galactomannan and Fish-Diseases

European sea bass were fed four low FM/FO (10%/6%) diets containing galactomannan oligosaccharides (GMOS), a mixture of garlic oil and labiatae plants oils (PHYTO), or a combination of both functional products (GMOSPHYTO) for 63 days before exposing the fish to an intestinal Vibrio anguillarum infection combined with crowding stress. In order to evaluate functional diets efficacy in terms of gut health maintenance, structural, cellular, and immune intestinal status were evaluated by optical and electron microscopy and gene expression analyses. A semi-automated software was adapted to determine variations in goblet cell area and mucosal mucus coverage during the challenge test. Feeding with functional diets did not affect growth performance; however, PHYTO and GMOS dietary inclusion reduced European sea bass susceptibility to V. anguillarum after 7 days of challenge testing. Rectum (post-ileorectal valve) showed longer (p = 0.001) folds than posterior gut (pre-ileorectal valve), whereas posterior gut had thicker submucosa (p = 0.001) and higher mucus coverage as a result of an increased cell density than rectum. Functional diets did not affect mucosal fold length or the grade of granulocytes and lymphocytes infiltration in either intestinal segment. However, the posterior gut fold area covered by goblet cells was smaller in fish fed GMOS (F = 14.53; p = 0.001) and PHYTO (F = 5.52; p = 0.019) than for the other diets. PHYTO (F = 3.95; p = 0.049) reduced posterior gut goblet cell size and increased rodlet cell density (F = 3.604; p = 0.068). Dietary GMOS reduced submucosal thickness (F = 51.31; p = 0.001) and increased rodlet cell density (F = 3.604; p = 0.068) in rectum. Structural TEM analyses revealed a normal intestinal morphological pattern, but the use of GMOS increased rectum microvilli length, whereas the use of PHYTO increased (p≤0.10) Ocln, N-Cad and Cad-17 posterior gut gene expression. After bacterial intestinal inoculation, posterior gut of fish fed PHYTO responded in a more controlled and belated way in terms of goblet cell size and mucus coverage in comparison to other treatments. For rectum, the pattern of response was similar for all dietary treatments, however fish fed GMOS maintained goblet cell size along the challenge test.

Topics: Animals; Bass; Cell Size; Dietary Supplements; Fish Diseases; Fish Proteins; Functional Food; Galactose; Gene Expression Profiling; Gene Expression Regulation, Developmental; Intestinal Mucosa; Mannans; Oligosaccharides; Software; Vibrio

Protein-polysaccharide conjugate was prepared as a functional biopolymer using protein and polysaccharide via a Maillard-type reaction. Ovalbumin and lysozyme were conjugated with galactomannan under controlled heating and humidity conditions. The antioxidant effect of ovalbumin and the antimicrobial activity of lysozyme were enhanced by the glycosylation. The emulsifying properties of the egg protein were also significantly improved by the modification. The increase in lipid affinity due to the conjugation resulted in the enhancement of the radical scavenging ability of ovalbumin. The effectiveness of lysozyme and its glycosylated derivative in restricting the activity of a Gram-negative pathogen, Edwardsiella tarda in fish was also investigated.

Topics: Animals; Anti-Bacterial Agents; Antioxidants; Biopolymers; Carps; Crystallization; Edwardsiella; Electrophoresis, Polyacrylamide Gel; Emulsions; Fish Diseases; Galactose; In Vitro Techniques; Lethal Dose 50; Maillard Reaction; Mannans; Muramidase; Mutagens; Ovalbumin; Rats

The protective effect of lysozyme-galactomannan or lysozyme-palmitic acid conjugates orally administered to carp, Cyprinus carpio L. was investigated using a virulent strain of Gram-negative Edwardsiella tarda isolated from an infected fish. Lysozyme-galactomannan conjugate was prepared through controlled Maillard reaction. Lysozyme-palmitic acid conjugate was prepared through base-catalyzed ester exchange using N-hydroxysuccinimide ester of palmitic acid. The conjugates provided substantial protection to carp infected with a Gram-negative bacteria fish pathogen E. tarda NG 8104. Lytic activities of lysozyme conjugates with galactomannan and palmitic acid were about 80 and 71% of native lysozyme using Micrococcus lysodeikticus as a substrate. Feeding with lysozyme conjugates, for 8 days, significantly enhanced fish protection against E. tarda infection. The survival rate was 30% for lysozyme-galactomannan conjugate treated fish and 20% for lysozyme-palmitic acid conjugate treated fish after 6 days cultivation while all control fish died within 3 days. On the other hand, a recovery rate of 40% after 6 days was observed in the fish group that were fed lysozyme-palmitic acid conjugate 3 and 2 h before and after E. tarda challenge, respectively, and for 6 consecutive days. The results of this work show the possibility of utilizing lysozyme conjugates with galactomannan or palmitic acid as a therapeutic for infection in fish.

Topics: Animals; Anti-Bacterial Agents; Fish Diseases; Galactose; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Maillard Reaction; Mannans; Microbial Sensitivity Tests; Muramidase; Palmitic Acid; Time Factors; Virulence