Microbiota composition and intestinal integrity remain unaltered after the inclusion of hydrolysed Nannochloropsis gaditana in Sparus aurata diet.

The use of lysed microalgae in the diet of carnivorous fish can increase the bioavailability of proteins and bioactive compounds, such as unsaturated fatty acids or vitamins in the digestive tract. These are essential molecules for the proper physiological development of fish in aquaculture. However, some antinutritional components and other undesirable molecules can be released from an excess of microalgae supplied, compromising the integrity of the intestine. The inclusion of small amounts of hydrolized microalgae in the fish diet can be a good strategy to avoid negative effects, improving the availability of beneficial compounds. Nannochloropsis gaditana is an interesting microalgae as it contains nutraceuticals. Previous studies reported beneficial effects after its inclusion in the diet of Sparus aurata, a widely cultured species in Europe and in all Mediterranean countries. However, administration of raw microalgae can produce intestinal inflammation, increased intestinal permeability, bacterial translocation and disturbance of digestion and absorption processes. The aim of this study was to evaluate changes in the intestinal microbiota and barrier stability of S. aurata fed with low inclusion (5%) hydrolysed N. gaditana. Intestinal microbiota was analyzed using Illumina MiSeq technology and libraries were constructed using variable regions V3-V4 of 16S rDNA molecules. Analysis were based in the identification, quantification and comparison of sequences. The predictive intestinal microbial functionality was analyzed with PICRUSt software. The results determined that the intestinal microbiota bacterial composition and the predictive intestinal microbiota functionality did not change statistically after the inclusion of N. gaditana on the diet. The study of gene expression showed that genes involved in intestinal permeability and integrity were not altered in fish treated with the experimental diet. The potential functionality and bacterial taxonomic composition of the intestinal microbiota, and the expression of integrity and permeability genes in the intestine of the carnivorous fish S. aurata were not affected by the inclusion of hydrolysed 5% N. gaditana microalgae.

La composición de la microbiota duodenal en niños con enfermedad celíaca activa está influenciada por el grado de enteropatía / The duodenal microbiota composition in children with active coeliac disease is influenced by the degree of enteropathy

OBJETIVOS: Comprobar diferencias en la microbiota duodenal al diagnóstico de la enfermedad celíaca (EC) en relación con un grupo control. MATERIAL Y MÉTODOS: Se obtuvieron muestras de biopsias duodenales en 11 pacientes con EC al diagnóstico y en 6 controles. Se analizó la microbiota duodenal total así como la perteneciente al género Lactobacillus mediante la técnica molecular PCR-electroforesis en gel con gradiente desnaturalizante (DGGE). Los patrones de bandas obtenidos en los geles resultantes fueron analizados para determinar las diferencias presentes entre la microbiota de pacientes con EC y de los controles (FPQuest 4.5), mientras que los índices ecológicos (riqueza, diversidad y habitabilidad) fueron calculados con el programa Past versión 2.17. RESULTADOS: La microbiota intestinal de los individuos con histología Marsh 3c presentó similitud del 98% y fue diferente del resto de pacientes celíacos. Las principales diferencias se obtuvieron en los índices ecológicos pertenecientes al género Lactobacillus, con importante reducción de especies en los celíacos respecto al grupo control (riqueza, diversidad y habitabilidad). En los pacientes con EC las bandas principalmente fueron catalogadas con las especies Streptococcus, Bacteroides y E.coli. En los controles las bandas predominantes fueron Bifidobacterium, Acinetobacter y Lactobacillus; sin embargo, los Streptococcus y Bacteroides fueron más bajos. CONCLUSIONES: Los índices ecológicos aplicados al género Lactobacillus fueron significativamente reducidos en los pacientes celíacos. Los casos con mayor afectación histológica presentaron una microbiota duodenal similar

OBJECTIVES: To establish whether the duodenal mucosa microbiota of children with active coeliac disease (CD) and healthy controls (HC) differ in composition and biodiversity. MATERIAL AND METHODS: Samples of duodenal biopsies in 11 CD patients were obtained at diagnosis, and in 6 HC who were investigated for functional intestinal disorders of non-CD origin. Total duodenal microbiota and the belonging to the genus Lactobacillus using PCR-denaturing gradient gel electrophoresis (DGGE) were analysed. The banding patterns obtained in the resulting gels were analysed to determine the differences between the microbiota of CD patients and HC (FPQuest 4.5) while environmental indexes (richness, diversity and habitability) were calculated with the Past version 2.17 program. RESULTS: The intestinal microbiota of patients with Marsh 3c lesion showed similarity of 98% and differs from other CD patients with other type of histologic lesion as Marsh3a, Marsh3b and Marsh2. The main differences were obtained in ecological indexes belonging to the genusLactobacillus, with significant richness, diversity and habitability reduction in CD patients. In CD bands were categorized primarily with Streptococcus, Bacteroides and E.coli species. In HC the predominant bands were Bifidobacterium, Lactobacillus and Acinetobacter, though theStreptococcus and Bacteroides were lower. CONCLUSIONS: The celiac patients with major histological affectation presented a similar microbiota duodenal. The ecological indexes applied to the genus Lactobacillus were significantly reduced in CD

[The duodenal microbiota composition in children with active coeliac disease is influenced by the degree of enteropathy]. / La composición de la microbiota duodenal en niños con enfermedad celíaca activa está influenciada por el grado de enteropatía.

