The effect of spray‐dried porcine plasma on gilthead seabream (Sparus aurata) intestinal microbiota

The effect of spray‐dried porcine plasma (SDPP) on the intestinal histological organization and autochthonous microbiota composition was evaluated in Sparus aurata. Fish were fed a basal diet (51 g/kg protein, 17 g/kg fat, 20.6 MJ/kg gross energy) and a diet containing 3 g/kg SDPP for 95 days (initial body weight, BW = 9.5 ± 0.2g, mean ± SD). The inclusion of SDPP promoted growth (p .05) between both groups. Intestinal microbiota was dominated by Proteobacteria (>85%) and Firmicutes (5%–12%), whereas Bacteroidetes never represented more than 1.5%. γ‐Proteobacteria, and Bacilli and Clostridia were the predominant classes. The short administration of SDPP (20 days) resulted in changes in microbiota diversity and richness associated with an increase in the sequences of the genus Lactobacillus and to a decrease in the genus Vibrio, whereas these changes were reverted at 95 days. Intestinal goblet cell density was not correlated to microbiota diversity and richness changes rather than to the immunostimulatory effect of the SDPP.info:eu-repo/semantics/acceptedVersio

Biofilm inhibition of pathogenic strains by extracellular products (ECPS) of Shewanella.sp Probiotic

Shewanella putrefaciens Pdp11 and V.proteolyticus DCF 12.2 are strains isolated by our research group. Recent works have been focused in the identification of substances as alternative of anti-biofilm methods and their implication in surface attachment inhibition. In this research, S. putrefaciens Pdp11 and V.proteolyticus DCF 12.2 have been cultured under different growth conditions (temperature, culture media and during 24 and 48 hours of incubation) and their extracellular products (ECPs) have been extracted and tested as potential postbiotics that affect the biofilm formation of several fish pathogenic strains. This assay results evidence that Pdp11_Pmix_2324 ECPs have showed the most impact in the biofilm formation of pathogenic strains. Therefore, ECPs secreted by Pdp11 and V.proteolyticus DCF 12.2 are implicated in the inhibition to adhesion of pathogens on surfaces.Proyecto de investigación PID2020-113637RB-C22. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Role of the capsule of Photobacterium damsela subsp. piscicida in protection against phagocytosis and killing by gilt-head seabream (Sparus aurata, L) macrophages

The role of the capsule in Photobacterium damsela subsp. piscicida (formerly Pasteurella piscicida) as a virulence factor was evaluated by determining the phagocytic and bactericidal activities of macrophages of gilt-head seabream. Five capsulated strains of P. damsela subsp. piscicida pathogenic for gilt-head seabream and one strain (EPOY-8803-II) described as noncapsulated and avirulent for this fish species were used in the study. Significant di#erences (P<0·025) in the percentages and index of phagocytosis between the EPOY-8803-II strain and capsulated strains were observed, the noncapsulated strain being phagocytosed to a greater degree (86·4%). The induction of the synthesis of a capsule in strain EPOY-8803-II produced a significant reduction in the phagocytic percentage and index for this strain. However, no significant di#erences (P<0·1) in the bactericidal activity of seabream macrophages were obtained between capsulated and noncapsulated strains. 1998 Academic Press Limite

Modified most-probable-number technique for the specific determination of Escherichia coli from environmental samples using a fluorogenic method

A specific and senstive modification of the most-probable-number (MPN) technique by addition of 4-methylumbelliferyl-β-D-glucuronide (MUG) to both presumptive and confirmatory media was performed. The use of this modification allows the precise determination of Escherichia coli from marine samples (seawater, sediment and shellfish) within 7 days compared to 10–12 days required by using of the standard methodology. No false-positive isolates for fluorescence reaction have been observed, although one E. coli strain fluorescent-positive on agar was isolated from nonfluorescent tubes. Klebsiella pneumoniae was the species most frequently detected from tubes with gas and fluorescence production and typical morphology on mFC agar, but failed on nutrient-MUG agar. Using a unifactorial variance analysis of the mean, fluorescence in tube and on agar has been determined as the factor which allows the detection of E. coli presence in the three sample types with high accuracy. The incorporation of MUG to the selective broth in the confirmatory test has been shown to avoid false-positive results due to shellfish tissue β-glucuronidase activity