Effects of long-term administration of various dietary prebiotic supplements on the growth, immune cell activity and digestive tract histology of juvenile vimba (Vimba vimba).

Introduction: The experiment was set to determine the effects of long-term (55-day) use of three commercial prebiotics including Saccharomyces cerevisiae-derived ß-glucans and one including inulin on juvenile vimba (Vimba vimba) reared intensively under controlled conditions. Material and Methods: Six-month-old fish were fed commercial feed (Control group, n = 90), or the same feed supplemented with 0.02% Leiber Beta-S (BS group, n = 90), 0.20% Biolex MB40 (MB group, n = 90), 0.30% CeFi (CE group, n = 90) or 1.00% inulin Orafti GR (IN group, n = 90) for 55 days. Results: In the BS group, the final growth parameters were significantly lower than in the Control group, while the feed conversion ratio was significantly higher. No significant differences were found between any other group and the Control group in the respective parameters. The respiratory burst activity of the head-kidney phagocytes was significantly lower in all fish groups fed the prebiotic-supplemented diets compared to the Control group. The proliferative response of the head-kidney lymphocytes stimulated by concanavalin A was lower in the BS group than in the Control group, while in other groups this response was not affected. No significant differences were found in histopathological analyses of the digestive tract, liver or pancreas. Conclusion: The long-term supplementation of fish diets with prebiotics can negatively influence the growth, feed conversion, nonspecific cellular resistance and proliferative activity of the T lymphocytes of vimba juveniles.

Dietary administration of ß-1,3/1,6-glucan and Lactobacillus plantarum improves innate immune response and increases the number of intestine immune cells in roach (Rutilus rutilus).

BACKGROUND: The aim of the study has been to compare the effect of dietary supplementation of ß-1,3/1,6-glucan, Lactobacillus plantarum bacteria or their mixture on the growth performance, selected parameters of the immune system as well as the liver and intestinal histology of roach. Fish were fed for 14 days with four different diets, each treatment being carried out in triplicate. In control group, fish were fed dry commercial starter feed Aller Performa 2 (Aller Aqua, Denmark). The other experimental fish groups received the same commercial starter feed supplemented with: 1% ß-1,3/1,6-glucan (Leiber® Beta-S) in group G; 108 cfu L. plantarum g- 1 in group L; 1% ß-1,3/1,6-glucan + 108 cfu L. plantarum g- 1 in group G + L. The stimulating effect of the tested preparations was evaluated once the feeding with commercial feed exclusively was resumed and 2 weeks afterwards. RESULTS: No effect on the survivability and growth performance of the fish was observed in any of the groups. Supplementation of feed with ß-1,3/1,6-glucan improved (P < 0.05) selected parameters of innate humoral immunity and the pinocytotic activity of phagocytes. Increased respiratory burst activity of head kidney phagocytes (RBA) was observed in groups L and G + L (P < 0.05), and the effect persisted for 2 weeks after the commercial feed regime was resumed. An analogous tendency was determined for the killing activity of phagocytes (PKA) of the head kidney with respect to Aeromonas hydrophila, although this effect appeared only during the feed supplementation period. Supplying roach with ß-1,3/1,6-glucan, singly or with L. plantarum, had no effect (P > 0.05) on the proliferation of mitogen-activated lymphocytes. However, an increase in the number of CD3-positive cells and goblet cells was noticed in the digestive system of the L group fish (P < 0.05). CONCLUSIONS: The results show that feeding fish with added L. plantarum and ß-1,3/1,6-glucan stimulates the non-specific resistance mechanisms and raises the counts of intestinal immune cells. Synbiotic may help to control serious bacterial diseases and offer an alternative to antibiotics commonly used in fish farming, and its prolonged immunostimulatory effect could increase fish surviving after release to the natural environment.

Immune-enhancing Activity of Potential Probiotic Strains of Lactobacillus Plantarum in the Common Carp (Cyprinus Carpio) Fingerling.

INTRODUCTION: Immune-potentiating functions of Lactobacillus plantarum strains in the common carp were evaluated. MATERIAL AND METHODS: Fourteen days of feeding fish dry diet supplemented with the bacteria provided parameters of nonspecific humoral immunity (lysozyme, ceruloplasmin, γ-globulin, total protein levels, and serum bactericidal activity) and cellular immunity (pinocytosis, respiratory burst activity, and potential killing activity of organ phagocytes), as well as the proliferative response of organ lymphocytes stimulated with mitogens. The resistance of fish to infection with Aeromonas hydrophila was also determined. RESULTS: Dietary supplementation with L. plantarum had a substantial influence on the activity of organ phagocytes, especially the potential killing activity of head kidney cells. A significant increase in the proliferative activity of LPS-stimulated B lymphocytes and in the levels of γ-globulins and total protein was observed. The supplemented diet conveyed higher resistance than the control diet as the cumulative fish mortalities after infection with A. hydrophila were 65% and 85%, respectively. CONCLUSION: The results indicate that dietary supplementation with L. plantarum stimulates the antibacterial resistance of common carp and may reinforce defence against bacterial infections, but further studies need to be conducted.

Influence of ß-glucan Leiber(®)Beta-S on selected innate immunity parameters of European eel (Anguilla anguilla) in an intensive farming system.

Nutritional support plays an important role in promoting high cellular and humoral innate immunity activity and in preventing outbreaks of disease. The effects of ß-glucan Leiber(®)Beta-S dietary supplementation on selected nonspecific immune parameters in juvenile European eel (Anguilla anguilla) in an intensive culture system were studied. The fish were fed commercial pellets containing either 0 (control group) or 200 mg Leiber(®)Beta-S kg-1 of feed (glucan-fed group). After four and eight weeks of feeding, the levels of the following immunological parameters were measured: phagocyte respiratory burst activity, phagocyte potential killing activity, lymphocyte proliferation stimulated by concanavaline A or lipopolysaccharide, serum lysozyme activity, and total immunoglobulin (Ig) serum levels. After four and eight weeks of feeding 200 mg Leiber(®)Beta-S kg feed-1 the levels of all immune parameters were statistically significantly higher (p < 0.05) in the glucan-treated group than in the control group. After eight weeks of feeding the fish 200 mg Leiber(®)Beta-S kg feed-1 and after an additional eight weeks in ponds, the levels of all immune parameters, excluding lymphocyte proliferation stimulated by concanavaline A, were statistically significantly higher (p < 0.05) in the glucan-fed group than in the control group. These data suggest that feeding juvenile eel Leiber(®)Beta-S for four and eight weeks might improve innate immunity.

Influence of deltamethrin on nonspecific cellular and humoral defense mechanisms in rainbow trout (Oncorhynchus mykiss).

The influence of deltamethrin on the innate immunity in rainbow trout was examined. Fish were immersed in deltamethrin at doses of 1, 2, and 4 microg/L for 30 min. The results showed that deltamethrin at doses of 2 and 4 microg/L decreased phagocytic activity of spleen macrophages and proliferative response of pronephros lymphocytes at days 1, 2, and 5 after immersion. Deltamethrin at these doses decreased the lysozyme activity, total protein, and immunoglobulin levels in serum. The greatest immunosuppressive influence of deltamethrin at dose 4 microg/L was observed at the end of the study.