OBJECTIVES: To establish whether the duodenal mucosa microbiota of children with active coeliac disease (CD) and healthy controls (HC) differ in composition and biodiversity. MATERIAL AND METHODS: Samples of duodenal biopsies in 11 CD patients were obtained at diagnosis, and in 6 HC who were investigated for functional intestinal disorders of non-CD origin. Total duodenal microbiota and the belonging to the genus Lactobacillus using PCR-denaturing gradient gel electrophoresis (DGGE) were analysed. The banding patterns obtained in the resulting gels were analysed to determine the differences between the microbiota of CD patients and HC (FPQuest 4.5) while environmental indexes (richness, diversity and habitability) were calculated with the Past version 2.17 program. RESULTS: The intestinal microbiota of patients with Marsh 3c lesion showed similarity of 98% and differs from other CD patients with other type of histologic lesion as Marsh3a, Marsh3b and Marsh2. The main differences were obtained in ecological indexes belonging to the genus Lactobacillus, with significant richness, diversity and habitability reduction in CD patients. In CD bands were categorized primarily with Streptococcus, Bacteroides and E.coli species. In HC the predominant bands were Bifidobacterium, Lactobacillus and Acinetobacter, though the Streptococcus and Bacteroides were lower. CONCLUSIONS: The celiac patients with major histological affectation presented a similar microbiota duodenal. The ecological indexes applied to the genus Lactobacillus were significantly reduced in CD.

Dietary administration of the probiotic SpPdp11: Effects on the intestinal microbiota and immune-related gene expression of farmed Solea senegalensis treated with oxytetracycline.

Few antimicrobials are currently authorised in the aquaculture industry to treat infectious diseases. Among them, oxytetracycline (OTC) is one of the first-choice drugs for nearly all bacterial diseases. The objective of this study was to evaluate the effect of the dietary administration of OTC both alone and jointly with the probiotic Shewanella putrefaciens Pdp11 (SpPdp11) on the intestinal microbiota and hepatic expression of genes related to immunity in Senegalese sole (Solea senegalensis) juveniles. The results demonstrated that the richness and diversity of the intestinal microbiota of fish treated with OTC decreased compared with those of the control group but that these effects were lessened by the simultaneous administration of SpPdp11. In addition, specimens that received OTC and SpPdp11 jointly showed a decreased intensity of the Denaturing Gradient Gel Electrophoresis (DGGE) bands related to Vibrio genus and the presence of DGGE bands related to Lactobacillus and Shewanella genera. The relationship among the intestinal microbiota of fish fed with control and OTC diets and the expression of the NADPH oxidase and CASPASE-6 genes was demonstrated by a Principal Components Analysis (PCA) carried out in this study. In contrast, a close relationship between the transcription of genes, such as NKEF, IGF-ß, HSP70 and GP96, and the DGGE bands of fish treated jointly with OTC and SpPdp11 was observed in the PCA study. In summary, the results obtained in this study demonstrate that the administration of OTC results in the up-regulation of genes related to apoptosis but that the joint administration of OTC and S. putrefaciens Pdp11 increases the transcription of genes related to antiapoptotic effects and oxidative stress regulation. Further, a clear relationship between these changes and those detected in the intestinal microbiota is established.

The treatment with the probiotic Shewanella putrefaciens Pdp11 of specimens of Solea senegalensis exposed to high stocking densities to enhance their resistance to disease.

Aquaculture industry exposes fish to acute stress events, such as high stocking density, and a link between stress and higher susceptibility to diseases has been concluded. Several studies have demonstrated increased stress tolerance of fish treated with probiotics, but the mechanisms involved have not been elucidated. Shewanella putrefaciens Pdp11 is a strain isolated from healthy gilthead seabream (Sparus aurata L.) and it is considered as probiotics. The aim of this study was to evaluate the effect of the dietary administration of this probiotics on the stress tolerance of Solea senegalensis specimens farmed under high stocking density (PHD) compared to a group fed a commercial diet and farmed under the same conditions (CHD). In addition, during the experiment, a natural infectious outbreak due to Vibrio species affected fish farmed under crowding conditions. Changes in the microbiota and histology of intestine and in the transcription of immune response genes were evaluated at 19 and 30 days of the experiment. Mortality was observed after 9 days of the beginning of the experiment in CHD and PHD groups, it being higher in the CHD group. Fish farmed under crowding stress showed reduced expression of genes at 19 day probiotic feeding. On the contrary, a significant increase in immune related gene expression was detected in CHD fish at 30 day, whereas the gene expression in fish from PHD group was very similar to that showed in specimens fed and farmed with the conventional conditions. In addition, the dietary administration of S. putrefaciens Pdp11 produced an important modulation of the intestinal microbiota, which was significantly correlated with the high number of goblet cells detected in fish fed the probiotic diet.

Characterization of Vibrio harveyi strains recovered from diseased farmed Senegalese sole (Solea senegalensis).

AIM: To characterize 16 Vibrio harveyi strains isolated from different epizootic outbreaks affecting farmed Senegalese sole. MATERIALS AND RESULTS: The Vibrio harveyi strains tested have broad phenotypic diversity based on their biochemical and exoenzymatic patterns, outer membrane proteins (OMP), extracellular product (ECP) patterns and presence of prophages. Lethal dose 50 (LD(50)) of the strains and in vitro antagonism tests with two probiotic strains were also determined. The OMP analysis revealed three different patterns (A, M and V). The electrophoretic analysis of the ECP showed two different groups. All strains considered virulent based on their LD(50) exhibited the same protein pattern in their ECP (pattern I), while all nonvirulent strains showed a different profile (pattern II). About 32% of the tested strains were positive for prophages, although a clear relationship between virulence and the presence of prophages has not been established. CONCLUSIONS: The results obtained have shown differences between virulent and avirulent strains isolated from diseased farmed Senegalese sole based on the protein patterns of their ECP. However, a clear relationship between virulence and presence of prophages has not been established. SIGNIFICANCE AND IMPACT OF THE STUDY: The differences observed between virulent and nonvirulent strains could be used to design prophylactic strategies against diseases caused by V. harveyi in farmed Senegalese sole.