|Hardy, Ronald - UNIV OF ID, HAGERMAN|
Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2007
Publication Date: February 9, 2008
Citation: Snyder, S.G., Gaylord, T.G., Barrows, F., Hardy, R.W. 2008. Carnosine supplementation to an all-plant protein diet for rainbow trout (Oncorhynchus mykiss). Book of Abstracts Aquaculture America Technical Abstract: Fishmeal may contain “unknown growth factors” that have yet to be identified for their physiological role. As fishmeal levels in rainbow trout (Oncorhynchus mykiss) feeds are reduced, the dietary loss of these compounds may contribute to growth reductions. One such compound, identified in fishmeal and other animal meals, is carnosine. Carnosine is a histidine-ß-alanine dipeptide found in muscle and nervous system tissue which has been demonstrated to have biological activity, but its physiological role is not well defined. A 9-week feeding trial was conducted comparing plant protein diets devoid of carnosine to a fishmeal diet. Four cooking extruded diets were formulated: 1) diet FM, containing 100% fishmeal protein, 2) diet SPI, replacing 100% of the fishmeal with soy protein isolate, 3) diet SPI+AA, diet SPI supplemented with 0.7 % met, 0.31% lys, 0.51% thr and 1.05% gly and 4) diet SPI+AA+CSN, diet SPI+AA supplemented with 0.39% carnosine (CSN). Feeding diet SPI resulted in significant differences in feed conversion ratio (FCR), percent gain and protein retention efficiency relative to fish fed diet FM. Feeding diets SPI+AA and SPI+AA+CSN resulted in FCR, percent gain and protein retention efficiency that were equivalent to fish fed diet FM. However, fish fed diets SPI, SPI+AA and SPI+AA+CSN resulted in reduced muscle ratio; and feeding diets SPI+AA and SPI+AA+CSN resulted in increased intraperitoneal fat relative to fish fed diet FM. In conclusion, it appears that carnosine did not significantly improve the 100% plant protein diets in regard to the measured growth characteristics above the amino acid supplemented treatments and other unidentified factors may be limiting in the diet causing the reductions in MR and elevated IPF.