Silas S.O. Hung, Ph.D.

Silas Hung

Position Title
Professor Emeritus



  • CEGEP , General Science, MacDonald College, McGill University, 1970-72.
  • B.S., Food Biochemistry, MacDonald College, McGill University, 1972-75.
  • M.S., Nutrition, University of Guelph, 1975-77.
  • Ph.D., Nutrition, University of Guelph, 1977-80.

Research Interests

Research in my laboratory has been focused on nutrition and feeding of different species of fish. I used growth trial to determine the essential nutrient requirements and utilization in different species of fish including white sturgeon, rainbow trout, Atlantic salmon, striped bass and hybrid tilapia. Biochemical analyses, enzyme assays, histology and histochemistry, and a combined technique of stomach intubation, dorsal aorta cannulation, and urinary catheterization I developed were used to evaluate the performance and to determine the optimum feeding rates, nutrient requirements and utilization of these fish, respectively.

Since 2000, I embarked on a new area of research, toxicology, because I always consider nutrition and toxicology as a continuum, from nutrient deficiency to excess of unwanted contaminants or toxicants. In 2000-2005, I was funded by the CalFed Bay-Delta Program to study the chronic toxicity of environmental contaminants in the Sacramento splittail using a biomarker approach.  In 2007-2010, I was funded by CalFed Science Program to study the quantitative indicators and life history implications of environmental stress on white and green sturgeon.  In this project I used the combined technique and growth trail, respectively, to study the short-term (48 h) and long-term (8 weeks) toxicokinetics and histopathology, respectively, of selenomethionine and/or methyl mercury in green and white sturgeon. Modeling was also used to determine the toxicokinetics of selenomethionine and/or methyl mercury in white sturgeon. In 2012-2015 I was funded by the CDFG ERP to study the effects of nutritional status on environmental stress tolerance in green and white sturgeon.  In this project I subjected green and white sturgeon to salinity and heat stress after they were feed restricted for 2 or 4 weeks. I measured their physiological response to determine their tolerance to these two stresses.  Currently I am studying the metabolome of green and white sturgeon after they were feed restricted.

Graduate Groups

Animal Biology

Lab Members

Full listing

Recent Publications

Bakke, A.M., Tashjian, D.H., Wang, C.F., Lee, S.H., Bai, S.C., and Hung, S.S.O.  2010.  Competition between selenomethionine and methionine absorption in the intestinal tract of green sturgeon (Acipenser medirostris).  Aquatic Toxicology 96:62-69

Rigby, M.C., Deng, X., Grieb, T.M., Teh, S.J., and Hung, S.S.O. 2010. Effect Threshold for Selenium Toxicity in Juvenile Splittail, Pogonichthys macrolepidotus A.  Bulletin of Environmental Contamination and Toxicology. 84:76-79.

Lee, S.H., Lee, J.H., Bai, S.C., and Hung, S.S.O. 2010. Evaluation of the dietary toxic level of selenium (Se) in juvenile olive flounder, Paralichthys olivaceus.  Journal of the World Aquaculture Society 41:245-254.

Tian, L.X., Liu, Y.L., Hung, S.S.O., Deng, D.F., Yang, H.J., Niu, J., and Liang, G.Y.  2010.  Effect of feeding strategy and carbohydrate source on carbohydrate utilization by grass carp (Ctenopharyngodon idella).  American Journal of Agricultural and Biological Science 5:135-142.

Bae, J.-Y., Ok, I.-H., S. Lee, Hung, S.S.O., Min, T.S., and Bai, S.C.  2010.  Reevaluation of dietary methionine requirement by plasma methionine and ammonia concentrations in surgically modified rainbow trout, Oncorhynchus mykiss. Journal of Applied Ichthyology 27:887-891. 

Lee, J.W., De Riu, N., Zheng, K.K., Bai, S.C., Moniello, G., and Hung, S.S.O.  2011. Effects of dietary methylmercury chloride on growth and tissue burden in green and white sturgeon.  Aquatic Toxicology 105:227-234.

