.659519

来源: DOAJ

【 摘 要 】

The present research tested the effects of dietary nisin-producing Lactococcus lactis on growth performance, feed utilization, intestinal morphology, transcriptional response, and microbiota in gilthead sea bream (Sparus aurata). A feeding trial was conducted with fish weighting 70–90 g. Fish were tagged with passive, integrated transponders and distributed in nine 500 L tanks with 40 fish each. Fish were fed for 12 weeks with either a control (diet A) or experimental diets (diets B and C) in triplicate (3 tanks/diet). Extruded pellets of diets B and C were supplemented with a low (2 × 109 CFU/kg) and a high (5 × 109 CFU/kg) dose of probiotic, respectively. No significant differences were found between groups for the feed conversion ratio or specific growth rates. However, the final body weight of fish fed diet C was significantly higher than the control group with intermediate values for fish fed diet B. Histological analysis conducted using a semi-quantitative scoring system showed that probiotic did not alter the morphology of the intestine and did not trigger inflammation. With regard to the transcriptomic response, a customized PCR array layout was designed to simultaneously profile a panel of 44 selected genes. Significant differences in the expression of key genes involved in innate and acquired immunity were detected between fish fed probiotic and control diets. To analyze the microbiota associated to the feeds and the gut autochthonous microbial communities, we used the Illumina MiSeq platform for sequencing the 16S rRNA gene and a metagenomics pipeline based on VSEARCH and RDP databases. The analysis of gut microbiota revealed a lack of colonization of the probiotic in the host’s intestinal mucosa. However, probiotic did modulate the fish gut microbiota, confirming that colonization is not always necessary to induce host modification. In fact, diets B and C were enriched with Actinomycetales, as compared to diet A, which instead showed a higher percentage of Pseudomonas, Sphyngomonas, and Lactobacillus genera. These results were confirmed by the clear separation of gut bacterial community of fish fed with the probiotic from the bacterial community of control fish group in the beta-diversity and PLS-DA (supervised partial least-squares discriminant analysis) analyses.

【 授权许可】

Unknown