Meeting Abstract
140.6 Monday, Jan. 7 Effects of Selenium-enriched meal on growth performance, endocrine control of growth and selenoprotein expression in tilapia (Oreochromis mossambicus) ROWELL, TR*; SEALE, LA; SEALE, AP; BANUELOS, GS; GRAU, EG; RILEY, LG; Fresno State Univ.; Univ. of Hawaii; Univ. of Hawaii; USDA-ARS; Univ. of Hawaii; Fresno State Univ. temperance15@mail.fresnostate.edu
Selenium (Se) is a naturally occurring essential trace element required for normal nutrition and health in animals. It has been shown to aid in the function of a healthy immune system as well as an antioxidant during cellular stress in tissues. Organic Se has been shown to prevent cardiomyopathies and improve antioxidative status as a nutritional supplement. Studies with Se supplemented diets in some fish species have shown increased growth with decreasing mortality and improved antioxidative status. However, the effects of Se supplementation on growth and metabolism in tilapia have yet to be investigated. Tilapia were offered varying doses of an organic Se-enriched or a control diet for 12 weeks. Tilapia fed Se-enriched diets exhibited decreased growth compared to the control group after 12 weeks. However, there was no difference in liver mRNA levels of two important proteins (IGF-1 and GHR-2) of the growth axis across treatment groups. Liver mRNA levels of the antioxidative enzyme (glutathione peroxidase) and selenoprotein (SelS) were decreased across treatments compared to the control. At this point it is not known if Se supplementation affected circulating levels of these proteins. There was also an increase in the concentration of Se in the liver of the Se-enriched treatment. Further speciation confirmed the Se present in the liver was predominantly selenomethionine, which is also the highest form of Se available in the supplemented diets. Currently, these data suggest that the dose and/or length of Se supplementation used in this study inhibits growth and down-regulates the activity of important selenoproteins in tilapia.
