Main » 2009 » September » 17 » Disease resistance of Pacific white shrimp, Litopenaeus vannamei, following the dietary administration of a yeast culture food supplement
2:51 PM
Disease resistance of Pacific white shrimp, Litopenaeus vannamei, following the dietary administration of a yeast culture food supplement
Disease resistance of Pacific white shrimp, Litopenaeus vannamei, following the dietary administration of a yeast culture food supplement
Joseph E. Burgents, Karen G. Burnett * , Louis E. Burnett Grice Marine Laboratory, College of Charleston, 205 Fort Johnson Road, Charleston, SC 29412, USA Received 19 February 2003; received in revised form 20 August 2003; accepted 2 September 2003 Aquaculture 231 (2004) 1 –8 D 2004 Elsevier B.V. All rights reserved.
Abstract
A yeast culture feed supplement (Diamond V XP Yeast CultureR, Diamond V Mills, Cedar Rapids, Iowa [IA]) was assessed for its impact on disease resistance in the Pacific white shrimp, Litopenaeus vannamei. Animals were fed a standard shrimp pellet diet supplemented with 0% (control with 1% grain carrier), 0.5% (with 0.5% carrier), or 1.0% XP daily for 4 weeks. To assess resistance to bacterial disease, at 1-week intervals 21 shrimp (0.5 –2.5 g) from each test diet were injected intramuscularly with an LD50 dose (2.0 10 5/g body weight) of a gram-negative shrimp pathogen, Vibrio sp. 90-69B3. Survival was monitored every 4 h for 48-h post injection. Each week, three independent bacterial challenges were performed for each diet and the results expressed as the mean percent survival Fstandard error (S.E.). A two-way analysis of variance (ANOVA) showed a significant effect of diet ( p = 0.003, df = 31), but not duration of feeding, on survival. A one-way ANOVA showed no differences among the treatment groups after 1 or 2 weeks. After 3 weeks, the mean survival of 1% XP-fed shrimp (74.2 F1.4%) was significantly higher than that of controls (42.9 F5.5%), while mean survival of shrimp fed 0.5% XP (54.8 F11.9%) was not significantly different from controls. After 4 weeks, mean survival of 1.0% XP-fed shrimp (63.4 F8.8%) remained higher than that of controls but the difference was not significant ( p = 0.07). An insufficient number of animals were available from the 0.5% XP-fed group to perform bacterial challenges at this timepoint. Mean survival of control shrimp declined significantly over the 4 weeks of study (slope of linear regression p 0, p = 0.005, df = 11), but no decline was observed in animals fed the 0.5% or 1.0% XP diets. After 4 weeks L. vannamei fed standard shrimp pellets, 0% XP control, or 1.0% XP diets showed no significant differences in weight, suggesting that the changes in disease resistance did not correlate with changes in growth rate among the treatment groups. These results indicate that dietary administration of Diamond V XP Yeast CultureR can protect shrimp against a decline in resistance to bacterial disease.
