The effect of feeding the leucine metabolite beta-hydroxy-beta-methylbutyrate (HMB) on cell-mediated immunity and protection against Yersinia ruckeri in pikeperch (Sander lucioperca)
2005
Siwicki, A.K. | Zakes, Z. | Fuller, J.C. Jr | Nissen, S. | Trapkowska, S. | Glabski, E. | Kazun, K. | Kowalska, A. | Terech-Majewska, E.
The present study examined the influence of leucine metabolite beta-hydroxy-beta-methylbutyrate (HMB), a natural product HMB, on nonspecific cell-mediated defence mechanisms and protection against enteric redmouth disease (ERM) in pikeperch (Sander lucioperca). beta-hydroxy-beta-methylbutyrate was fed in a pelletted ration at 50 mg kg(-1) of the feed for 8 weeks. The phagocytic ability and potential killing activity of blood and pronephric phagocytes were examined in HMB- and control-fed fish before and after 8 weeks of feeding HMB. Simultaneously, the proliferative response of blood and pronephric lymphocytes stimulated by mitogens concanavaline A and lipopolisaccharide were examined in experimental and control groups. Following 8 weeks of HMB feeding, a challenge test was performed by injecting the fish with live pathogenic bacteria Yersinia ruckeri. beta-hydroxy-beta-methylbutyrate applied in the diet for 8 weeks prompted a statistically significant (P < 0.05) increase in phagocytic ability and potential killing activity of the blood and pronephric phagocytes and the proliferative response of blood and pronephric lymphocytes. The changes in these mechanisms correlated with protection against Y. ruckeri, the ERM pathogen. The results showed that feeding HMB increased the nonspecific cell-mediated defence mechanisms and protection against ERM by reducing cumulative mortality (30%) following the challenge with pathogenic bacteria. Future studies will include determination of optimal doses and protocols of oral application of HMB to maximize the immunomodulatory effects and protection against viral diseases in intensive pikeperch culture.
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