A Tentative Study of the Effects of Heat-Inactivation of the Probiotic Strain Shewanella putrefaciens Pdp11 on Senegalese Sole (Solea senegalensis) Intestinal Microbiota and Immune Response

Abstract

Concerns about safety, applicability and functionality associated with live probiotic cells have led to consideration of the use of non-viable microorganisms, known as paraprobiotics. The present study evaluated the effects of dietary administration of heat-inactivated cells of the probiotic strain Shewanella putrefaciens Ppd11 on the intestinal microbiota and immune gene transcription in Solea senegalensis. Results obtained were evaluated and compared to those described after feeding with viable Pdp11 cells. S. senegalensis specimens were fed with basal (control) diet or supplemented with live or heat inactivated (60 °C, 1 h) probiotics diets for 45 days. Growth improvement was observed in the group receiving live probiotics compared to the control group, but not after feeding with a probiotic heat-inactivated diet. Regarding immune gene transcription, no changes were observed for tnfα, il-6, lys-c1, c7, hsp70, and hsp90aa in the intestinal samples based on the diet. On the contrary, hsp90ab, gp96, cd4, cd8, il-1β, and c3 transcription were modulated after probiotic supplementation, though no differences between viable and heat-inactivated probiotic supplemented diets were observed. Modulation of intestinal microbiota showed remarkable differences based on the viability of the probiotics. Thus, higher diversity in fish fed with live probiotic cells, jointly with increased Mycoplasmataceae and Spirochaetaceae to the detriment of Brevinemataceae, was detected. However, microbiota of fish receiving heat-inactivated probiotic cells showed decreased Mycoplasmataceae and increased Brevinemataceae and Vibrio genus abundance. In short, the results obtained indicate that the viable state of Pdp11 probiotic cells affects growth performance and modulation of S. senegalensis intestinal microbiota. On the contrary, minor changes were detected in the intestinal immune response, being similar for fish receiving both, viable and inactivated probiotic cell supplemented diets, when compared to the control diet.

Fish Microbiome Modulation and Convenient Storage of Aquafeeds When Supplemented with Vitamin K1

“…Present results showed that Proteobacteria and Gammaproteobacteria were the most abundant phylum and class, respectively. This is in agreement with Tapia-Paniagua et al [ 63 ] who found this phylum to be dominant in the anterior and posterior section of the digestive tract of Senegalese sole juveniles, although Domínguez-Maqueda et al [ 62 ] only report its dominance in the anterior section. Other phyla such as Bacteroidetes, Firmicutes, and Fusobacteria were detected with lower relative abundances in the present study, also reported to represent up to 90% of the intestinal microbiota of different fishes [ 26 ], suggesting that these taxa are involved in important functions of the host, such as digestion, absorption of nutrients and/or the immune response.…”

“…Previous studies about Senegalese sole microbiota have mainly focused on determining the effects of supplementation with probiotics, prebiotics, parabiotics, immunostimulants, algal extracts or physicochemical parameters in water [ 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ]. Present results showed that Proteobacteria and Gammaproteobacteria were the most abundant phylum and class, respectively.…”

Heat-Killed Lactiplantibacillus plantarum LRCC5314 Mitigates the Effects of Stress-Related Type 2 Diabetes in Mice via Gut Microbiome Modulation

“…Many studies related to postbiotics have been performed to explore their beneficial properties in cells, animals, and clinical trials [ 8 - 10 ]. The heat-killed form shows beneficial effects such as stimulation of the immune system in various diseases and modulation of the gut environment, which regulates anti-inflammatory, anti-obesogenic, and anti-hypertensive activities [ 11 , 12 ].…”

Draft Genome Sequence of Lactococcus lactis Subsp. cremoris WA2-67: A Promising Nisin-Producing Probiotic Strain Isolated from the Rearing Environment of a Spanish Rainbow Trout (Oncorhynchus mykiss, Walbaum) Farm

“…This temperature tolerance becomes even more significant when talking about probiotics for veterinary use as feed supplements and, within this sector, aquaculture is the most challenging market, due to the extreme temperatures that are reached during the processing of fish feed. In fact, although a multitude of solutions and technologies have been developed to minimize the impact that temperatures can have, not only on the probiotic microorganisms, but also on the nutrients themselves, the possession of intrinsic mechanisms that allow them to face diverse challenges broadens the possibilities of use [ 55 , 56 , 57 ]. In this regard, the finding of several genes involved in increased resistance to suboptimal temperature conditions, both heat and cold (such as molecular chaperones GroES and GroEL, and several CSP), supports the probiotic potential of L. cremoris WA2-67 [ 58 , 59 ].…”