HISTOCHEMICAL EVALUATION OF IRON CONTENT IN THE LIVER OF WILD FEMALE OHRID TROUT (SALMO LETNICA KAR.) ALONG THE BREEDING CYCLE

Maja Jordanova Jordanova,Katerina Rebok,Maria João Rocha,Eduardo Rocha

doi:10.20903/csnmbs.masa.2018.39.2.125

Abstract

Iron is an essential micronutrient for the normal metabolism of all cells. Intracellular iron varies within normality ranges, and depletion or overload of brings serious consequences. As such, iron can also be deleterious when appearing as an environmental toxicant. The aim of this study was to estimate semi-quantitatively the liver iron content in female Ohrid trout, from the Lake Ohrid, during the breeding cycle. Seasonal variations in hepatocytic iron were observed. The maximum content occurred at post-spawning, which was significantly higher than loads detected at pre- and early-vitellogenesis. Positive correlations existed between iron amounts and stages of ovary maturation. By the contrary, there were no correlations between iron contents and plasma oestradiol levels. The new uncovered "iron-breeding associa-tion" strongly endorses that normal seasonal variations in hepatocytic iron content should be taken into consideration in field studies investigating and monitoring the metal burden and toxicological effects of metals on wild fish.

Highlights

Taking into account that large number of toxic chemicals were present in the environment, eutrophication, and, potentially, global climate changes, wildlife population in aquatic ecosystems throughout the world is faced with a wide variety of stressors
The semi-quantitative data on the iron load are presented in Figure 1, with animals grouped per gonadal maturation stage
Histochemistry and semi-quantification at light microscopy were applied to investigate the seasonality of liver iron load in Ohrid trout, possibly in connection with the stage of ovary maturation and the E2 plasma levels

Summary

Introduction

Taking into account that large number of toxic chemicals were present in the environment, eutrophication, and, potentially, global climate changes, wildlife population in aquatic ecosystems throughout the world is faced with a wide variety of stressors. In such ecosystems, among other species, fish do bioaccumulate multiple environmental contaminants, and their presence/overload may well be taken as an indicator of environmental contamination [1,2,3,4]. There is only one available report on heavy metal concentrations in organic samples (of liver and muscle) in fishes from Lake Ohrid [6]. Certain authors exposed seasonal variations in the occurrence of metals in fish living in metalcontaminated lakes [8]

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