Lee, J.W., Kim, J.W., De Riu, N., Moniello, G., and Hung, S.S.O.  2012. Histopathological alterations of juvenile green (Acipenser medirostris) and white sturgeon (A. transmontanus) exposed to elevated dietary methylmercury.  Aquatic Toxicology. 109:90-99.

Dong, H., Huang, S.S.Y., Wang, W.F., Deng, D.F., and Hung, S.S.O.  2012. Starvation reduced heat shock protein responses in white sturgeon larvae.  Environmental Biology of Fishes. 93:333-342.

Huang, S.S.Y., Strathe, A.B., Wang, W.F., Deng, D.F., Fadel, J.G., and Hung, S.S.O.  2012. Evaluation of blood, tissue and urine Se concentration in juvenile white sturgeon after a single oral dose of selenocompounds.  Aquatic Toxicology.  109:158-165.

Huang, S.S.Y., Strathe, A.B., Hung, S.S.O., Boston, R.C., and Fadel, J.G. 2012. Estimating absorption, disposition and elimination of selenocompounds in juvenile white sturgeon using Bayesian hierarchical modeling.  Aquatic Toxicology. 109:150-157.

Deng, X, Teh, S.J., Doroshov, S.I., and Hung, S.S. O.  2012. Embryonic and larval development of Sacramento Splittail Pogonichthys macrolepidotus. San Francisco Estuary and Watershed Science. 10: 1-11.

De Riu, N., Zheng, K.K., Lee, J.W., Lee, S.H., Bai, S.C., Moniello, G., and  Hung, S.S.O. 2012. Effects of feeding rates on growth performances of white sturgeon fries.  Aquaculture Nutrition. 18:290-296.

Bae, J.Y., Park, G.H., Yoon, H.H., Hung, S.S.O., and Bai, S.C.C.  2012. The dietary valine requirement for rainbow trout, Oncorhynchus mykiss, can be estimated by plasma free valine and ammonia concentrations after dorsal aorta cannulation.  Journal of Applied Animal Research.   40:73-79.

Huang, S.S.Y., Strathe, A.B., Fadel, J.G., Lin, P.P., Liu, T.Y., and Hung, S.S.O. 2012.   Absorption, distribution, and elimination of graded oral doses of methylmercury in juvenile white sturgeon.   Aquatic Toxicology. 122-123:163-171.

Huang, S.S.Y., Strathe, A.B., Fadel, J.G., Lin, P., Liu, T.Y., and Hung, S.S.O. 2013. The interactive effects of selenomethionine and methymercury on their absorption, disposition, and elimination in juvenile white sturgeon.  Aquatic Toxicology. 126: 274-282.

Jirsa, D., Deng, D.F., Wang, W.F., Hung, S.S.O., Davis, D.A., and Drawbridge, M. 2013.  Dietary lipid levels affect growth performance and heat shock response of juvenile white seabass, Atractoscion nobilis.  Aquaculture Nutrition. 19: 227-232.

Wang, W.F., Deng, D.F., De Riu, N., Moniello, G., and Hung, S.S.O.  2013. Heat shock protein 70 responses in tissues of white (Acipenser transmontanus) and green sturgeon (A. medirostris) exposed to different stressors.  North American Journal of Aquaculture. 75:164-169.

De Riu, N., Lee, J.W., Huang, S.S.Y., Moniello, G., and Hung, S.S.O.  2014. Effect of dietary selenomethionine on growth performance, tissue burden, and histopathological alteration in juvenile green and white sturgeon. Aquatic Toxicology. 148:65-73.

Lee, S.H, Wang, Y.C., Hung, S.S.O., Strathe, A.B., Fangue, N.A., and Fadel, J.G. 2014. Development of optimum feeding rate model for white sturgeon (Acipenser transmontanus). Aquaculture 433: 411-420.

Huang, S.S.Y., Hung, S.S.O., and Chan, H.M. 2014. Maintaining tissue Se species distribution as a potential defense mechanism against Hg toxicity in juvenile white sturgeon (Acipenser transmontanus). Aquatic Toxicology. 156:88-95.

