Influence of two closely related probiotics on juvenile Senegalese sole ( Solea senegalensis, Kaup 1858) performance and protection against Photobacterium damselae subsp. piscicida

This study aimed to evaluate the influence of dietary administration of two probiotic strains belonging to Shewanella genus (Pdp11 and Pdp13), on juvenile Senegalese sole ( Solea senegalensis, Kaup 1858). Fish were fed three experimental diets for 2 months: two diets supplemented with 10 9 cfu g − 1 feed of Pdp11 and Pdp13 probiotics and one control group. At the end of the experiment, samples were collected to determine muscle and liver body composition and to study digestive tract and liver histology. A challenge with Photobacterium damselae subsp. piscicida (ip) was performed. Results showed a protection for fish receiving probiotic supplemented diets (Relative Percentage Survival 27.5 ± 2.5% for Pdp11; 32.5 ± 2.5% for Pdp13) and a better growth for control and Pdp11 diets. Higher total protein in muscle were detected for fish fed the probiotic diets and significant differences in muscle and liver fatty acid profiles were observed for Pdp11 and Pdp13 compared to the control. Light microscopy images from sole specimens fed the Pdp11 diet showed scarce presence of lipid droplets inside of enterocytes and hepatocytes while greater numbers were found in fish fed the control and Pdp13 diets. Finally, the DGGE technique results suggest that the addition of the probiotic strains of Shewanella genus highly influenced the intestinal microbiota of Senegalese sole specimens, although this effect may depend on the probiotic strain assayed.