Effects of Dietary beta-Hydroxy-beta-Methylbutyrate on Growth and Survival of Nile Tilapia, Oreochromis niloticus, Vaccinated Against Streptococcus iniae

摘要

beta-hydroxy-beta-methylbutyrate (HMB), a leucinc catabolite, has been shown to cause increased disease resistance and growth in animal production. A vaccine produced from formalin killed bacteria and concentrated extracellular products of the ARS-98-60 Streptococcus iniae isolate has been used for the prevention of streptococcal disease in Nile tilapia, Oreochromis niloticus. In the present study, the effects of feeding HMB were determined in tilapia vaccinated by intraperitoneal (IP) injection of the S. iniae vaccine or unvaccinated (controls). Nile tilapia were fed diets containing either 0, 12.5, 25, or 50 mg HMB/kg diet for 14 days. The mean daily growth rate and feed efficiency showed no significant (P > 0.05) differences between the treatmentgroups. Dietary HMB supplementation did not enhance antibody production in unvaccinated Nile tilapia following challenge. Dietary HMB supplementation did not enhance the survival of vaccinated Nile tilapia following challenge injection with 1 X 10~8 CFUof S. iniae