Haller, L.Y., Hung, S.S.O., Lee, S.H., Fadel, J.G, Lee, J.H., McEnroe, M., and Fangue, N.A. 2015. Effect of nutritional status on the osmoregulation of green sturgeon (Acipenser medirostris). Physiological and Biochemical Zoology. 88:22-49.

Zheng, K.K., Deng, D.F., De Riu, N., Moniello, G., and Hung, S.S.O. 2015. The effect of feeding rate on the growth performance of green sturgeon (Acipenser medirostris) fry. Aquaculture Nutrition 2015:489-495.

Yun, H.O., Park, G.J. Ok, I.O., Katya, K., Hung, S.S.O., and Bai, S.C. 2015. Evaluation of optimum dietary threonine requirement by plasma free threonine and ammonia concentrations in surgically modified rainbow trout, Oncorhynchus mykiss. Asian-Australasian J. Anim. Sci. 28:551-559.

Zheng, K.K., Wang, W.F. Hung, S.S.O., and Deng, D.F. Feeding rates affect heat shock protein 70 expression in green sturgeon (Acipenser medirostris). 2015. North American Journal of Aquaculture 77:206-210.

Lee, S., Haller, L.Y. Verhille, C., Fadel, J.G., Fangue, N.A., and Hung, S.S.O. 2015. Effect of feed restriction on salinity tolerance in white sturgeon (Acipenser transmontanus). Comp. Biochem. Physiol. Part A 188:156-167.

De Riu, N., Hung, S.S.O., and Moniello, G.  2012. Chapter 31: White Sturgeon (Acipenser transmontanus) Optimum Feeding Rates at Week 6 and 10 After Initiation of Feeding. A. Pugliese, A. Gaiti, and C. Boiti, Eds., Veterinary Science, Current Aspects in Biology, Animal Pathology, Clinic and Food Hygiene. Springer-Verlag Berlin Heidelberg, 2012, pp. 187-191.

Vaz, P.G., Kebreab, E., Hung, S.S.O., Fadel, J.G, Lee, S.H., and Fangue, N.A. 2015. Impact of nutrition and salinity changes on biological performances of green and white sturgeon. PLoS ONE 10(4):e0122029, 2015. doi:10.1371/journal.pone.0122029.

Verhille, C.V., Lee, S., Todgham, A.T., Cocherell, D., Hung, S.S.O., and Fangue, N.A.  2015. Effects of Nutritional Deprivation on Juvenile Green Sturgeon Swimming Performance and Thermal Tolerance. Environmental Biology of Fishes. 99:145-159.

Park, J.J., Shin, Y. K., Hung, S.S.O., Romano, N., Cheon, Y.P., and Kim, J.W. 2015. Reproductive impairment and intersexuality in Gomphina veneriformis (Bivalvia: Veneridae) by the tributyltin compound.  Animal Cells and System. 19:61-68.

Lee, S., Haller, L.Y., Fadel, J.G., Fangue, N.A., and Hung, S.S.O. 2016. Effects of feeding rate on growth performance and nutrient partitioning of young-of-the-year white sturgeon (Acipenser transmontanus). Aquaculture Nutrition. 22:400-409.

Lee, S., Hung, S.S.O., Fangue, N.A., Haller, L., Verhille, C.E., Zhao, J., and Todgham, A.E.  2016. Effects of feed restriction on the upper temperature tolerance and heat shock response in juvenile green and white sturgeon. Comp. Biochem. Physiol. Part A 198:87-95.

Wang, W.F., Lee, S.H., Hung, S.S.O., and Deng, D.F. 2016. Responses of heat shock protein 70 and caspas-3/7 to dietary selenomethionine in juvenile white sturgeon. Animal Nutrition. 2:45-50.

Yun, H.H., Park, G.J.. Ok, I.H., Katya, K., Hung, S.S.O., and Bai, S.C.C. 2016. Determination of the dietary lysine requirement by measuring plasma free lysine concentrations in rainbow trout, Oncorhynchus mykiss after dorsal aorta cannulation. Fisheries and Aquatic Sciences. In press.