Effects of dietary oxidized fish oil on thyroid hormones in Sturgeon hybrid

Fish oil in the diet of fish is constantly at the risk of oxidation. In this study, the effects of feeding sturgeon hybrid (Huso huso ♂ ×Acipenser ruthenus ♀) with different levels of oxidized fish oil (OFO) on thyroid hormones were investigated. Three experimental diets were made by replacing 0 (control), 50 and 100% OFO were made. Ninety hybrid sturgeon, with the initial weights of 212.6 ± 07g were distributed in 9 fiberglass tanks (2 m3) randomly after 2 weeks of adaptation with experimental conditions. Feeding was performed three times daily (08:00, 14:00 and 20:00) for 6 weeks for satisfaction. At the end of the period, blood samples were taken and their serum was separated. Serum thyroxine and triiodotyronine were measured by radioimmunoassay in blood samples. Serum thyroxine, triiodotyronine and thyroxine/triiodotyronine level showed no significant change related to dietary OFO. Our findings showed that dietary-oxidized oil had no effect on blood thyroid hormones levels.