The nutritional physiology and molecular biology of trace metal homeostasis during dietary iron deficiency and excess in rainbow trout (Oncorhynchus mykiss).

CARRIQUIRIBORDE P.; HANDY R.D.; DAVIES S.J.; SERWATA R.

Southampton, UK

Conferencia; Society for Experimental Biology Annual Main Meeting; 2003

Society for Experimental Biology

The effect of dietary iron levels on the health of rainbow trout was studied. Fish weighting 79.1±12.2 g were fed a semi-purified diet supplemented with 0 (Low), 100 (Normal) and 1500 (High) mg/kg of iron during eight weeks. Survival, growth rate, condition factor and hepatosomatic index were not affected by diet-iron content. Hb and Hct were significantly higher in high-iron fed fish (HIFF) at week-6 but became normal at week-8, low-iron fed fish (LIFF) showed a significantly decrees in Hb (from 7.7±0.6 to 6.6±0.6 mg/dL) and MEH (from 68.9±6.8 to 57.3±6.2 ìg/cell) since week-6 and 8 respectively. Iron increased significantly with time in serum, stomach, intestine and liver of HIFE. There was an inverse relationship between tissue iron status and Mn levels, with Mn levels decreasing in HIFE Cu content was always lower in the intestine of HIFF and was significantly increased in LIFF at week-8. Serum unsaturated iron-binding capacity was significantly reduced from 396.0±40.1 to 354.0±49.3 ìg/dL in HIFF since week-4, total iron-binding capacity was significantly lower in LIFF (482.0±55.03 ìg/dL) than in HIFF (575.6±107.07 ìg/dL) after week-8 and percentage of transferrin saturation was increased 12.6% in HIFF since week-4 and reduced 11.8% in LIFF since week eight. Ferrireductase activity was increased 3.7 fold in the intestine of LIFF and in the liver of HIFF since week-4 and 6 respectively. Lipid peroxidation was significantly increased in intestine and liver of HIFF since week-4 and 8 respective1y. Results indicate that rainbow trout is able to regulate iron metabolism in a wide range of dietary iron concentrations and during relative long periods of exposure without detriment in growth and survival.