Research in our laboratory is focused on nutrition and feeding of
different species of fish. We use growth trial to determine the
essential nutrient requirements of different species of fish including
white sturgeon, rainbow trout, Atlantic salmon, striped bass and hybrid
tilapia. Biochemical analyses, enzyme assays, histology and
histochemistry are used to evaluate the performance and to determine the
optimum feeding rates and nutrient requirements of these fish. Other
techniques such as oral tolerance tests, esophagus intubation, aorta
cannulation, urinary catheterization, and isotope tracing are used to
study the nutrient utilization by these fish. On going projects
includes: Carbohydrate utilization by Atlantic salmon, white sturgeon
and hybrid tilapia; Protein and lipid requirements and utilization by
and optimum feeding rate of sturgeon larvae; and Selenium requirement of
juvenile sturgeon.
By training, I am a fish nutritionist but I always consider fish
nutrition and toxicology as a continuum, from nutrient deficiency to
excess of unwanted contaminants or toxicants. Since 2000, we embark on a
new area of research, nutrition and toxicology, of Sacramento splittail.
The CalFed Bay-Delta Program funded us for five years (2000-2005) to use
a biomarker approach to study the chronic toxicity of environmental
contaminants in the Sacramento splittail. Recently, we used a combined
technique of esophagus intubation, aorta cannulation, and urinary
catheterization to study the 48-h toxicokinetics of L-selenomethionine
(SeMet) in sturgeon. We have completed a study on the competition of
intestinal uptake of SeMet and L-methionine using the everted gut sleeve
method and our combined technique in sturgeon. Future studies include
using brush boarder membrane vesicle, identifying and characterizing the
membrane bound PHE transport protein, and its gene expression to
determine the absorption rate and study the mechanism of
gastrointestinal uptake of SeMet in sturgeon.
We are funded currently (2007-2010) to study the quantitative
indicators and life history implications of environmental stress on
sturgeon. In this project we use the combined technique, gelatin capsule
feeding technique, and growth trail, respectively, to study the
short-term (48 h), intermediate-term (2-8 days), and long-term (8 weeks)
toxicokinetics of SeMet and/or methyl mercury (MeHg) in green and white
sturgeon. Furthermore, we are collaborating with our colleague, Dr.
Dietmar Kueltz, a stress proteomic expert, to study the key proteins and
pathways that are critical for the adaptive response of sturgeon when
expose to dietary SeMet alone or in combination with dietary MeHg as
well as salinity challenge and heat shock. We will use the tissue
microarray technique developed by Dr. Kueltz to study the critical
oxidative stress protein expression and localization in the sturgeon.
