Influence of dietaryl-carnitine on growth, biological traits and meat quality in Tilapia
This study was designed to determine whetherl-carnitine supplementation is necessary in a tilapia diet containing low-fish meal and a high lipid level, which is beneficial economically and for the environment. The effects of dietaryl-carnitine on the growth, body composition, blood traits and post-thaw drip from muscle in hybrid tilapia were investigated. Five isonitrogenous and isocaloric diets were fed to the fish with a mean body weight of 141.7 g for 168 days. The control diet contained fish meal as the major protein source with 7% lipid. Other diets contained 7% or 12% lipid, in which fish meal was largely replaced by plant proteins, and supplemented withl-carnitine or not. Results showed that supplemental dietaryl-carnitine did not affect the growth performance, feed efficiency or protein efficiency ratio, while the supplementation significantly reduced the mesenteric fat ratio. Whole body and muscle proximate compositions were unaltered by any dietary treatment. The total plasma lipid, triacylglycerol and cholesterol values of tilapia fed diets with alternative plant proteins were significantly lower than those of the control fish, whereas increasing the dietary lipid content increased the aforementioned blood traits. A decrease in plasma ammonia and an increase in urea were observed in dietaryl-carnitine-supplemented fish. Post-thaw drip from muscle was reduced in fish fed supplemental dietaryl-carnitine. The observations of this study revealed that neither the growth performance nor the feed utilization of hybrid tilapia was improved by a dietaryl-carnitine treatment, but that it did lead to a reduced mesenteric fat ratio, altered nitrogen metabolism and improved meat quality.
Document Type: Research Article
Affiliations: 1: Chupei Station, Freshwater Aquaculture Research Center, Fisheries Research Institute, Taiwan 2: Department of Aquaculture, National Taiwan Ocean University, Taiwan
Publication date: August 1, 2009