Submitted to: Journal of Applied Aquaculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/18/2002
Publication Date: 6/21/2003
Citation: Whittington, R., Shoemaker, C.A., Lim, C.E., Klesius, P.H. 2003. Effects of dietary beta-hydroxy-beta-methylbutyrate on growth and survival of tilapia (Oreochromis niloticus) vaccinated against Streptococcus iniae. Journal of Applied Aquaculture. 3(4): 25-36. Interpretive Summary: A nutritional supplement, beta-hydroxy-beta-methylbutyrate (HMB), has resulted in increased disease resistance and growth in pigs and chickens. The purpose of this study was to evaluate the effect of feeding HMB to tilapia vaccinated with Streptococcus iniae killed vaccine and non-vaccinated on weight gain and disease resistance of tilapia in a controlled environment. Streptococcus iniae, a Gram positive bacterium, is responsible for $10 million in annual losses to the tilapia and hybrid striped bass industry in the United States. Results of this study showed that dietary HMB supplementation did not enhance antibody production in unvaccinated tilapia following challenge. Further, HMB supplementation for 14 days did not increase the growth or weight gain of tilapia fed HMB. Vaccination did protect tilapia from S. iniae regardless of dietary supplementation of HMB.
Technical Abstract: Beta-hydroxy-Beta-methylbutyrate (HMB), a leucine 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 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 non-vaccinated (controls). Tilapia were fed diets containing either 0, 12.5, 25, or 50 mg HMB/kg feed for 14 days. The mean daily growth rate and feed efficiency showed no significant (P>0.05) differences between the treatment groups. Dietary HMB supplementation did not enhance antibody production in unvaccinated tilapia. Dietary HMB supplementation did not enhance the survival of vaccinated tilapia following challenge injection with 1 x 108 CFU of S. iniae.