Influence of probiotic and prebiotic supplementation on intestinal microbiota and resistance to Edwardsiella ictaluri infection in channel catfish (Ictalurus punctatus) following florfenicol administration.

Enteric septicemia of catfish (ESC), caused by the gram-negative enteric bacteria Edwardsiella ictaluri, is a significant threat to catfish aquaculture in the southeastern United States. Antibiotic intervention can reduce mortality; however, antibiotic use results in an imbalance, or dysbiosis, of the gut microbiota, which may increase susceptibility of otherwise healthy fish to enteric infections. Herein, recovery of the intestinal microbiota and survivability of channel catfish in response to ESC challenge was evaluated following a 10-day course of florfenicol and subsequent probiotic or prebiotic supplementation. Following completion of florfenicol therapy, fish were transitioned to a basal diet or diets supplemented with a probiotic or prebiotic for the remainder of the study. Digesta was collected on Days 0, 4, 8 and 12, beginning on the first day after cessation of antibiotic treatment, and gut microbiota was characterized by Illumina sequencing of the 16S rRNA gene (V4 region). Remaining fish were challenged with E. ictaluri and monitored for 32 days post-challenge. Florfenicol administration resulted in dysbiosis characterized by inflated microbial diversity, which began to recover in terms of diversity and composition 4 days after cessation of florfenicol administration. Fish fed the probiotic diet had higher survival in response to ESC challenge than the prebiotic (p = .019) and negative control (p = .029) groups.

Dietary Supplementation of a Commercial Prebiotic, Probiotic and Their Combination Affected Growth Performance and Transient Intestinal Microbiota of Red Drum (Sciaenops ocellatus L.).

In the present study, the potential synergism between beneficial lactic acid bacteria (Pediococcus acidilactici) contained in a probiotic and a mixture of fermentable complex carbohydrates and autolyzed brewer's yeast (or prebiotic) were explored in red drum. Four experimental diets were formulated from practical ingredients, and the basal diet was supplemented with either probiotic, prebiotic, or both supplements. Red drum juveniles (~5.5 g) were offered the four experimental diets for 56 days, and at the end of the feeding trial fish fed diets supplemented with probiotic had significantly better weight gain than those fed the non-supplemented diets, and higher protein content in their whole-body composition. Transient intestinal microbiome alpha and beta diversity were significantly affected by the dietary treatments. Interestingly, a higher relative abundance of the lactic acid genus Pediococcus was observed for fish fed diets supplemented with the prebiotic. A higher relative abundance was also observed for the predicted functions of the microbial metagenome, and many of these pathways involved the biosynthesis of essential amino acids, vitamins, and nucleotides. Even though no potential synergistic effect was observed, the individual inclusion of these prebiotic and probiotic supplements positively affected the intestinal health and growth performance of red drum, respectively.

Novel association of Psychrobacter and Pseudomonas with malodour in bloodhound dogs, and the effects of a topical product composed of essential oils and plant-derived essential fatty acids in a randomized, blinded, placebo-controlled study.

BACKGROUND: The pathogenesis and treatment of cutaneous malodour in dogs have not been investigated previously. Staphylococcus and Corynebacterium spp. are associated with human axillary malodour. HYPOTHESIS: Staphylococcus and Corynebacterium spp. are associated with cutaneous malodour in dogs, and treatment with a topical essential oil-based product will improve malodour and reduce the abundance of odour-causing bacteria. ANIMALS: Twenty seven bloodhound dogs from a south Texas boarding facility were enrolled in this study. METHODS AND MATERIALS: Skin swabs were taken from the axilla and dorsum of 27 dogs at initiation of the study. Mean malodour scores were used to assign dogs to control or malodour groups. The malodourous dogs were randomly assigned to a treatment or placebo group, received four weekly topical applications of the spot-on or placebo, and samples were recollected. Next-generation sequencing (NGS) and real-time quantitative PCR (qPCR) were performed on all swabs. RESULTS: Psychrobacter and Pseudomonas spp. were significantly more abundant (P < 0.001, P = 0.006; respectively), and overall bacterial diversity was reduced (P = 0.0384) on the skin of malodourous dogs. Staphylococcus and Corynebacterium spp. were not associated with malodour. The topical essential oil-based product significantly (P = 0.0078) improved malodour in the treatment group and shifted their bacterial community structure. CONCLUSIONS AND CLINICAL IMPORTANCE: A novel association of bacterial genera with malodour in bloodhound dogs, identified by NGS, highlights future targets for odour control. The topical treatment significantly reduced malodour. The interaction between the topical treatment and cutaneous microbiota should be further investigated and may be useful in other dermatological conditions involving microbiota.