Abstract
A feeding experiment was conducted in juvenile yellowtail to examine the effects of six graded levels of supplementation taurine (0, 1, 2, 3, 4 and 5%) to a soy protein concentrate based no-fishmeal diet for 10 weeks. The final body weight and tissue (red muscle and liver) taurine concentrations in fish fed 0% diet were the lowest among the dietary treatment but they were significantly improved by a diet supplemented with 1% taurine. Furthermore, a diet supplemented with 1% taurine improved tissue seine concentration, and hematocrit value. On the other hand, dietary supplementation level of 3% was necessary to improve plasma osmotic pressure and prevent green liver. Therefore, even though the tissue taurine concentration could be saturated with supplementation level at 1% (0.8% content in a diet), more than 3% taurine supplementation (2.4% content in a diet) to no-fishmeal diet is necessary to maintain the normal physiology of yellowtail used in this study. Yellowtail might not increase dietary taurine requirement even soybean protein is a dietary protein source.
