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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATION OF NUTRITIONAL, GENETIC AND PHYSIOLOGICAL APPROACHES TO IMPROVE PRODUCTION EFFICIENCY OF RAINBOW TROUT Title: Evaluation of the ability of partially autolyzed yeast and Grobiotic-A to improve disease resistance in rainbow trout.

Authors
item Sealy, Wendy - UNIV OF ID, HAGERMAN, ID
item Barrows, Frederic
item Johansen, Katherine - FORMER ARS EMPLOYEE
item Overturf, Kenneth
item Lapatra, Scott - CLEAR SPRINGS FOODS, INC.
item Hardy, Ronald - UNIV OF ID, HAGERMAN, ID

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 10, 2006
Publication Date: September 17, 2007
Repository URL: http://riley.nal.usda.gov/nal_web/digi/submission.html
Citation: Sealy, W.M., Barrows, F., Johansen, K.A., Overturf, K.E., Lapatra, S.E., Hardy, R.W. 2007. Evaluation of the ability of partially autolyzed yeast and Grobiotic-A to improve disease resistance in rainbow trout.. North American Journal of Aquaculture.

Interpretive Summary: Due to the lack of approved aquaculture drugs to treat disease, the need for diets that are nutritionally complete and balanced is critical. In addition, any dietary supplement that can increase immunocompetence, and thus ward off disease, is vitally important for the continued expansion of the aquaculture industry. Components of plants and yeast, known as b-glucans, have been demosntrated to improve disease resistance in many species of animals. A study was conducted to determine the ability of partially autolyzed yeast and Grobiotic-A to improve immune response and disease resistance in rainbow trout Oncorhynchus mykiss. Experimental diets were prepared by adding partially autolyzed yeast or Grobiotic-A to a practical trout diet at the manufacturer-recommended level of 2%; the control was the same diet without supplementation. At the conclusion of the feeding trial fish were exposed to infectous hematopoietic necrosis virus (IHNV). Dietary inclusion of 2% partially autolyzed yeast or Grobiotic-A had no negative impacts on health or growth of rainbow trout. In contrast, although substantial variability was observed for immune response variables, use of 2% partially autolyzed yeast or Grobiotic-A produced striking improvements in survival of rainbow trout after experimental challenge with IHNV. Feeding either of these compounds may help in reducing the impact of this disease in trout production, without the use of drugs.

Technical Abstract: We evaluated the ability of partially autolyzed yeast and Grobiotic-A to improve immune response and disease resistance in rainbow trout Oncorhynchus mykiss. Experimental diets were prepared by adding partially autolyzed yeast or Grobiotic-A to a practical trout diet at the manufacturer-recommended level of 2%; the control was the same diet without supplementation. Rainbow trout (initial weight = approximately 14.3 g) were cultured in 145-L fiberglass tanks (50 fish/tank; 3 tanks/diet) in a freshwater flow-through system. Fish were hand-fed the diets to apparent satiation 3 times/d, 6 d/week for 9 weeks. At 3 and 9 weeks postweighing, fish were sampled to determine respiratory burst activity, plasma protein, total immunoglobulin and lysozyme, and tumor necrosis factor-alpha (TNF-a) expression. At the conclusion of the feeding trial (9 weeks), fish remaining after sampling were pooled by diet; one subsample was examined for the ability to respond humorally to infectious hematopoietic necrosis virus (IHNV), and another subsample was challenged by intraperitoneal injection with IHNV. Dietary inclusion of 2% partially autolyzed yeast or Grobiotic-A had no negative impacts on health or growth of rainbow trout. In contrast, although substantial variability was observed for immune response variables, use of 2% partially autolyzed yeast or Grobiotic-A produced striking improvements in survival of rainbow trout after experimental challenge with IHNV.

Last Modified: 11/28/2014
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