Effect of Dietary Administration of the b-Hydroxy-b- Methylbutyrate (HMB) on the Innate Immunity and Protection against Aeromonas Septicaemia in European Catfish (Silurus Glanis) Fingerlings - Abstract
The present study examined the influence of leucine metabolite ?-hydroxy-?-methylbutyrate (HMB) on the nonspecific cellular and humoral defence mechanisms in european catfish (Silurus glanis). The fish were fed a commercial feed with 50 mg or 100 mg HMB kg-1 feed per day (HMB-50 or HMB-100) for 4 weeks. The control group of fish was fed pellets without HMB (control group). After feeding HMB, 50 healthy european catfish of approximately 40 g from each group were anaesthetised and blood was drawn from the caudal vein into heparinized syringes. Also the pronephros and spleen of each fish was removed aseptically and single cells suspension were obtained for isolating individual cells using either a Gradisol (Polfa) or Percoll (Pharmacia) gradient. A disease challenge test using Aeromonas hydrophila were conducted after 4 weeks of feeding. Briefly, 100 fish from each group were each given a single intraperitoneal injection of a 48 h growth of A. hydrophila (0.2 ml). Mortalities were tabulated and the presence of pathogens was confirmed by isolation from the kidney. The results of this experimental study showed that HMB at a dose of 50 and 100 mgkg-1 feed per day statistically stimulated the non-specific cellular and humoral defence mechanisms and protection against Aeromonas septicaemia in european catfish.