Effects of hunger stress on the gill microstructure and Na+/K+-ATPase, antioxidant enzyme of blunt snout bream Megalobrama amblycephala

Abstract:

In order to research the effects of different hunger time(duration 0, 5, 10, 15, 20, 25 and 30 d)on gills of hypoxia-tolerant F₄ generation of blunt snout bream, the gill microstructure, Na⁺/K⁺-ATPase and antioxidant enzyme of hypoxia-tolerant F₄ generation of blunt snout bream were studied by light, scanning electron microscopy and absorptiometry at (25±1.0)℃ and dissolved oxygen(7.0±0.5)mg/L.The results showed that with the increase of the hunger time, the activity of Na⁺/K⁺-ATP, SOD and CAT in the hypoxia-tolerant F₄ generation of blunt snout bream was gradually decreased and then restored to normal level after 7 days of re-feeding.Gill microstructure observation showed that the protruding lamella lengths were enlarged, which caused the expansion of the lamella surface area, and the height and volume of the ILCM decreased.After 7 days of re-feeding recovery, the changes in gill morphology were reversed.These results indicated that the hunger stress could seriously disturb the antioxidant system, but fish showed the capacity to alter respiratory surface area in response to hunger.